Peer-reviewed Articles

Please use the year list below to look at past peer-reviewed articles.

2021

Bai,Y., Ngo,W., Khanal,S., Nichols,K. K., Nichols,J. J. Human precorneal tear film and lipid layer dynamics in meibomian gland dysfunction Ocular Surface 2021;Online ahead of print [ Show Abstract ]

Purpose: To evaluate the precorneal tear film (PCTF) and lipid layer (TFLL) thicknesses and thinning rates in meibomian gland dysfunction (MGD) using a combined ultra-high-resolution optical coherence tomography (OCT) and thickness dependent fringe (TDF) interferometry system.

Methods: Based on the Tear Film and Ocular Surface Society (TFOS) International Workshop on Meibomian Gland Dysfunction diagnostic algorithm, the Ocular Surface Disease Index (OSDI) and meibum grade score (MGS) were used to classify subjects into four groups: Normal (OSDI<13 and MGS<10), MGD (OSDI≥13 and MGS≥10), Asymptomatic MGD (OSDI<13 and MGS≥10), and Mixed (OSDI≥13 and MGS<10). The OCT/TDF system was used to capture PCTF and TFLL thicknesses and thinning rates. Kruskal-Wallis was used to compare median PCTF and TFLL thicknesses and thinning rates.

Results: There were 190 subjects categorized into four groups: Normal (n = 63), MGD (n = 51), Asymptomatic MGD (n = 29), and Mixed (n = 47). The PCTF was significantly thinner in the Mixed group (3.3 [1.2]) than in the Normal (p < 0.001), MGD (p < 0.001) and Asymptomatic MGD (p = 0.009) groups. Relative to the Normal (4.5 [4.5] μm/min) and Mixed (5.0 [2.0] μm/min) groups, the rate of PCTF thinning was faster in the MGD (8.1 [3.0] μm/min, both p < 0.001) and Asymptomatic MGD (6.9 [3.1] μm/min, p = 0.009 and p = 0.04, respectively) groups. The correlation between PCTF thinning rate and TFLL thickness was ρ = −0.46, p < 0.001.

Conclusions: Symptomatic and asymptomatic MGD shows rapid PCTF thinning rates (evaporation), while the PCTF thickness was reduced in mixed disease. Thicker lipid layers were associated with slower PCTF thinning.

Chan,V. W. Y., Phan,C-M., Ngo,W., Jones,L. Lysozyme Deposition on Contact Lenses in an In Vitro Blink-Simulation Eye Model Versus a Static Vial Deposition Model Eye & Contact Lens 2021;47(7):388-393 [ Show Abstract ]

Purpose:
To evaluate active lysozyme deposition on daily disposable (DD) contact lenses (CL) using a novel in vitro blink model.

Methods:
Three conventional hydrogel DD CL materials (etafilcon A, omafilcon A, nelfilcon A) and three silicone hydrogel DD CL materials (delefilcon A, senofilcon A, somofilcon A) were tested. The device blink rate was set to 6 blinks/min with a tear flow rate of 1 μL/min using an artificial tear solution (ATS) containing lysozyme and other typical tear film components. After incubation at 2, 4, or 8 hr, lenses were removed, and lysozyme activity was measured. A separate experiment was conducted with lenses incubated in a static vial containing 480 μL of ATS.

Results:
Etafilcon A deposited significantly higher amounts of active lysozyme (402±102 μg/lens) than other lens materials after 8 hr (P<0.0001). Etafilcon A had a higher amount of active lysozyme using the blink model compared with the static vial (P=0.0435), whereas somofilcon A (P=0.0076) and senofilcon A (P=0.0019) had a higher amount of lysozyme activity in the vial compared with the blink model.

Conclusion:
The blink model can be tuned to provide quantitative data that closely mimics ex vivo studies and can be used to model deposition of lysozyme on CL materials.

Chan,V. W. Y., Phan,C-M., Walther,H., Ngo,W., Jones,L. Effects of Temperature and Blinking on Contact Lens Dehydration of Contemporary Soft Lens Materials Using an In Vitro Blink Model Translational Vision Science & Technology 2021;10(8):Article 11 [ Show Abstract ]

Purpose: The purpose of this studywas to evaluate the effects of temperature and blinking on contact lens (CL) dehydration using an in vitro blink model.

Methods: Three silicone hydrogel (delefilcon A, senofilcon A, and comfilcon A) and two conventional hydrogel (etafilcon A and omafilcon A) CL materials were evaluated at 1
and 16 hours. The water content (WC) of the CLs was measured using a gravimetric method. Lenses were incubated on a blink model, internally heated to achieve a clinically relevant surface temperature of 35°C. An artificial tear solution (ATS) was delivered to the blink model at 4.5 μL/min with a blink rate of 6 blinks/min. A comparison set of lenses were incubated in a vial containing either 2 mL of ATS or phosphate-buffered saline (PBS) at 35°C.

Results: Increasing temperature to 35°C resulted in a decrease in WC for all tested CLs over time (P ≤ 0.0052). For most CLs, there was no significant difference in WC over time between ATS or PBS in the vial (P > 0.05). With the vial system, WC decreased and plateaued over time. However, on the blink model, for most CLs, the WC significantly decreased after 1 hour but returned toward initial WC levels after 16 hours (P > 0.05).

Conclusions: The reduction in WC of CLs on the eye is likely due to both an increase in temperature and dehydration from air exposure and blinking.

Translational Relevance: This study showed that the novel, heated, in vitro blink model could be used to provide clinical insights into CL dehydration on the eye.

Chang,J. M. L., Seo,J., Kwan,M. M. Y., Oh,S., McCanna,D. J., Subbaraman,L., Jones,L. Determining the Toxicity of UV Radiation and Chemicals on Primary and Immortalized Human Corneal Epithelial Cells Journal of Visualized Experiments 2021;173(July):Article # e62675 [ Show Abstract ]

This article describes the methods of measuring the toxicity of ultraviolet (UV) radiation and ocular toxins on primary (pHCEC) and immortalized (iHCEC) human corneal epithelial cell cultures. Cells were exposed to UV radiation and toxic doses of benzalkonium chloride (BAK), hydrogen peroxide (H2O2), and sodium dodecyl sulfate (SDS). Metabolic activity was measured using a metabolic assay. The release of inflammatory cytokines was measured using a multi-plex interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-α) assay, and cells were evaluated for viability using fluorescent dyes.

The damaging effects of UV on cell metabolic activity and cytokine release occurred at 5 min of UV exposure for iHCEC and 20 min for pHCEC. Similar percent drops in metabolic activity of the iHCEC and pHCEC occurred after exposure to BAK, H2O2, or SDS, and the most significant changes in cytokine release occurred for IL-6 and IL-8. Microscopy of fluorescently stained iHCEC and pHCEC BAK-exposed cells showed cell death at 0.005% BAK exposure, although the degree of ethidium staining was greater in the iHCECs than pHCECs. Utilizing multiple methods of assessing toxic effects using microscopy, assessments of metabolic activity, and cytokine production, the toxicity of UV radiation and chemical toxins could be determined for both primary and immortalized cell lines.

Craig,J.P., Muntz,A., Wang,M.T.M., Luensmann,D., Tan,J., Travé-Huarte,S., Xue,A.L., Jones,L.W., Willcox,M.D.P., Wolffsohn,J.S. Developing evidence-based guidance for the treatment of dry eye disease with artificial tear supplements: A six-month multicentre, double-masked randomised controlled trial Ocular Surface 2021;20(April):62-69 [ Show Abstract ]

Purpose
To assess the six-month therapeutic profiles of lipid and non-lipid-based artificial tear supplements in managing dry eye disease (DED).

Methods
Ninety-nine participants fulfilling the TFOS DEWS II diagnostic criteria for DED (64% females; mean ± SD age, 44 ± 16 years) were enrolled in a prospective, multicentre, double-masked, parallel group, randomised controlled trial. Participants instilled lipid-based nanoemulsion drops or non-lipid-based aqueous drops for six months, at least four times daily. Symptomology, tear film and ocular surface characteristics were assessed at Days 0, 30, 60, 90, 120, 150 and 180.

Results
Sustained reductions in OSDI, DEQ-5, and SANDE symptom scores from baseline were observed from Day 30 onwards in both groups (all p < 0.05) and decreased superior lid wiper epitheliopathy grades from Day 60 onwards (all p ≤ 0.01). Improvements in non-invasive tear film breakup time, and sodium fluorescein and lissamine green staining scores followed from Day 120 onwards in both groups (all p < 0.05). Tear lipid layer grades increased from Day 90 onwards only with the lipid-based drops, and with significantly greater improvement in those with suboptimal lipid layer thickness at baseline (grade ≤3; p = 0.02). By Day 180, 19% of participants no longer fulfilled the diagnostic criteria for DED.

Conclusions
Over a six-month treatment period, improvements in dry eye symptomology preceded tear film and ocular surface changes with regular use of both lipid and non-lipid-based artificial tear supplements. Both formulations addressed most mild-to-moderate forms of aqueous deficient and evaporative DED, while evaporative cases benefitted preferentially from lipid-based supplementation. This represents a first step towards mapping DED therapeutic strategies according to disease subtype and severity.

Downie,L. E., Bandlitz,S., Bergmanson,J. P. G., Craig,J. P., Dutta,D., Maldonado-Codina,C., Ngo,W., Sowjanya Siddireddy,J., Wolffsohn,J. S. CLEAR - Anatomy and physiology of the anterior eye Contact Lens Anterior Eye 2021;44(2):132-156 [ Show Abstract ]

A key element of contact lens practice involves clinical evaluation of anterior eye health, including the cornea and limbus, conjunctiva and sclera, eyelids and eyelashes, lacrimal system and tear film. This report reviews the fundamental anatomy and physiology of these structures, including the vascular supply, venous drainage, lymphatic drainage, sensory innervation, physiology and function. This is the foundation for considering the potential interactions with, and effects of, contact lens wear on the anterior eye. This information is not consistently published as academic research and this report provides a synthesis from all available sources. With respect to terminology, the report aims to promote the consistent use of nomenclature in the field, and generally adopts anatomical terms recommended by the Federative Committee for Anatomical Terminology. Techniques for the examination of the ocular surface are also discussed.

Efron,N., Jones,L. W., Morgan,P. B., Nichols,J. J. Bibliometric analysis of the literature relating to scleral contact lenses Contact Lens Anterior Eye 2021;44(4):Article number 101447 [ Show Abstract ]

Adolf Eugene Fick, a German ophthalmologist working in Zurich, published the first journal paper on contact lenses in 1888. In this paper, he described the process of fabricating and fitting afocal scleral contact lenses first on rabbits, then on himself and finally on a small group of volunteer patients with keratoconus.

Efron,N., Jones,L. W., Morgan,P. B., Nichols,J. J. On the art and science of rigid contact lens fitting Clinical and Experimental Optometry 2021;104(6):684-690 [ Show Abstract ]

Examination of the literature can help answer the age-old question of the extent to which rigid contact lenses can be considered an art versus a science.

Efron,N., Jones,L. W., Morgan,P. B., Nichols,J. J. Bibliometric analysis of the literature relating to silicone hydrogel and daily disposable contact lenses Journal of Optometry 2021;Online ahead of print [ Show Abstract ]

Purpose
Publication metrics are derived for the fields of silicone hydrogel (SH) and daily disposable (DD) contact lenses.

Methods
A search of the Scopus database for papers in the fields of SH and DD contact lenses found 979 SH and 291 DD papers. Subject-specific h-indices for SH lenses (hSH-index) and DD lenses (hDD-index) were derived, in relation to five categories – authors, institutions, countries and journals – to serve as measures of impact. A short list of the most impactful entities was generated for each of the above five categories in the SH and DD fields.

Results
A paper entitled “Soft contact lens polymers: An evolution” by Nicholson and Vogt was the most highly cited article (495 citations) in both SH and DD fields. The most impactful entities for the SH and DD fields were: authors – Lyndon Jones (hSH = 33) and Philip Morgan (hDD = 15); institutions – the University of Waterloo (hSH = 37) and the University of New South Wales (hDD = 15); countries – the United States (hSH = 45) and the United Kingdom (hDD = 24); and journals – Optometry and Vision Science (hSH = 33) and Contact Lens and Anterior Eye (hDD = 17). Overall, the SH field (hSH = 64) is far more impactful than the DD field (hDD = 34).

Conclusions
Impactful papers, authors, institutions, countries and journals in the SH and DD fields are identified. Optometry is revealed as the leading profession in relation to SH and DD publications.

Efron,N., Morgan,P. B., Jones,L. W., Morgan,G. A., Nichols,J. J. Global optometrist top 200 research ranking Clinical and Experimental Optometry 2021;104(4):471-485 [ Show Abstract ]

Clinical relevance: Clinical optometric practice is underpinned by a rigorous research base, the
primary evidence for which is publications in refereed scientific journals. Leading optometrists who
publish this work should be identified and celebrated.
Background: This work aims to derive publication metrics of the leading optometric researchers
worldwide.
Methods: An extensive global search was conducted to discover leading optometric researchers; 480
names were identified. A custom-designed bibliographic search tool was developed to interrogate
the Scopus database (Elsevier) and extract publication metrics using the unique Scopus Author
Identifier number for each optometrist. On 13 January 2021, the full list was reduced to 200
optometrists (the ‘Top 200’) ranked by h-index – the ‘Global Optometrist Top 200 Research
Ranking’. The output from the custom tool automatically updates every 24 hours and is available at
www.optomrankings.com.
Results: The Top 200 have h-indices ranging from 20 to 67 and have published between 28 and 440
papers. Sixty one (30.5%) are women. Konrad Pesudovs has the highest h-index (67) and citations
(51,193). The most prolific author is Robert Hess (442 papers). David Piñero is publishing at the
fastest rate (17.6 papers per year). The Top 200 work in 13 nations, of whom 172 (86.0%) work in
four nations: USA – 76 (38.0%), Australia – 43 (21.5%), UK – 41 (20.5%) and Canada – 16 (8.0%). Of
the 72 institutions represented, the University of California, Berkeley, USA is home to the most Top
200 optometrists (17) and has the highest combined h-index of Top 200 optometrists (132).
Conclusions: The optometric profession is supported by a robust research base, prosecuted by
a large international cohort of optometric researchers who publish extensively on a broad range of
ophthalmic issues and whose work is highly cited. The 200 most impactful optometrists in the world
are identified

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. 21st century citation analysis of the field of contact lenses Clinical and Experimental Optometry 2021;104(5):634-638 [ Show Abstract ]

Clinical relevance: The scientific foundations for clinical contact lens practice are rooted in the ophthalmic literature. This analysis of contact lens papers celebrates contemporary research achievements in the contact lens field.

Background: This work aims to assemble contact lens-related publication metrics so as to identify the most impactful papers published so far this century, as well the top countries, authors, institutions and journals.

Methods: A search was undertaken of the titles of papers on the Scopus database to identify contact lens-related articles published this century. The ten most highly cited papers were determined from the total list of 4,164 papers found. Rank-order lists by count were assembled for the ‘top 25ʹ in each of four categories: authors, institutions, countries and journals. A 20-year subject-specific contact lens h-index (hCL-20-index) was derived for each author, institution, country and journal to serve as a measure of impact in the field. The top 10 constituents (of the top 25) of each category were ranked by hCL-20-index and tabulated for consideration.

Results: The most highly cited paper this century is entitled ‘Soft contact lens polymers: An evolution’, by Nicholson and Vogt. Lyndon Jones is the most impactful author, with a hCL-20-index of 32. The University of New South Wales (Australia) produces the most impactful contact lens-related papers, and the United States is the most highly-ranked country. Optometry and Vision Science is the most impactful journal in the contact lens field.

Conclusions: Contact lens materials and lens-associated keratitis are topics of high interest in the contemporary contact lens literature, with an emerging interest in orthokeratology for myopia control and glucose monitoring. Impactful 21st century authors, institutions, countries and journals are identified. Optometry is revealed as the leading profession in relation to the publication of impactful contact lens-related papers.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Bibliometric analysis of the refractive error field Clinical and Experimental Optometry 2021;104(5):641-643 [ Show Abstract ]

Research into the epidemiology, aetiology, and optics of ametropia is a fundamental cornerstone of the correction and management of refractive errors by eye care practitioners. At present, much of this work is driven by the clinical concern that myopia is a common cause of vision loss, with uncorrected myopia the leading cause of vision impairment globally. Holden et al. predict that by 2050, about 50% of the population of the world will be myopic.
The aetiology of myopia continues to be hotly debated, centring around the relative impact of nature (genetics) versus nurture (environment). Research aimed at optimising optical (spectacles and contact lenses) and surgical (laser refractive techniques) modes of correcting refractive error continues unabated, and novel approaches for arresting the progression of myopia, using ophthalmic lenses, contact lenses (including orthokeratology), pharmacological approaches, or lifestyle modification, are also under active investigation. As is the case in all fields of investigation, the foundation of these various lines of refractive error research is rooted in the ophthalmic literature. Modern bibliographic search tools enable targeted interrogation of this vast literature to facilitate identification of the research foundations that underpin our understanding of refractive error. This Viewpoint uses
these bibliographic search tools and employs a subjectspecific measure of impact to identify key papers, authors, institutions, countries, and journals in the field of refractive error research.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Bibliometric analysis of the keratoconus literature Clinical and Experimental Optometry 2021;Online ahead of print [ Show Abstract ]

Clinical Relevance
Clinicians, researchers funding agencies and indeed the general public can benefit from knowledge of the most highly cited papers and most impactful authors, institutions, countries and journals in the field of keratoconus.

Background
Bibliometrics relating to the keratoconus literature were derived to enable identification of the most impactful papers published, as well as the leading authors, institutions, countries and journals.

Methods
A search was undertaken of the titles of papers on the Scopus database to identify keratoconus-related articles. The 20 most highly cited papers were determined from the total list of 4,419 papers found. Rank-order lists by count were assembled for the ‘top 20ʹ in each of four categories: authors, institutions, countries and journals. A subject-specific keratoconus-related h-index (hKC-index) was derived for each constituent of each category to serve as a measure of impact in the field. The top 10 constituents of each category were ranked by hKC-index and tabulated for consideration.

Results
The hKC-index of the keratoconus field is 125. The 4,419 papers have been cited a total of 98,010 times, and 18.5% of these papers have never been cited. The most highly cited paper is a general review of keratoconus by Yaron Rabinowitz, who is also the most impactful author in the field (hKC = 31). The Cedars Sinai Medical Center in the United States produces the most impactful keratoconus-related papers (hKC = 36), and the United States is the most impactful country (hKC = 91). The Journal of Cataract and Refractive Surgery is the most impactful journal (hKC = 55).

Conclusion
Keratoconus is a topic of high interest in the clinical and scientific literature. Highly cited papers and impactful authors, institutions, countries and journals are identified.

Efron,N., Morgan,P. B., Jones,L. W., Nichols,J. J. Topical Review: Bibliometric Analysis of the Emerging Field of Myopia Management Optometry & Vision Science 2021;98(9):1039-1044 [ Show Abstract ]

SIGNIFICANCE
Identification of the most impactful articles, authors, institutions, countries, and journals in myopia management provides a useful baseline reference for clinicians, researchers, and funding agencies in respect of this emerging field.

This work aims to assemble publication metrics for myopia management to identify the most impactful articles, authors, institutions, countries, and journals in this emerging field of research. A search of the titles of articles was undertaken on the Scopus database to identify myopia management–related articles. The 25 most highly cited articles were determined from the total list of 1064 articles found. Rank-order lists by count were assembled for the top 25 in each of four categories: authors, institutions, countries, and journals. A subject-specific myopia management–related h-index (hMM-index) was derived for the entire field, in addition to each of the four categories, to serve as measures of impact in the field. Top 15 lists were generated for each category ranked by hMM-index and tabulated for consideration. An article by Christine Wildsoet and colleagues, describing choroidal and scleral mechanisms of compensation for spectacle lenses in chicks, has generated the most citations (412); Earl Smith is the most impactful author (hMM = 19); the University of Houston produces the most impactful articles (hMM = 31); the United States is the most highly ranked country (hMM = 60); and Optometry and Vision Science is the most impactful journal. Although still in its infancy, myopia management is a topic of emerging interest in the clinical and scientific ophthalmic literature. Impactful authors, institutions, countries, and journals are identified. Optometry is revealed as the leading profession in relation to the publication of myopia management–related articles.

Efron,N., Morgan,P. B., Nichols,J. J., Walsh,K., Willcox,M. D., Wolffsohn,J. S. Jones,L. W. All soft contact lenses are not created equal Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Abstract
Soft contact lenses that have been prescribed by eye care practitioners are sometimes substituted for alternative lenses by unqualified, unregulated and sometimes even fully regulated lens suppliers, in the mistaken belief that there is essentially no difference between different soft lens types. This review considers the implications of inappropriately substituting soft contact lens types in terms of (a) lens properties: surface treatment, internal wetting agents, material, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, colour (tint) and ultraviolet protection; and (b) lens usage: wearing modality (daily versus overnight wear) and replacement frequency. Potential aspects of patient dissatisfaction and adverse events when prescribed soft lenses are substituted for lenses with different properties or intended usage are considered. Substitution of 15 of the 16 lens properties considered (i.e. except for back surface design) was found to be related to at least one – and as many as six – potential sources of patient dissatisfaction and adverse ocular events. Contact lens are medical devices which are prescribed and fitted; they should never be substituted for another lens type in the absence of a new prescription further to a full finalised fitting, for the simple reason that all soft contact lenses are not created equal. A substituted lens may have properties that results in undesirable consequences in respect of vision, ocular health, comfort and cosmetic appearance, and may be incompatible with the lifestyle of the patient.

Heynen,M., Ng,A., Martell,E., Subbaraman,L. N., Jones,L. Activity of Deposited Lysozyme on Contemporary Soft Contact Lenses Exposed to Differing Lens Care Systems Clinical Ophthalmology 2021;15(April):1727-1733 [ Show Abstract ]

Purpose: The amount of protein deposition on soft contact lenses and to what extent the proteins are denatured may have an impact on comfortable wearing times of contact lenses. The purpose of this study was to evaluate the effects of two lens care systems on total protein and the quantity and activity of lysozyme deposited on worn senofilcon A, silicone hydrogel contact lenses.

Participants and Methods: Thirty symptomatic soft contact lens wearers were enrolled into a 4-week prospective, randomized, bilateral eye, daily-wear, crossover, double-masked study. Participants were fitted with biweekly senofilcon A lenses and were assigned either a polyquaternium-1 and myristamidopropyl dimethylamine-containing system (OPTI-FREE RepleniSH) or a peroxide-based system (CLEAR CARE). After each wear period, proteins were extracted from the lenses and analyzed for total protein, total lysozyme quantity and activity.

Results: The use of either the peroxide-based system or the polyquaternium-1 and myristamidopropyl dimethylamine-containing system resulted in no difference (P> 0.05) to the amount of total protein deposited on the lenses (6.7 ± 2.8 micrograms/lens versus 7.3 ± 2.8 micrograms/lens, respectively) or to the amount of denatured lysozyme deposits (0.8 ± 0.7 versus 0.9 ± 0.7 micrograms/lens), respectively. The total amount of lysozyme deposited on the lenses was significantly lower when using the peroxide-based system (1.3 ± 0.9 micrograms/lens) compared to the polyquaternium-1 and myristamidopropyl dimethylamine-containing system (1.7 ± 1.0 micrograms/lens) (P=0.02).

Conclusion: The inactivation of lysozyme deposited on senofilcon A lenses when disinfected with the peroxide-based or the polyquaternium-1 and myristamidopropyl dimethylamine-containing systems were neither statistically nor clinically significant and the overall amounts of denatured lysozyme recovered from the lenses were low (< 1 microgram/lens).

Huynh,C. B., Ngo,W. Quantifying the Effect of Spectacle Frame Dimensions on Wind-Induced Ocular Plane Evaporation Using an in Vitro Model Eye & Contact Lens 2021;47(347):351 [ Show Abstract ]

Purpose: To quantify the effect of spectacle frame dimensions on wind-induced ocular plane evaporation.

Methods: A drop of 0.5 μL water was pipetted onto an eye of a mannequin head. The face was fitted with a spectacle frame. A fan positioned 10 cm away directed air (185 CFM) toward the face and the time required for the drop to evaporate was recorded. This procedure was repeated with 31 different frames to obtain evaporation times for various eye sizes, vertical heights, vertex distances, temperature, and humidity. This was also repeated 30 times without spectacle wear to obtain evaporation times for various temperature and humidity conditions.

Results: Spectacle wear increased evaporation times compared with nonspectacle wear, in both high (>35%) and low humidity (<30%) conditions (both P<0.01). Humidity was correlated with evaporation time, regardless of spectacle and nonspectacle wear (both P<0.01). Evaporation time did not correlate with spectacle eye size, vertical height, or vertex distance (all P≥0.21).

Conclusion: This study showed that spectacle wear guarded against wind-induced evaporation at the ocular plane compared with nonspectacle wear. However, once spectacles were worn, eye size, vertical height, and vertex distance were not correlated with evaporation times. Humidity drove evaporation independent of spectacle wear.

Jones,L., Hui,A., Phan,C-M., Read,M. L., Azar,D., Buch,J., Ciolino,J. B., Naroo,S. A., Pall,B., Romond,K., Saknaridurg,P., Schnider,C. M., Terry,L., Willcox,M. CLEAR - Contact lens technologies of the future Contact Lens Anterior Eye 2021;44(2):398-430 [ Show Abstract ]

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses.

This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases.

The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.

Khanal,S., Ngo,W., Nichols,K. K., Wilson,L., Barnes,S., Nichols,J. J. Human meibum and tear film derived (O-acyl)-omega-hydroxy fatty acids in meibomian gland dysfunction Ocular Surface 2021;21(July):118-128 [ Show Abstract ]

Purpose: The molecular basis of the tear film and lipid layer alterations in meibomian gland dysfunction (MGD) is unknown. This study aimed to identify and compare (O-acyl)-omega-hydroxy fatty acids (OAHFAs) derived from human meibum and tears in MGD. Methods: Of 195 eligible subjects (18–84 years, 62.6% female), 183 and 174 provided samples for tears and meibum, respectively. Subjects were classified into four groups: Normal, Asymptomatic MGD, MGD, and Mixed. Samples from the right eye of each subject were infused into the SCIEX 5600 TripleTOF mass spectrometer in negative ion mode. Lipid intensities identified with Analyst1.7 TF and SCIEX LipidView1.3 were normalized by an internal standard and total ion current, then statistically compared in MetaboAnalyst 4.0. Results: In meibum and tears, 76 and 78 unique OAHFAs were identified, respectively. The five most frequent and abundant OAHFAs were 18:2/16:2, 18:1/32:1, 18:1/30:1, 18:2/32:1, and 18:1/34:1. Two OAHFAs, 18:2/20:2 and 18:2/20:1, were identified only in tears. Initial univariate analysis revealed three differently regulated OAHFAs in meibum and eight in tears. Partial Least Square Discriminant Analysis showed 18:1/32:1, 18:2/16:2, 18:1/34:1 and 18:0/32:1 in tears, and 18:2/16:2, 18:1/32:1 and 18:2/32:2 in meibum, had variable importance in projection scores >1.5 and contributed the most to the separation of groups. In both meibum and tears, all OAHFAS except 18:2/16:2 were reduced in MGD compared to the normal group. Conclusion: MGD is accompanied by differential expression of specific OAHFAs in meibum and tears. These results suggest OAHFAs play a role in the altered biochemical profile of the tear film lipid layer in humans with MGD.

Kondela,T., Dushanov,@., Vorobyeva,M., Mamatkulov,K., Drolle,E., Soloviov,D., Hrubovcak,P., Kholmurodov,K., Arzumanyan,G., Leonenko,Z., Kucerka,N Investigating the competitive effects of cholesterol and melatonin in model lipid membranes Biochimica et Biophysica Acta - Biomembranes 2021;1863(9):183651 [ Show Abstract ]

We have studied the impact of cholesterol and/or melatonin on the static and dynamical properties of bilayers made of DPPC or DOPC utilizing neutron scattering techniques, Raman spectroscopy and molecular dynamics simulations. While differing in the amplitude of the effect due to cholesterol or melatonin when comparing their interactions with the two lipids, their addition ensued recognizable changes to both types of bilayers. As expected, based on the two-component systems of lipid/cholesterol or lipid/melatonin studied previously, we show the impact of cholesterol and melatonin being opposite and competitive in the case of three-component systems of lipid/cholesterol/melatonin. The effect of cholesterol appears to prevail over that of melatonin in the case of structural properties of DPPC-based bilayers, which can be explained by its interactions targeting primarily the saturated lipid chains. The dynamics of hydrocarbon chains represented by the ratio of trans/gauche conformers reveals the competitive effect of cholesterol and melatonin being somewhat more balanced. The additive yet opposing effects of cholesterol and melatonin have been observed also in the case of structural properties of DOPC-based bilayers. We report that cholesterol induced an increase in bilayer thickness, while melatonin induced a decrease in bilayer thickness in the three-component systems of DOPC/cholesterol/melatonin. Commensurately, by evaluating the projected area of DOPC, we demonstrate a lipid area decrease with an increasing concentration of cholesterol, and a lipid area increase with an increasing concentration of melatonin. The demonstrated condensing effect of cholesterol and the fluidizing effect of melatonin appear in an additive manner upon their mutual presence.

Luensmann,D., Schaeffer,J. L., Rumney,N. J., Stanberry,A., Fonn,D. Magnitude of astigmatism – A comparison between eyes Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Purpose
Astigmatism is a highly prevalent refractive error and while studies typically focus to describe the axis symmetry between eyes, little is known about the refractive symmetry. Therefore, this study determined the astigmatic power symmetry between eyes in a large clinic population.

Methods
A clinical chart review was conducted at three optometric practices in the United States, the United Kingdom and Canada and subjective refraction data from 88,891 patients 14–70 years of age who presented with at least −0.25DC refractive astigmatism in at least one eye were included in the analysis. Data were obtained at these practices between January 2014 and March 2017. The overall distribution (%) and magnitude (DC) of astigmatism was determined and refractive differences between eyes were identified.

Results
The mean age of the patients was 42.1 ± 15.9 years and included 51,685 (58%) female and 37,206 (42%) male patients. In this data pool of 177,782 eyes, 10.9% required zero astigmatic correction, while 56.2% had astigmatism of −0.25 to −0.75DC. In total 23.9% of patients presented with astigmatism of at least −0.75DC in only one eye, while the other eye had 0 to −0.50DC. Overall, the difference in astigmatism between eyes was less than −0.75DC for 82.1% of astigmatic patients. For patients who presented with astigmatism of −1.00DC in the right eye, 80.8% of them had an astigmatic prescription of −1.00 ± 0.50DC in the left eye. For an astigmatic prescription of −4.00DC in the right eye, only 40.6% of patients exhibited astigmatism of −4.00DC ± 0.50DC in the left eye.

Conclusions
The majority of patients exhibited a difference in astigmatism between eyes of less than −0.75DC, however the refractive cylinder power symmetry was significantly lower in patients with higher refractive astigmatism.

Mirzapour,P., McCanna,D. J., Jones,L. In vitro analysis of the interaction of tear film inflammatory markers with contemporary contact lens materials Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Purpose
Several clinical studies have suggested that reusable silicone hydrogel contact lens materials exhibit a two-times increased rate of corneal infiltrative events compared to reusable hydrogels. One potential factor contributing to this complication relates to the differential uptake of tear film-based pro-inflammatory cytokines. The purpose of this study was to use an in vitro assay to investigate whether four pro-inflammatory cytokines differed in their uptake onto six contemporary contact lens materials.

Methods
Conventional hydrogel (etafilcon A, omafilcon A) and silicone hydrogel (balafilcon A, comfilcon A, senofilcon A, somofilcon A) contact lens materials were soaked in solutions containing pro-inflammatory cytokines IL-1β, IL-6, IL-8 and TNF-α. Samples of the soaking solutions were collected over various time points and analyzed using the Meso Scale Discovery system, which served as a measurement of cytokine uptake onto the contact lens materials.

Results
Both conventional hydrogels (etafilcon A, omafilcon A) and two of the four silicone hydrogels tested (balafilcon A, comfilcon A), exhibited some uptake of IL-1β, IL-8 or TNF-α (p < 0.05). Senofilcon A and somofilcon A did not exhibit uptake of any of these cytokines (p > 0.05). There was no uptake of IL-6 onto any of the contact lens materials investigated (p > 0.05).

Conclusion
The contact lens materials tested did not exhibit any uptake of IL-6 and furthermore, did not exhibit more than 10 ± 3 % to 25 ± 12 % uptake of IL-1β, IL-8 or TNF-α. Numerous factors could contribute to the reported increase in corneal infiltrative events with reusable silicone hydrogel materials, however, based on these results, it appears that uptake of these four cytokines are unlikely to contribute to this finding.

Morgan,P. B., Murphy,P. J., Gifford,K. L., Gifford,P., Golebiowski,B., Johnson,L., Makrynioti,D., Moezzi,A. M., Moody, K., Navascues-Cornago,M., Schweizer,H., Swiderska,K., Young,G., Willcox,M. CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye Contact Lens Anterior Eye 2021;44(2):192-219 [ Show Abstract ]

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia).

However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation.

In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

Nichols,J. J., Jones,L., Morgan,P. B., Efron,N. Bibliometric analysis of the meibomian gland literature Ocular Surface 2021;20(April):212-214 [ Show Abstract ]

There is a rich history of interest in the sebaceous glands located posterior to the tarsal plates in the eyelids, to which we refer today as the meibomian glands (MGs). Although there is acknowledgement of the MGs preceding the work of Johann Heinrich Meibom in the 1600's, he is credited with advancing our knowledge and study of these glands.

The MGs produce a distinct lipid secretion (‘meibum’) made up of a variety of lipid classes, mostly composed of nonpolar wax and cholesterol esters, although other nonpolar and polar lipids are certainly known to exist in the meibum. The normal function of meibum is to make its way to the tear film lipid layer, ultimately forming a resistive barrier to evaporation of the aqueous component of the tear film. In disease, the MGs lose their ability to secrete a normal meibum composition and/or are impeded due to factors such as atrophy of the MGs, keratinization of the orifice of the gland from which the meibum is secreted onto the eyelid margin, or bacterial colonization of the eyelid, altering the secretion itself once expressed. These conditions today are known as blepharitis, including anterior and posterior blepharitis (which includes meibomian gland dysfunction).

Given the extensive study of MGs, a bibliometric analysis is warranted to acknowledge and celebrate those contributing to this important part of ophthalmic research.

Nichols,J. J., Morgan,P. M., Jones,L. W., Efron,N 21st century bibliometric analysis of the field of dry eye disease Clinical and Experimental Optometry 2021;104(5):639-640 [ Show Abstract ]

In 2012, the lead author of this paper (JJN) conducted a citation analysis of dry eye research to identify the leading papers, authors, institutions, countries and journals in the field. That analysis was essentially an historical overview of publications on this topic extending back over the past century. Because a strong and growing foundation of scientific literature is a fundamental component of evidenced-based clinical care of patients, the current work was conducted to update the research community on trends in the 21st century dry eye literature, and to compare this new literature with the prior analysis in the context of events or trends in the dry eye field.

Omali,N. B., Subbaraman,L. N., Heynen,M., Lada,M., Canavan,K., Fadli,Z., Ngo,W., Jones,L. Lipid deposition on contact lenses in symptomatic and asymptomatic contact lens wearers Cont Lens Anterior Eye 2021;44(1):56-61 [ Show Abstract ]

Purpose
Lipid deposition on contact lenses (CL) has traditionally been believed to reduce comfort during CL wear. The purpose of this study was to quantify lipid deposition on CL in a group of symptomatic and asymptomatic adapted CL wearers.

Methods
This was a single-masked, randomized clinical trial. Only confirmed symptomatic (comfortable lens wear time (CWT) < 8 h and a noticeable reduction in comfort over the course of the day) and asymptomatic (CWT > 10 h and minimal reduction in comfort over the course of the day) participants were recruited to participate in the study. Participants wore senofilcon A lenses in combination with a polyquaternium-based care solution (OPTI-FREE Replenish). Worn CL samples were collected on Day 14. Deposited lipid amounts from the lenses (including cholesteryl ester, cholesterol and triolein) were quantified using a liquid chromatography-mass spectrometry technique.

Results
Lipid deposition was significantly higher in CL extracts of asymptomatic wearers compared to the symptomatic wearers for all lipid types quantified, including cholesteryl ester (2.1 ± 0.6 vs 1.6 ± 0.5 log μg/lens), cholesterol (1.5 ± 0.3 vs 1.1 ± 0.3 log μg/lens) and triolein (0.3 ± 0.2 vs 0.1 ± 0.1 log μg/lens) (all p < 0.002). The amount of cholesteryl ester deposited was greatest (p = 0.0001), followed by cholesterol, then triolein, for both the asymptomatic and symptomatic groups (both p = 0.0001).

Conclusion
This study demonstrated that the asymptomatic group deposited a significantly greater amount of lipid on their CL. Although lipid levels measured are considered low to trigger any observable clinical deposition, they may influence other clinical outcomes, particularly comfort.

Phan,C. M., Qiao,H., Yee,A., Jones,L. Deposition of Fluorescently Tagged Lysozyme on Contact Lenses in a Physiological Blink Model Eye & Contact Lens 2021;47(2):127-133 [ Show Abstract ]

PURPOSE: To visualize the deposition of fluorescein isothiocyanate (FITC) lysozyme on daily disposable contact lenses (CLs) using a novel blink model.

METHODS: Three daily disposable conventional hydrogel CLs (etafilcon A, omafilcon A, and nelfilcon A) and three silicone hydrogel CLs (delefilcon A, senofilcon A, and somofilcon A) were evaluated in the study. The CLs were mounted onto a novel blink model and exposed to an artificial tear solution containing FITC lysozyme for 2 and 10 hr. The flow rate and blink speed were set to 1 μL/min and 6 blinks/min, respectively. After the incubation period, a 5-mm-diameter disc was punched out from the center of the lens and mounted on a microscope slide. The slides were imaged using the Zeiss 510 Meta confocal laser scanning microscope, which scanned the lens from the front to the back surface at 5-μm increments.

RESULTS: There was an increase in deposition of FITC lysozyme for all lens types with increasing incubation time (P<0.05), with the exception of somofilcon A, which did not show statistical significance between 2 and 10 hr (P>0.05). The conventional hydrogel CLs deposited higher amounts of FITC lysozyme than the silicone hydrogel CLs (P<0.001), with etafilcon A depositing the highest at all time points (P<0.05). Interestingly, at the 2-hr incubation time, most CLs showed a higher amount of deposition at the front surface than the back surface of the lens. In particular, etafilcon A showed preferred deposition at the front surface at all time points.

CONCLUSION: The results suggest that there is differential deposition at the front surface of the CL, which is exposed to the prelens tear film, compared with the back surface of the CL, which is exposed to the postlens tear film. Therefore, it may be beneficial to design CL materials with differing surface properties for the front and back surfaces of the CL to enhance interactions with the tear film and ocular surface.

Phan,C. M., Shukla,M., Walther,H., Heynen,M., Suh,D., Jones,L. Development of an In Vitro Blink Model for Ophthalmic Drug Delivery Pharmaceutics 2021;13(Article 300):1-10 [ Show Abstract ]

Purpose: The purpose of this study was to develop an advanced in vitro blink model that
can be used to examine the release of a wide variety of components (for example, topical ophthalmic
drugs, comfort-inducing agents) from soft contact lenses. Methods: The model was designed using
computer-aided design software and printed using a stereolithography 3D printer. The eyelid and
eyeball were synthesized from polyvinyl alcohol and silicone material, respectively. Simulated
tear fluid was infused through tubing attached to the eyelid using a syringe pump. With each
blink cycle, the eyelid slides and flexes across the eyeball to create an artificial tear film layer. The
flow-through fluid was collected using a specialized trough. Two contact lenses, etafilcon A and
senofilcon A, were incubated in 2 mL of a water-soluble red dye for 24 h and then placed on the eye
model (n = 3). The release of the dye was measured over 24 h using a tear flow rate of 5 µL/min.
Results: Approximately 25% of the fluid that flowed over the eye model was lost due to evaporation,
nonspecific absorption, and residual dead volume. Senofilcon A absorbed more dye (47.6 ± 2.7 µL)
than etafilcon A (22.3 ± 2.0 µL). For etafilcon A, the release of the dye followed a burst-plateau
profile in the vial but was sustained in the eye model. For senofilcon A, the release of the dye was
sustained in both the vial and the eye model, though more dye was released in the vial (p < 0.05).
Overall, the release of the dye from the contact lenses was higher in the vial compared with the eye
model (p < 0.05). Conclusion: The blink model developed in this study could be used to measure
the release of topical ophthalmic drugs or comfort agents from contact lenses. Simulation of a blink
mechanism, an artificial tear film, and nonspecific absorption in an eye model may provide better
results than a simple, static vial incubation model.

Schulze,M., Ng,A. Y., Yang,M., Panjwani,F., Srinivasan,S., Jones,L., Senchyna,M. Bulbar redness and dry eye disease: comparison of a validated subjective grading scale and an objective automated method Optometry & Vision Science 2021;98(2):113-120 [ Show Abstract ]

SIGNIFICANCE
In this study, assessments of conjunctival redness were performed to evaluate whether patients with or without dry eye disease (DED) could be discriminated based on this measure. Our findings suggest that subjectively grading redness by quadrant, as opposed to automated en face measurements, may be more suitable for this purpose.

PURPOSE
This study aimed to quantify bulbar redness using the validated bulbar redness (VBR) grading scale and an automated objective method (Oculus Keratograph 5M; K5M) in participants with DED and non-DED controls.

METHODS
Participants with DED (Ocular Surface Disease Index score ≥20 and Oxford scale corneal staining ≥2) and controls (Ocular Surface Disease Index score ≤10 and corneal staining ≤1) attended two study visits. In part 1A of visit 1, baseline bulbar redness was graded with the VBR scale in each conjunctival quadrant of both eyes, followed by automated measurements of temporal and nasal redness with the K5M. This was immediately followed by part 1B, during which a topical vasoconstrictor was instilled into both eyes. Redness assessments were repeated 5 and 30 minutes after instillation with both instruments. Participants returned 14 days later for visit 2, where the same assessments as for visit 1A were repeated.

RESULTS
Seventy-four participants (50 DED and 24 controls) completed the study. There were statistically significant differences in redness between the DED and control groups when assessed with the VBR scale (14/16 comparisons; all, P < .05), whereas no significant differences in K5M-derived redness between the DED and non-DED groups were found at any location or time point. Both subjective and objective instruments detected statistically significant reductions in redness 5 and 30 minutes after instillation of the vasoconstrictor (all, P < .01).

CONCLUSIONS
Although both subjective and objective instruments were sensitive to detecting changes in redness induced by vasoconstriction, statistically significant differences in redness between DED and control groups were only found using the VBR scale.

Stapleton,F., Bakkar,M., Carnt,N., Chalmers,R., Kumar Vijay,A., Marasini,S., Ng,A. Y., Tam,J., Wagner,H., Woods,C., Wolffsohn,J. S. CLEAR - Contact lens complications Contact Lens Anterior Eye 2021;44(2):330-367 [ Show Abstract ]

Contact lens-related complications are common, affecting around one third of wearers, although most are mild and easily managed. Contact lenses have well-defined anatomical and physiological effects on the ocular surface and can result in other consequences due to the presence of a biologically active material. A contact lens interacts with the tear film, ocular surface, skin, endogenous and environmental microorganisms, components of care solutions and other antigens which may result in disease specific to contact lens wear, such as metabolic or hypersensitivity disorders. Contact lens wear may also modify the epidemiology or pathophysiology of recognised conditions, such as papillary conjunctivitis or microbial keratitis. Wearers may also present with intercurrent disease, meaning concomitant or pre-existing conditions unrelated to contact lens wear, such as allergic eye disease or blepharitis, which may complicate the diagnosis and management of contact lens-related disease.

Complications can be grouped into corneal infection (microbial keratitis), corneal inflammation (sterile keratitis), metabolic conditions (epithelial: microcysts, vacuoles, bullae, tight lens syndrome, epithelial oedema; stromal: superficial and deep neovascularisation, stromal oedema [striae/folds], endothelial: blebs, polymegethism/ pleomorphism), mechanical (corneal abrasion, corneal erosion, lens binding, warpage/refractive error changes; superior epithelial arcuate lesion, mucin balls, conjunctival epithelial flaps, ptosis, discomfort), toxic and allergic disorders (papillary conjunctivitis, solution-induced corneal staining, incomplete neutralisation of peroxide, Limbal Stem Cell Deficiency), tear resurfacing disorders/dry eye (contact lens-induced dry eye, Meibomian gland dysfunction, lid wiper epitheliopathy, lid parallel conjunctival folds, inferior closure stain, 3 and 9 o'clock stain, dellen, dimple veil) or contact lens discomfort. This report summarises the best available evidence for the classification, epidemiology, pathophysiology, management and prevention of contact lens-related complications in addition to presenting strategies for optimising contact lens wear.

Thite,N., Desiato,A., Shinde,L., Wolffsohn,J. S., Naroo,S. A., Santodomingo-Rubido,J., Cho,P., Jones,D., Villar-Collar,C., Carillo,G., Chan,O., Wang,H., Iomdina,E., Tattura,E., Proskurina,O., Shing Fan,C., Zeri,F., Bakkar,M. M., Barodawala,F., Dabral,N., Lafosse,E., Lee,C., Nichols,J. J., Chan,J., Park,K., Nair,V., van der Worp,E., Vankudre,G., Maseedupalli,V., Bhattarai,Y., Nagzarkar,D., Brauer,P., Gil-Cazorla,R. Opportunities and threats to contact lens practice: A global survey perspective Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Aim
To understand the views of contact lens (CL) practitioners across the globe regarding what they perceive as opportunities and threats in CL practice.

Methods
A self-administered anonymised questionnaire, constructed in English and translated in six more languages, was distributed through reputed international professional bodies and academic institutions worldwide. The questionnaire included items on demographic characteristics, type of practice, and questions designed to explore practitioners’ perspective on the future of their CL practice over the next five years.

Results
A total of 2408 valid responses were analysed. Multifocal CLs for presbyopia, CLs for myopia control, use of daily disposable (DD) CLs for occasional wear, and biocompatible materials to improve comfort were identified as promising areas of opportunities by practitioners (all 8/10). Respondents from North America, and Europe valued DDCLs for occasional wear moderately more favourable (Median: 9/10 for all) as compared to colleagues in Asia (Median: 8/10, p < 0.001), South America (Median: 8/10, p < 0.01), and Africa (Median: 8/10p < 0.01). Multifocal CLs for presbyopia was perceived as a better opportunity by practitioners in North America and Europe (Median: 9/10 for both), as well as in Australasia (Median: 8/10), in comparison to Asia, Africa, and Middle East (for all Median: 6/10, p < 0.001). Practitioners expressed concerns about the availability of CLs and CL prescriptions online without direct professional involvement (both 9/10).

Conclusions
Overall, the most appealing opportunities for CL practice growth were identified in occasional use of DD CLs, biocompatible materials to reduce CL discomfort, multifocal CLs for presbyopia correction and management of myopia control with CLs. Lack of regulation in CL sales, especially online, seemed to be a constant threat. The insights from this study can be used to design targeted strategies to enhance CL practice across the globe and in specific geographical areas.

Tichenor,A,, Cofield,S., Gann,D., Elder,M., Ng,A. Y., Walsh,K., Jones,L., Nichols,J. Frequency of Contact Lens Complications Between Contact Lens Wearers Using Multipurpose Solutions Versus Hydrogen Peroxide in the United States and Canada Eye & Contact Lens 2021;47(5):277-282 [ Show Abstract ]

Objectives: To retrospectively compare frequency of contact lens (CL) complications in soft CL users of hydrogen peroxide (H2O2) and multipurpose solutions (MPS).

Methods: This was a multicenter, retrospective chart review of CL records from each patient's three most recent eye examinations at academic and private practices. Patients must have used the same solution type for at least 3 years. Univariate analyses were conducted using t tests, and chi-square or Fisher's exact test for categorical measures.

Results: There were 1,137 patients included, with 670 (59%) using MPS and 467 (41%) H2O2. In total, 706 (62%) experienced at least one complication; 409 used MPS and 297 used H2O2. There was no difference in the proportion of patients experiencing at least one complication between MPS (61%) and H2O2 (64%) (P=0.38). Multipurpose solutions users were more likely to report discomfort compared with H2O2 users (P=0.04). Presumed microbial keratitis was experienced by 16 MPS and nine H2O2 users (P=0.60).

Conclusions: No significant differences were found in the frequency of CL complications between MPS and H2O2. H2O2 users were less likely to report discomfort and thus switching to a H2O2 system may be an alternative in CL users with discomfort.

Ulkuseven,E., McCanna,D. J., Subbaraman,L. N., Jones,L. W. The Effect of Antimicrobial Peptides on the Viability of Human Corneal Epithelial Cells Probiotics and Antimicrobial Proteins 2021;13(2):518-526 [ Show Abstract ]

Antimicrobial peptides are polypeptides composed of less than 100 amino acids and are a class of antibiotics with strong activity against some infectious bacteria. This study examined the safety of four chosen antimicrobial peptides using primary human corneal epithelial cells (HCEC) and explored their potential therapeutic use. The efficacy of the peptides was also studied by evaluating the minimum inhibitory concentrations (MIC) against Gram-negative and Gram-positive bacteria. One of the peptides (polymyxin E) was found to have antibacterial efficacy against a common Gram-negative bacterium (MIC 1.56 μg/mL for Pseudomonas aeruginosa), and another one (nisin) was found to have antibacterial efficacy against a common Gram-positive bacterium (MIC 125 μg/mL for Staphylococcus aureus). Metabolic activity and live/dead/apoptotic effects were measured with fluorescent dyes after HCEC were exposed to the peptides for 30 min. Three of the peptides exhibited lower toxicity against HCEC than a currently marketed eye drop product. Regarding both efficacy and safety, two of the peptides (polymyxin E and nisin) were found to have potential use for treating ocular infections.

Vincent,S. J., Cho,P., Yin Chan,K., Fadel,D., Ghorbani-Mojarrad,N., González-Méijome,J. M., Johnson,L., Michaud,L., Simard,P., Jones,L. CLEAR - Orthokeratology Contact Lens Anterior Eye 2021;44(2):240-269 [ Show Abstract ]

Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children.

This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size.

Walther,H., Lorentz,H., Heynen,M., Kay,L., Jones,L. W. The Impact of Incubation Conditions on in Vitro Phosphatidylcholine Deposition on Contact Lens Materials Optometry & Vision Science 2021;98(4):341-349 [ Show Abstract ]

SIGNIFICANCE: Previous in vitro measurements of contact lenses commonly investigate the impact of nonpolar
tear film lipids (i.e., sterols). Polar lipids, however, are equally important stabilizing components of the tear film.
This research explores and presents further knowledge about various aspects of polar lipid uptake that may impact
contact lens performance.

PURPOSE: This study evaluated the impact of incubation time, lipid concentration, and replenishment of an artificial
tear solution (ATS) on the uptake of phosphatidylcholine (PC) onto conventional hydrogel (CH) and silicone
hydrogel (SH) contact lens materials.

METHODS: Four SHs and two CH lens materials (n = 4) were soaked in a complex ATS containing radioactive
14C-PC as a probe molecule. Phosphatidylcholine uptake was monitored at various incubation time points (1, 3,
7, 14, and 28 days), with different ATS lipid concentrations (0.5, 1, 2) and with and without regular replenishment
of the ATS. Phosphatidylcholine was extracted from the lenses, processed, and counted by a β counter,
and accumulated PC (μg/lens) was extrapolated from standard lipid calibration curves.

RESULTS: All materials exhibited increasing PC deposition over time. Conventional hydrogel materials showed significantly lower PC uptake rates (P < .001) than any of the SH materials. Increasing lipid concentration in the ATS
resulted in increased PC binding onto the contact lens materials (P < .001). Replenishing the ATS every other day,
however, impacted the PC deposition differently, showing increased binding (P < .001) on CHs and reduced PC
deposition for SH materials (P < .001).

CONCLUSIONS: Length of incubation, lipid concentration in the ATS, and renewal of the incubation solution all
influenced the amount of PC that sorbed onto various lens materials and therefore need to be considered when
conducting future in vitro deposition studies.

Willcox,M., Keir,N., Maseedupallu,V., Masoudi,S., McDermott,A., Mobeen,R., Purslow,C., Santodomingo-Rubio,J., Tavazzi,S., Zeri,F., Jones,L. W. CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears Contact Lens Anterior Eye 2021;44(2):157-191 [ Show Abstract ]

Contact lens materials have undergone significant changes over the past 20 years, particularly with respect to the introduction of silicone hydrogel materials. Whilst this development addressed hypoxic issues, other important areas relating to contact lens success, notably comfort, require further research.

Contact lens wettability remains a crucially important part of biocompatibility. Contact lenses can be made more wettable by incorporation of surfactants into blister packs, internal wetting agents, surface treatments or care solutions. However, there remains no clear association between contact lens wettability and comfort, making it challenging to determine the potential for these approaches to be of significant clinical benefit. Most contact lenses are used on a daily wear, reusable basis, which requires them to be disinfected when not worn. The ideal disinfecting solution would also improve comfort during wear. However, balancing these requirements with other factors, including biocompatibility, remains a challenge. Soft lens materials invariably take up and subsequently release certain components of disinfecting solutions onto the ocular surface. This may affect tear film stability and the normal ocular microbiome, and further research is needed in this area to determine whether this has any affect on comfort. Finally, contact lens materials sorb components of the tear film, and these interactions are complex and may change the biochemistry of the tear film, which in turn may affect their comfort.

In conclusion, the interaction between lens materials, tear film and disinfection solution plays an important role in the biocompatibility of lenses. However, the exact role and whether this can be altered to improve biocompatibility and comfort during wear remains debatable. This report summarises the best available evidence to examine this complex relationship and the opportunities for practitioners to enhance in-eye comfort of contemporary lenses, along with providing suggestions for areas of study that may provide further information on this topic.

Wolffsohn,J. S., Dumbleton,K., Huntjens,B., Kandel,H., Koh,S., Kunnen,C. M. E., Nagra,M., Pult,H., Sulley,A. L., Vianya-Estopa,M., Walsh,K., Wong,S., Stapleton,F. CLEAR - Evidence-based contact lens practice Contact Lens Anterior Eye 2021;44(2):368-397 [ Show Abstract ]

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

Wolffsohn,J. S., Morgan,P. B., Barnett,M., Downie,L. E., Jacobs,D. S. Jones,L. W., Richdale, K., Stapleton,F., Vincent,S. J., Willcox,M. Contact Lens Evidence-Based Academic Reports (CLEAR) Contact Lens Anterior Eye 2021;44(2):129-131 [ Show Abstract ]

Since contact lenses were invented in 1887, innovations have included advances in optical design, material, care systems, wear modality, lens size, lens shape and applications. Over 19,000 peer reviewed academic papers on the contact lenses have been published. The Contact Lens Evidence-based Academic Reports (CLEAR) follow the exemplary work of organisations such as the Tear Film and Ocular Surface Society dry eye, meibomian gland disease, contact lens discomfort and dry eye II workshops and the International Myopia Institute white papers on myopia control, in collating and appraising the academic literature in an ocular field of interest. CLEAR represent the work of nearly 100 multidisciplinary experts in the field, who set out to critically review, synthesise and summarise the research evidence on contact lenses to date; this serves to inform both clinical practice, manufacturing innovation and future research directions.

Wolffsohn,J. S., Travé-Huarte,S., Jones,L., Craig,J. P., Wang,M. T. M., the TFOS ambassadors. Clinical practice patterns in the management of dry eye disease: A TFOS international survey Ocular Surface 2021;21(July):78-86 [ Show Abstract ]

Purpose
To examine clinical management and prescribing patterns for dry eye disease (DED), in relation to severity and subtype, by eye care practitioners across the globe.

Methods
An online, anonymous cross-sectional survey (on Qualtrics) translated into 14 languages was distributed to eye care practitioners across the globe. The survey included six questions around the management of DED, in relation to severity and subtype.

Result
The survey was completed by 1139 eyecare professionals (37% ophthalmologists and 58% optometrists) from 51 countries. Management varied significantly by continent and country (p < 0.01). The most commonly recommended management approaches, internationally, included general advice (87%), low (85%) and high (80%) viscosity-enhancing unpreserved lubricants and lid wipes/scrubs (81%). Some treatments were prescribed largely independently of severity (e.g. artificial tears and nutritional supplements) while oral antibiotics, punctal occlusion, topical anti-inflammatory/immunosuppressants, secretagogues, biologics, therapeutic contact lenses and surgical approaches were prescribed by more practitioners as severity increased. Essential fatty acids, lipid sprays/drops, lid hygiene, warm compresses, intense pulsed light therapy and antibiotics (topical or oral) were more commonly recommended for evaporative DED, while punctal occlusion, therapeutic contact lenses, secretagogues and biologics were more commonly recommended for aqueous deficient DED.

Conclusions
DED management differs across continents and countries. A wide range of management strategies are utilised at each severity level and between subtypes. The survey results enable clinicians to benchmark their practice to that of their peers, indicate where further research is required to optimise patient management and inform industry on how best to target product development.

Woods,J., Jones,D., Jones,L., Jones,S., Hunt,C., Chamberlain,P., McNally,J Ocular health of children wearing daily disposable contact lenses over a 6-year period Contact Lens Anterior Eye 2021;44(4):Article 101391 [ Show Abstract ]

Purpose
To report on the ocular health and safety of children fit with soft hydrogel daily-disposable contact lenses, and followed for 6-years in a double-masked clinical trial investigating the performance of a dual-focus contact lens designed to control myopia progression.

Methods
Children aged 8−12 years, naïve to contact lens wear, were enrolled across four international sites. During years 1–3, children were randomised to either MiSight® 1 day or Proclear® 1 day (both omafilcon A, CooperVision, Inc.). The lenses were identical in material and geometry except for the front optical zone design. At the end of year-3, all those wearing Proclear 1 day were switched to MiSight 1 day, therefore all wore MiSight 1 day in years 4−6. Subjects agreed to wear the lenses at least 10-hours/day, 6-days/week. After dispensing, study visits were at 1-week, 1-month, 6-months and every 6-months until 6-years. At each visit, ocular measurements and subjective responses were recorded. Biomicroscopy used 0–4 grading scales; grade 0 represented no findings.

Results
144 children were enrolled: 69F:75M; mean age 10.1 years; mean cycloplegic spherical-equivalent refraction -2.11D; ethnicities included 34 East-Asian, 12 West-Asian, and 79 Caucasian. 92 completed the 6-years. Only three subjects discontinued due to an ocular adverse event (AE). No contact lens related AEs were classified as serious. The incidence rate of infiltrative AEs was 0.61% (6.1/1000 wearing-years; 95%CI: 0.24%–1.57%). The most common biomicroscopy findings were limbal, bulbar and tarsal hyperaemia and tarsal roughness. 99% of all biomicroscopy findings were grade-1 or lower. After 6-years of lens wear, ocular health by biomicroscopy was similar to pre-lens wear.

Conclusions
Across the 6-years, there were no contact lens related serious AEs and biomicroscopy showed no significant changes. Results suggest that children this age can successfully wear daily-disposable hydrogel contact lenses with minimal impact on ocular physiology.

Xu,M., Sivak,J. G., McCanna,D. J. Neutralization of the eye and skin irritant benzalkonium chloride using UVC radiation Cutaneous and Ocular Toxicology 2021;40(2):78-84 [ Show Abstract ]

Benzalkonium chloride (BAK) is a widely used disinfectant and preservative which is effective against a wide range of viruses (e.g. SARS-CoV and SARS-CoV-2), bacteria and fungi. However, it is toxic to the eye and skin. This study investigated the neutralization of BAK using ultraviolet C (UVC) radiation as an effort to reduce BAK toxicity potential.

Methods
BAK solutions were irradiated with a germicidal UVC lamp at various doses. Human corneal epithelial cells (HCEC) were then exposed to the UVC-irradiated BAK solutions for 5 minutes. After exposure, the cultures were assessed for metabolic activity using PrestoBlue; for cell viability using confocal microscopy with viability dyes; and for tight junction proteins using immunofluorescence staining for zonula occludens (ZO)-1.

Results
UVC radiation reduced BAK toxicity on cell metabolic activity in a dose-dependent manner. When the solution depth of BAK was 1.7 mm, the UVC doses needed to completely neutralize the toxicity of BAK 0.005% and 0.01% were 2.093 J/cm2 and 8.374 J/cm2, respectively. The cultures treated with UVC-neutralized BAK showed similar cell metabolic activity and cell viability to those treated with phosphate buffered saline (PBS) (p = 0.806 ∼ 1.000). The expression of ZO-1 was greatly disturbed by untreated BAK; in contrast, ZO-1 proteins were well maintained after exposure to UVC-neutralized BAK.

Conclusions
Our study demonstrates that the cell toxicity of BAK can be neutralized by UVC radiation, which provides a unique way of detoxifying BAK residues. This finding may be of great value in utilizing the antimicrobial efficacy of BAK (e.g. fighting against SARS-CoV-2) while minimizing its potential hazards to human health and the environment.

Yamasaki,K., Drolle,E., Nakagawa,H., Hisamuare,R., Ngo,W., Jones,L. W. Impact of a low molecular weight hyaluronic acid derivative on contact lens wettability Cont Lens Anterior Eye 2021;44(3):101334 [ Show Abstract ]

Purpose
To investigate the interaction of a novel low molecular weight hyaluronic acid derivative containing hydrophobic groups with soft contact lenses and its effect on lens hydrophilicity compared with a conventional form of hyaluronic acid.

Methods
This investigation studied the uptake of fluorescently-labelled hyaluronic acid and a low molecular weight hyaluronic acid derivative to four types of contact lenses using fluorescent microscopy and confocal laser scanning microscopy. Further, the four lens types were used to compare efficacy in improving hydrophilicity, as well as maintenance of contact angle measurements, in commercially available multipurpose solutions that contained either hyaluronic acid, the low molecular weight hyaluronic acid derivative, or an alternative wetting agent.

Results
The low molecular weight hyaluronic acid derivative was found to sorb more readily to silicone hydrogel lenses and exhibit a greater accumulation over time than conventional hyaluronic acid. Multipurpose solutions containing the low molecular weight hyaluronic acid derivative showed an increase in lens hydrophilicity through decreases in contact angle measurements when compared with those obtained from lenses treated with multipurpose solutions containing conventional hyaluronic acid or alternative wetting agents. This increase in lens hydrophilicity associated with the low molecular weight hyaluronic acid derivative was also maintained over multiple cycles in phosphate buffered saline, while alternative solutions with conventional hyaluronic acid did not.

Conclusion
Overall, lens treatment using a low molecular weight hyaluronic acid derivative-based solution lead to improved in vitro lens hydrophilicity.

Yamasaki,K., Mizuno,Y., Kitamura,Y., McCanna,D. J., Ngo,W., Jones,L. W. The efficacy of povidone-iodine, hydrogen peroxide and a chemical multipurpose contact lens care system against Pseudomonas aeruginosa on various lens case surfaces Cont Lens Anterior Eye 2021;44(1):18-23 [ Show Abstract ]

Purpose
To determine the antimicrobial efficacy of a povidone-iodine system (PVP-I; cleadew, OPHTECS Corporation, Kobe, Japan), a peroxide system (AOSEPT Plus with HydraGlyde, Alcon, Fort Worth, TX), and a chemical multipurpose system (renu fresh, Bausch & Lomb, Rochester, NY) on contact lens case surfaces that are both in contact and not in contact with the solutions during lens disinfection.

Methods
The surfaces of the inner walls, underside of the lid, and lens holder (if applicable) of the cases were inoculated with P. aeruginosa ATCC 27853. The cases were disinfected with the solutions as per their manufacturer instructions. After disinfection, the inoculated surfaces were swabbed and the amount of surviving P. aeruginosa was determined. Following this experiment, separate cases were inoculated and disinfected as before. This time the cases were agitated after recommended disinfection time and the amount of P. aeruginosa in the disinfecting solution was quantified immediately, and again after resting for 7 days. Experiments were conducted in triplicate (n = 3).

Results
Units are expressed in log CFU. All three solutions significantly reduced P. aeruginosa on direct-contact surfaces (all p < 0.039). On non-contact surfaces, the reduction of P. aeruginosa in the PVP-I system (pre-disinfection: 6.8 ± 0.5, post-disinfection: 1.0 ± 0.0; p < 0.001) was significant, but not for the hydrogen peroxide system (pre-disinfection: 6.3 ± 0.6, post: 5.5 ± 0.5; p = 0.194) and the chemical multipurpose system (pre-disinfection: 6.6 ± 0.1, post-disinfection: 5.6 ± 0.8; p = 0.336). After 7 days post-disinfection, no P. aeruginosa regrowth was observed in the PVP-I system (Day 1: 1.0 ± 0.0, Day 7: 1.0 ± 0.0; p = 1) and the chemical multipurpose system (Day 1: 4.2 ± 0.2, Day 7: 1.8 ± 0.9; p = 0.012), however regrowth was observed in the hydrogen peroxide system (Day 1: 3.4 ± 0.6, Day 7: 6.1 ± 0.4; p = 0.003).

Conclusion
The PVP-I system was more effective against P. aeruginosa on non-contact surfaces than the hydrogen peroxide system or the chemical multipurpose system and is capable of inhibiting regrowth of P. aeruginosa for at least 7 days post-disinfection.

Yang,M., Ngo,W., Srinivasan,S., Heynen,M. L., Dantam,J., Subbaraman,L. N., Jones,L., Senchyna,M. Optimization of goblet cell density quantification methods Experimental Eye Research 2021;207(June):108607 [ Show Abstract ]

The purpose of this study was to develop a standardized, accurate and efficient method for estimating conjunctival goblet cell density (GCD) via optimizing sample storage conditions and quantification methods. Conjunctival impression cytology (CIC) membranes were collected from both eyes of 32 participants and were randomized to two storage durations (2-3 weeks, 6-7 weeks) and two storage container types (microcentrifuge tube, flat histology cassette). The CIC membranes were stained and subdivided into 25 areas (5 mm × 5 mm) for imaging and the GCs were counted under 200X magnification using three different methods: (1) full CIC membrane GC count of the 25 images with cell-counting software ("full"; reference method), (2) partial membrane GC count of 9 images with cell-counting software ("partial"), and (3) manual counting of the 25 images ("manual"). In all cases, GCD was determined by dividing the GC count by the counting area. The average time required for quantification was recorded to gauge efficiency. Results showed no significant difference in GC count between the two storage durations (p = 0.745) or storage container types (p = 0.552). The median (interquartile range (IQR)) time required to quantify a CIC membrane for the full, partial, and manual methods of GC counting, was 14.8(17.6), 4.6(5.2) and 5.0 (5.0) minutes, respectively. The agreement of GCD values between the full and manual methods (bias: 0.4, 95% LOA: [-4.6, 5.5]) was stronger than that comparing the full and partial methods (bias: 0.5, 95% LOA: [-18, 17]). All together, through systematic examination of key procedural variables, an optimized method for GCD quantification within 7 weeks of sample collection was outlined. Adaption of procedures described in this paper to facilitate accurate and efficient GCD quantification may serve as a valuable step in clinical trials investigating DED pathophysiology and/or novel DED treatment strategies.

Yee,A., Chan,V., Heynen,M., Phan,C. M., Jones,L. Uptake and release of a multipurpose solution biocide (MAP-D) from hydrogel and silicone hydrogel contact lenses using a radiolabel methodology Eye & Contact Lens 2021;47(5):249-255 [ Show Abstract ]

Purpose:
The purpose of this study was to evaluate the uptake and release of radiolabelled myristamidopropyl dimethylamine (MAP-D) on reusable daily wear contact lenses (CLs) over 7 days.

Methods:
Three silicone hydrogel (SH) CL materials (lotrafilcon B, balafilcon A, senofilcon A) and two conventional hydrogel (CH) materials (etafilcon A, omafilcon A) were tested. A short-term (experiment 1, N=4) and a longer-term (experiment 2, N=3) study was conducted. In experiment 1, the CLs were incubated in 2 mL of phosphate buffered solution (PBS) containing 14C MAP-D (5 μg/mL) for 8 hrs. The release of 14C MAP-D was measured at t=0.25, 0.5, 1, 2, 4, 8, and 24 hr in PBS. In experiment 2, the CLs were incubated in the 14C MAP-D solution for 8 hrs followed by a 16-hr release in PBS. This cycle was repeated daily for 7 days. At the end of both experiments, lenses were extracted to determine the total uptake of MAP-D. The radioactivity was measured using a beta scintillation counter.

Results:
In experiment 1, all three SH lenses sorbed similar amounts of MAP-D (P=0.99), all of which were higher than the two CH materials (P<0.01). However, the CH materials released a greater amount of MAP-D than the SH materials (P<0.01). In experiment 2, the uptake of MAP-D in SH materials increased over 7 days, whereas the amount of MAP-D remained constant in the CH materials (P=0.99). Similar to experiment 1, the CH lenses released more MAP-D than SH lenses after 7 days (P<0.01).

Conclusion:
The SH materials absorbed greater amounts of MAP-D compared to CH materials. However, the CH materials released the greatest amount of MAP-D. Radioactive labelling of MAP-D offers a highly sensitive method of assessing the uptake and release profiles of biocides to CL materials.

Yee,A., Walsh,K., Schulze,M., Jones,L The impact of patient behaviour and care system compliance on reusable soft contact lens complications Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Reusable soft daily wear contact lenses (CLs) remain popular and were fit to just over half of all wearers in the most recent international CL prescribing survey. Unlike daily disposable CLs, reusables require cleaning and disinfecting after every use, along with storage in a CL case. These additional requirements add a number of steps to the daily wear and care routine, increasing the opportunities for CL wearers to exhibit non-compliant behaviour. The impact of non-compliance ranges from poor lens comfort through to potentially sight- threatening infective keratitis. The coronavirus pandemic has refocused the profession on the importance of hand hygiene in particular, and the need for promoting safe CL wear in general. This review summarises typical non-compliant behaviour related to reusable CLs, and examines strategies and opportunities to better support wearers. Patient education has a central role in encouraging compliant behaviour, although patient recall of information is low, and personal belief systems may result in continuation of non-compliant behaviour despite awareness of the risks. CL care solutions are required for the daily disinfection of lenses, however misuse of multipurpose solutions (MPS) and hydrogen peroxide (H2O2)-based care systems can challenge their ability to be fully efficacious. Standard efficacy testing is reviewed, with consideration of how well current protocols model real-world use of CL solutions. Although some recommendations are in place for the inclusion of additional variables such as lens cases, CL materials, organic soil and efficacy against Acanthamoeba, opportunity still exists to reevaluate global standards to ensure consistency of testing in all markets. Finally, potential future innovations are discussed which may further support increased safety in reusable lens wear through novel antimicrobial additions to both CL materials and cases