Effect of school eye health promotion on children's eye health literacy in Vietnam.

Health promotion intervention in schools is a useful strategy to improve students' health awareness. The purpose of this study was to assess the effect of eye health promotion interventions on eye health literacy in school children in Vietnam. A piloted questionnaire was administered to 300 children from five secondary schools in Ba Ria-Vung Tau, Vietnam at baseline and re-administered after the eye health promotion interventions. McNemar chi-square and logistic regression were used for statistical analysis. A total of 300 children aged 12-15 years (mean, 13.3 ± 1.3 years; 60% female) participated in the baseline survey. The participation rate in the post-health promotion survey was 94.7%. After the health promotion interventions, number of children who had correct eye health knowledge increased by 10-20% (60-75% to 70-95%), more children reported having had an eye examination (63.3% to 84.7%; p < 0.001) and more reported wearing spectacles (36.1% to 43.4%; p = 0.04). Children in urban schools were twice as likely to have improved knowledge of vision loss compared with children in rural schools (odds ratio, 2.1-4.1; p = 0.01 to p < 0.001). Children from rural schools had significantly higher odds of visiting doctor after the eye problems worsened (odds ratio, 4.5; p < 0.001). These results imply that eye health promotion interventions significantly improve eye health knowledge, attitudes and practices of school children. Additionally, participation of parents and teachers as change agents may further improve children's health literacy.

Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050.

PURPOSE: Myopia is a common cause of vision loss, with uncorrected myopia the leading cause of distance vision impairment globally. Individual studies show variations in the prevalence of myopia and high myopia between regions and ethnic groups, and there continues to be uncertainty regarding increasing prevalence of myopia. DESIGN: Systematic review and meta-analysis. METHODS: We performed a systematic review and meta-analysis of the prevalence of myopia and high myopia and estimated temporal trends from 2000 to 2050 using data published since 1995. The primary data were gathered into 5-year age groups from 0 to ≥100, in urban or rural populations in each country, standardized to definitions of myopia of -0.50 diopter (D) or less and of high myopia of -5.00 D or less, projected to the year 2010, then meta-analyzed within Global Burden of Disease (GBD) regions. Any urban or rural age group that lacked data in a GBD region took data from the most similar region. The prevalence data were combined with urbanization data and population data from United Nations Population Department (UNPD) to estimate the prevalence of myopia and high myopia in each country of the world. These estimates were combined with myopia change estimates over time derived from regression analysis of published evidence to project to each decade from 2000 through 2050. RESULTS: We included data from 145 studies covering 2.1 million participants. We estimated 1406 million people with myopia (22.9% of the world population; 95% confidence interval [CI], 932-1932 million [15.2%-31.5%]) and 163 million people with high myopia (2.7% of the world population; 95% CI, 86-387 million [1.4%-6.3%]) in 2000. We predict by 2050 there will be 4758 million people with myopia (49.8% of the world population; 3620-6056 million [95% CI, 43.4%-55.7%]) and 938 million people with high myopia (9.8% of the world population; 479-2104 million [95% CI, 5.7%-19.4%]). CONCLUSIONS: Myopia and high myopia estimates from 2000 to 2050 suggest significant increases in prevalences globally, with implications for planning services, including managing and preventing myopia-related ocular complications and vision loss among almost 1 billion people with high myopia.

Short-Term Visual Performance of Novel Extended Depth-of-Focus Contact Lenses.

PURPOSE: To compare the objective and subjective visual performance of a novel contact lens which extends depth of focus by deliberate manipulation of higher-order spherical aberrations and a commercially available zonal-refractive multifocal lens. METHODS: A prospective, cross-over, randomized, single-masked, short-term clinical trial comprising 41 presbyopes (age 45 to 70 years) wearing novel Extended Depth of Focus lenses (EDOF) and ACUVUE OAYS for Presbyopia (AOP). Each design was assessed on different days with a minimum overnight wash-out. Objective measures comprised high-contrast visual acuity (HCVA, logMAR) at 6 m, 70 cm, 50 cm, and 40 cm; low-contrast visual acuity (LCVA, logMAR) and contrast sensitivity (log units) at 6 m; and stereopsis (seconds of arc) at 40 cm. HCVA at 70 cm, 50 cm, and 40 cm were measured as "comfortable acuity" rather than conventional resolution acuity. Subjective performance was assessed on a 1-10 numeric rating scale for clarity of vision and ghosting at distance, intermediate and near, overall vision satisfaction, ocular comfort, and lens purchase. Statistical analysis included repeated measures ANOVA and paired t tests. RESULTS: HCVA, clarity of vision, and ghosting with EDOF were significantly better than AOP (p < 0.01); however, differences were dependent on testing distances and add groups. Post hoc analysis showed EDOF was significantly better than AOP for HCVA at 70 cm (0.11 ± 0.11 vs. 0.21 ± 0.16, p < 0.001), 50 cm (0.26 ± 0.17 vs. 0.36 ± 0.18, p = 0.003), 40 cm (0.42 ± 0.17 vs. 0.52 ± 0.21, p = 0.001), and LCVA at 6 m (0.22 ± 0.08 vs. 0.27 ± 0.12, p = 0.024). EDOF was significantly better than AOP for clarity of vision at distance (7.7 ± 1.6 vs. 6.8 ± 2.3, p = 0.029), intermediate (8.8 ± 1.4 vs. 7.0 ± 2.2, p < 0.001), and near (7.4 ± 2.4 vs. 5.2 ± 2.7, p < 0.001), ghosting at distance (9.1 ± 1.2 vs. 8.1 ± 2.5, p = 0.005), and overall vision satisfaction (7.6 ± 1.6 vs. 6.0 ± 2.6, p < 0.001). More participants chose to purchase EDOF compared to AOP (61 vs. 39%) and significantly more chose to only-purchase EDOF compared to only-purchase AOP (27 vs. 5%, p = 0.022). CONCLUSIONS: When compared with AOP, EDOF lenses provide better intermediate and near vision performance in presbyopic participants without compromising distance vision.

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

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.

The Global Burden of Potential Productivity Loss from Uncorrected Presbyopia.

PURPOSE: The onset of presbyopia in middle adulthood results in potential losses in productivity among otherwise healthy adults if uncorrected or undercorrected. The economic burden could be significant in lower-income countries, where up to 94% of cases may be uncorrected or undercorrected. This study estimates the global burden of potential productivity lost because of uncorrected functional presbyopia. DESIGN: Population data from the US Census Bureau were combined with the estimated presbyopia prevalence, age of onset, employment rate, gross domestic product (GDP) per capita in current US dollars, and near vision impairment disability weights from the Global Burden of Disease 2010 study to estimate the global loss of productivity from uncorrected and undercorrected presbyopia in each country in 2011. To allow comparison with earlier work, we also calculated the loss with the conservative assumption that the contribution to productivity extends only up to 50 years of age. PARTICIPANTS: The economic modeling did not require the use of subjects. METHODS: We estimated the number of cases of uncorrected or undercorrected presbyopia in each country among the working-age population. The number of working-age cases was multiplied by the labor force participation rate, the employment rate, a disability weight, and the GDP per capita to estimate the potential loss of GDP due to presbyopia. MAIN OUTCOME MEASURES: The outcome being measured is the lost productivity in 2011 US dollars resulting from uncorrected or undercorrected presbyopia. RESULTS: There were an estimated 1.272 billion cases of presbyopia worldwide in 2011. A total of 244 million cases, uncorrected or undercorrected among people aged <50 years, were associated with a potential productivity loss of US $11.023 billion (0.016% of global GDP). If all those people aged <65 years are assumed to be productive, the potential productivity loss would be US $25.367 billion or 0.037% of global GDP. Correcting presbyopia to the level achieved in Europe would reduce the burden to US $1.390 billion (0.002% of global GDP). CONCLUSIONS: Even with conservative assumptions regarding the productive population, presbyopia is a significant burden on productivity, and correction would have a significant impact on productivity in lower-income countries.

The Charles F. Prentice Award Lecture 2014: A 50-Year Research Journey: Giants and Great Collaborators.

This article, an edited version of the 2014 Charles F. Prentice Medal presentation, recounts my 50-year journey in research, from graduation in 1965 to PhD to 2015. The most important lessons I have learned are that great people, "Giants" as I call them, are generous of spirit, creative, insightful, sharing, and caring, and second, that collaboration is really the only way to do what I want to get done. I have been very fortunate to have worked with many outstanding people. As someone said to me at the Prentice Medal presentation, "I don't like you very much but the people you work with are wonderful."My journey started with a PhD investigation into seeing if orthokeratology could control myopia at the City University London in 1966. It then moved to Australia where all aspects of contact lenses were researched to try to make contact lenses safer and more effective by understanding the cornea and anterior eye systems. That journey has now turned to making contact lenses the best they can be to slow the progress of myopia. An extremely high proportion of people who are involved with global eye care initiatives and ambitious projects to develop treatments and interventions for the major vision problems impacting the world are a joy to work with. Evidence-based systems for delivering vision to the more than 600 million people globally that are blind or vision impaired because of uncorrected refractive error have involved amazing people and collaborations. This article pays tribute to the generosity and humanity of my family and the Giants in and outside the field, and many more not so well known, and the people I work with, who have punctuated and greatly enriched this journey and made many of the scientific advances documented here possible.

Effect of Daily Contact Lens Cleaning on Ocular Adverse Events during Extended Wear.

PURPOSE: The purpose of the study was to assess what effect daily cleaning of contact lenses with a multipurpose disinfection solution (MPDS), during 30 nights extended wear, would have on contact lens-related adverse events. METHODS: This was a prospective, open-label, randomized, controlled, parallel-group, 3-month clinical study in which 193 participants were dispensed with lotrafilcon A silicone hydrogel lenses for a 30-day extended-wear schedule and with lenses replaced monthly. Participants were randomized to a control or test group. Test subjects were required to remove lenses daily after waking, clean them with the MPDS, and reinsert the lenses. Control subjects wore lenses without removal for 30 days extended wear. Handling-related lens contamination was assessed at the baseline visit. RESULTS: There was no significant difference between the test and control groups for the incidence of significant corneal infiltrative events (1.3 vs. 4.9%, p = 0.368), total corneal infiltrative events (2.6 vs. 4.9%, p = 0.682), or mechanical events (1.3 vs. 2.5%, p = 1.00). The test group had greater corneal staining (p < 0.047) and fewer mucin balls (p = 0.033). Handling-related lens contamination (unworn lenses) resulted in isolation of Gram-positive bacteria from 92.5% of test lenses compared with 87.5% of control lenses (p = 0.712). Gram-negative bacteria were isolated from 5% of test subjects compared with 2.5% of control subjects (p = 1.00). Fungus was isolated from 2.5% of subjects in both the test and control groups (p = 1.00). CONCLUSIONS: The intervention of daily morning cleaning of the lens surface with an MPDS during extended wear did not significantly influence the incidence of adverse events.

Influence of contact lens power profile on peripheral refractive error.

PURPOSE: To measure the power profile across the optic zone (OZ) of four commercially available soft contact lenses and establish the impact on the peripheral refractive error of the eye. METHODS: The power profiles of a spherical conventional hydrogel contact lens (etafilcon A, J&J Vistakon, Jacksonville, FL USA) and three spherical silicone hydrogel contact lenses (lotrafilcon A and B, CIBA Vision, Duluth, GA USA; enfilcon A, CooperVision, Pleasanton, CA USA) with a labeled power of -3.00 and -6.00 diopters were measured using a Shack-Hartmann wavefront sensor power mapping device. Central and peripheral refraction across the horizontal meridian (nasal and temporal visual field at 20, 30, and 40 degrees) was measured with an open-field autorefractor (Shin Nippon NVision K5001, Osaka Japan) with and without contact lenses in 26 myopic subjects. The relative peripheral refractive error on the eye was estimated and compared with and without contact lenses and between contact lenses. RESULTS: Differences in the distribution of the power profile across the OZ were apparent between contact lens types and powers. No significant differences (p > 0.05) were found between contact lens types for their effect on on-axis refraction. Significant differences (p < 0.05) were found at all peripheral retinal eccentricities between contact lens types. CONCLUSIONS: For a given central power, the four contact lenses exhibited variations in optical power across the OZ of the lens. The distribution of optical power across the OZ has an influence on the peripheral refractive error of the eye.

The BHVI-EyeMapper: peripheral refraction and aberration profiles.

PURPOSE: The aim of this article was to present the optical design of a new instrument (BHVI-EyeMapper, EM), which is dedicated to rapid peripheral wavefront measurements across the visual field for distance and near, and to compare the peripheral refraction and higher-order aberration profiles obtained in myopic eyes with and without accommodation. METHODS: Central and peripheral refractive errors (M, J180, and J45) and higher-order aberrations (C[3, 1], C[3, 3], and C[4, 0]) were measured in 26 myopic participants (mean [±SD] age, 20.9 [±2.0] years; mean [±SD] spherical equivalent, -3.00 [±0.90] diopters [D]) corrected for distance. Measurements were performed along the horizontal visual field with (-2.00 to -5.00 D) and without (+1.00 D fogging) accommodation. Changes as a function of accommodation were compared using tilt and curvature coefficients of peripheral refraction and aberration profiles. RESULTS: As accommodation increased, the relative peripheral refraction profiles of M and J180 became significantly (p < 0.05) more negative and the profile of M became significantly (p < 0.05) more asymmetric. No significant differences were found for the J45 profiles (p > 0.05). The peripheral aberration profiles of C[3, 1], C[3, 3], and C[4, 0] became significantly (p < 0.05) less asymmetric as accommodation increased, but no differences were found in the curvature. CONCLUSIONS: The current study showed that significant changes in peripheral refraction and higher-order aberration profiles occurred during accommodation in myopic eyes. With its extended measurement capabilities, that is, permitting rapid peripheral refraction and higher-order aberration measurements up to visual field angles of ±50 degrees for distance and near (up to -5.00 D), the EM is a new advanced instrument that may provide additional insights in the ongoing quest to understand and monitor myopia development.

The effect of compliance on contact lens case contamination.

PURPOSE: To determine the efficacy of written instructions on contact lens case hygiene and to quantify the effect of noncompliance on contact lens case contamination. METHODS: Data were retrospectively analyzed from 16 prospective, 3-month daily-wear studies during which six commercially available silicone hydrogel contact lenses and seven lens care solutions (LCS) were tested following a similar protocol. Verbal instructions regarding case hygiene (rinse case with LCS, not tap water) were given in nine studies, while the same instructions were given verbally and in written format in seven studies. A survey on contact lens, LCS, and lens case hygiene was completed at 1- and 3-month visits and compliance with case hygiene instructions was determined. Regular contact lens cases were used for 1 month and collected for microbial analysis at the 1- and 3-month visits. The rate of case contamination and the types of microbes contaminating cases were evaluated. RESULTS: Participants given verbal and written instructions were more likely to be compliant with case hygiene instructions than those just given verbal instructions (odds ratio [OR]: 2.19, p < 0.001, 95% confidence interval [CI]: 1.40-3.44). The overall case contamination rate was 79%. Use of tap water to rinse contact lens cases was associated with significantly more cases contaminated with Gram-negative bacteria (GNB) (30% vs. 10%, p < 0.001), a greater risk of GNB case contamination (OR: 2.91, p < 0.001. 95% CI: 1.72-4.92), and a higher quantity of GNB in cases (mean colony-forming unit/case ± SD: 28,286 ± 131,935 vs. 6477 ± 60,447, p < 0.001). CONCLUSIONS: Lens case hygiene can be improved by effective communication of instructions. Contact lens wearers should be actively discouraged from rinsing contact lens cases with tap water because of the increased risk of GNB contamination.

Effect of antibiotic drops on adverse events during extended lens wear.

PURPOSE: Overnight lens wear is associated with increased lens contamination and risk of developing a corneal infiltrate or infectious event. Antibacterial lenses have been proposed as a potential strategy for reducing lens contamination. A proof-of-principle study was conducted to investigate what effect control of potential pathogens, through the use of antibiotic eye drops, would have on the incidence of corneal infiltrative events (CIEs) and on the ocular microbiota and lens contamination. METHODS: This is a prospective, open-label, controlled, parallel-group, 1-month clinical study in which 241 subjects were dispensed with lotrafilcon A silicone hydrogel lenses for 30 days of continuous wear. Subjects were randomized into either test (moxifloxacin 0.5%) or control (rewetting solution) group. One drop was instilled into each eye on waking and before sleeping, while lenses were on-eye. Follow-ups were conducted after one night and 1 month. Lid margin swabs were taken at baseline and at 1 month and worn lenses were aseptically collected at 1 month. RESULTS: The incidence of CIEs was not significantly different between the test (2.6%) and control (3.9%) groups (p = 0.72). Microorganism levels from the test group swabs were significantly lower than those from the control group (p = 0.001). Gram-positive bacteria were less frequently recovered from lower lid swabs from the test group (39.6% vs. 66.0% [p < 0.001], test vs. control, respectively) or from contact lens samples (1.9% vs. 10.5% [p = 0.015], test vs. control, respectively), but there was no difference in gram-negative bacteria (GNB). Corneal infiltrative events were associated with higher levels of lens contamination (p = 0.014) and contamination of lenses with GNB (CIE: 7.3% vs. 0.6% [p = 0.029], GNB contamination vs. no GNB contamination, respectively). DISCUSSION: Twice-daily antibiotic instillation during continuous wear of lenses did not significantly influence the rate of inflammatory events. Corneal infiltrative events were associated with higher levels of lens contamination in general and with contamination by GNB specifically.

Utility and uncorrected refractive error.

PURPOSE: To investigate utility (a preference-based quality of life [QoL] measure) associated with uncorrected refractive error (URE). DESIGN: Cross-sectional study. PARTICIPANTS: A cohort of 341 consecutive patients 40 to 65 years of age with refractive error and no ocular disease impairing vision worse than 20/25 (0.1 logarithm of the minimum angle of resolution [logMAR] units) in the better eye. Without vision correction, 30 had no vision impairment, 65 had only distance vision impairment (DVI), 97 had only near vision impairment (NVI), 112 had moderate amounts of both distance and near vision impairment (DNVI), and 37 had severe impairment (distance or near worse than 20/200 [>1.0 logMAR]) in the better eye. METHODS: All participants underwent a comprehensive eye examination with refraction, aided and unaided visual acuity (VA) at 6 m and 40 cm, and ocular health assessment. Utilities were elicited for a number of scenarios using a standardized, face-to-face time trade-off (TTO) interview method. MAIN OUTCOME MEASURES: The main outcome measure was TTO utility for the participant's own uncorrected vision state. Utilities ranged from 0 to 1, where 0 = death and 1 = perfect vision, and were scaled to account for comorbidities so that 1 = perfect health (adjusted utility). RESULTS: Unaided VA was 0.50 ± 0.24 logMAR at distance in the DVI group, 0.43 ± 0.17 logMAR at near in the NVI group, and 0.72 ± 0.36 and 0.56 ± 0.29 at distance and near, respectively, in the DNVI group. Adjusted utilities for the 3 groups were 0.82 ± 0.16 in the DVI group, 0.81±0.17 in the NVI group, and 0.68 ± 0.25 in the DNVI group. The DVI and NVI group utilities (adjusted and unadjusted) did not differ significantly (P = 0.73 and P = 0.77, respectively). The DNVI utility was significantly worse than that of the DVI and NVI groups (adjusted and unadjusted, P<0.01). CONCLUSIONS: The URE is associated with measurable reductions in utility (and therefore QoL). Reductions are similar regardless of whether near or distance vision is impaired, but worse when both are impaired. The results underscore the significance of the effect of URE on QoL, particularly with respect to uncorrected presbyopia, which has been a relatively neglected area in research and policy. The utility figures in this study can be used as inputs for cost-effectiveness studies relating to URE to assist resource allocation decisions. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Effect of contact lens wear on the diurnal profile of matrix metalloproteinase 9 in tears.

PURPOSE: This study set out to determine how contact lens wear affects the profile of matrix metalloproteinase 9 (MMP-9) in the tear film. METHODS: Flush tears were collected from 47 healthy neophytes before lens wear, during the first day of lens wear, and after 1 month adaptation. Participants were randomized to either Acuvue Oasys or O2OPTIX with the choice of extended (EW) or daily wear (DW). Each time, tears were collected at midday, before sleep, and on waking and analyzed for concentrations of total protein, MMP-9, and its regulators TIMP-1 (tissue inhibitor of metalloproteinases 1) and NGAL (neutrophil gelatinase-associated lipocalin). RESULTS: Initial extended contact lens wear resulted in significantly elevated MMP-9 levels on waking (3598.7 ± 3229.1 ng/mL) compared with the same time point at baseline (2123.3 ± 1762.8; p = 0.02), whereas DW remained unchanged (2373.0 ± 2091.6 ng/mL; p = 0.61). After 1 month of EW, the levels on awakening were no longer different to those of baseline (2408.2 ± 1376.1 ng/mL; p = 0.63). The MMP:TIMP ratio during EW was greater after the first night (18.6 ± 19.9) than both no wear (13.2 ± 13.4) and 1 month (10.4 ± 7.7), but only the latter was significant (p = 0.048). The profile of NGAL did not differ from baseline (p = 0.055). CONCLUSIONS: In the neophyte, the initial period of overnight lens wear seems to disturb the tear film homeostasis, as indicated by a significant increase in MMP-9 on awakening. The return to baseline by 1 month suggests that an adaptive process takes place. No comparable changes are seen in DW.

Combined effect of comfort and adverse events on contact lens performance.

PURPOSE: To report the performance of various contact lenses and lens care solution combinations based on the combined response of subjective comfort and adverse events (AEs). METHODS: A retrospective analysis of 28 lens/solution combinations each tested on approximately 40 participants who wore their assigned combination on a daily wear basis and were followed for a 3-month period, with visits at baseline, 2 weeks, and 1 and 3 months. Lenses included frequent replacement and daily disposables. Solutions included hydrogen peroxide and multipurpose types. Subjective comfort (scale of 1 to 10) and AEs were collected and reported as a group mean and percentage, respectively. The data were converted into a ratio between 0 and 1 to represent the relative performance within the combination series, with a higher ratio indicating better performance in both AE rates and comfort. RESULTS: The overall AE rate was 3.6 events per 100 participant-months (95% confidence interval [95% CI], 2.7 to 4.7%). The rate was found to be lower in daily disposables compared with that in daily wear lenses (3.1 vs. 10.9%, p < 0.001). The overall comfort on insertion rating was 8.3 (95% CI, 8.1 to 8.4), and comfort at end of day was 7.2 (95% CI, 7.0 to 7.4). Based on the 28 lens/solution combinations, there was no significant correlation between overall AE rates and comfort on insertion or at end of day (Pearson correlation, -0.34, p = 0.08; and Pearson correlation, -0.23, p = 0.25, respectively). Less than 18% of the combinations tested combined good comfort with low AE rates. CONCLUSIONS: Both subjective comfort responses and AE rates varied according to the combination of lens type and care system in use. The combinations with the best comfort ratings did not necessarily have a favorable AE rate. Practitioners can maximize behavior with respect to both these factors by choosing an appropriate care system for the lenses they prescribe.

Effect of lens and solution choice on the comfort of contact lens wearers.

PURPOSE: To determine if the ocular comfort of symptomatic contact lens (CL) wearers can be substantially influenced by choosing a better or worse performing CL-lens care product (LCP) combination. METHODS: Twenty-four symptomatic and 13 nonsymptomatic CL wearers were enrolled into a prospective, crossover, randomized clinical trial. Two CL-LCP combinations were chosen from studies previously conducted at the Brien Holden Vision Institute that were found to provide the best (galyfilcon A/polyhexanide, combination 1) and worst performance (balafilcon A/polyquaternium-1 and myristamidopropyl dimethylamine + TearGlyde, combination 2) in terms of end-of-day comfort. Subjects were not informed whether they were categorized as symptomatic or nonsymptomatic nor were they aware of the rankings of each CL-LCP combination. Subjects were randomly allocated to one of the CL-LCP combinations for 8 days on a daily wear basis. Contact lens fitting was assessed after insertion from the packaging solution. Take-home questionnaires assessing ocular comfort and dryness (1 to 10 numeric rating scale) were completed on insertion and after 2 and 8 hours of wear on days 2, 4, and 6. Ocular symptoms were assessed on days 2, 4, and 6 after 8 hours of wear. A 48-hour washout period during which CLs were not worn was applied, with the procedure repeated using the second combination. RESULTS: In symptomatic subjects, combination 1 was rated significantly better than combination 2 after 8 hours of wear for ocular comfort (7.7 ± 1.3 vs. 7.1 ± 1.5, p = 0.01) and ocular dryness (7.5 ± 1.6 vs. 7.0 ± 1.6, p = 0.045), with less frequent symptoms of ocular dryness (p < 0.01) and lens awareness (p < 0.01) reported. No significant differences were found in nonsymptomatic subjects. CONCLUSIONS: Ocular comfort and symptoms in symptomatic CL wearers can be perceptibly improved by switching to an alternative CL-LCP combination. This finding provides justification for the efforts of both eye care practitioners and researchers to improve the comfort of CL wearers.

Adverse events during 2 years of daily wear of silicone hydrogels in children.

PURPOSE: Type and incidence of adverse events and rate of discontinuations for 2 years of daily wear with silicone hydrogel contact lenses in Chinese children with myopia. METHODS: Two hundred forty children aged 7 to 14 years were enrolled in a prospective randomized clinical trial from November 2008 to April 2009. Children with myopia of up to -3.50 diopters (D) spherical equivalent with astigmatism less than or equal to -0.75 D were randomized to one commercial and three experimental lens designs of Lotrafilcon B silicone hydrogel lenses (four groups) used bilaterally on a daily wear, monthly replacement schedule. The main outcome measures were incidence per 100 patient-years (incidence, in percentage) of adverse events and rate of discontinuations. RESULTS: There were no events of microbial keratitis. Fifty-five adverse events (incidence, 14.2%) were seen. There were also 12 recurrent events. The type and incidence percentage were contact lens papillary conjunctivitis (16 events, 4.1%), superior epithelial arcuate lesions (SEALs, six events, 1.5%), corneal erosions (eight events, 2.1%), infiltrative keratitis (five events, 1.3%), asymptomatic infiltrative keratitis (seven events, 1.8%), and asymptomatic infiltrates (13 events, 3.42%). There were differences in the incidence of SEALs between groups (p = 0.023), with the incidence of SEALs being greater with one of the experimental designs. No event resulted in any vision loss. Seventy participants (29.2%) discontinued, with one-third (26 participants, 10.8%) occurring in the first month of lens wear. Discomfort and non-lens-related reasons such as safety concern and disinterest were frequently cited reasons for discontinuations. CONCLUSIONS: Adverse events with daily wear of silicone hydrogels in children were mainly mechanical in nature, and significant infiltrative events were few. The large number of dropouts in the early days of lens wear and their reasons for discontinuation suggest that adaptation and patient motivation are critical for survival in lens wear.

Effect of lens care systems on the clinical performance of a contact lens.

PURPOSE: To evaluate subjective responses, rates of solution-induced corneal staining (SICS), and corneal infiltrative events (CIEs) associated with a silicone hydrogel when worn under a daily disposable (DD) or daily wear (DW) modality. METHODS: Data were obtained from seven prospective clinical trials, involving 283 subjects wearing Senofilcon A contact lenses (Johnson and Johnson Vision Care, Jacksonville, FL). Four groups wore the contact lens on a DW basis using multipurpose solutions (DW-MPS, n = 160), two groups using hydrogen peroxide (DW-H2O2, n = 83), and one group as a DD (n = 40). Participants were followed for 3 months using the same protocol. Subjective ratings were compared between DD and DW groups using a linear mixed model. Rates of SICS and CIE were calculated as the percent frequency of first events within the 3-month study. Association of SICS and CIE with subjective responses was analyzed using a linear mixed model. RESULTS: End-of-day comfort and dryness ratings were significantly better for DD (8.5 ± 1.7 and 8.6 ± 1.7, respectively) compared with DW-H2O2 (7.7 ± 1.8, p = 0.01; 7.6 ± 1.9, p = 0.006, respectively) and DW-MPS (7.7 ± 1.7, p = 0.004; 7.6 ± 2.0, p = 0.003, respectively). Compared with DD, a higher incidence of CIE and SICS was found for DW-MPS (0.0 vs. 3.9%, p = 0.021; 0.9 vs. 8.6%, p = 0.002, respectively). Comfort at insertion and end of day and end-of-day dryness scores were significantly lower for participants who experienced SICS (8.2 ± 1.6, 7.0 ± 1.9, and 7.0 ± 2.2) than those who did not (8.8 ± 1.2, p = 0.004; 7.9 ± 1.7, p = 0.002; and 7.9 ± 1.8, p = 0.003, respectively). Comfort at insertion scores were significantly lower for participants who experienced CIEs than those who did not (8.2 ± 1.5 vs. 8.8 ± 1.4, p = 0.032). CONCLUSIONS: Senofilcon A clinical response is modulated by the lens care products. All lens care products tested reduced subjective responses relative to DD modality, whereas MPS increased the incidence of CIEs and SICS. Senofilcon A performs best when used on a DD basis.

The epidemiology of microbial keratitis with silicone hydrogel contact lenses.

It was widely anticipated that after the introduction of silicone hydrogel lenses, the risk of microbial keratitis would be lower than with hydrogel lenses because of the reduction in hypoxic effects on the corneal epithelium. Large-scale epidemiological studies have confirmed that the absolute and relative risk of microbial keratitis is unchanged with overnight use of silicone hydrogel materials. The key findings include the following: (1) The risk of infection with 30 nights of silicone hydrogel use is equivalent to 6 nights of hydrogel extended wear; (2) Occasional overnight lens use is associated with a greater risk than daily lens use; (3) The rate of vision loss due to corneal infection with silicone hydrogel contact lenses is similar to that seen in hydrogel lenses; (4) The spectrum of causative organisms is similar to that seen in hydrogel lenses, and the material type does not impact the corneal location of presumed microbial keratitis; and (5) Modifiable risk factors for infection include overnight lens use, the degree of exposure, failing to wash hands before lens handling, and storage case hygiene practice. The lack of change in the absolute risk of disease would suggest that exposure to large number of pathogenic organisms can overcome any advantages obtained from eliminating the hypoxic effects of contact lenses. Epidemiological studies remain important in the assessment of new materials and modalities. Consideration of an early adopter effect with studies involving new materials and modalities and further investigation of the impact of second-generation silicone hydrogel materials is warranted.

The future of silicone hydrogels.

Significant advances during the past decade in silicone hydrogel lenses have made them the primary mode for new contact lens wear. Their dominance in the market place is driven largely by the elimination of structural and physiological changes induced by contact lens-induced hypoxia, as exemplified especially by the reduction in limbal redness. However, end-of-day dryness and discomfort still drives many to discontinue lens wear. Evidence also indicates that the rate of serious adverse events, such as microbial keratitis, have not been impacted with the use of silicone hydrogel lenses. Moreover, there are additional challenges relating to 'corneal staining' and corneal infiltrates associated with the incompatibility of lens care product with contact lens polymers. On the other hand, technological advances enabled by the high oxygen platform present opportunities for expanding the use of contact lenses in areas that have exhibited limited uptake in the past such as astigmatism, presbyopia, and importantly myopia control. The challenges and opportunities facing the field will be discussed.

Risk factors for moderate and severe microbial keratitis in daily wear contact lens users.

OBJECTIVE: To establish risk factors for moderate and severe microbial keratitis among daily contact lens (CL) wearers in Australia. DESIGN: A prospective, 12-month, population-based, case-control study. PARTICIPANTS: New cases of moderate and severe microbial keratitis in daily wear CL users presenting in Australia over a 12-month period were identified through surveillance of all ophthalmic practitioners. Case detection was augmented by record audits at major ophthalmic centers. Controls were users of daily wear CLs in the community identified using a national telephone survey. TESTING: Cases and controls were interviewed by telephone to determine subject demographics and CL wear history. Multiple binary logistic regression was used to determine independent risk factors and univariate population attributable risk percentage (PAR%) was estimated for each risk factor. MAIN OUTCOME MEASURES: Independent risk factors, relative risk (with 95% confidence intervals [CIs]), and PAR%. RESULTS: There were 90 eligible moderate and severe cases related to daily wear of CLs reported during the study period. We identified 1090 community controls using daily wear CLs. Independent risk factors for moderate and severe keratitis while adjusting for age, gender, and lens material type included poor storage case hygiene 6.4× (95% CI, 1.9-21.8; PAR, 49%), infrequent storage case replacement 5.4× (95% CI, 1.5-18.9; PAR, 27%), solution type 7.2× (95% CI, 2.3-22.5; PAR, 35%), occasional overnight lens use (<1 night per week) 6.5× (95% CI, 1.3-31.7; PAR, 23%), high socioeconomic status 4.1× (95% CI, 1.2-14.4; PAR, 31%), and smoking 3.7× (95% CI, 1.1-12.8; PAR, 31%). CONCLUSIONS: Moderate and severe microbial keratitis associated with daily use of CLs was independently associated with factors likely to cause contamination of CL storage cases (frequency of storage case replacement, hygiene, and solution type). Other factors included occasional overnight use of CLs, smoking, and socioeconomic class. Disease load may be considerably reduced by attention to modifiable risk factors related to CL storage case practice.