Publications by authors named "Eric Papas"

79 Publications

Filaggrin Expression in the Lid Margin During Contact Lens Wear.

Eye Contact Lens 2021 Jun 22. Epub 2021 Jun 22.

Department of Optometry (W.A.), College of Applied Medical Science, Qassim University, Qassim, Saudi Arabia; and School of Optometry & Vision Science (W.A., M.M., E.P.), University of New South Wales, Sydney, Australia.

Aim: To investigate the expression of the keratinization-related protein, filaggrin, in the lid margin epithelium of contact lens (CL) wearers compared with nonwearers.

Methods: This was a cross-sectional study of 100 individuals with different exposures to CL wear: short, moderate, and long experience; previous CL wearers; and nonwearers as controls. Impression cytology samples were collected from the lid wiper (LW) area of the central upper lid margin. After fixing, an equal, random sample was selected from each group (n=13) for immunocytochemistry analysis using antihuman primary anybody (mouse filaggrin), then stained with secondary antibody (fluorescein isothiocyanate-conjugated donkey anti-mouse immunoglobulin G horseradish peroxidase) to detect filaggrin. Imaging was performed with the 3i-Vivo 2-photon microscope equipped with a Zeiss 20×-objective and SlideBook-reader software.

Results: Sixty-five samples from 65 participants (37 women; mean age±SD: 25.1±4.1 years) were collected. Filaggrin was detected in all 65 randomly selected immunostained marginal epithelium samples. All samples were similar in showing patchy areas of filaggrin immunostaining, regardless of CL wear, symptoms or epithelium morphology. Because the filaggrin immunostaining showed similar patterns across almost all the observed samples, comparison between subject groups was impractical. The presence of filaggrin in the healthy LW was additionally confirmed by an independent laboratory.

Conclusion: Filaggrin expression seems to be a normal part of epithelial cell differentiation in the lid margin and may not be a useful keratinization/stress biomarker in the marginal epithelium. Investigating other keratinization biomarkers that are not detected in the normal mucocutaneous junction/LW may help to understand the keratinization nature of LW epithelium changes in CL wearers.
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http://dx.doi.org/10.1097/ICL.0000000000000805DOI Listing
June 2021

Photobiomodulation (low-level light therapy) and dry eye disease.

Clin Exp Optom 2021 Jul 27;104(5):561-566. Epub 2021 Feb 27.

School of Optometry & Vision Science, University of New South Wales, Sydney, Australia.

Dry eye disease is one of the most common, chief-complaints presenting in clinical practice, with a prevalence of up to 50%. Evaporative dry eye, as a result of meibomian gland dysfunction, is thought to be the biggest component factor. Treatments for meibomian gland dysfunction aim to restore tear film homoeostasis and include warm compress therapy, eyelid hygiene, in-office meibomian gland expression and lipid-containing, artificial tears. A recent introduction to the in-office treatments available for meibomian gland dysfunction has been low-level light therapy, also known as photobiomodulation. The technique involves applying red, or near infra-red, radiation using low-power light sources and is suggested to promote tissue repair, decrease inflammation, and relieve pain. This work aims to review the available literature on the efficacy and safety of photobiomodulation in meibomian gland dysfunction and dry eye disease, as well as what is currently known about its mechanism of action.
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http://dx.doi.org/10.1080/08164622.2021.1878866DOI Listing
July 2021

Temporal considerations in contact lens discomfort.

Cont Lens Anterior Eye 2021 Feb 29;44(1):14-17. Epub 2020 Aug 29.

School of Optometry & Vision Science, University of New South Wales, Sydney, Australia.

Purpose: To determine the relative contributions to perceived discomfort during contact lens wear of contact time with the lens and the time of day at which wear begins, using a wearing framework similar to that of regular users.

Methods: Twenty-three participants reported ocular discomfort using a 1-100 visual analogue rating scale, when prompted by email, during one day without contact lenses and on three other days while wearing soft contact lenses for twelve hours. Contact lens wear began at a different time on each day. The effect of start time on the change in discomfort during the wearing period was evaluated.

Results: The average (± 95 % CI) change in discomfort over 12 h without contact lenses was -0.3 ± 3.5. The corresponding values during contact lens wear were 23.5 ± 14.6 when starting wear before 8am, 16.8 ± 11.0 when starting between 8am & 10am and 22.7 ± 8.4 when starting after 10am. While the increased discomfort was significant irrespective of start time (p < 0.01), there were no statistically significant differences between start times (p = 0.98).

Conclusion: Discomfort during contact lens wear is associated with the length of time lenses are on-eye but not with the time of day when lenses are placed on-eye. This relationship is variable in the population and does not, of itself, explain why contact lenses become uncomfortable during wear. Active monitoring of participant compliance should be a consideration in all studies involving time critical responses.
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http://dx.doi.org/10.1016/j.clae.2020.08.007DOI Listing
February 2021

Changes in the tarsal conjunctiva viewed by in vivo confocal microscopy are associated with ocular symptoms and contact lens wear.

Ophthalmic Physiol Opt 2019 09 28;39(5):328-336. Epub 2019 Aug 28.

School of Optometry & Vision Science, University of New South Wales, Sydney, Australia.

Purpose: To investigate the effect of soft contact lens (CL) wear on the morphology of the epithelial-lamina propria junction as well as the possible association with symptoms of discomfort.

Methods: Ninety-two subjects were recruited, including 60 soft CL wearers, 16 previous wearers, and 16 non-wearers. Additionally, subjects were classified as symptomatic or asymptomatic using the Contact Lens Dry Eye Questionnaire 8 for the CL wearers (a score ≥ 12 was considered symptomatic) and the Dry Eye Questionnaire 5 for the previous wearers and non-wearers (a score ≥ 5 was considered symptomatic). In vivo confocal microscopy of the tarsal conjunctiva was performed on a single occasion. Papillae density, shortest diameter, longest diameter, area, circularity, lumen/wall brightness ratio, irregularity, reflectivity, inhomogeneous appearance of wall and inhomogeneous appearance of rete ridges were evaluated. Effects of CL wear, symptoms and their interaction were analysed using two-way analysis of variance. Correlations were investigated using Spearman's coefficient. Data are presented as mean (standard deviation) or median [interquartile range].

Results: Contact lens wearers, compared to previous wearers and non-wearers, showed higher circularity [0.65 (0.08) vs 0.59 (0.10) vs 0.57 (0.11), p = 0.003]. Subjects with symptoms, compared to asymptomatic participants, showed higher circularity [0.64 (0.08) vs 0.61 (0.10), p < 0.001] and lower irregularity (1.0 [0.7-2.0] vs 1.3 [1.0-2.3], p = 0.009). For previous wearers, those with symptoms showed greater density (135.4 [107.3-183.3] vs 87.5 [85.4-116.7], p = 0.013) and circularity [0.64 (0.07) vs 0.54 (0.10), p = 0.016]. For non-wearers, those with symptoms showed higher circularity [0.65 (0.08) vs 0.50 (0.08), p < 0.001]. DEQ-5 correlated with circularity (ρ = 0.55, p = 0.001).

Conclusions: Soft CL wear modifies papillae of the epithelial-lamina propria junction into a more rounded shape; however, CL cessation appears to resolve this alteration. Additionally, a more rounded papillae shape is associated with ocular symptoms in subjects not actively wearing CLs.
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http://dx.doi.org/10.1111/opo.12638DOI Listing
September 2019

The relationship between tear film MMP-9 and meibomian gland changes during soft contact lens wear.

Cont Lens Anterior Eye 2020 04 6;43(2):154-158. Epub 2019 Aug 6.

School of Optometry & Vision Science, University of New South Wales, Sydney, Australia.

Purpose: To investigate the association between levels of MMP-9, a common marker of inflammation in tears, and changes to the meibomian glands accompanying soft contact lens (CL) wear.

Methods: Flush tears were collected from: (1) three groups of CL wearers who had worn CLs on a daily basis for different durations (Short: 2 ± 1 years, Moderate: 5 ± 1 years and Long experience: 10 ± 2 years); (2) a group of previous CL wearers (PWs) who had ceased wear for at least 6 months; and (3) healthy non-wearers (NW) as a control group. Total MMP-9 and its inhibitor, tissue inhibitor of MMPs-1 (TIMP-1) concentration were established using sandwich enzyme-linked immunosorbent assay. The MMP-9: TIMP-1 ratio was calculated for every individual, and then the average of all ratios for each group were compared. The non-parametric statistical Kruskal Wallis one-way analysis of variance was used for comparison, with Dunn's testing post-hoc.

Results: Tear samples from 100 participants (51 females; mean age ± SD: 25.4 ± 4.1 years) were analysed. MMP-9 concentrations and MMP-9:TIMP-1 ratio were significantly different between groups (Kruskal Wallis p = 0.001 and p < 0.001 respectively), while the concentration of TIMP-1 did not vary statistically between study groups (Kruskal Wallis, p = 0.32). Post hoc analysis indicated that only CL wearers with short experience had MMP-9 concentrations that were significantly high compared to NWs (23.1 ± 17.9 ng/mL and 4.1 ± 4.1 ng/mL, respectively, Dunn p < 0.001). Additionally, the ratio of MMP-9 to TIMP-1 concentration was only significantly greater in CL wearers with short experience (mean ratio ± SD = 1.15 ± 0.76) when compared to NWs (0.19 ± 0.29, Dunn P < 0.001), CL wearers with moderate experience (0.37 ± 0.41; P = 0.01) and PWs (0.38 ± 0.36; P = 0.02).

Conclusions: The early years of CL wear appear to be associated with increased expression of MMP-9 relative to its inhibitor TIMP-1. This may be indicative of low-level inflammation during this phase of wear. The role this plays in propagating dry eye disease and MGD in CL wear requires further exploration.
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http://dx.doi.org/10.1016/j.clae.2019.07.007DOI Listing
April 2020

Authors' Response.

Optom Vis Sci 2019 06;96(6):466-467

Brien Holden Vision Institute, Sydney New South Wales, Australia

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http://dx.doi.org/10.1097/OPX.0000000000001390DOI Listing
June 2019

Prevalence of Primary Glaucoma as Diagnosed by Study Optometrists of L. V. Prasad eye Institute - Glaucoma Epidemiology and Molecular Genetics Study.

Ophthalmic Epidemiol 2019 06 29;26(3):150-154. Epub 2018 Nov 29.

d School of Optometry and Vision Science , UNSW , Sydney , Australia.

Purpose: To report the prevalence of primary glaucoma as identified by study optometrists of the L. V. Prasad Eye Institute - Glaucoma Epidemiology and Molecular Genetics Study (LVPEI-GLEAMS).

Methods: Two study optometrists and a total number of 3833 individuals participated in the LVPEI-GLEAMS. All subjects underwent a complete medical history and comprehensive eye examination including slit lamp photography, imaging of anterior and posterior segment, frequency doubling technology and standard automated perimetry including gonioscopy with a Sussman 4 mirror goniolens, post dilated evaluation of the optic disc and fundus was done with a 90 D lens by the study optometrist. A diagnosis of primary open angle glaucoma (POAG), primary angle closure suspect (PACS), primary angle closure (PAC), primary angle closure glaucoma (PACG), normal tension glaucoma (NTG), glaucoma/disc suspect or no glaucoma was made based on the clinical examination.

Results: Estimated prevalence of OAG (POAG and NTG) was 1.07% (0.74-1.39), PACS 2.03% (1.58-2.48), PAC 1.77% (1.35-2.19), PACG 0.21% (0.06-0.35) as identified by the study optometrists on site.

Conclusions: Prevalence of all the categories of primary glaucoma, as reported by the study optometrists of LVPEI-GLEAMS was comparable to previous findings of other regions in South India.
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http://dx.doi.org/10.1080/09286586.2018.1551961DOI Listing
June 2019

Measuring Daily Disposable Contact Lenses against Nonwearer Benchmarks.

Optom Vis Sci 2018 12;95(12):1088-1095

Brien Holden Vision Institute, Sydney, New South Wales, Australia.

Significance: Since becoming a popular form of refractive error correction, contact lenses have aspired to replicate the nonwearer experience. This study assessed how well currently available daily disposable soft lenses have achieved that goal, using a graphical representation to show individual lens behavior relative to benchmarks.

Purpose: The purpose of this study was to assess comfort, vision, and adverse events during daily disposable contact lens wear, relative to emmetropes and spectacle wearers.

Method: Three-month clinical studies, where participants either wore one of five daily disposable contact lenses (n = 201), were full-time spectacle wearers with no history of contact lens wear (n = 34), or emmetropic non-contact lens wearers (n = 40). Vision quality and comfort were assessed at the beginning and end of the day (1 to 10). Corneal infiltrative events were recorded. Between-group comparisons were made using a linear mixed model and literature estimates of clinical significance.

Results: Initial comfort among emmetropes (mean ± 95% confidence interval, 8.0 ± 0.5) was not significantly different from any of the lens types (range, 7.2 ± 0.4 to 8.0 ± 0.4, all P > .06) or spectacle wearers (7.3 ± 0.5, P = .45). Comfort deteriorated during the day in all groups (P < .05). End-of-day comfort for emmetropes (7.3 ± 0.6) was significantly better, only than lenses B (5.7 ± 0.6, P < .001) and D (6.2 ± 0.5, P = .01). Vision quality for emmetropes (8.6 ± 0.5) was better than spectacle wearers (7.8 ± 0.5, P = .04) and lenses A (7.6 ± 0.4, P = .003) and B (7.5 ± 0.4, P < .001). Corneal infiltrative events occurred in 0% of emmetropes and 2.9% of spectacle wearers and ranged from 2.4 to 7.5% in lens wearers.

Conclusions: Under the conditions of this study, comfort and vision with some contemporary daily disposable contact lenses were indistinguishable from nonwearing emmetropes. Although the contact lens-wearing groups had rates of corneal infiltrative events that were not statistically different from the nonwearers, the study had insufficient power to permit robust conclusions in this respect.
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http://dx.doi.org/10.1097/OPX.0000000000001304DOI Listing
December 2018

The Effect of Contact Lens Wear on the Cellular Morphology of the Lid Wiper Area.

Optom Vis Sci 2018 06;95(6):491-497

School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia.

Significance: This cross-sectional study presented a link between contact lens wear and changes on the cellular morphology characteristics of the lid wiper (LW) epithelium, which was not visible by LW staining.

Purpose: The aim of this study was to establish if the duration of contact lens (CL) wear affects the cellular morphology of the LW epithelium.

Methods: This was a cross-sectional study of 100 individuals with different exposures to CL wear: short, moderate, and long experience of CL wear; previous CL wearers; and nonwearers (NWs) as controls. Impression cytology samples were collected from the central upper lid margin (LW area). After fixing, samples were stained with periodic acid-Schiff and haematoxylin for cell morphology analysis and subsequently graded according to the Nelson 0- to 3-point scale. Lid wiper staining was assessed with the aid of lissamine green and graded using the Korb (0- to 3-point) scale. One-way Kruskal-Wallis analysis followed by the Dunn multiple-comparisons test was used for statistical comparison.

Results: The Nelson grade for LW epithelium morphology was significantly different between groups (P = .003). Abnormal epithelial morphology as defined by grade 2 or 3 was evident in 66.7% of CL wearers with short experience and 76.5% of CL wearers with moderate experience. This was significantly higher than NWs of whom only 21.5% showed greater than grade 1 (P = .02 and .005, respectively). There was no significant difference between NWs and other groups. Lid wiper staining did not significantly differ between groups (P = .50) or correlate with the Nelson grade (Spearman r = 0.02, P = .08).

Conclusions: Metaplasia of the LW epithelium was significantly greater in the early to moderate stages of CL. This supports the view that mechanical irritation is responsible for LW changes in CL wear. Ceasing CL wear seems to lead to recovery. Lid wiper staining did not reflect the underlying morphological changes.
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http://dx.doi.org/10.1097/OPX.0000000000001224DOI Listing
June 2018

Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia: Systematic Review, Meta-analysis, and Modelling.

Ophthalmology 2018 10 9;125(10):1492-1499. Epub 2018 May 9.

Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, Australia; African Vision Research Institute, University of KwaZulu-Natal, Durban, South Africa.

Topic: Presbyopia prevalence and spectacle-correction coverage were estimated by systematic review and meta-analysis of epidemiologic evidence, then modeled to expand to country, region, and global estimates.

Clinical Relevance: Understanding presbyopia epidemiologic factors and correction coverage is critical to overcoming the burden of vision impairment (VI) from uncorrected presbyopia.

Methods: We performed systematic reviews of presbyopia prevalence and spectacle-correction coverage. Accepted presbyopia prevalence data were gathered into 5-year age groups from 0 to 90 years or older and meta-analyzed within World Health Organization global burden of disease regions. We developed a model based on amplitude of accommodation adjusted for myopia rates to match the regionally meta-analyzed presbyopia prevalence. Presbyopia spectacle-correction coverage was analyzed against country-level variables from the year of data collection; variation in correction coverage was described best by a model based on the Human Development Index, Gini coefficient, and health expenditure, with adjustments for age and urbanization. We used the models to estimate presbyopia prevalence and spectacle-correction coverage in each age group in urban and rural areas of every country in the world, and combined with population data to estimate the number of people with near VI.

Results: We estimate there were 1.8 billion people (prevalence, 25%; 95% confidence interval [CI], 1.7-2.0 billion [23%-27%]) globally with presbyopia in 2015, 826 million (95% CI, 686-960 million) of whom had near VI because they had no, or inadequate, vision correction. Global unmet need for presbyopia correction in 2015 is estimated to be 45% (95% CI, 41%-49%). People with presbyopia are more likely to have adequate optical correction if they live in an urban area of a more developed country with higher health expenditure and lower inequality.

Conclusions: There is a significant burden of VI from uncorrected presbyopia, with the greatest burden in rural areas of low-resource countries.
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http://dx.doi.org/10.1016/j.ophtha.2018.04.013DOI Listing
October 2018

Genetic factors and molecular mechanisms in dry eye disease.

Ocul Surf 2018 04 10;16(2):206-217. Epub 2018 Mar 10.

University of New South Wales, New South Wales, Australia.

Dry eye disease (DED) is a complex condition with a multifactorial etiology that can be difficult to manage successfully. While external factors are modifiable, treatment success is limited if genetic factors contribute to the disease. The purpose of this review is to compile research describing normal and abnormal ocular surface function on a molecular level, appraise genetic studies involving DED or DED-associated diseases, and introduce the basic methods used for conducting genetic epidemiology studies.
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http://dx.doi.org/10.1016/j.jtos.2018.03.003DOI Listing
April 2018

Imaging the Tear Film: A Comparison Between the Subjective Keeler Tearscope-Plus™ and the Objective Oculus® Keratograph 5M and LipiView® Interferometer.

Curr Eye Res 2018 02 14;43(2):155-162. Epub 2017 Nov 14.

a School of Optometry & Vision Science, University of New South Wales , Sydney , Australia.

Purpose: To compare non-invasive break-up time (NIBUT) when measured with the Tearscope-Plus™ and the Oculus® Keratograph 5M, and to compare lipid layer thicknesses (LLT) when measured with the Tearscope-Plus™ and the LipiView®. This study also set out to establish the repeatability of these methods.

Methods: The following measurements were taken from both eyes of 24 participants on two occasions: non-invasive keratograph break-up time using the Oculus® (NIKBUT-1 and NIKBUT-average), NIBUT using the Tearscope-Plus™, and LLT using the LipiView® (minimum, maximum, and average) and Tearscope-Plus™. The Tearscope-Plus™ grades were converted to nanometers.

Results: There were no significant differences between eyes (Tearscope-Plus™ NIBUT: p = 0.52; NIKBUT-1: p = 0.052; NIKBUT-average: p = 0.73; Tearscope-Plus™ LLT: p = 0.13; LipiView® average, maximum, or minimum: p = 0.68, 0.39 and 0.50, respectively) or days (Tearscope-Plus™ NIBUT: p = 0.32; NIKBUT-1: p = 0.65; NIKBUT-average: p = 0.54; Tearscope-Plus™ LLT: p = 0.26; LipiView® average, maximum, or minimum: p = 0.20, 0.09, and 0.10, respectively). LLT was significantly greater with the Tearscope-Plus™ (80.4 ± 34.0 nm) compared with the LipiView® average (56.3 ± 16.1 nm, p = 0.007), minimum (50.1 ± 15.8 nm, p < 0.001) but not maximum (67.2 ± 19.6 nm, p = 0.55). NIBUT was significantly greater with the Tearscope-Plus™ (15.9 ± 10.7 seconds) compared to the NIKBUT-1 (8.2 ± 3.5 seconds, p = 0.006) but not NIKBUT-average (10.9 ± 3.9 seconds, p = 0.08).

Conclusions: The Tearscope-Plus™ is not interchangeable with either the Oculus® K5M measurement of tear stability (NIKBUT-1) or the LipiView® maximum and minimum lipid thickness.
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http://dx.doi.org/10.1080/02713683.2017.1393092DOI Listing
February 2018

Discrimination of subjective responses between contact lenses with a novel questionnaire.

Cont Lens Anterior Eye 2017 Dec 6;40(6):367-381. Epub 2017 Oct 6.

Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Science, University of New South Wales, Australia; Vision Cooperative Research Centre, Sydney, Australia.

Purpose: To describe a ranked symptoms scale (RSS) discriminating subjective responses in contact lens (CL) wear in various situations.

Method: Forty experienced clinical trial participants were interviewed for their perceptions of ocular comfort scales, resulting in a numerical RSS. For further evaluation, 20 CL wearers enrolled into a prospective, randomised, crossover trial. Two silicone-hydrogel CLs and a lens care solution (LCS) [Combinations A & B] were selected based on prior performance identifying best/worst combinations for end-of-day comfort. The RSS and a numerical rating scale (NRS) were administered at two time-points (insertion/removal) on alternating days for 6 days.

Results: Both NRS and RSS showed acceptable internal consistency for comfort, vision and handling (Cronbach alpha=0.71 for both scales) and similar repeatability for comfort and handling (coefficients-of-repeatability within 0.1 and 0.2 units, respectively, for each scale). The NRS and RSS discriminated differences between combinations for comfort (p≤0.031) and vision (p≤0.026) at both time-points. Additionally, the RSS showed lens/edge awareness influenced discomfort the most, ranking higher at insertion (p=0.038) and higher for Combination-B at both time-points (p≤0.002). Symptoms of dryness and tired eyes increased for both combinations at removal (p<0.02). The RSS also showed haziness and blurred distance vision influenced vision dissatisfaction with Combination-B at lens removal (p≤0.038) while eye strain/headache increased for both combinations by time of removal (p≤0.013).

Conclusions: The RSS is able to discriminate subjective responses between combinations and time-of-day. The RSS's ability to rank symptoms may be a useful tool in understanding perceptions of discomfort or dissatisfaction with CL wear.
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http://dx.doi.org/10.1016/j.clae.2017.09.016DOI Listing
December 2017

Contact lens technology to 2020 and beyond: a review of recent patent literature.

Authors:
Eric B Papas

Clin Exp Optom 2017 Sep 3;100(5):529-536. Epub 2017 Sep 3.

School of Optometry and Vision Science, The University of New South Wales, Kensington, New South Wales, Australia.

Contact lenses have been a common means of vision correction for more than half a century. Recent developments raise the possibility that the next several years will see the range of applications in which they are used broaden considerably, with an associated expansion in both the number and type of individuals who consider them to be a valuable option. To describe this new landscape, a review of recent patent submissions covering the period 1 January 2014 to 1 February 2017 was undertaken. The results show that in the main, areas where contact lenses will be applied include drug delivery, visual augmentation and biosensing.
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http://dx.doi.org/10.1111/cxo.12596DOI Listing
September 2017

TFOS DEWS II Tear Film Report.

Ocul Surf 2017 07 20;15(3):366-403. Epub 2017 Jul 20.

Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Canada.

The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership.
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http://dx.doi.org/10.1016/j.jtos.2017.03.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6035753PMC
July 2017

Treatment Practices and Outcomes of Meibomian Gland Dysfunction at a Tertiary Center in Southern India.

Eye Contact Lens 2018 Sep;44 Suppl 1:S138-S143

Brien Holden Vision Institute (L.L., J.L.F., E.B.P.), Sydney, New South Wales, Australia; Vision Cooperative Research Centre (L.L., J.L.F., E.B.P.), Sydney, New South Wales, Australia; School of Optometry and Vision Science (L.L., Q.G., J.L.F., E.B.P.), The University of New South Wales, Sydney, New South Wales, Australia; The University of Notre Dame Australia (Q.G.), Sydney, New South Wales, Australia; and L V Prasad Eye Institute (P.K.V.), Hyderabad, India.

Objective: To describe the current treatment practices for meibomian gland dysfunction (MGD) at a tertiary eye center, together with the subjective outcomes and compliance behaviors of patients.

Methods: This retrospective cohort study reviewed medical records for MGD severity grading, treatment prescribed, and follow-up schedule. In addition, participants were surveyed to gauge subjective outcomes and treatment adherence.

Results: Eight hundred ten patients were diagnosed with "MGD" or "meibomitis" and had a total of 14 different treatment combinations prescribed. In 3.0% of cases, there was no treatment specified. As MGD severity increased, it became more likely that management would be applied and this was also associated with significantly longer treatment durations (P=0.02) and shorter follow-up periods (P<0.001). Posttreatment subjective outcomes and treatment adherence surveys had a response rate of 36.7% and 24.1% respectively. Overall, 53.5% reported sustained improvement, 40.7% no improvement, and 5.7% experienced temporary relief. Although no treatment regimen seemed to be more efficacious than others, patients showed greater adherence when using topical reagents compared with lid hygiene measures (P≤0.002).

Conclusion: Clinicians, in this large tertiary eye center, use a wide range of treatment regimens to manage MGD. This suggests the need for development of standard management protocols. Whether alone, or in combination, no MGD treatment significantly improved subjective symptoms, a result that may be influenced by compliance behaviors. Use of topical reagents (eye drops or ointment) seemed to be associated with the best compliance. Future focus on more effective MGD treatments is needed to improve practical outcomes.
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http://dx.doi.org/10.1097/ICL.0000000000000356DOI Listing
September 2018

Temporal Characteristics of Sodium Fluorescein in the Tear Meniscus.

Optom Vis Sci 2017 02;94(2):166-173

*PhD, MOptom, FAAO †MOptom ‡PhD, BScOptom, FAAO School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia (all authors).

Purpose: To observe the emission intensity profile of sodium fluorescein in the human tear film as a function of time and concentration.

Methods: Twenty-two participants with no dry eye signs or symptoms were randomly allocated to receive 1 μL of either a 2 or 10% concentration of fluorescein to one eye. Images of the inferior tear meniscus were captured at regular intervals over 30 minutes and the process repeated for the other eye with the alternate concentration. Fluorescence intensity was quantified on the basis of the grayscale pixel values in the tear meniscus images. The fluorescein-decay profile over time and between concentrations was determined.

Results: Peak fluorescence intensity was reached in 3.9 ± 3.0 and 8.7 ± 4.4 minutes after instillation for the 2 and 10% concentrations, respectively. The 10% concentration of fluorescein maintained its peak fluorescence intensity longer than the 2% concentration (about 9 and 2 minutes, respectively). The peak fluorescence intensity was not significantly different between the higher and lower concentrations (44 ± 37 vs. 38 ± 32 units, P = .22). For both concentrations, the observed intensity did not return to baseline levels by the end of the 30-minute observation time.

Conclusions: The fluorescence intensity of fluorescein in a clinical setting varies with time such that both the onset and duration of maximum brightness are concentration dependent. At low concentration (2%), maximum brightness occurs almost immediately after instillation and lasts about 2 minutes. With a higher concentration (10%), the effective working window is delayed for about 7 to 8 minutes. Irrespective of initial concentration, observable fluorescence remains in the tear film beyond 30 minutes post-instillation.
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http://dx.doi.org/10.1097/OPX.0000000000001012DOI Listing
February 2017

Interpreting the corneal response to oxygen: Is there a basis for re-evaluating data from gas-goggle studies?

Exp Eye Res 2016 Oct 3;151:222-6. Epub 2016 Sep 3.

Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.

When anoxia (0% oxygen) is created within a gas-tight goggle, ocular physiological responses, including corneal swelling, limbal hyperaemia and pH change, are known to vary, depending on the presence or absence of a low, oxygen transmissibility contact lens. A new theory is proposed to account for this discrepancy based on the concept of lid derived oxygen, whereby oxygen originating from the vascular plexus of the palpebral conjunctiva supplements that available to the ocular surface in an open, normally blinking eye, even when the surrounding gaseous atmosphere is anoxic. The effect of a lid derived contribution to corneal oxygenation was assessed by using existing experimental data to model open-eye, corneal swelling behavior as a function of atmospheric oxygen content, both with and without the presence of a contact lens. These models predict that under atmospheric anoxia, contact lens wear results in 13.2% corneal swelling compared with only 5.4% when the lens was absent. Lid derived oxygen acts to provide the ocular surface in the non-contact lens wearing, normally blinking, open-eye with up to 4.7% equivalent oxygen concentration, even within the anoxic environment of a nitrogen filled goggle. Correcting for lid derived oxygen eliminates previously observed discrepancies in corneal swelling behavior and harmonizes the models for the contact lens wearing and gas-goggle cases. On this basis it is proposed that true anoxia at the ocular surface cannot be achieved by atmospheric manipulation (i.e. a gas-goggle) alone but requires an additional presence, e.g. a low, oxygen transmissibility contact lens, to prevent access to oxygen from the eyelids. Data from previously conducted experiments in which the gas-goggle paradigm was used, may have been founded on underestimates of the real oxygen concentration acting on the ocular surface at the time and if so, will require re-interpretation. Future work in this area should consider if a correction for lid derived oxygen is necessary.
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http://dx.doi.org/10.1016/j.exer.2016.08.019DOI Listing
October 2016

Functional and Morphologic Changes of Meibomian Glands in an Asymptomatic Adult Population.

Invest Ophthalmol Vis Sci 2016 08;57(10):3996-4007

Brien Holden Vision Institute University of New South Wales, Sydney, New South Wales, Australia 2Vision CRC, Sydney, New South Wales, Australia 3School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia.

Purpose: The aim of the study was to understand natural changes of meibomian glands (MG) that occur with aging in the absence of any ocular pathology or ocular discomfort symptoms, to differentiate between "age normal" and pathologic or dysfunctional changes of the MG.

Methods: A total of 185 subjects (109 females) with no pre-existing ocular and systemic abnormalities were recruited and divided into four age groups: 25 to 34, 35 to 44, 45 to 54, and 55 to 66 years. At a single visit, the following MG measures were collected: meibum quality (MQ) and MG expressibility (MGE) of the lower lid, and MG drop-out score (meiboscale) using infrared meibography of the upper and lower lids. Assessments of anterior eye, tear function variables, noninvasive and invasive tear breakup time (TBUT), corneal integrity, and lid wiper epitheliopathy were also performed during the visit. An Ocular Surface Disease Index (OSDI) questionnaire was used to record dry eye symptoms. Meibum lipids samples were collected and analyzed.

Results: A majority of the study population (61%) was asymptomatic. There was a significant worsening in the MQ (P< 0.048), MGE (P < 0.03), and meiboscale (P < 0.01) with increasing age. Significant increase was observed in anterior blepharitis (P < 0.001) and telangiectasia (P< 0.02) with aging. Interestingly, tear osmolarity decreased significantly (P < 0.001), while tear meniscus height (P < 0.001) and invasive TBUT (P = 0.02) increased with increase in age. There was no significant association between MG variables and sex, ocular discomfort symptoms, or meibum lipids classes.

Conclusions: Progressive MG loss occurs normally with age accompanied by reduced quality and quantity of the meibum produced. However, clinical presentation of ocular discomfort symptoms is stalled without corresponding disruption to tear function.
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http://dx.doi.org/10.1167/iovs.15-18467DOI Listing
August 2016

Contact Lens Comfort.

Optom Vis Sci 2016 08;93(8):790-2

Toronto, Ontario, Canada Tokyo, Japan Waterloo, Ontario, Canada Berkeley, California Birmingham, Alabama Sydney, New South Wales, Australia Columbus, Ohio Weinheim, Germany Sydney, New South Wales, Australia.

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http://dx.doi.org/10.1097/OPX.0000000000000968DOI Listing
August 2016

Demographic Factors Affect Ocular Comfort Ratings During Contact Lens Wear.

Optom Vis Sci 2016 08;93(8):1004-10

*PhD †PhD, FAAO Brien Holden Vision Institute, Sydney, New South Wales, Australia (TN, EBP, PLdlJ); School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia (EBP, PLdlJ); and Vision Cooperative Research Centre, Sydney, New South Wales, Australia (EBP, PLdlJ).

Purpose: To determine if rating of ocular comfort during soft contact lens wear is affected by demographic factors.

Methods: Retrospective analysis of ocular comfort ratings during soft contact lens wear extracted from 44 nonrandomized similar clinical trials (n = 986). Subjects wore one of seven daily wear silicone hydrogels (SiHy) in combination with one of nine lens care products (LCP), and two daily disposables lenses. The effects on comfort rating of demographic factors were examined after adjusting for lens and LCP effects using general linear model.

Results: Males reported lower comfort on insertion than females (7.9 ± 1.6 vs. 8.1 ± 1.6, p = 0.001). Over 45 years old had higher comfort ratings than those between 26 and 45 or <26 years old at insertion (8.7 ± 1.3 vs. 8.1 ± 1.6 vs. 7.8 ± 1.6, p < 0.001), during the day (8.6 ± 1.2 vs. 8.0 ± 1.6 vs. 8.2 ± 1.2, p < 0.001), and end of day (7.7 ± 1.6 vs. 6.8 ± 2.0 vs. 7.0 ± 1.6, p < 0.001). Neophytes reported lower comfort on insertion (7.3 ± 1.6 vs. 8.2 ± 1.5, p < 0.001) and during day (8.0 ± 1.3 vs. 8.3 ± 1.3, p = 0.020) than experienced wearers. Participants with Rx ≥-3.50D had higher comfort ratings than those with ≤-3.50D on insertion (8.3 ± 1.4 vs. 7.8 ± 1.6, p < 0.001), during the day (8.4 ± 1.3 vs. 8.1 ± 1.3, p = 0.010), and end of day (7.2 ± 1.7 vs. 6.9 ± 1.8, p = 0.046). Comfort during the day was different between participants of different ethnic origin (p = 0.024) with Asians reporting the lowest (8.1 ± 1.3).

Conclusions: Demographic factors such as age, gender, lens wear experience, ethnicity, and refractive status can influence the rating of ocular comfort in clinical studies. The confounding effects of such demographic factors can be controlled by implementing randomization and appropriate multivariable statistical analysis.
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http://dx.doi.org/10.1097/OPX.0000000000000884DOI Listing
August 2016

Revolutionary Future Uses of Contact Lenses.

Optom Vis Sci 2016 Apr;93(4):325-7

Waterloo, Canada Glassboro, NJ Boston, MA Jupiter, FL Sydney, Australia Sydney, Australia Waterloo, Canada.

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http://dx.doi.org/10.1097/OPX.0000000000000847DOI Listing
April 2016

Impact of duration of contact lens wear on the structure and function of the meibomian glands.

Ophthalmic Physiol Opt 2016 Mar;36(2):120-31

Brien Holden Vision Institute, Sydney, Australia.

Purpose: To investigate the effects of the duration of contact lens (CL) wear on the meibomian glands (MGs), eyelid and tear film.

Methods: This was a cross-sectional study of CL wearers and non-wearers (NWs) aged between 18 and 35 years. The sample comprised of: (i) Three groups of CL wearers of different duration profiles (short, moderate and long experience of CL wear); (ii) a group of previous CL wearers (PWs) who had ceased wear for at least 6 months prior to the present study; (iii) healthy non-wearers as a control group. Study procedures were conducted in the order from least invasive to most invasive as follows: symptom assessment, lipid assessment, non-invasive break-up time, tear meniscus area, tear osmolarity and evaporation, Phenol red thread, MG expressibility, ocular surface and eyelid assessments, meibography, Marx line and lid wiper assessment using lissamine green. For statistical comparison of continuous data, one-way analysis of variance was used with Bonferroni post-hoc correction, where appropriate. Kruskal-Wallis test and Pearson Chi-Square respectively were used for ordinal and categorical variables.

Results: A total of 100 participants (49 males and 51 females; mean age ± SD: 25.4 ± 4.1) were enrolled across the five groups, such that each was composed of 20 age/sex matched individuals. Significant differences between the study groups were found for MG expressibility (p < 0.001), number of plugged orifices (p = 0.001), number of expressed orifices (p < 0.001), MG dropout (p = 0.001), Marx line score (p < 0.001), palpebral redness (p = 0.003), and roughness (p = 0.002), non-invasive break-up time (p < 0.001), Phenol red thread (p = 0.005), and tear meniscus area (p = 0.029). For all these variables, the NW group was statistically different from all other groups. Duration of wear was not a significant factor, except for Marx line score which was different in PWs compared to those with longer experience of CL wear (p = 0.03) CONCLUSION: Alterations to MG morphology and function accompany contact lens wear. Although these changes onset during the first 2 years of wear, prolonged CL exposure beyond this point does not appear to be associated with further modification. Cessation of wear for at up to 6 months does not lead to resolution.
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http://dx.doi.org/10.1111/opo.12278DOI Listing
March 2016

Taking care of the future for contact lenses.

Authors:
Eric Papas

Ophthalmic Physiol Opt 2016 Mar;36(2):75-6

School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.

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http://dx.doi.org/10.1111/opo.12281DOI Listing
March 2016

Glycerol Monolaurate Inhibits Lipase Production by Clinical Ocular Isolates Without Affecting Bacterial Cell Viability.

Invest Ophthalmol Vis Sci 2016 Feb;57(2):544-50

Brien Holden Vision Institute Sydney, Australia 2School of Optometry and Vision Science, University of New South Wales, Sydney, Australia 3Vision Cooperative Research Centre, Sydney, Australia.

Purpose: We sought to determine the relative lipase production of a range of ocular bacterial isolates and to assess the efficacy of glycerol monolaurate (GML) in inhibiting this lipase production in high lipase-producing bacteria without affecting bacterial cell growth.

Methods: Staphylococcus aureus,Staphylococcus epidermidis,Propionibacterium acnes, and Corynebacterium spp. were inoculated at a density of 10(6)/mL in varying concentrations of GML up to 25 μg/mL for 24 hours at 37 °C with constant shaking. Bacterial suspensions were centrifuged, bacterial cell density was determined, and production of bacterial lipase was quantified using a commercial lipase assay kit.

Results: Staphylococcus spp. produced high levels of lipase activity compared with P. acnes and Corynebacterium spp. GML inhibited lipase production by Staphylococcal spp. in a dose-dependent manner, with S. epidermidis lipase production consistently more sensitive to GML than S. aureus. Glycerol monolaurate showed significant (P < 0.05) lipase inhibition above concentrations of 15 μg/mL in S. aureus and was not cytotoxic up to 25 μg/mL. For S. epidermidis, GML showed significant (P < 0.05) lipase inhibition above 7.5 μg/mL.

Conclusions: Lipase activity varied between species and between strains. Staphylococcal spp. produced higher lipase activity compared with P. acnes and Corynebacterium spp. Glycerol monolaurate inhibited lipase production by S. aureus and S. epidermidis at concentrations that did not adversely affect bacterial cell growth. GML can be used to inhibit ocular bacterial lipase production without proving detrimental to commensal bacteria viability.
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http://dx.doi.org/10.1167/iovs.15-17180DOI Listing
February 2016

Presbyopia: physiology, prevention and pathways to correction.

Ophthalmic Physiol Opt 2016 Jan;36(1):1-4

University of Manchester, Manchester, UK.

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http://dx.doi.org/10.1111/opo.12272DOI Listing
January 2016

Influence of Meibomian Gland Expression Methods on Human Lipid Analysis Results.

Ocul Surf 2016 Jan 31;14(1):49-55. Epub 2015 Oct 31.

Brien Holden Vision Institute, Sydney, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia; Vision Cooperative Research Centre, Sydney, NSW, Australia.

Purpose: To compare the lipid composition of human meibum across three different meibum expression techniques.

Methods: Meibum was collected from five healthy non-contact lens wearers (aged 20-35 years) after cleaning the eyelid margin using three meibum expression methods: cotton buds (CB), meibomian gland evaluator (MGE) and meibomian gland forceps (MGF). Meibum was also collected using cotton buds without cleaning the eyelid margin (CBn). Lipids were analyzed by chip-based, nano-electrospray mass spectrometry (ESI-MS). Comparisons were made using linear mixed models.

Results: Tandem MS enabled identification and quantification of over 200 lipid species across ten lipid classes. There were significant differences between collection techniques in the relative quantities of polar lipids obtained (P<.05). The MGE method returned smaller polar lipid quantities than the CB approaches. No significant differences were found between techniques for nonpolar lipids. No significant differences were found between cleaned and non-cleaned eyelids for polar or nonpolar lipids.

Conclusion: Meibum expression technique influences the relative amount of phospholipids in the resulting sample. The highest amounts of phospholipids were detected with the CB approaches and the lowest with the MGE technique. Cleaning the eyelid margin prior to expression was not found to affect the lipid composition of the sample. This may be a consequence of the more forceful expression resulting in cell membrane contamination or higher risk of tear lipid contamination as a result of reflex tearing.
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http://dx.doi.org/10.1016/j.jtos.2015.10.001DOI Listing
January 2016

Intersubject and Interday Variability in Human Tear and Meibum Lipidomes: A Pilot Study.

Ocul Surf 2016 Jan 28;14(1):43-8. Epub 2015 Sep 28.

Illawarra Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, NSW, Australia. Electronic address:

Purpose: Our aim was to quantitate day-to-day changes in the tear and meibum lipid profile of individual subjects in a pilot study of healthy humans.

Methods: Matched tear and meibum samples were obtained from four subjects on three consecutive days. Quantitative lipid profiles of human basal tears and meibum were compared using multivariate analysis by principal components.

Results: Substantial differences in the lipid profile between subjects were observed, while lipid profiles were steady across the three consecutive days of sampling. Multivariate principal component analysis demonstrated that lysophosphatidylcholine was the largest variant lipid class between subjects in tears, while wax esters comprised the most variation between subjects in meibum secretions.

Conclusion: Interday variability is shown to be much smaller than interpatient variability, suggesting that tears and meibum subjects both have unique profiles in humans.
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http://dx.doi.org/10.1016/j.jtos.2015.08.005DOI Listing
January 2016

Ocular discomfort responses after short periods of contact lens wear.

Optom Vis Sci 2015 Jun;92(6):665-70

*PhD, FAAO †MOptom, FAAO ‡OD, FAAO §PhD Brien Holden Vision Institute, Sydney, New South Wales, Australia (EP, DT, PLdlJ); Vision Cooperative Research Centre, Sydney, Australia (EP, PLdlJ); School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia (EP, PLdlJ); and CIBA Vision, Duluth, Georgia (JMc).

Purpose: To investigate if contact lens-related discomfort is a function of the time of day at which lenses are worn.

Methods: This was a randomized, crossover, open-label clinical trial where subjective responses, with and without contact lenses, were assessed every 2 hours during five stages (A to E). Each stage began at the time when subjects would normally have inserted their contact lenses (T0). During stage A, no lenses were worn, whereas in stage B, lenses were worn continuously for 12 hours. In stages C to E, lenses were worn for only 4 hours. Contact lenses were inserted at T0 for stage C, but for stages D and E, lenses were not inserted until T0 + 4 and T0 + 8 hours, respectively. Mixed linear models were used for statistical analysis.

Results: In the absence of contact lenses, ocular comfort and dryness remained reasonably constant throughout the observation period. Ocular comfort and dryness decreased during 12 hours of continuous lens wear and became significantly worse from the 8-hour time onward compared with insertion (p < 0.023). There were no significant differences in terms of ocular comfort and dryness between any of the 4-hour lens wear stages (p < 0.82). During each 4-hour stage, both comfort and dryness behaved in a similar fashion (p > 0.05) to the first 4 hours of continuous contact lens wear. Comparing the scores of each of these stages with the no-lens response at the corresponding time showed no significant differences for comfort (p > 0.23) or dryness (p > 0.37).

Conclusions: Short periods of wear can be experienced at any time of day without significant change in ocular discomfort and dryness. This suggests that subjective responses at the end of the day are determined by the length of time lenses are in contact with the eye, rather than the time of day at which lenses are worn.
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http://dx.doi.org/10.1097/OPX.0000000000000607DOI Listing
June 2015

The significance of oxygen during contact lens wear.

Authors:
Eric B Papas

Cont Lens Anterior Eye 2014 Dec 16;37(6):394-404. Epub 2014 Aug 16.

Brien Holden Vision Institute, Sydney, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, Australia; Vision CRC, Sydney, Australia. Electronic address:

In order to establish the relevance of oxygen to contemporary contact lens practice, a review of the literature was conducted. The results indicate that there are a number of processes occurring in the normal healthy eye where oxygen is required and which are potentially affected by the presence of a contact lens. These activities appear to take place at all corneal levels, as well as at the limbus. Evidence from laboratory, clinical and modelling studies indicates that what constitutes normal oxygenation (normoxia) depends on, among other things, the physiological system under consideration, corneal location and the state of eye closure. This diversity is reflected in the wide range of minimum lens oxygen transmissibility (Dk/t) requirements that are present in a literature.
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http://dx.doi.org/10.1016/j.clae.2014.07.012DOI Listing
December 2014
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