Publications

Showing 25 results out of 100 in total.

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.

Walsh,K., Jones,L., Moody,K. Addressing common myths and misconceptions in soft contact lens practice Clinical and Experimental Optometry 2021;Online ahead of print [ Show Abstract ]

Advances in contact lens technology over the past 50 years since the commercialisation of the first soft lenses in 1971 have been incredible, with significant changes in contact lens materials, frequency of replacement, care systems and lens designs occurring. However, despite the widespread availability of contact lenses, penetration rates for those who need vision correction remain in the low single digits and many practitioners seem to hold on to concepts around the potential value of contact lenses that appear based in the dim and distant past and are certainly no longer valid today. This review addresses 10 common ‘myths and misconceptions’ around soft contact lenses using an evidence-based approach that can hopefully dispel some of these incorrect assumptions.

Walsh K. Managing lid margin disease in dry eye and contact lens wearers Online Optometry Learning Series, April, 2021

Walsh K. BCLA CLEAR Summary https://contactlensupdate-com.s3.amazonaws.com/uploads/2021/06/BCLA-CLEAR-summary.pdf 2021 [ Show Abstract ]

The BCLA Contact Lens Evidence-based Academic Report (CLEAR) totals more than 300 pages across 11 papers. Coordinated by 10 committee chairs, written by 102 authors based in 16 countries, it was published in March 2021 and is available here.

BCLA CLEAR sets the standard to which eye care professionals (ECPs) can refer for the latest information in the contact lens field whilst also highlighting opportunities for future research. This summary draws on key points from the reports to help inform evidence-based practice.

Walsh K. Sharing the unique perspective of a practitioner, a patient, and a parent. Reshaping the future of community eye health virtual conference, Singapore, March 2021, 2021

Walsh K, Jones L. Ein Jahr Covid-19 und die Auswirkungen auf die Kontaktlinsenpraxis (German translation of "COVID-19: A Year in Review and the Impact on Contact Lens Practice", as published in CL Spectrum in Feb 2021); Deutsche Optikerzeitung 2021, 06: 96-103 [ Show Abstract ]

Das Jahr 2020, in dem die Corona-Pandemie begann, hat die gesamte Weltgemeinschaft und damit das Leben jedes einzelnen Menschen verändert. Folglich sind die Auswirkungen der Pandemie auch in der augenoptischen Branche zu spüren. Die Autoren Karen Walsh, MCOptom und PGDip, und Lyndon Jones, DSc und FCOptom, ziehen Bilanz.

Walsh K, Jones L. COVID-19: A year in review and the impact on CL practice Contact Lens Spectrum 2021;36, February: E1-E6 [ Show Abstract ]

For everyone involved in eye care, 2020 was going to be a special year. The numerous “20/20” puns and articles circulating in January were full of hope and future-gazing. No one could have predicted the direction that the year would take and its resulting impact on the world at large and, for this audience specifically, on the delivery of routine contact lens care. As the end of this unprecedented year has finally come to pass, it feels right to pause and reflect on the last 12 months, to examine the journey that the profession has taken, and to summarize the situation. This article reviews what the profession has learned and asks whether enough is known to successfully navigate the months and years ahead. With no small amount of irony and a large nod to those aforementioned puns, does being approximately one year into the pandemic result in having a useful amount of “20/20 hindsight”?

Walsh K, Jones L. Covid-19 and contact lenses: Keeping it simple in the ‘new normal’ Optician 2021, March: 25-30 [ Show Abstract ]

Karen Walsh and Professor Lyndon Jones examine how Covid-19 has affected routine contact lens practice and what that means for both eye care practitioners and their patients (C77595, one distance learning CET point suitable for optometrists, contact lens opticians and dispensing opticians).

In the first quarter of 2020, routine clinical eye care underwent a temporary cessation in most regions around the world due to the coronavirus pandemic. Optometric practice is now predominantly back up and running, albeit with the occasional return to a higher alert level as the infection rates in countries ebb and flow over time. The demands
of working in a world with Covid-19 have necessitated changes to how routine practice is conducted. As a result, the attitudes and needs of eye care practitioners (ECPs) and patients related to eye care in general, and contact lenses (CLs) in particular, may have altered. Within this new shape of optometric practice, the question of where CL practice fits naturally arises. While aftercare for the routine assessment and resupply of existing wearers may seem acceptable, how does the profession approach the option of new fits and upgrades? Given the wider challenges faced by practitioners, is this really the time to focus on such areas? Is it even ‘safe’ to fit CL now, given the close contact required? However, looking at it from a different point of view, are there in fact opportunities arising from the changes dictated by Covid-19 that could be beneficial for CL practice? This article reviews the recommendations
for safe CL practice, looks at their relevance for both practitioners and patients, and addresses how CL can be accommodated into the daily clinic routine as easily as possible.

Walsh K, Sulley A. Soft toric lens fitting practices not meeting patient needs Optometry Times Journal 2021;13, 2: 34-37 [ Show Abstract ]

The inclusion of astigmatic correction in spectacles is common practice. Outside of the need to reduce a high or previously uncorrected astigmatism to ease adaption, eyecare professionals (ECPs) routinely prescribe the full toric correction in spectacles. Historically, the lack of availability of consistently performing, comfortable soft toric contact lens designs resulted in different prescribing practices for astigmats compared to those wearing spectacles, with spherical lenses often recommended over toric lenses for low to moderate levels of astigmatism.

Modern soft toric designs are significantly different from early non-planned replacement versions of 20 or more years ago. Their overall performance—which includes ease of fitting, comfort, rotational stability, vision performance, and consistent manufacturing in a range of designs and materials—enables them to be fit successfully to a wide range of astigmatic patients.

This review provides an overview of current soft toric prescribing, comparing and contrasting different fitting practices around the globe, and explores patient expectations and the opportunities that exist to meet their needs.

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.

Williams R, Srinivasan S, Jones L. Career Transitions ARVO Advance Research Career Development Conference, Virtual Conference, February 26, 2021

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.

Wong S. CLEAR report summary: Evidence-Based Contact Lens Practice https://contactlensupdate.com/2021/06/15/evidence-based-contact-lens-practice/ 2021

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):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.

Woods J, Luensmann D, Schulze M, Vega J, Orsborn G. Subjective lens experience when refit with daily disposable multifocal contact lenses BCLA Virtual Clinical Conference & Exhibition, 2021 [ Show Abstract ][ PDF ]

Purpose: Practitioners can be reluctant to switch successful multifocal soft contact lens (MF) wearers to different materials or replacement frequencies, fearing the new MF will be less accepted. Subjective responses are highly valued in MF fitting and this study investigated subjective responses from habitual MF (hab-MF) wearers after a refit into daily disposable MF; stenfilcon A (stenA-MF) and delefilcon A (delA-MF).

Method: After optimising the lens powers, subjects wore hab-MF and both study-MFs for 2-weeks each. Study-MF brands were masked and randomised. Throughout the study, subjects answered 13 experience questions per lens type, and 6 preference questions (comfort and vision for distance, intermediate, near, digital-device use, overall vision) to compare between hab-MF and each study MF, and also between study MFs.

Results: Fifty-eight subjects (50F:8M), mean age 54.4±7.3 years were included. Mean spherical-equivalent OD refraction: -1.10±2.7D [range -6.50D to +3.75D], mean near add +2.00±0.4D. 44% habitually wore daily disposable MF yet all were naïve to the study-MFs. Hab-MF wear resulted in positive responses for all experience questions (p<0.05); for stenA-MF 12 answers were positive (p<0.05), 1 was equivocal (p=0.90); for delA-MF 6 were positive (p<0.05), 7 were equivocal (p>0.05). Preferences between stenA-MF and hab-MF showed no differences (p>0.05). Subjects preferred hab-MF over delA-MF for intermediate vision (p=0.03) but no other preference (p>0.05). Comparing between study MFs, the preference for stenA-MF was stronger than delA-MF for comfort (p=0.03), intermediate vision (p=0.03), digital-device use (p=0.03) and overall vision (p=0.02) with no difference for distance or near vision (p>0.05).

Conclusions: This study showed that even when habitual MF wearers are already successful, refitting with a new design does not necessarily lead to compromised performance; stenA-MF performed comparably to hab-MF, and for some metrics better than delA-MF. These results should give practitioners confidence to recommend newer materials and different replacement frequencies when managing their existing MF wearers.

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.

Yang M. CLEAR report summary: Medical Use of Contact Lenses https://contactlensupdate.com/2021/06/15/medical-use-of-contact-lenses/ 2021

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;44(5):101432 [ 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