Myopia prevalence and risk factors among medical trainees in Lebanon.

PURPOSE: Myopia is known to be one of the most common causes of impaired vision. It is on the rise, especially among high-risk groups such as medical students. Our study aims to estimate the prevalence of myopia and characterize the associated risk factors among medical trainees in Lebanon. METHODS: This descriptive cross-sectional study targeted all medical students and residents enrolled at the Lebanese University in April 2020. Ocular history data, including refractive errors and daily activities, were collected using an online survey. The primary measure was the prevalence of myopia. The secondary measures were myopia risk factors. Associations of demographic and behavioral factors were explored, and risk factors were analyzed using multivariate logistic regression. RESULTS: Among 365 participants (mean age 22.8 years), 51.6% (185) were female. Myopia was found to be prevalent in 52.8% (193) of medical trainees, with a mean reported refractive error of -2.46 diopters in the study eye (right eye) and -2.41 diopters in the fellow eye (left eye). Three factors were significantly and independently associated with myopia prevalence, namely, history of myopia in siblings (P < 0.001), more hours of near activities (P = 0.026), and less outdoor activity (P = 0.007). CONCLUSION: By quantifying the high prevalence of myopia among medical trainees in Lebanon, as well as the established familial and behavioral risk factors, our findings congruently contribute to the global perspective of this long-studied refractive error.

Machine learning OCT predictors of progression from intermediate age-related macular degeneration to geographic atrophy and vision loss.

Objective: To describe optical coherence tomography (SD-OCT) features, age, gender, and systemic variables that may be used in machine/deep learning studies to identify high-risk patient subpopulations with high risk of progression to geographic atrophy (GA) and visual acuity (VA) loss in the short term. Design: prospective, longitudinal study. Subjects: We analyzed imaging data from patients with iAMD (N= 316) enrolled in Age-Related Eye Disease Study 2 (AREDS2) Ancillary SD-OCT with adequate SD-OCT imaging for repeated measures. Methods: Qualitative and quantitative multimodal variables from the database were derived at each yearly visit over 5 years. Based on statistical analyses developed in the field of cardiology, an algorithm was developed and used to select person-years without GA on colour fundus photography or SD-OCT at baseline. The analysis employed machine learning approaches to generate classification trees. Eyes were stratified as low, average, above average and high risk in 1 or 2 years, based on OCT and demographic features by the risk of GA development or decreased VA by 5+ and 10+ letters. Main outcome measures: new onset of SD-OCT-determined GA and VA loss. Results: We identified multiple retinal and subretinal SD-OCT and demographic features from the baseline visit, each of which independently conveyed low to high risk of new-onset GA or VA loss on each of the follow-up visits at 1 or 2 years. Conclusion: We propose a risk-stratified classification of iAMD based on the combination of OCT-derived retinal features, age, gender and systemic variables for progression to OCT-determined GA and/or VA loss. After external validation, the composite early endpoints may be used as exclusion or inclusion criteria for future clinical studies of iAMD focused on prevention of GA progression or VA loss.

Local Anatomic Precursors to New-Onset Geographic Atrophy in Age-Related Macular Degeneration as Defined on OCT.

PURPOSE: In macula-wide analyses, spectral-domain (SD) optical coherence tomography (OCT) features including drusen volume, hyperreflective foci, and OCT-reflective drusen substructures independently predict geographic atrophy (GA) onset secondary to age-related macular degeneration (AMD). We sought to identify SD OCT features in the location of new GA before its onset. DESIGN: Retrospective study. PARTICIPANTS: Age-Related Eye Disease Study 2 Ancillary SD OCT Study participants. METHODS: We analyzed longitudinally captured SD OCT images and color photographs from 488 eyes of 488 participants with intermediate AMD at baseline. Sixty-two eyes with sufficient image quality demonstrated new-onset GA on color photographs during study years 2 through 7. The area of new-onset GA and one size-matched control region in the same eye were segmented separately, and corresponding spatial volumes on registered SD OCT images at the GA incident year and at 2, 3, and 4 years previously were defined. Differences in SD OCT features between paired precursor regions were evaluated through matched-pairs analyses. MAIN OUTCOME MEASURES: Localized SD OCT features 2 years before GA onset. RESULTS: Compared with paired control regions, GA precursor regions at 2, 3, and 4 years before (n = 54, 33, and 25, respectively) showed greater drusen volume (P = 0.01, P = 0.003, and P = 0.003, respectively). At 2 and 3 years before GA onset, they were associated with the presence of hypertransmission (P < 0.001 and P = 0.03, respectively), hyperreflective foci (P < 0.001 and P = 0.045, respectively), OCT-reflective drusen substructures (P = 0.004 and P = 0.03, respectively), and loss or disruption of the photoreceptor zone, ellipsoid zone, and retinal pigment epithelium (RPE, P < 0.001 and P = 0.005-0.045, respectively). At 4 years before GA onset, precursor regions were associated with photoreceptor zone thinning (P = 0.007) and interdigitation zone loss (P = 0.045). CONCLUSIONS: Evolution to GA is heralded by early local photoreceptor changes and drusen accumulation, detectable 4 years before GA onset. These precede other anatomic heralds such as RPE changes and drusen substructure emergence detectable 1 to 2 years before GA. This study thus identified earlier end points for GA as potential therapeutic targets in clinical trials.

Volumetric Measurement of Subretinal Blebs Using Microscope-Integrated Optical Coherence Tomography.

PURPOSE: We advance studies of subretinal treatments by developing a microscope-integrated optical coherence tomography (MIOCT) image-based method for measuring the volume of therapeutics delivered into the subretinal space. METHODS: A MIOCT image-based volume measurement method was developed and assessed for accuracy and reproducibility by imaging an object of known size in model eyes. This method then was applied to subretinal blebs created by injection of diluted triamcinolone. Bleb volumes obtained from MIOCT were compared to the intended injection volume and the surgeon's estimation of leakage. RESULTS: Validation of the image-based volume measurement method showed accuracy to ±1.0 µL (6.0% of measured volume) with no statistically significant variation under different imaging settings. When this method was applied to subretinal blebs, four of 11 blebs without surgeon-observed leakage yielded a mean volume of 32 ± 12.5 µL, in contrast to the intended 50 µL volume injected from the delivery device. This constituted a mean difference of -18 µL (mean percent error, 36 ± 25%). For all 11 blebs, the surgeon's estimations of leakage were significantly different from and showed no correlation with the volume loss based on image-based volume measurements (P < 0.001, paired t-test; intraclass correlation = 0). CONCLUSIONS: We validated an accurate and reproducible method for measuring subretinal volumes using MIOCT. Use of this method revealed that the intended volume might not be delivered into the subretinal space. MIOCT can allow for accurate assessment of subretinal dose delivered, which may have therapeutic implications in evaluating the efficacy and toxicity of subretinal therapies. TRANSLATIONAL RELEVANCE: Use of MIOCT can provide feedback on the accuracy of subretinal injection volumes delivered.

Optical Coherence Tomography Predictors of Risk for Progression to Non-Neovascular Atrophic Age-Related Macular Degeneration.

PURPOSE: Appearance of geographic atrophy (GA) on color photography (CP) is preceded by specific features on spectral-domain optical coherence tomography (SD OCT). We aimed to build SD OCT-based risk assessment models for 5-year new onset of GA and central GA on CP. DESIGN: Prospective, longitudinal study. PARTICIPANTS: Age-Related Eye Disease Study 2 Ancillary SD OCT study participants with age-related macular degeneration (AMD) with bilateral large drusen or noncentral GA and at least 1 eye without advanced disease (n = 317). METHODS: For 1 eye per participant, qualitative and quantitative SD OCT variables were derived from standardized grading and semiautomated segmentation, respectively, at baseline. Up to 7 years later, annual outcomes were extracted and analyzed to fit multivariate logistic regression models and build a risk calculator. MAIN OUTCOME MEASURES: New onset of CP-visible GA and central GA. RESULTS: Over a follow-up median of 4.0 years and among 292 AMD eyes (without advanced disease at baseline) with complete outcome data, 46 (15.8%) developed central GA. Among 265 eyes without any GA on baseline CP, 70 (26.4%) developed CP-visible GA. Final multivariate models were adjusted for age. In the model for GA, the independent predicting SD OCT factors (P < 0.001-0.03) were: hyperreflective foci and retinal pigment epithelium (RPE) layer atrophy or absence, followed by choroid thickness in absence of subretinal drusenoid deposits, photoreceptor outer segment loss, RPE drusen complex volume, and RPE drusen complex abnormal thinning volume. For central GA, the factors (P < 0.001) were RPE drusen complex abnormal thinning volume, intraretinal fluid or cystoid spaces, hyperreflective foci, and RPE layer atrophy or absence. The models yielded a calculator that computes the probabilities of CP-visible, new-onset GA and central GA after 1 to 5 years. CONCLUSIONS: For AMD eyes with large drusen and no advanced disease, we built a novel risk assessment model-based on age and SD OCT segmentation, drusen characteristics, and retinal pathology-for progression to CP-visible GA over up to 5 years. This calculator may simplify SD OCT grading and with future validation has a promising role as a clinical prognostic tool.

Single-step transepithelial versus alcohol-assisted photorefractive keratectomy in the treatment of high myopia: a comparative evaluation over 12†months.

BACKGROUND/AIMS: To evaluate refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) versus alcohol-assisted PRK (EtOH-PRK) for the correction of high myopia. METHODS: This was a retrospective non-randomised comparative study conducted at the American University of Beirut Medical Center, Beirut, Lebanon. Eyes with myopia (spherical equivalent (SE) larger than -6.00 D) that had undergone EtOH-PRK treatment combined with mitomycin C and TransPRK (SE: -7.53±0.90 D and -7.24±0.77 D, p=0.062), using the Schwind Amaris excimer laser, were included. 59 eyes (37 patients) that had single-step TransPRK were compared with 59 eyes (36 patients) that had EtOH-PRK. Visual and refractive outcomes, including analysis of astigmatism, and corneal higher order aberrations (HOAs) at 6.0 mm optical zone, were compared for 12 months postoperatively. RESULTS: Baseline characteristics were similar between the two groups (p>0.05). The SE deviation from target (SEDT) at 1 week, 1, 3, 6 and 12 months follow-up visits were similar between groups (p=0.428). At 12 months, 81.3% and 73.3% of eyes that had undergone TransPRK and EtOH-PRK, respectively, were between ±0.50 D SEDT (p=0.381). Mean cylinder power was 0.33±0.26 D versus 0.41±0.30 D at 12 months follow-up (p=0.140). The mean success index was 0.50±0.50 for the TransPRK group and 0.49±0.52 for the EtOH-PRK group (p=0.939), while the absolute mean angle of error was 7.81°±61.98° vs 13.12°±71.86° (p=0.667), respectively. The change in total, spherical and comatic corneal HOAs were similar in both groups at 12 months (p>0.05). Haze was similar between both groups; two eyes had +1 haze at 12 months in the TransPRK group versus zero eyes among the EtOH-PRK group (p=0.154). CONCLUSIONS: Single-step TransPRK for high myopia with or without astigmatism appears to yield similar visual, refractive and safety results as EtOH-PRK.