Peer-reviewed Articles

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


Bzovey,B., Ngo,W. Eyelid Warming Devices: Safety, Efficacy, and Place in Therapy Clinical Optometry 2022;14133-147 [ Show Abstract ]

Meibomian gland dysfunction (MGD) is characterized by the obstruction and/or inflammation of the meibomian glands that result in decreased and altered meibum secretion. This results in deficiencies in the tear film lipid layer which contributes to increased evaporation and destabilization of the tear film. One of the mainstay therapies for MGD is medical devices that apply heat and/or pressure to the eyelids and promote the liquification and outflow of meibum into the tear film. Over the past two decades, there have been a surge of interest in diagnosing and managing MGD. As a result, numerous medical devices have been developed and each have their own unique approach to treating MGD. This narrative review was conducted to summarize the current state of knowledge on eyelid warming devices, specifically warm eye coverings, devices that direct heat and/or pressure to the eyelids, moisture chamber goggles, and light-based therapy. This review summarized 58 human clinical studies and found that most eyelid warming devices were efficacious in improving signs and symptoms in a wide range of MGD severities and were generally safe to use.

Chamberlain,P., Bradley,A., Arumugam,B., Hammond,D., McNally,J., Logan N., Jones,D., Ngo,C., Peixoto-de-Matos S., Hunt,C., Young G. Long-term Effect of Dual-focus Contact Lenses on Myopia Progression in Children: A 6-year Multicenter Clinical Trial Optom Vis Sci 2022;99(3):204-212 [ Show Abstract ]

Significance: Treatment of myopic children with a dual-focus soft contact lens (DFCL; MiSight 1 day) produced sustained slowing of myopia progression over a six-year period. Significant slowing was also observed in children switched from control to treatment lenses (3 years in each lens).

Purpose: Evaluate the effectiveness of DFCLs in sustaining slowed progression of juvenile-onset myopia over a 6-year treatment period. Assess myopia progression in children who were switched to DFCL at the end of year 3.

Methods: Part 1 was a 3-year clinical trial comparing DFCLs with control CLs (Proclear 1 day) at four investigational sites. In Part 2, subjects completing Part 1 were invited to continue for 3 additional years during which all children were treated with MiSight 1 day DFCLs (52 and 56 from the initially treated (T6) and control (T3) groups, respectively). 85 subjects (45 (T3) and 40 (T6)) completed Part 2. Cyclopleged spherical equivalent refractive errors (SERE) and axial lengths (AL) were monitored and linear mixed model was used to compare their adjusted change annually.

Results: Average age at Part 2 baseline was 13.2 ± 1.3 and 13.0 ± 1.5 for the T6 & T3 groups respectively. Slowed myopia progression in the T6 group observed during Part 1 was sustained throughout Part 2 (Mean ± SEM: Change from baseline SERE(D) = -0.52 ± 0.076 vs -0.51 ± 0.076; change in AL(mm) = 0.28 ± 0.033 vs 0.23 ± 0.033, both P > .05). Comparing progression rates in Part 2 for the T6 and T3 groups respectively indicate that prior treatment does not influence efficacy (SERE -0.51 ± 0.076 vs -0.34 ± 0.077; AL 0.23 ± 0.03 vs 0.18 ± 0.03, both P > .05). Within-eye comparisons of AL growth revealed a 71% slowing for the T3 group (3-years older than Part 1), and further revealed a small subset of eyes (10%) that did not respond to treatment.

Conclusions: DFCLs continue to slow the progression of myopia in children over a six-year period revealing an accumulation of treatment effect. Eye growth of the initial control cohort with DFCL was slowed by 71% over the subsequent 3-year treatment period.

Christian LW, Rose K, Opoku-Yamoah V, Jones D, Irving EL, McCulloch D, Leat S Changes in Canadian pediatric optometric vision care in a 14-year period 2022

Craig,J. P., Bitton,E., Dantam,J., Jones,L., Ngo,W., Wang,m. T. M Short-term tolerability of commercial eyelid cleansers: A randomised crossover study Contact Lens Anterior Eye 2022;45(6):101733 [ Show Abstract ]

To evaluate the short-term tolerability of five commercially available anti-demodectic eyelid cleansers; OCuSOFT Oust Demodex (OD), I-MED I-Lid’n Lash Plus (ILL+), Labtician BlephaDex (BD), Chrissanthe Eye Cleanse (EC), and Théa Blephademodex (BDdx).

Thirty healthy non-contact lens wearers (18 female; mean ± SD age, 33 ± 12 years) were enrolled in a prospective randomised crossover study. On separate visits, spaced at least 48 h apart, participants were randomised to receive topical application of one of five eyelid cleansers or saline. Participants rated subjective ocular discomfort during the 10-minute post-application period. Visual acuity, non-invasive tear film stability, conjunctival hyperaemia, and ocular surface staining were assessed at baseline and 10 min.

No inter-group differences in ocular parameters were noted at baseline (all p > 0.05). Ocular discomfort scores significantly exceeded baseline scores for 60 s following BD application, 120 s with OD, 135 s with BDdx, 150 s with ILL+, and 195 s with EC (all p < 0.05). Deterioration in non-invasive tear film stability, limbal conjunctival hyperaemia, as well as corneal, conjunctival, and lid margin staining was detected following EC application (all p < 0.05), and increased bulbar conjunctival hyperaemia was observed following both EC and ILL+ treatment (both p < 0.05).

Study outcomes highlight varying tolerability profiles with different anti-demodectic lid cleanser preparations, and the potential to induce tear film instability, conjunctival hyperaemia and ocular surface staining on application. Awareness of possible adverse effects arising from topical application of commercial anti-demodectic lid cleanser formulations may help clinicians set realistic patient expectations and encourage better compliance in their use of lid hygiene therapies.

Dare,E. V., Fung,C. K., McCanna,D. J., Subbaraman, L. V., Jones,L. W. Establishment of optimal culture media in corneal epithelial wound healing models Journal of Cellular Biotechnology 2022;8(1):1-12 [ Show Abstract ]

BACKGROUND: Wound healing needs to occur after injury to prevent vision loss. Models of wound healing need to be optimized to assure treatments for corneal wounds can be developed in vitro prior to investigating with in vivo studies.

OBJECTIVE: The purpose of this study was to establish the optimum media to use as a control solution in wound healing models.

METHODS: Immortalized human corneal epithelial cells were cultured in different growth media using a scratch and exclusion zone model. The effect of normoxic and hypoxic conditions on tight junctional integrity and metabolic activity of cells grown in different growth medium were also investigated.

RESULTS: Wound healing with DMEMF12 media was significantly faster than both Keratinocyte serum-free media (p < 0.05) and EpiLife (p < 0.05) after 10 hours recovery under normoxic or hypoxic conditions using the scratch model and 9 days after wounding using the exclusion zone technique (p < 0.05). Using the culture media DMEMF12, cells stained for abundant ZO-1, Cx43 and had a high metabolic activity indicating significant epithelial barrier formation, gap junction formation and high cell viability.

CONCLUSIONS: DMEMF12 led to superior wound healing under hypoxic and normoxic conditions and in two different wound healing models. © 2022-IOS Press. All rights reserved.

Desai,D. T., Maulvi,F. A., Desai,A. R., Shukla,M. R., Desai,B. V., Khadela,A. D., Shetty,K. H., Shah,D. O., Willcox,M. D. P. In vitro and in vivo evaluation of cyclosporine-graphene oxide laden hydrogel contact lenses International Journal of Pharmaceutics 2022;613121414 [ Show Abstract ]

Drug-eluting contact lens can substitute the multiple eye drop therapy. However, loading hydrophobic drug like cyclosporine in the contact lens is very challenging, due to low drug uptake (via soaking method); and alteration in the swelling and optical properties which restricts its clinical application. To address the above issues, graphene oxide (GO, large surface area with oxygen containing functional groups) was incorporated in the contact lenses during fabrication. These GO-laden contact lenses (SM-GO-Cys) as well as blank contact lenses (SM-Cys) were soaked in the solution of cyclosporine. Alternatively, cyclosporine-laden contact lenses (DL-Cys-20) and cyclosporine-GO-laden contact lenses (DL-Cys-20-GO) were fabricated by adding drug and drug-GO (at various level of GO) during fabrication, respectively. Contact angle and swelling data showed increase in water holding capacity of GO laden contact lenses. Optical property was significantly improved due to molecular dispersion of drug on the surface of GO sheets. The drug uptake and in vitro release profile was improved with GO-laden contact lenses by soaking method (SM-GO-Cys-400n) due to hydrophobic interactions between GO and drug. Adding cyclosporine-GO (DL-Cys-20-GO-800n) during fabrication significantly improved drug release kinetics with higher drug leaching (during extraction and sterilization) due to increased swelling, improved dissolution and molecular dispersion of drug on GO sheets. Ocular irritation and histopathological studies demonstrated the safety of GO-contact lens. The in vivo drug release studies in the rabbit eye showed significant improvement in mean residence time (MRT) and area under the curve (AUC) using DL-Cys-20-GO-800n contact lens compared to eye drop solution with reduction in protein adherence value. The study demonstrated that the incorporation of GO into the contact lens can control the release of cyclosporine as well as improved the lens swelling and transmittance properties.

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 2022;15(1):44-52 [ Show Abstract ]

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

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.

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).

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., 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 2022;45(2):Article 101515 [ Show 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.

Guthrie,S., Ng,A. Y., Woods,J., Vega,J., Orsborn,G., Jones,L. Exploring the factors which impact overall satisfaction with single vision contact lenses Contact Lens Anterior Eye 2022;45(5):101579 [ Show Abstract ]

To explore the impact of subjective factors (lens handling, comfort and vision) on overall single vision contact lens satisfaction.

Correlation analysis of a prospective, randomised, double-masked, bilateral crossover study involving 55 adapted lens wearers fitted with somofilcon A (SiHy) (clariti® 1 day, CooperVision) and etafilcon A (Hy) (1 DAY ACUVUE® MOIST, Johnson & Johnson Vision) was conducted. Subjective ratings of lens handling, comfort and vision collected after 1 week of lens wear for each lens type were correlated with overall satisfaction. Data were analysed by combining data for both lens types and also for each lens separately.

For the combined analysis, significant correlations (p < 0.01) were found between subjective ratings of overall satisfaction and ratings of handing for application (r = 0.64), handling for removal (r = 0.50), comfort upon application (r = 0.59), comfort at end of day (r = 0.61), overall satisfaction with comfort (r = 0.88) and overall satisfaction with vision (r = 0.64).

Correlation analysis of the per lens data showed that lens specific correlations of overall satisfaction with handling for lens application varied greatly with lens material (SiHy: r = 0.26, p = 0.05 vs Hy: r = 0.72, p < 0.01). Correlation strength of comfort upon application/at end of day with overall satisfaction also varied with lens material (Application: SiHy: r = 0.40 vs Hy: r = 0.61; End of day: SiHy: r = 0.76 vs Hy: r = 0.58; all p ≤ 0.01).

Overall satisfaction was significantly correlated with the specific subjective evaluations of handling, vision and comfort. Correlations of overall satisfaction and ease of handling for each lens type suggest that, for habitual contact lens wearers, dissatisfaction with handling at the time of lens application can play a major role in overall dissatisfaction with a lens. Handling for application had a similar correlation (r) value as vision, suggesting that handling for application should not be underestimated when considering overall patient satisfaction.

Kao,E. C. Y., Seo,J., McCanna,D. J., Subbaraman,L. N., Jones,L. In vitro assessment of the biocompatibility of chemically treated silicone materials with human lens epithelial cells Nature - Scientific Reports 2022;12(1):Article 4649 [ Show Abstract ]

Cytotoxicity testing is a regulatory requirement for safety testing of new ocular implants. In vitro toxicity tests determine whether toxic chemicals are present on a material surface or leach out of the material matrix. A method of evaluating the cytotoxicity of ocular implants was developed using fluorescent viability dyes. To assess the assay’s sensitivity in detecting toxic substances on biomaterials, zinc diethydithiocarbamate (ZDEC) and benzalkonium chloride (BAK) were deposited on silicone surfaces at different concentrations. Human lens epithelial cells (HLEC) were added to the surface of these treated silicone surfaces and were assessed for viability. The viability of both the adherent and non-adherent cells was determined using confocal microscopy with, annexin V, ethidium homodimer, and calcein. Cell metabolism was also evaluated using resazurin and the release of inflammatory cytokines was quantified using a multiplex Mesoscale Discovery platform. Confocal microscopy was shown to be a sensitive assay for evaluating material toxicity, as significant toxicity (p < 0.05) from ZDEC and BAK-treated surfaces compared to the untreated silicone control was detected. Patterns of cytokine release from cells varied depending on the toxin evaluated and the toxin concentration and did not directly correlate with the reduction in cell metabolic activity measured by alamarBlue.

Kapadia,W., Qin,N., Zhao,P., Phan,C.-M., Haines,L., Jones,L. Ren,C. L. Shear-Thinning and Temperature-Dependent Viscosity Relationships of Contemporary Ocular Lubricants Translational Vision Science & Technology 2022;11(3):Article 1 [ Show Abstract ]

Purpose: To evaluate the shear viscosity of contemporary, commercially available ocular lubricants at various shear rates and temperatures and to derive relevant mathematical
viscosity models that are impactful for prescribing and developing eye drops to treat dry eye disease.

Methods: The shear viscosity of 12 ocular lubricants was measured using a rheometer and a temperature-controlled bath at clinically relevant temperatures at which users may experience exposure to the drops (out of the refrigerator [4.3°C]; room temperature [24.6°C]; ocular surface temperature [34.5°C]). Three replicates for each sample at each temperature were obtained using a standard volume (0.5 mL) of each sample. The viscosity of each ocular lubricant was measured over the full range of shear rates allowed
by the rheometer.

Results: The shear viscosity of the same ocular lubricant varied significantly among the three temperatures. In general, a higher temperature resulted in smaller viscosities than a lower temperature (an average of −48% relative change from 4.3°C to 24.6°C and −21% from 24.6°C to 34.5°C). At a constant temperature, the viscosity of an ocular lubricant over the studied shear rates can be well approximated by a power-law model.

Conclusions: Rheological analysis revealed that the ocular lubricants exhibited shear-thinning behavior at the measured temperatures. Differences in the ocular lubricants’ formulations and measured temperatures resulted in different viscosities.

Translational Relevance: When prescribing eye drops, eye care professionals can select the optimal one for their patients by considering a variety of factors, including its
rheological property at physiologically relevant shear rates and temperatures, which can improve residence time on the ocular surface, while ensuring appropriate comfort and vision. However, care must be taken when using the derived mathematical models in this study because the in vivo shear behavior of the ocular lubricants has not been examined and might show deviations from those reported when placed on the ocular surface.

Khanal,S., Bai,Y., Ngo,W., Nichols,K. K., Wilson,L., Barnes,S., Nichols,J. J. Human meibum and tear film derived cholesteryl and wax esters in meibomian gland dysfunction and tear film structure: Cholesteryl and wax esters in meibomian gland dysfunction Ocular Surface 2022;23(January):12-23 [ Show Abstract ]

This study evaluated the presence and roles of cholesteryl esters (CEs) and wax esters (WEs) from human tear film and meibum in meibomian gland dysfunction (MGD).

Out of 195 enrolled subjects, 164 and 179 subjects provided tear and meibum samples, respectively. Subjects were classified into normal, asymptomatic MGD, MGD, and mixed (MGD & aqueous deficient). The precorneal tear film (PCTF) thinning rate (evaporation) was measured using optical coherence tomography. Lipids extracted from tear and meibum samples were infused into a SCIEX 5600 TripleTOF mass spectrometer. CE and WE intensities quantified with Analyst 1.7 TF and LipidView 1.3 were compared across disease groups in MetaboAnalyst 5.0 and correlated with PCTF thinning rates.

The numbers of unique CEs and WEs identified in the samples were 125 and 86, respectively. Unsupervised Principal Component (PC) analysis and supervised Partial Least Square Discriminant analysis exhibited little separation among groups for both CEs and WEs in tears and meibum. Spearman's correlation analyses showed no association between either the first or second PC scores with PCTF thinning rates.

The abundances of human PCTF and meibum-derived CEs and WEs were independent of MGD disease status and PCTF thinning (evaporation). CEs and WEs alterations do not contribute to alterations in tear film dynamics in MGD, such as has been demonstrated by the (O-acyl) ω-hydroxy fatty acids (OAHFAs).

Leat,S. J., Saraf,A., Rose,K., Christian,L. W., Irving,E. L., Jones, D. A., McCulloch, D. L. Measuring recognition visual acuity in young children–testability with the Waterloo Differential Acuity Test (WatDAT) Clinical and Experimental Optometry 2022;Online ahead of print [ Show Abstract ]

Clinical relevance: Visual acuity measurement is important for the detection and monitoring of eye disorders. Developing accurate and sensitive visual acuity tests suitable for young children is therefore desirable.

Background: Recognition or form visual acuity (VA), which is measured with matching in children aged 3 years and up, is more sensitive for detecting visual deficits compared to resolution VA. The Waterloo Differential Acuity Test (WatDAT) is a proposed recognition VA test using the concept of identifying the "odd one out" among distractors. The WatDAT is expected to be cognitively easier than matching tests and therefore may be used in younger children. The purpose of this study is to investigate the testability of the WatDAT paradigm in children aged 12-36 months, and to determine the optimum format and number of distractors.

Methods: Fifty-one typically-developing children aged 12-36 months participated in the study. Data for Patti Pics (PP) and Face targets (FT) were collected for formats with 3, 4 and 5 distractors. The targets were presented binocularly on a computer touch screen at 30 cm. The task was to touch the face among identical non-faces or a house among circles. Following initial training, there were 5 presentations for each distractor format. Testability was defined as correctly identifying at least 4/5 presentations and was also determined for uncrowded PP symbols using matching.

Results: Of participants aged 18-36 months, 87% could perform the WatDAT PP targets with 3 distractors compared to 68% for the FT, while 48% could perform matching with PP. The testability for FT increased to 85% for children ≥22 months. Younger children showed lower testability. For the 3 distractor format, PP targets gave 9% testability in children 12 to <18 months, and FT gave a testability of 16% in children 12 to <22 months.

Conclusion: WatDAT testability is higher than matching VA tests. This indicates that the newly developed WatDAT has potential for measuring recognition VA in children 18 months and older.

Leat,S., Saraf,A., Rose,K., Christian,L., Irving,E., Jones,D., McCulloch,D Measuring recognition in young children - testability with the Waterloo Differential Acuity Test (WatDAT) Clinical and Experimental Optometry 2022;Online ahead of print [ Show Abstract ]

Clinical relevance
Visual acuity measurement is important for the detection and monitoring of eye disorders. Developing accurate and sensitive visual acuity tests suitable for young children is therefore desirable.

Recognition or form visual acuity (VA), which is measured with matching in children aged 3 years and up, is more sensitive for detecting visual deficits compared to resolution VA. The Waterloo Differential Acuity Test (WatDAT) is a proposed recognition VA test using the concept of identifying the “odd one out” among distractors. The WatDAT is expected to be cognitively easier than matching tests and therefore may be used in younger children. The purpose of this study is to investigate the testability of the WatDAT paradigm in children aged 12–36 months, and to determine the optimum format and number of distractors.

Fifty-one typically-developing children aged 12–36 months participated in the study. Data for Patti Pics (PP) and Face targets (FT) were collected for formats with 3, 4 and 5 distractors. The targets were presented binocularly on a computer touch screen at 30 cm. The task was to touch the face among identical non-faces or a house among circles. Following initial training, there were 5 presentations for each distractor format. Testability was defined as correctly identifying at least 4/5 presentations and was also determined for uncrowded PP symbols using matching.

Of participants aged 18–36 months, 87% could perform the WatDAT PP targets with 3 distractors compared to 68% for the FT, while 48% could perform matching with PP. The testability for FT increased to 85% for children ≥22 months. Younger children showed lower testability. For the 3 distractor format, PP targets gave 9% testability in children 12 to <18 months, and FT gave a testability of 16% in children 12 to <22 months.

WatDAT testability is higher than matching VA tests. This indicates that the newly developed WatDAT has potential for measuring recognition VA in children 18 months and older.

Lourenco Nogueira,C., Boegel,S. C., Shukla,M., Ngo,W., Jones,L., Aucoin,M. G. Antiviral Activity of Contemporary Contact Lens Care Solutions against Two Human Seasonal Coronavirus Strains Pathogens 2022;11(4):472 [ Show Abstract ]

Background: Given that reports have suggested SARS-CoV-2 can be transmitted via conjunctiva, the ability of contact lens (CL) care products to reduce the infectiousness of two seasonal human coronavirus (HCoV) (HCoV-229E and HCoV-OC43) surrogates for SARS-CoV-2 was investigated.

Methods: Biotrue and Boston Simplus (Bausch&Lomb), OPTI-FREE Puremoist and Clear Care (Alcon), and cleadew and cleadew GP (Ophtecs) were tested. Their ability to inactivate HCoV was evaluated using contact times of 4 and 6 h as well as 1% and 10% of virus inoculum.

Results: Non-oxidative systems (Biotrue, Boston Simplus, and OPTI-FREE) did not exhibit a significant log10 reduction compared to controls for the two viral strains for either incubation time (all p > 0.05) when 10% tests were performed. For the 1% test, while Boston Simplus and OPTI-FREE exhibited a significant log10 reduction of both HCoV-229E (after 6 h) and HCoV-OC43 (after either 4 or 6 h incubation), those products showed less than 1 log10 reduction of the two infectious viruses. Oxidative systems based on hydrogen peroxide or povidone-iodine showed a significant log10 reduction compared with the controls for both HCoV-229E and HCoV-OC43 in all tested conditions (all p < 0.01). Clear Care led to virus inactivation to below the limit of quantification for tests performed with 1% of inoculum after 6 h incubation, while cleadew and cleadew GP led to inactivation of the two viruses to below the limit of quantification in all tested conditions.

Conclusion: Oxidative CL disinfection systems showed significant virucidal activity against HCoV-229E and HCoV-OC43, while non-oxidative systems showed minimal ability to inactivate the HCoV species examined.

Lourenco Nogueira,C., Boegel,S. C., Shukla,M., Ngo,W., Jones,L. Aucoin,M. G. The impact of a rub and rinse regimen on removal of human coronaviruses from contemporary contact lens materials Contact Lens Anterior Eye 2022;45(6):101719 [ Show Abstract ]

To assess the influence of contemporary contact lens (CL) materials on human coronavirus attachment and the influence of a rub and rinse step to remove these viruses.

The binding rates of HCoV-229E and HCoV-OC43 to eight soft CL materials and four rigid gas permeable materials were analyzed. The impact of a rub and rinse step to remove these viruses from all materials was examined. The efficacy of Biotrue (Bausch & Lomb), OPTI-FREE Puremoist (Alcon), Clear Care (Alcon) and cleadew (Ophtecs) to remove virus contamination from two representative soft lens materials (etafilcon A and lotrafilcon B) was also determined.

Approximately 102 to 103 infectious viral particles were recovered from each CL material. Although some materials were more prone to coronavirus adhesion, contamination of both viral types was reduced to below the limit of quantification (LQ) from all materials using a simple saline rinse step. Exposure to Clear Care and cleadew reduced the number of infectious viral particles from both etafilcon A and lotrafilcon B to below the LQ, while for Biotrue and OPTI-FREE Puremoist, infectious viral particles were reduced to below the LQ only when additional rub and rinse steps were included.

Human coronavirus contamination can be easily removed from CL surfaces. Although CL care products containing hydrogen peroxide and povidone-iodine efficiently removed virus contamination from CL surfaces without the need for a rub and rinse step, a full regimen including rub and rinse steps is crucial when using CL care products based on non-oxidative systems.

Luensmann,D., Schaeffer,J. L., Rumney,N. J., Stanberry,A., Fonn,D. Magnitude of astigmatism – A comparison between eyes Contact Lens Anterior Eye 2022;45(5):101510 [ Show Abstract ]

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.

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.

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.

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.

Nagaarudkumaran,N., Mirzapur,P., McCanna,D. J., Ngo,W. Temporal Change in Pro-Inflammatory Cytokine Expression from Immortalized Human Corneal Epithelial Cells Exposed to Hyperosmotic Stress Current Eye Research 2022;Online ahead of print [ Show Abstract ]

To determine the metabolic activity, and cytokine expression over time from immortalized human corneal epithelial cells (HCECs) exposed to hyperosmotic stress.

HCECs were cultured and expanded in DMEM/F-12 with 10% FBS. The cells were exposed to either normal media (295 mmol/kg) or hyperosmolar media (500 mmol/kg) for 0.25, 3, 6, and 12 hours. After each exposure duration, metabolic activity was quantified using alamarBlue, and a panel of pro-inflammatory cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α, IFN-γ, and IL-17A) was quantified using multiplexed electrochemiluminescence (Meso Scale Diagnostics, Rockville, MD).

Metabolic activity of the HCEC exposed to hyperosmolar conditions was significantly reduced at the 3-, 6-, and 12-hour mark compared to the control (all p < 0.01). There was no significant difference in cytokine expression between the hyperosmolar media and control at the 0.25- and 3-hour mark for all cytokines (all p ≥ 0.28). The difference in cytokine expression between the hyperosmolar media and the control was significant for IL-1β, IL-4, IL-6, IL-8, IL-12p70, IL-13, and TNF-α at the 6-hour mark (all p ≤ 0.02). No significant change in cytokine expression between the hyperosmolar media and control was noted for IL-2, IL-10, IL-17A, and IFN-γ (all p ≥ 0.74) at the 6-hour mark.

Hyperosmolar stress reduced cell metabolic activity and increased expression of IL-1β, IL-4, IL6, IL8, IL-12p70, IL-13, and TNF-α over a 6-hour period in an immortalized HCEC line.

Ng,A. Y., Woods,J., Jahn,T., Jones,L., Ritter,J. Effect of a novel omega-3 and omega-6 fatty acid supplement on dry eye disease: a 3-month randomized controlled trial Optometry & Vision Science 2022;99(1):67-75 [ Show Abstract ]

Supplementing diet with a novel combination of omega-3 and omega-6 fatty acids significantly improved symptoms in extremely symptomatic participants with dry eye disease (DED).

This study aimed to determine the effect of daily intake of a novel combination of essential fatty acids on signs and symptoms of DED.

Participants with moderate to severe DED were enrolled in a prospective, randomized, double-masked parallel group study. Participants ingested either the treatment supplement containing omega-3 and omega-6 fatty acids (1200 mg eicosapentaenoic acid, 300 mg docosahexaenoic acid, 150 mg γ-linoleic acid) or the placebo (coconut and olive oil) daily for 3 months. To determine compliance, Omega-3 Index blood tests were conducted. At baseline and at 1 and 3 months, the following assessments were conducted: Ocular Surface Disease Index (OSDI) questionnaire and Symptom Assessment Questionnaire in Dry Eye, noninvasive tear breakup time, tear meniscus height, tear osmolarity, ocular redness, surface staining, Schirmer test, and meibography.

Fifty participants (mean ± standard deviation baseline OSDI score, 52.2 ± 16.5) completed the study: 24 randomized to treatment and 26 randomized to placebo. Although there was an improvement in OSDI score at 3 months for both groups (treatment: −13.4 points, P = .003; placebo: −7.8 points, P = .02), participants with baseline OSDI scores >52 demonstrated an even larger significant improvement in symptoms with the treatment at 3 months compared with baseline (n = 13, −20.8 points, P = .002). There were no significant changes in any of the ocular assessments at 1 or 3 months (all P > .05). After 3 months, Omega-3 Index increased by 34% in the treatment group (baseline, 5.3 ± 0.8; 3 months, 8.0 ± 2.1; P < .001) and did not change in the placebo group (baseline, 4.8 ± 0.8; 3 months, 4.8 ± 0.6; P = .95).

Supplementation with eicosapentaenoic acid, docosahexaenoic acid, and γ-linoleic acid resulted in a significant and clinically meaningful improvement of dry eye symptoms in extremely symptomatic participants with DED (OSDI ≥52).

Nichols,J. J., Morgan,P. M., Efron,N, Jones,L. W. Global optometrist research ranking derived from a science-wide author database of standardised citation indicators Clinical and Experimental Optometry 2022;105(1):20-25 [ Show Abstract ]

Clinical relevance
Publications in refereed scientific journals provide a rigorous research base that underpins clinical optometric practice. Leading optometrists who generate this literature can be identified and ranked using standardised citation indicators.

This work seeks to identify and rank all optometrists included in a Science-Wide author database of standardised citation indicators (S-W) and to compare this ranking with the Global Optometrist Top 200 Research Ranking (T200).

A search was conducted for the names of all optometrists in the T200 who were included in the S-W, which is a world-wide listing of the top 2% of scientists in each of 174 subfield disciplines, ranked according to a composite citation indicator (cns) that excludes self-citations and corrects for multiple authorships and author order.

The names of 66 optometrists are found in the S-W. Of these, 58 are designated as working in the primary sub-field ‘Ophthalmology & Optometry’; this listing, in rank-order of cns, is referred to as the ‘S-W-derived Optometrist Research Ranking’ (S-WORR). Australian optometrist Nathan Efron is ranked #1 in the S-WORR. The number (%) of optometrists in the S-WORR from each country is: the United States – 26 (45%), Australia – 12 (21%), the United Kingdom – 11 (19%), Canada – 5 (9%), Spain – 2 (3%), Hong Kong – 1 (2%) and South Africa – 1 (2%). The universities housing the equal highest number of optometrists in the S-WORR (five each) are the University of California, Berkeley, USA; the University of New South Wales, Australia; and Queensland University of Technology, Australia. There is a moderately strong correlation between T200 and S-WORR rankings (ρ = 0.6017, N = 58, p < 0.0001).

The S-WORR represents an elite cohort of optometrists who ought to be celebrated for their outstanding, leading and impactful contributions to optometric research.

Osae,E. A., Jones,L., Nichols,J. J. The impact of contact lenses on meibomian gland morphology Ocular Surface 2022;24(April):148-155 [ Show Abstract ]

Despite years of experience with contact lenses, controversy remains as to whether contact lenses adversely impact the meibomian glands (MG). This review summarizes the present body of evidence, showing that contact lens wear is associated with alterations in MG morphology (up to 80% higher gland atrophy compared to non-wearers) and qualitative changes in MG secretion. Key factors such as duration of contact lens wear, contact lens type (e.g., soft vs. rigid), edge design, and material modulus of elasticity are discussed in relation to the extent of MG morphological changes, the quality of MG secretion and other ocular surface parameters. Longitudinal studies of sufficient statistical power are needed to better understand how contact lens wear affects the MG, risk factors, and the clinical sequelae of these changes.

Pereira-da-Mota,A. F., Phan,C-M., Concheiro,A., Jones,L., Alvarez-Lorenzo,C. Testing drug release from medicated contact lenses: The missing link to predict in vivo performance Journal of Controlled Release 2022;343(March):672-702 [ Show Abstract ]

Contact lenses (CLs) offer a wide variety of advantages as ocular drug-releasing platforms, but the feasibility of medicated CL development is constrained by numerous scientific, technological, and regulatory challenges. One main difficulty is the setting of release rate specifications for each drug, since at present there are no standardized in vitro release models that can appropriately predict the performance of drug-eluting CLs once placed onto the eye. CL-adapted release tests may provide knowledge on how the drug release pattern should perform in vivo to trigger and maintain the therapeutic effects for both anterior and posterior ocular tissues. Moreover, in vitro release tests are valuable tools for quality assessment during production and to investigate the effect of a change in composition or process variables. This review aims to shed light on biorelevant ways of evaluating in vitro drug release from CLs and the feasibility of establishing in vitro-in vivo correlations (IVIVC) to predict in vivo performance. First, general guidelines and Pharmacopeia release tests for topical ophthalmic formulations as well as in vitro release tests implemented for drug-CLs in the last two decades are analyzed. Then, development of an appropriate method to investigate IVIVC is attempted from the few papers simultaneously reporting in vitro release profiles and either in vivo release or therapeutic response. Finally, key points to be considered for in vitro testing drug release from a medicated CL are suggested to pave the way to the clinical arena.

Pereira-da-Mota,A. F., Vivero-Lopez, M., Garg,P., Phan,C-M., Concheiro,A., Jones,L., Alvarez-Lorenzo,C. In vitro–in vivo correlation of drug release profiles from medicated contact lenses using an in vitro eye blink model Drug Delivery and Translational Research 2022;Online ahead of print [ Show Abstract ]

There is still a paucity of information on how in vitro release profiles from drug-loaded contact lenses (CLs) recorded in 3D printed eye models correlate with in vivo profiles. This work aims to evaluate the release profiles of two drug-loaded CLs in a 3D in vitro eye blink model and compare the obtained results with the release in a vial and the drug levels in tear fluid previously obtained from an animal in vivo study. In vitro release in the eye model was tested at two different flow rates (5 and 10 µL/min) and a blink speed of 1 blink/10 s. Model CLs were loaded with two different drugs, hydrophilic pravastatin and hydrophobic resveratrol. The release of both drugs was more sustained and lower in the 3D eye model compared to the in vitro release in vials. Interestingly, both drugs presented similar release patterns in the eye model and in vivo, although the total amount of drugs released in the eye model was significantly lower, especially for resveratrol. Strong correlations between percentages of pravastatin released in the eye model and in vivo were found. These findings suggest that the current 3D printed eye blink model could be a useful tool to measure the release of ophthalmic drugs from medicated CLs. Nevertheless, physiological parameters such as the composition of the tear fluid and eyeball surface, tear flow rates, and temperature should be optimized in further studies.

Rueff,E., Tichenor,A. A., Ngo,W., Pucker,A. D. A review of meibomian gland structure, function, and contact lens wear Contact Lens Anterior Eye 2022;45(5):101560 [ Show Abstract ]

Purpose: To provide a balanced literature review of the studies that have evaluated the effect of contact lenses on meibomian gland (MG) health.

Methods: A literature search was conducted on or before May 15, 2021. No other time constraints were applied. Search terms included the following: "meibomian gland(s)" plus "contact lens(es)" or "meibography" plus "contact lens(es)". Only full text articles written in English were considered. The reference lists of recovered papers were used to identify articles missed during the primary search. Included articles were required to discuss the impact of contact lenses on MG morphology or function and were graded according to the level of evidence presented.

Results: The literature indicates that contact lenses impact MG function; however, the data are equivocal regarding contact lenses inducing MG structural changes. The literature likewise indicates that the mechanism(s) by which contact lenses impact the MGs are likely multifactorial. Recent data suggests that MGs may have some plasticity. Detected differences between studies likely stem from varied populations evaluated, study designs, and the duration of the evaluation periods.

Conclusions: With this literature review finding conflicting relationships between MG health and contact lens use, future longitudinal studies with standardized clinical MG assessments are needed to determine the true impact of contact lenses on MG health. Until these data are obtained, contact lens wearers should undergo a full MG evaluation, especially because recent data suggest that MG treatments may restore MG structure and function.

Thite,N., Desiato,A., Shinde,L., Wolffsohn,J. S., Naroo,S. A., Santodomingo Rubido,J., Cho,P., Jones,D., Villa-Collar,C., Carrillo,G., Chan,O., Wang,H., Iomdina,E., Tarutta,E., Proskurina,O., Fan,C. S., 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., Maseedupally,V., Bhattarai,Y., Nagzarkar,D., Brauer,P., Gil-Cazorla,R. Differences in Practitioner Experience, Practice Type, and Profession in Attitudes Toward Growing Contact Lens Practice Eye & Contact Lens 2022;48(9):369-376 [ Show Abstract ]

Objective: To investigate eye care practitioners' attitudes and perceptions toward potential interventions that can enhance contact lens (CL) practice across the world, and how this is influenced by their practice setting.

Methods: A self-administered, anonymized survey was constructed in English and then forward and backward translated into six more languages. The survey was distributed online via social media platforms and mailing lists involving reputed international professional bodies.
Results: In total, 2,222 responses from 27 countries with sufficient responses were analyzed (53% females, median age- 37 years). Most of the respondents were optometrists (81.9%) and 47.6% were from stand-alone/independent practices. Median working experience in CL prescribing was 11.0 years (IQR: 18.0, 4-22 years). Over two-third of them declared themselves to be very hopeful (22.9%) or hopeful (45.1%) about the future of their CL practice. Among the potential interventions proposed, continuous update of knowledge and skills and competently managing CL-related complications were rated the most important (median score: 9/10 for each). Practitioners working in national/regional retail chains expressed higher proactivity in recommending CLs (9/10) than those in local chains, hospitals, and universities (for all 8/10, P<0.05). National differences were also identified in eye care practitioner attitudes and perceptions (P<0.05).

Conclusions: The study provided important information to delineate a variety of elements characterizing CL practice across the world. These insights can serve as a basis to design strategies at national and international levels

von Ahrenschildt,A., Hanneberg,L., Robich,M., Jones-Jordan,L., Marx,S., Sickenberger,W., Powell,D., Kwan,J. T., Wong,S., Srinivasan,S., Jones,L., Pucker,A. D. Morphological characteristics of Meibomian Glands and their Influence on Dry Eye disease in contact lens wearers Ocular Surface 2022;24(April):93-99 [ Show Abstract ]

Meibomian glands (MG) are now easily imaged via clinical meibography machines. The purpose of this work was to explore the utility of the known MG morphology metrics for predicting dry eye disease (DED) in contact lens (CL) wearers.

Successful and previous CL wearers were recruited. DED was diagnosed if the participant's worst eye had a reduced tear meniscus height (TMH) of <0.2 mm or non-invasive tear break-up time (NITBUT) of [removed]5.0. Meibography was performed and images were subjectively graded by two examiners for the following MG characteristics: distorted, tortuous, hooked, abnormal gap, overlapping, fluffy areas, tadpoling, thinned, thickened, ghost, no extension to lid margin, shortened and dropout (atrophy). DED diagnostic ability of each metric was determined with receiver operating characteristic (ROC) analysis.

A total of 112 participants were recruited, with 18.8% having DED and 60.7% being female. The only MG morphology metrics that were marginally predictive of DED were thickened upper eyelid MGs (p = 0.046), thickened mean upper plus lower eyelid MGs (p = 0.007), and atrophy of upper eyelid MGs (p = 0.043); however, none of these metrics reached a meaningful area under the curve in ROC analysis (all <0.70).

While abnormal MG morphology is likely suggestive of DED in CL wearers, none of the MG morphology metrics evaluated alone in this study had clinically meaningful predictive value for detecting DED in this group of current and previous CL wearers.

Walsh,K., Jones,L., Moody,K. Addressing common myths and misconceptions in soft contact lens practice Clinical and Experimental Optometry 2022;105(5):459-473 [ 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.

Wolffsohn,J. S., Dhallu,S., Aujla,M., Laughton,D., Tempany,K., Powell,D., Gifford,K., Gifford,P., Wan,K., Cho,P, Stahl,U., Woods,J. International multi-centre study of potential benefits of ultraviolet radiation protection using contact lenses Contact Lens Anterior Eye 2022;Online ahead of print [ Show Abstract ]

To examine the effects of long-term ultraviolet radiation (UVR) blocking wearing contact lenses on ocular surface health, eye focus and macular pigment.

210 pre-presbyopic patients were recruited from Birmingham UK, Brisbane Australia, Hong Kong China, Houston USA and Waterloo Canada (n = 42 at each site). All patients had worn contact lenses for ≥ 5 years, half (test group) of a material incorporating a UVR-blocking filter. Ocular health was assessed using slit-lamp biomicroscopy and UV autofluorescence. Accommodation was measured subjectively with a push-up test and overcoming lens-induced defocus. Objective stimulus response and dynamic measures of the accommodative response were quantified with an open-field aberrometer. Macular pigment optical density (MPOD) was assessed using heterochromatic flicker photometry (MPS II).

The two groups of participants were matched for age, sex, race, body-mass-index, diet, lifestyle, UVR exposure, refractive error and visual acuity. Limbal (p = 0.035), but not bulbar conjunctival redness (p = 0.903) was lower in eyes that had worn UVR-blocking contact lenses compared to controls. The subjective (8.0 ± 3.7D vs 7.3 ± 3.3D; p = 0.125) and objective (F = 1.255, p = 0.285) accommodative response was higher in the test group, but the differences did not reach significance. However, the accommodative latency was shorter in eyes that had worn UVR-blocking contact lenses (p = 0.003). There was no significant different in MPOD with UVR filtration (p = 0.869).

Blocking the transmission of UVR is beneficial in maintaining the eye’s ability to focus, suggesting that presbyopia maybe delayed in long-term UVR-blocking contact lenses wearers. These lenses also provide protection to the critical limbal region.

Yee,A., Phan,C-M., Jones,L. Uptake and release of polyhexamethylene biguanide (PHMB) from hydrogel and silicone hydrogel contact lenses using a radiolabel methodology Contact Lens Anterior Eye 2022;Online ahead of print [ Show Abstract ]

The purpose of this study was to evaluate the uptake and release of radiolabelled polyhexamethylene biguanide (PHMB) on reusable daily wear contact lenses (CLs) over 7 days.

Three silicone hydrogel (SH) contact lens materials (lotrafilcon B, balafilcon A, senofilcon A) and two conventional hydrogel (CH) materials (etafilcon A, omafilcon A) were examined. In experiment 1 (1-day study), CLs were soaked in 2 mL of phosphate buffered solution (PBS) containing radiolabelled 14C PHMB (1 µg/mL) for 8 h. The release kinetics of 14C PHMB from the CLs was measured at t = 0.25, 0.5, 1, 2, 4, 8, and 24 h in fresh 2 mL PBS. In experiment 2 (7-day study), the CLs were soaked in the 14C PHMB (1 µg/mL) solution for 8 h followed by a 16-hour release in 2 mL PBS. The lens cycle was repeated daily for 7 days. After both experiments, the residual amount of PHMB remaining within the lenses was extracted to determine the total uptake of PHMB.

In experiment 1, the total uptake of PHMB for etafilcon A was significantly greater than senofilcon A (p = 0.01). There were no significant differences in total uptake of PHMB between other lens materials (p > 0.05). Etafilcon A released more PHMB compared to all other lens types over a 24-hr period (p < 0.001). In experiment 2, all CL materials continued to sorb more PHMB over time (p < 0.001). By day 7, the amount of PHMB sorbed by etafilcon A was significantly greater than senofilcon A (p = 0.02). After day 2, the CH materials released significantly more PHMB than the SH materials (p < 0.01).

The CL materials continued to sorb PHMB with no signs of saturation after 7 days. All lens materials released a consistent amount of PHMB each day. Radioactive labelling provides a sensitive method of assessing the uptake and release of PHMB from CL materials.