Evaluating the efficacy and safety of therapeutic interventions for corneal neuropathy: A systematic review.

Corneal neuropathy involves corneal nerve damage that disrupts ocular surface integrity, negatively impacting quality-of-life from pain and impaired vision. Any ocular or systemic condition that damages the trigeminal nerve can lead to corneal neuropathy. However, the condition currently does not have standardized diagnostic criteria or treatment protocols. The primary aim of this systematic review was to evaluate the efficacy and safety of interventions for treating corneal neuropathy. Randomized controlled trials (RCTs) that investigated corneal neuropathy treatments were eligible if the intervention(s) was compared to a placebo or active comparator. Comprehensive searches were conducted in Ovid MEDLINE, Ovid Embase and clinical trial registries from inception to July 2022. The Cochrane Risk-of-Bias 2 tool was used to assess study methodological quality. Certainty of the body of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Overall, 20 RCTs were included. Evaluated interventions comprised regenerative therapies (n=6 studies), dietary supplements (n=4), anti-glycemic agents (n=3), combination therapy (n=3), supportive therapies (n=2) and systemic pain pharmacotherapies (n=2). Nine RCTs were judged at high risk of bias for most outcomes. Definitions for corneal neuropathy in the populations varied substantially across studies, consistent with lack of consensus on diagnostic criteria. A diverse range of outcomes were quantified, likely reflecting absence of an agreed core outcome. There was insufficient evidence to draw definitive conclusions on the efficacy or safety of any intervention. There was low or very low certainty evidence for several neuroregenerative agents and dietary supplements for improving corneal nerve fiber length in corneal neuropathy due to dry eye disease and diabetes. Low or very low certainty evidence was found for neuroregenerative therapies and dietary supplements not altering corneal immune cell density. This review identifies a need to standardize the clinical definition of corneal neuropathy and define a minimum set of core outcome measures. Together, this will provide a foundation for improved phenotyping of clinical populations in studies, and improve capacity to synthesize data to inform evidence-based based care. Protocol registration: PROSPERO ID: CRD42022348475.

Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults.

BACKGROUND: 'Blue-light filtering', or 'blue-light blocking', spectacle lenses filter ultraviolet radiation and varying portions of short-wavelength visible light from reaching the eye. Various blue-light filtering lenses are commercially available. Some claims exist that they can improve visual performance with digital device use, provide retinal protection, and promote sleep quality. We investigated clinical trial evidence for these suggested effects, and considered any potential adverse effects. OBJECTIVES: To assess the effects of blue-light filtering lenses compared with non-blue-light filtering lenses, for improving visual performance, providing macular protection, and improving sleep quality in adults. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; containing the Cochrane Eyes and Vision Trials Register; 2022, Issue 3); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and WHO ICTRP, with no date or language restrictions. We last searched the electronic databases on 22 March 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs), involving adult participants, where blue-light filtering spectacle lenses were compared with non-blue-light filtering spectacle lenses. DATA COLLECTION AND ANALYSIS: Primary outcomes were the change in visual fatigue score and critical flicker-fusion frequency (CFF), as continuous outcomes, between baseline and one month of follow-up. Secondary outcomes included best-corrected visual acuity (BCVA), contrast sensitivity, discomfort glare, proportion of eyes with a pathological macular finding, colour discrimination, proportion of participants with reduced daytime alertness, serum melatonin levels, subjective sleep quality, and patient satisfaction with their visual performance. We evaluated findings related to ocular and systemic adverse effects. We followed standard Cochrane methods for data extraction and assessed risk of bias using the Cochrane Risk of Bias 1 (RoB 1) tool. We used GRADE to assess the certainty of the evidence for each outcome. MAIN RESULTS: We included 17 RCTs, with sample sizes ranging from five to 156 participants, and intervention follow-up periods from less than one day to five weeks. About half of included trials used a parallel-arm design; the rest adopted a cross-over design. A variety of participant characteristics was represented across the studies, ranging from healthy adults to individuals with mental health and sleep disorders. None of the studies had a low risk of bias in all seven Cochrane RoB 1 domains. We judged 65% of studies to have a high risk of bias due to outcome assessors not being masked (detection bias) and 59% to be at high risk of bias of performance bias as participants and personnel were not masked. Thirty-five per cent of studies were pre-registered on a trial registry. We did not perform meta-analyses for any of the outcome measures, due to lack of available quantitative data, heterogenous study populations, and differences in intervention follow-up periods. There may be no difference in subjective visual fatigue scores with blue-light filtering lenses compared to non-blue-light filtering lenses, at less than one week of follow-up (low-certainty evidence). One RCT reported no difference between intervention arms (mean difference (MD) 9.76 units (indicating worse symptoms), 95% confidence interval (CI) -33.95 to 53.47; 120 participants). Further, two studies (46 participants, combined) that measured visual fatigue scores reported no significant difference between intervention arms. There may be little to no difference in CFF with blue-light filtering lenses compared to non-blue-light filtering lenses, measured at less than one day of follow-up (low-certainty evidence). One study reported no significant difference between intervention arms (MD - 1.13 Hz lower (indicating poorer performance), 95% CI - 3.00 to 0.74; 120 participants). Another study reported a less negative change in CFF (indicating less visual fatigue) with high- compared to low-blue-light filtering and no blue-light filtering lenses. Compared to non-blue-light filtering lenses, there is probably little or no effect with blue-light filtering lenses on visual performance (BCVA) (MD 0.00 logMAR units, 95% CI -0.02 to 0.02; 1 study, 156 participants; moderate-certainty evidence), and unknown effects on daytime alertness (2 RCTs, 42 participants; very low-certainty evidence); uncertainty in these effects was due to lack of available data and the small number of studies reporting these outcomes. We do not know if blue-light filtering spectacle lenses are equivalent or superior to non-blue-light filtering spectacle lenses with respect to sleep quality (very low-certainty evidence). Inconsistent findings were evident across six RCTs (148 participants); three studies reported a significant improvement in sleep scores with blue-light filtering lenses compared to non-blue-light filtering lenses, and the other three studies reported no significant difference between intervention arms. We noted differences in the populations across studies and a lack of quantitative data. Device-related adverse effects were not consistently reported (9 RCTs, 333 participants; low-certainty evidence). Nine studies reported on adverse events related to study interventions; three studies described the occurrence of such events. Reported adverse events related to blue-light filtering lenses were infrequent, but included increased depressive symptoms, headache, discomfort wearing the glasses, and lower mood. Adverse events associated with non-blue-light filtering lenses were occasional hyperthymia, and discomfort wearing the spectacles. We were unable to determine whether blue-light filtering lenses affect contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels or overall patient visual satisfaction, compared to non-blue-light filtering lenses, as none of the studies evaluated these outcomes. AUTHORS' CONCLUSIONS: This systematic review found that blue-light filtering spectacle lenses may not attenuate symptoms of eye strain with computer use, over a short-term follow-up period, compared to non-blue-light filtering lenses. Further, this review found no clinically meaningful difference in changes to CFF with blue-light filtering lenses compared to non-blue-light filtering lenses. Based on the current best available evidence, there is probably little or no effect of blue-light filtering lenses on BCVA compared with non-blue-light filtering lenses. Potential effects on sleep quality were also indeterminate, with included trials reporting mixed outcomes among heterogeneous study populations. There was no evidence from RCT publications relating to the outcomes of contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels, or overall patient visual satisfaction. Future high-quality randomised trials are required to define more clearly the effects of blue-light filtering lenses on visual performance, macular health and sleep, in adult populations.

TFOS Lifestyle: Impact of the digital environment on the ocular surface.

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).

TFOS Lifestyle: Impact of nutrition on the ocular surface.

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

TFOS Lifestyle - Evidence quality report: Advancing the evaluation and synthesis of research evidence.

Evidence-based practice is a dominant paradigm in healthcare that emphasizes the importance of ensuring the translation of the best available, relevant research evidence into practice. An Evidence Quality Subcommittee was established to provide specialized methodological support and expertise to promote rigorous and evidence-based approaches for the Tear Film and Ocular Surface Society (TFOS) Lifestyle Epidemic reports. The present report describes the purpose, scope, and activity of the Evidence Quality Subcommittee in the undertaking of high-quality narrative-style literature reviews, and leading prospectively registered, reliable systematic reviews of high priority research questions, using standardized methods for each topic area report. Identification of predominantly low or very low certainty evidence across the eight systematic reviews highlights a need for further research to define the efficacy and/or safety of specific lifestyle interventions on the ocular surface, and to clarify relationships between certain lifestyle factors and ocular surface disease. To support the citation of reliable systematic review evidence in the narrative review sections of each report, the Evidence Quality Subcommittee curated topic-specific systematic review databases and relevant systematic reviews underwent standardized reliability assessment. Inconsistent methodological rigor was noted in the published systematic review literature, emphasizing the importance of internal validity assessment. Based on the experience of implementing the Evidence Quality Subcommittee, this report makes suggestions for incorporation of such initiatives in future international taskforces and working groups. Content areas broadly relevant to the activity of the Evidence Quality Subcommittee, including the critical appraisal of research, clinical evidence hierarchies (levels of evidence), and risk of bias assessment, are also outlined.

Is critical flicker-fusion frequency a valid measure of visual fatigue? A post-hoc analysis of a double-masked randomised controlled trial.

PURPOSE: Critical flicker-fusion frequency (CFF) has been used in clinical studies as a measure of visual fatigue. We examine the correlation between CFF and subjective reports of visual fatigue in a group of symptomatic computer users, to consider whether CFF may be used as a surrogate measure of visual fatigue symptoms. METHODS: We analysed data from a previous randomised controlled trial. One hundred and twenty adults, diagnosed with computer vision syndrome, had CFF and visual fatigue symptoms quantified before and after a visually demanding 2-h computer task. Symptoms were assessed using a questionnaire with nine subcomponents that summed to a total score of 900. CFF was measured using a two-interval forced-choice method, with the flicker rate altered by a computer-controlled staircase procedure. For our primary analysis, we determined Spearman correlation coefficients between post-task symptom scores and CFF, and between change from baseline symptom scores and CFF. We also used a bootstrap procedure to consider whether symptom score subcomponents were significantly (Bonferroni-corrected) different from overall scores with regard to their correlations with CFF. RESULTS: Although visual fatigue symptom scores altered significantly post-task (mean change: 92 units; 95% confidence interval [CI]: 11 to 122), CFF did not (mean change -0.7 Hz; 95% CI: -1.7 to 0.3). There was no significant correlation between overall symptom scores and CFF, either for the post-task (r = -0.13; 95% CI: -0.31 to 0.05) or the change from baseline (r = -0.18; 95% CI: -0.35 to 0.01) analysis. Subcomponents of the symptom questionnaire did not show a significant correlation with CFF, either for the post-task or the change from baseline analysis. CONCLUSIONS: We find that CFF is not a useful surrogate for symptoms of visual fatigue, given its low correlation with scores on a visual fatigue symptom questionnaire.

Interventions for the Management of Computer Vision Syndrome: A Systematic Review and Meta-analysis.

TOPIC: To evaluate the efficacy and safety of interventions for treating eye strain related to computer use relative to placebo or no treatment. CLINICAL RELEVANCE: Computer use is pervasive and often associated with eye strain, referred to as computer vision syndrome (CVS). Currently, no clinical guidelines exist to help practitioners provide evidence-based advice about CVS treatments, many of which are marketed directly to patients. This systematic review and meta-analysis was designed to help inform best practice for eye care providers. METHODS: Eligible randomized controlled trials (RCTs) were identified in Ovid MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and trial registries, searched from inception through November 23, 2021. Eligible studies were appraised for risk of bias and were synthesized. The certainty of the body of evidence was judged using the Grading of Recommendations, Assessment, Development, and Evaluation system. Standardized mean differences (SMDs) were used when differently scaled measures were combined. RESULTS: Forty-five RCTs, involving 4497 participants, were included. Multifocal lenses did not improve visual fatigue scores compared with single-vision lenses (3 RCTs; SMD, 0.11; 95% confidence interval [CI], -0.14 to 0.37; P = 0.38). Visual fatigue symptoms were not reduced by blue-blocking spectacles (3 RCTs), with evidence judged of low certainty. Relative to placebo, oral berry extract supplementation did not improve visual fatigue (7 RCTs; SMD, -0.27; 95% CI, -0.70 to 0.16; P = 0.22) or dry eye symptoms (4 RCTs; SMD, -0.10; 95% CI, -0.54 to 0.33; P = 0.65). Likewise, berry extract supplementation had no significant effects on critical flicker-fusion frequency (CFF) or accommodative amplitude. Oral omega-3 supplementation for 45 days to 3 months improved dry eye symptoms (2 RCTs; mean difference [MD], -3.36; 95% CI, -3.63 to -3.10 on an 18 unit scale; P < 0.00001) relative to placebo. Oral carotenoid supplementation improved CFF (2 RCTs; MD, 1.55 Hz; 95% CI, 0.42 to 2.67 Hz; P = 0.007) relative to placebo, although the clinical significance of this finding is unclear. DISCUSSION: We did not identify high-certainty evidence supporting the use of any of the therapies analyzed. Low-certainty evidence suggested that oral omega-3 supplementation reduces dry eye symptoms in symptomatic computer users.

Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial.

PURPOSE: To investigate if blue-blocking lenses are effective in reducing the ocular signs and symptoms of eye strain associated with computer use. DESIGN: Double-masked, randomized controlled trial. METHODS: A total of 120 symptomatic computer users were randomly assigned (1:1) into a "positive" or "negative" advocacy arm (ie, a clinician either advocating or not advocating for the intervention via a prerecorded video). Participants were further sub-randomized (1:1) to receive either clear (placebo) or blue-blocking spectacles. All participants were led to believe they had received an active intervention. Participants performed a 2-hour computer task while wearing their assigned spectacle intervention. The prespecified primary outcome measures were the mean change (post- minus pre-computer task) in eye strain symptom score and critical flicker-fusion frequency (CFF, an objective measure of eye strain). The study also investigated whether clinician advocacy of the intervention (in a positive or negative light) modulated clinical outcomes. RESULTS: All participants completed the study. In the primary analysis, for CFF, no significant effect was found for advocacy type (positive or negative, p = .164) and spectacle intervention type (blue-blocking or clear lens, p = .304). Likewise, for eye strain symptom score, no differences were found for advocacy (p = .410) or spectacle lens types (p = .394). No adverse events were documented. CONCLUSIONS: Blue-blocking lenses did not alter signs or symptoms of eye strain with computer use relative to standard clear lenses. Clinician advocacy type had no bearing on clinical outcomes.

Migraine Screening in Primary Eye Care Practice: Current Behaviors and the Impact of Clinician Education.

BACKGROUND: Migraine is underdiagnosed and undertreated. Optometrists are primary eye care providers, who regularly encounter people with migraine as an incidental finding during routine eye examinations, or when patients present to rule out whether visual or ocular problems are contributing to headache symptoms. Knowledge and use of a migraine screening tool in optometric practice is, therefore, important to be able to identify and refer people with migraine for appropriate management. OBJECTIVE: We sought to investigate optometrists' current behaviors regarding screening for migraine, and to assess the effectiveness of an educational resource in promoting the use of a 3-item validated migraine screening questionnaire, the ID-Migraine. METHODS: We first conducted a cross-sectional study using a survey to assess optometrists' current knowledge and behaviors about migraine screening and willingness to participate in a pilot implementation program. Participants who provided their contact details were invited to watch an online educational resource about a validated migraine screening tool. After 6 weeks, these participants were invited to participate in a follow-up cohort study involving a survey to assess the effectiveness of the educational resource. RESULTS: Ninety-eight optometrists completed the initial survey as part of the cross-sectional study. We found that most optometrists actively asked patients about migraine (79/98 respondents, 81%) as part of routine eye examinations and self-rated themselves as confident in identifying migraine (71/98 respondents, 72%). However, the majority (90/98 respondents, 92%) were not aware of any validated migraine screening tools. Seventy-eight respondents provided their contact details to receive information about the subsequent cohort study. In response to the follow-up study survey (31/78 participants, 40%), 45% (14/31 respondents) of participants self-reported using the ID-Migraine tool after watching our educational video, and most of these participants (12/14 respondents, 86%) were likely or extremely likely to continue to use the tool in their practice. CONCLUSIONS: From our initial cross-sectional survey, we conclude that optometrists do not currently use validated screening tools for migraine and as such, there is an opportunity for continuing professional development in this area. Our follow-up cohort study demonstrates that educating optometrists on the importance and utility of a validated migraine screening tool is achievable with a relatively simple, low-time investment intervention (an online educational video). Such education may result in improved identification of migraine, which may lead to improved management.

Omega-3 Fatty Acids and Eye Health: Opinions and Self-Reported Practice Behaviors of Optometrists in Australia and New Zealand.

This study investigated optometrists' attitudes and self-reported practice behaviors towards omega-3 fatty acids for eye health, and knowledge and understanding of their potential risks and benefits. An anonymous online survey was distributed to optometrists in Australia and New Zealand. Questions included practitioner demographics and practice modality; self-reported practices and recommendations relating to diet, nutritional supplements, and omega-3 fatty acids for age-related macular degeneration (AMD) and dry eye disease (DED); and practitioner knowledge about omega-3 fatty acids. Of 206 included surveys, most respondents (79%) indicated recommending for their patients to consume omega-3 fatty acids to improve their eye health. Sixty-eight percent of respondents indicated recommending omega-3-rich foods for AMD management, while 62% indicated recommending omega-3 supplements. Most respondents (78%) indicated recommending omega-3-rich foods or supplements for DED. For DED, recommended omega-3 supplement dosages were (median [inter-quartile range, IQR]) 2000 mg [1000-2750 mg] per day. The main sources of information reported by respondents to guide their clinical decision making were continuing education articles and conferences. In conclusion, optometrists routinely make clinical recommendations about diet and omega-3 fatty acids. Future education could target improving optometrists' knowledge of differences in the evidence for whole-food versus supplement sources of omega-3 fatty acids in AMD. Further research is needed to address uncertainties in the evidence regarding optimal omega-3 dosage and formulation composition in DED.

Correlation of retinal changes with choroidal changes in acute and recurrent central serous chorioretinopathy assessed by swept-source optical coherence tomography.

PURPOSE: To evaluate affected choroidal regions and corresponding retinal changes in acute and recurrent central serous chorioretinopathy using swept-source optical coherence tomography. METHODS: The foveal and subfoveal choroidal thicknesses were measured with swept-source optical coherence tomography. The retina was divided into five zones on the swept-source optical coherence tomography image based on baseline choroidal thickness being <100, 100-199, 200-299, 300-399 and ⩾400 µm. The retinal and choroidal thicknesses in the same five regions were evaluated during follow-up. The measurements were then compared between baseline (when central serous chorioretinopathy was active) and follow-up (after complete resolution of disease). RESULTS: At baseline, in the acute group, the mean outer retinal layer thickness was significantly higher in areas with thicker choroid and lower in areas with thinner choroid. No such change was noticed in the recurrent group. In the acute group, the overall retinal thickness from baseline to follow-up decreased from 269.84 to 251.9 µm, ganglion cell layer thickness decreased from 107.14 to 101.28 µm, retinal nerve fibre layer thickness decreased from 56.96 to 49.33 µm, and no significant difference was noted in choroidal thickness. In the recurrent group, choroidal thickness significantly increased from 254.58 to 262.55 µm and ganglion cell layer decreased from 103.43 to 94.01 µm. No significant difference was noted in overall retina and retinal nerve fibre layer. Reduction in choroidal and retinal layer thicknesses was better in eyes which underwent laser treatment than the observation group. CONCLUSION: Swept-source optical coherence tomography might serve as an important non-invasive tool for both evaluating the extent of pathology and to predict the recurrence rate.

Management of macular edema with branch retinal vein occlusion in a case of secondary polycythemia.

Purpose: We report a case of polycythemia with an ocular complication of branch retinal vein occlusion associated with macular edema that was managed by anti-vascular endothelial growth factor (VEGF) and systemic management. Methods: A 43-year-old, one-eyed male, a known case of polycythemia presented with complaints of decreased vision in the right eye. He underwent comprehensive eye evaluation, fundus photography and optical coherence tomography at the baseline visit and post intravitreal ranibizumab 1-, 3-, 4- and 11-month follow-up. Results: A patient with polycythaemia was diagnosed in the right eye with superotemporal branch retinal vein occlusion and macular edema, which clinically and on optical coherence tomography resolved after 1 intravitreal injection of ranibizumab. However, as he discontinued systemic management, macular edema reappeared and the edema resolved well after intravitreal ranibizumab. He then became more compliant to the systemic therapy and was asymptomatic for the last 7 months. Conclusion: In a case of retinal vein occlusion with macular edema of recognizable cause, the management of systemic disease and anti-VEGF can give satisfactory results.

Insights into Australian optometrists' knowledge and attitude towards prescribing blue light-blocking ophthalmic devices.

PURPOSE: The aim of this cross-sectional study was to survey Australian optometrists regarding their attitudes towards, and knowledge of, blue light-blocking lenses designed to attenuate blue light transmission to the eye. METHODS: A 29-item survey was distributed at a major national optometry education conference and through professional networks. Respondents provided information regarding their demographics and practice modalities, knowledge about the potential effects of blue light, and attitudes towards prescribing blue light-blocking ophthalmic devices. Ordinal logistic regression analysis was performed to assess the factors that predicted optometrists' prescribing of blue light-blocking lenses. RESULTS: Of 372 respondents, 75.3% indicated prescribing blue light-blocking spectacle lenses in their clinical practice. Forty-four per cent of optometrists considered daily environmental exposure to blue light as a potential cause of retinal damage, and approximately half of respondents thought blue light emitted from computer screens was an important factor in causing computer vision syndrome. About half of optometrists considered placebo effects to potentially play a role, at least sometimes, in patients' experiences with blue light-blocking lenses. Most optometrists estimated that they first prescribed a blue light-blocking lens in 2016. The most common reason optometrists prescribed these devices was for patients who were computer or electronic device users (87.9%). The two main sources of information used to guide practitioners' management approaches were conference presentations and manufacturer product information. Practitioners were significantly more likely to prescribe blue light-blocking lenses if they considered blue light to cause either retinal damage (odds ratio, OR 2.28, 95%CI 1.34-3.88, p = 0.002) or computer vision syndrome (OR 2.52, 95%CI 1.41-4.50, p = 0.002) compared with practitioners who did not consider such factors to be relevant. CONCLUSION: Prescribing trends by Australian optometrists in relation to blue light-blocking lenses reflect the inconclusive nature of several aspects of the evidence in this field. Blue light-blocking lens prescribing has increased since 2010, despite practitioners acknowledging the lack of high-quality evidence to support their use and also commonly believing that placebo effects may have a role in patient responses to these lenses. Information from this study will help inform the development of resources to guide evidence-based prescribing of blue light-blocking lens products.

Age of Onset of Diabetes and Its Comparison with Prevalence and Risk Factors for Diabetic Retinopathy in a Rural Population of India.

AIM: To compare the age of onset of diabetes with the prevalence and risk factors of diabetic retinopathy (DR) in a rural population of India. METHODS: This is a population-based study for which 1,190 people with diabetes were recruited from rural areas of the districts of Kanchipuram and Thiruvallur, Tamil Nadu, India. The fundi of all patients were photographed using a 45°, four-field stereoscopic digital fundus camera. The diagnosis of DR was based on the Klein classification of the Early Treatment Diabetic Retinopathy Study scale. RESULTS: The prevalence of DR was 11.5% in individuals with known onset of diabetes (aged ≤40 years) compared to 10.0% in those with late onset. The risk factors for any DR in both groups included longer known duration of diabetes, use of insulin, and the presence of high systolic blood pressure and hypertension. In the group with known onset of diabetes at ≤40 years, older age (p < 0.0001) and male gender (p = 0.018) were the significant factors for DR. In the group with age of onset of diabetes at > 40 years, high diastolic pressure (p = 0.001), higher HbA1c (p < 0.0001), high microalbuminuria (p < 0.0001), and high macroalbuminuria (p < 0.008) were the significant risk factors for DR. CONCLUSION: Control of risk factors in people with younger age of onset of diabetes may reduce both the prevalence and impact of retinopathy in rural populations.

The prevalence and risk factors for cataract in rural and urban India.

PURPOSE: To report the prevalence and risk factors of cataract and its subtypes in older age group. METHODS: A total of 6617 subjects were recruited from both rural and urban areas. A detailed history including data on demographic, socioeconomic and ocular history was obtained. Lens opacity was graded according to the Lens Opacity Classification System III (LOCS III). RESULTS: Cataract was present in 1094 of the rural and 649 subjects in the urban population. Monotype subtype cataracts were found in 32% and 25% in rural and urban population and 12.68% and 18.6% were mixed cataracts in the rural and urban groups. In baseline characteristics history of diabetes, alcohol intake and presence of age-related macular degeneration were the risk factors in urban group. On multivariate analysis, the only significant risk factors for any cataract in subjects ≥60 years were increasing age in both rural [odds ratio (OR), 1.07] and urban (OR, 1.08) population, and HbA1c (OR, 1.14) in rural population. Overweight (OR, 0.6) was found to be a protective factor, and lower social economic status (OR, 1.52) a risk factor for cataract in urban population. A significant urban-rural difference was found in the prevalence of cataract and its subtypes (P ≤ 0.05). CONCLUSION: We found the risk factors for any cataract in older age group to be increasing age and HbA1c in rural group. Age and lower social economic status were found to be the risk factors in urban arm. A statistically significant difference was found on comparison of the prevalence of cataract and its subtypes between the rural and urban population.

Anesthesia Considerations in Modified Osteo-odonto-keratoprosthesis.

PURPOSE: To elucidate anesthesia-related challenges in patients who underwent modified osteo-odonto-keratoprosthesis (MOOKP). DESIGN: Retrospective cohort study. METHODS: Medical records of consecutive patients who underwent MOOKP surgery between January 2007 and January 2015 were reviewed. Data including demographic details, systemic comorbidities, indications for MOOKP, and anesthesia techniques at various stages of MOOKP were collected and analyzed. RESULTS: A total of 74 patients (47 men, 27 women) were included in this study. The mean age of the patients was 29.7 ± 9.1 years. The most common indication for MOOKP was Stevens-Johnson syndrome (53%), followed by chemical burn (38%). In all stages of the MOOKP procedure, 94.6% of patients were American Society of Anesthesiologists (ASA) grade II, whereas 5.4% were ASA grade III. Mallampati score 1 was found in 79.7% of patients in stage 1A, 82.4% of patients in stage 1B + 1C, and 81.1% of patients in stage 2. Recovery grade of 10 was noted in all patients at all stages of the MOOKP procedure. Intubation in the second attempt was carried out in 8 patients and oral intubation in stage 1B + 1C was performed in 4 patients. Difficulty in intubation was noted in 3 patients in stage 1A, 4 patients in stage 1B + 1C, and 1 patient in stage 2. CONCLUSIONS: In patients undergoing MOOKP, a good preoperative anesthetic evaluation and intraoperative anesthesia plan before each stage could help in successful administration of anesthesia in these patients.

Reasons for spectacle reassessment in a tertiary eye care centre over a period of six years.

BACKGROUND: To determine the spectacle reassessment rates of dissatisfied patients returning to the optical services department of a tertiary eye centre in India over a period of six years. METHODS: A total of 169,567 spectacles were dispensed from the optical services department between January 2010 and December 2015. The spectacle reassessment forms of dissatisfied patients who returned to the optical services department with their spectacles were analysed. RESULTS: A total of 797 spectacle reassessment forms were analysed. The overall spectacle reassessment rate during the study period was found to be 0.5% (95% CI: 0.467-0.472). The mean age of patients returning back for spectacle reassessment was 48 years (SD 19.9, range 3-97 years). Error in refractive correction measurement was found to be the most common reason for spectacle reassessment (54.7%), followed by dispensing error (21.1%), documentation errors while writing the prescription from the medical records in the tertiary eye care centre (12.7%), transcription error occurring at the optical services department (10.8%) and ocular pathologies (0.8%). No statistically significant difference was observed in the year-wise spectacle reassessment rates during the study period (p = 0.14). CONCLUSIONS: The frequency of spectacle reassessment rate in a tertiary eye care centre was low, with errors in measuring refractive errors contributing the most to the reassessment and reorder of spectacles.