Biometry-Based Technique for Determining the Anterior Scleral Thickness: Validation Using Optical Coherence Tomography Landmarks.

Purpose: Considering the potential role of anterior scleral thickness (AST) in myopia and the ubiquitous use of optical biometers, we applied and validated a biometry-based technique for estimating AST using optical coherence tomography (OCT) landmarks. Methods: The AST was determined across four meridians in 62 participants (aged 20-37 years) with a swept-source OCT and a noncontact optical biometer at a mean ± SD distance of 3.13 ± 0.88 mm from the limbus. The biometer's graticule was focused and aligned with the anterior scleral reflex, which led to the generation of four prominent A-scan peaks: P1 (anterior bulbar conjunctiva), P2 (anterior episclera), P3 (anterior margin of anterior sclera), and P4 (posterior margin of anterior sclera), which were analyzed and compared with the corresponding OCT landmarks to determine tissue thickness. Results: The AST measurements between biometer and OCT correlated for all meridians (r ≥ 0.70, overall r = 0.82; coefficient of variation [CV], 9%-12%; P < 0.01). The mean difference ± SD between two instruments for overall AST measures was 3 ± 2.8 µm (range, -18 to +16 µm; lower limits of agreement, -89 to +83 µm; P = 0.23) across all meridians. The mean ± SE AST with both instruments was found to be thickest at the inferior (562 ± 7 µm and 578 ± 7 µm) and thinnest at the superior (451 ± 7 µm and 433 ± 6 µm) meridian. The biometer demonstrated good intrasession (CV, 8.4%-9.6%) and intersession (CV, 7.9%-13.3%) repeatability for AST measurements across all meridians. Conclusions: The noncontact optical biometer, which is typically used to determine axial length, is capable of accurately estimating AST based on OCT landmarks. Translational Relevance: The high-resolution optical biometers can demonstrate wider application in the field of myopia research and practice to determine AST.

Is There Any Association between Nutrition and Myopia? A Systematic Review.

SIGNIFICANCE: This systematic review highlights the possible role of nutrition in myopia based on qualitative analysis of vast and diverse literature that investigated this association. PURPOSE: We systematically reviewed the outcomes of the studies that previously investigated the association between nutrition and myopia. METHODS: EMBASE, MEDLINE, and PubMed were searched by two independent authors to identify cross-sectional, cohort, retrospective, or interventional studies that assessed the association of nutrition with myopia from inception to the year 2021. Furthermore, the reference list of the included articles was screened. The data from the included studies were extracted, and qualitative analysis was performed. Quality assessment for noninterventional studies and interventional trials was performed using the Newcastle-Ottawa Scale and Cochrane RoB 2, respectively. RESULTS: Twenty-seven articles were included in the review. Most of the nutrients and dietary elements investigated in noninterventional studies showed inconsistencies in their association with myopia, with the majority indicating no association. Nine studies showed a significant association of diverse nutrients and dietary elements with either an increase (odds ratio, 1.07) or a decrease (odds ratio, 0.5 to 0.96) in the risk of myopia development. However, a majority of these studies have minimal odds ratios with wider or overlapping confidence intervals, implicating weaker associations. All three nutrients and dietary elements assessed in the interventional trial had implications for myopia control, with two trials indicating a clinically minimal effect. CONCLUSIONS: This review implies that there is some evidence to indicate a potential influence of specific nutrients and dietary elements in myopia development, which are supported by several theories. However, given the vast, diverse, and complex nature of nutrition, more systematic investigation is warranted to comprehend the extent to which these specific nutrients and dietary elements are associated with myopia through longitudinal studies by subduing the limitations in the existing literature.

Myopia progression risk assessment score (MPRAS): a promising new tool for risk stratification.

Timely identification of individuals "at-risk" for myopia progression is the leading requisite for myopia practice as it aids in the decision of appropriate management. This study aimed to develop 'myopia progression risk assessment score' (MPRAS) based on multiple risk factors (10) to determine whether a myope is "at-risk" or "low-risk" for myopia progression. Two risk-score models (model-1: non-weightage, model-2: weightage) were developed. Ability of MPRAS to diagnose individual "at-risk" for myopia progression was compared against decision of five clinicians in 149 myopes, aged 6-29 years. Using model-1 (no-weightage), further 7 sub-models were created with varying number of risk factors in decreasing step-wise manner (1a: 10 factors to 1g: 4 factors). In random eye analysis for model-1, the highest Youden's J-index (0.63-0.65) led to the MPRAS cut-off score of 41.50-43.50 for 5 clinicians with a sensitivity ranging from 78 to 85% and specificity ranging from 79 to 87%. For this cut-off score, the mean area under the curve (AUC) between clinicians and the MPRAS model ranged from 0.89 to 0.90. Model-2 (weighted for few risk-factors) provided similar sensitivity, specificity, and AUC. Sub-model analysis revealed greater AUC with high sensitivity (89%) and specificity (94%) in model-1g that has 4 risk factors compared to other sub-models (1a-1f). All the MPRAS models showed good agreement with the clinician's decision in identifying individuals "at-risk" for myopia progression.

Interventions for myopia control in children: a living systematic review and network meta-analysis.

BACKGROUND: Myopia is a common refractive error, where elongation of the eyeball causes distant objects to appear blurred. The increasing prevalence of myopia is a growing global public health problem, in terms of rates of uncorrected refractive error and significantly, an increased risk of visual impairment due to myopia-related ocular morbidity. Since myopia is usually detected in children before 10 years of age and can progress rapidly, interventions to slow its progression need to be delivered in childhood. OBJECTIVES: To assess the comparative efficacy of optical, pharmacological and environmental interventions for slowing myopia progression in children using network meta-analysis (NMA). To generate a relative ranking of myopia control interventions according to their efficacy. To produce a brief economic commentary, summarising the economic evaluations assessing myopia control interventions in children. To maintain the currency of the evidence using a living systematic review approach.  SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE; Embase; and three trials registers. The search date was 26 February 2022.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) of optical, pharmacological and environmental interventions for slowing myopia progression in children aged 18 years or younger. Critical outcomes were progression of myopia (defined as the difference in the change in spherical equivalent refraction (SER, dioptres (D)) and axial length (mm) in the intervention and control groups at one year or longer) and difference in the change in SER and axial length following cessation of treatment ('rebound').  DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods. We assessed bias using RoB 2 for parallel RCTs. We rated the certainty of evidence using the GRADE approach for the outcomes: change in SER and axial length at one and two years. Most comparisons were with inactive controls. MAIN RESULTS: We included 64 studies that randomised 11,617 children, aged 4 to 18 years. Studies were mostly conducted in China or other Asian countries (39 studies, 60.9%) and North America (13 studies, 20.3%). Fifty-seven studies (89%) compared myopia control interventions (multifocal spectacles, peripheral plus spectacles (PPSL), undercorrected single vision spectacles (SVLs), multifocal soft contact lenses (MFSCL), orthokeratology, rigid gas-permeable contact lenses (RGP); or pharmacological interventions (including high- (HDA), moderate- (MDA) and low-dose (LDA) atropine, pirenzipine or 7-methylxanthine) against an inactive control. Study duration was 12 to 36 months. The overall certainty of the evidence ranged from very low to moderate. Since the networks in the NMA were poorly connected, most estimates versus control were as, or more, imprecise than the corresponding direct estimates. Consequently, we mostly report estimates based on direct (pairwise) comparisons below. At one year, in 38 studies (6525 participants analysed), the median change in SER for controls was -0.65 D. The following interventions may reduce SER progression compared to controls: HDA (mean difference (MD) 0.90 D, 95% confidence interval (CI) 0.62 to 1.18), MDA (MD 0.65 D, 95% CI 0.27 to 1.03), LDA (MD 0.38 D, 95% CI 0.10 to 0.66), pirenzipine (MD 0.32 D, 95% CI 0.15 to 0.49), MFSCL (MD 0.26 D, 95% CI 0.17 to 0.35), PPSLs (MD 0.51 D, 95% CI 0.19 to 0.82), and multifocal spectacles (MD 0.14 D, 95% CI 0.08 to 0.21). By contrast, there was little or no evidence that RGP (MD 0.02 D, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.07 D, 95% CI -0.09 to 0.24) or undercorrected SVLs (MD -0.15 D, 95% CI -0.29 to 0.00) reduce progression.  At two years, in 26 studies (4949 participants), the median change in SER for controls was -1.02 D. The following interventions may reduce SER progression compared to controls: HDA (MD 1.26 D, 95% CI 1.17 to 1.36), MDA (MD 0.45 D, 95% CI 0.08 to 0.83), LDA (MD 0.24 D, 95% CI 0.17 to 0.31), pirenzipine (MD 0.41 D, 95% CI 0.13 to 0.69), MFSCL (MD 0.30 D, 95% CI 0.19 to 0.41), and multifocal spectacles  (MD 0.19 D, 95% CI 0.08 to 0.30). PPSLs (MD 0.34 D, 95% CI -0.08 to 0.76) may also reduce progression, but the results were inconsistent. For RGP, one study found a benefit and another found no difference with control. We found no difference in SER change for undercorrected SVLs (MD 0.02 D, 95% CI -0.05 to 0.09). At one year, in 36 studies (6263 participants), the median change in axial length for controls was 0.31 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.33 mm, 95% CI -0.35 to 0.30), MDA (MD -0.28 mm, 95% CI -0.38 to -0.17), LDA (MD -0.13 mm, 95% CI -0.21 to -0.05), orthokeratology (MD -0.19 mm, 95% CI -0.23 to -0.15), MFSCL (MD -0.11 mm, 95% CI -0.13 to -0.09), pirenzipine (MD -0.10 mm, 95% CI -0.18 to -0.02), PPSLs (MD -0.13 mm, 95% CI -0.24 to -0.03), and multifocal spectacles (MD -0.06 mm, 95% CI -0.09 to -0.04). We found little or no evidence that RGP (MD 0.02 mm, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.03 mm, 95% CI -0.10 to 0.03) or undercorrected SVLs (MD 0.05 mm, 95% CI -0.01 to 0.11) reduce axial length. At two years, in 21 studies (4169 participants), the median change in axial length for controls was 0.56 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.47mm, 95% CI -0.61 to -0.34), MDA (MD -0.33 mm, 95% CI -0.46 to -0.20), orthokeratology (MD -0.28 mm, (95% CI -0.38 to -0.19), LDA (MD -0.16 mm, 95% CI -0.20 to  -0.12), MFSCL (MD -0.15 mm, 95% CI -0.19 to -0.12), and multifocal spectacles (MD -0.07 mm, 95% CI -0.12 to -0.03). PPSL may reduce progression (MD -0.20 mm, 95% CI -0.45 to 0.05) but results were inconsistent. We found little or no evidence that undercorrected SVLs (MD -0.01 mm, 95% CI -0.06 to 0.03) or RGP (MD 0.03 mm, 95% CI -0.05 to 0.12) reduce axial length. There was inconclusive evidence on whether treatment cessation increases myopia progression. Adverse events and treatment adherence were not consistently reported, and only one study reported quality of life. No studies reported environmental interventions reporting progression in children with myopia, and no economic evaluations assessed interventions for myopia control in children. AUTHORS' CONCLUSIONS: Studies mostly compared pharmacological and optical treatments to slow the progression of myopia with an inactive comparator. Effects at one year provided evidence that these interventions may slow refractive change and reduce axial elongation, although results were often heterogeneous. A smaller body of evidence is available at two or three years, and uncertainty remains about the sustained effect of these interventions. Longer-term and better-quality studies comparing myopia control interventions used alone or in combination are needed, and improved methods for monitoring and reporting adverse effects.

ANTECEDENTES: La miopía es un defecto de refracción frecuente, en el que el alargamiento del globo ocular hace que los objetos lejanos aparezcan borrosos. La creciente prevalencia de la miopía es un problema de salud pública mundial cada vez mayor, en cuanto a tasas de defectos de refracción no corregidos y un significativamente mayor riesgo de discapacidad visual debido a la morbilidad ocular relacionada con la miopía. Dado que la miopía se suele detectar en niños antes de los 10 años y puede evolucionar rápidamente, las intervenciones para frenar su avance se deben realizar en la infancia. OBJETIVOS: Evaluar la eficacia comparativa de las intervenciones ópticas, farmacológicas y ambientales para frenar la progresión de la miopía en niños mediante un metanálisis en red (MAR). Generar una clasificación relativa de las intervenciones de control de la miopía en función de su eficacia. Elaborar un breve comentario económico que resuma las evaluaciones económicas de las intervenciones de control de la miopía en niños. Mantener la vigencia de la evidencia mediante un enfoque de revisión sistemática continua. MÉTODOS DE BÚSQUEDA: Se realizaron búsquedas en CENTRAL (que contiene el Registro de ensayos del Grupo Cochrane de Salud ocular y de la visión [Cochrane Eyes and Vision]), MEDLINE; Embase; y en tres registros de ensayos. La fecha de búsqueda fue el 26 de febrero de 2022. CRITERIOS DE SELECCIÓN: Se incluyeron ensayos controlados aleatorizados (ECA) de intervenciones ópticas, farmacológicas y ambientales para retrasar la progresión de la miopía en niños de hasta 18 años. Los desenlaces fundamentales fueron la progresión de la miopía (definida como la diferencia en el cambio del equivalente esférico de la refracción [EER, dioptrías (D)] y la longitud axial [mm] en los grupos de intervención y control al año o más) y la diferencia en el cambio del EER y la longitud axial tras el cese del tratamiento ("rebote"). OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Se utilizaron los métodos Cochrane estándar. El sesgo se evaluó mediante la herramienta RoB 2 en el caso de los ECA paralelos. La certeza de la evidencia se calificó mediante el método GRADE para los desenlaces: cambio del EER y la longitud axial al año y a los dos años. La mayoría de las comparaciones se realizaron con controles inactivos. RESULTADOS PRINCIPALES: Se incluyeron 64 estudios que asignaron al azar a 11 617 niños de cuatro a 18 años de edad. Los estudios se realizaron principalmente en China u otros países asiáticos (39 estudios; 60,9%) y Norteamérica (13 estudios; 20,3%). Cincuenta y siete estudios (89%) compararon intervenciones de control de la miopía (gafas multifocales, gafas periféricas plus [PPSL por sus siglas en inglés], gafas monofocales [SVL por sus siglas en inglés] subcorregidas, lentes de contacto multifocales blandas [MFSCL por sus siglas en inglés], ortoqueratología, lentes de contacto rígidas permeables al gas [RGP por sus siglas en inglés]); o intervenciones farmacológicas (incluidas atropina a dosis alta, media y baja, pirenzipina o 7­metilxantina) contra un control inactivo. La duración de los estudios fue de 12 a 36 meses. La certeza global de la evidencia varió entre muy baja y moderada. Debido a que las redes del MAR estaban mal conectadas, la mayoría de las estimaciones versus control fueron tan imprecisas o más que las correspondientes estimaciones directas. En consecuencia, a continuación se presentan principalmente estimaciones basadas en comparaciones directas (por pares). Al año, en 38 estudios (6525 participantes analizados), la mediana del cambio del EER para los controles fue de ­0,65 D. Las siguientes intervenciones podrían reducir la progresión del EER en comparación con los controles: atropina a dosis alta (diferencia de medias [DM] 0,90 D; intervalo de confianza [IC] del 95%: 0,62 a 1,18), atropina a dosis media (DM 0,65 D; IC del 95%: 0,27 a 1,03), atropina a dosis baja (DM 0,38 D; IC del 95%: 0,10 a 0,66), pirenzipina (DM 0,32 D; IC del 95%: 0,15 a 0,49), MFSCL (DM 0,26 D; IC del 95%: 0,17 a 0,35), PPSL (DM 0,51 D; IC del 95%: 0,19 a 0,82) y gafas multifocales (DM 0,14 D; IC del 95%: 0,08 a 0,21). Por el contrario, hubo poca o ninguna evidencia de que las RGP (DM 0,02 D; IC del 95%: ­0,05 a 0,10), la 7­metilxantina (DM 0,07 D; IC del 95%: ­0,09 a 0,24) o las SVL subcorregidas (DM ­0,15 D; IC del 95%: ­0,29 a 0,00) redujeran la progresión. A los dos años, en 26 estudios (4949 participantes), el cambio medio del EER para los controles fue de ­1,02 D. Las siguientes intervenciones podrían reducir la progresión del EER en comparación con los controles: atropina a dosis alta (DM 1,26 D; IC del 95%: 1,17 a 1,36), atropina a dosis media (DM 0,45 D; IC del 95%: 0,08 a 0,83), atropina a dosis baja (DM 0,24 D; IC del 95%: 0,17 a 0,31), pirenzipina (DM 0,41 D; IC del 95%: 0,13 a 0,69), MFSCL (DM 0,30 D; IC del 95%: 0,19 a 0,41) y gafas multifocales (DM 0,19 D; IC del 95%: 0,08 a 0,30). Las PPSL (DM 0,34 D; IC del 95%: ­0,08 a 0,76) también podrían reducir la progresión, pero los resultados no fueron consistentes. Para las RGP, un estudio encontró un efecto beneficioso y otro no encontró diferencias con el control. No se observaron diferencias en el cambio del EER para las SVL subcorregidas (DM 0,02 D; IC del 95%: ­0,05 a 0,09). Al año, en 36 estudios (6.263 participantes), el cambio medio en la longitud axial de los controles fue de 0,31 mm. Las siguientes intervenciones podrían reducir la elongación axial en comparación con los controles: atropina a dosis alta (DM ­0,33 mm; IC 95%: ­0,35 a 0,30), atropina a dosis media (DM ­0,28 mm; IC 95%: ­0,38 a ­0,17), atropina a dosis baja (DM ­0,13 mm; IC 95%: ­0,21 a ­0,05), ortoqueratología (DM ­0,19 mm; IC 95%: ­0,23 a ­0,15), MFSCL (DM ­0,11 mm; IC del 95%: ­0,13 a ­0,09), pirenzipina (DM ­0,10 mm; IC del 95%: ­0,18 a ­0,02), PPSL (DM ­0,13 mm; IC del 95%: ­0,24 a ­0,03) y gafas multifocales (DM ­0,06 mm; IC del 95%: ­0,09 a ­0,04). Se encontró poca o ninguna evidencia de que las RGP (DM 0,02 mm; IC del 95%: ­0,05 a 0,10), la 7­metilxantina (DM 0,03 mm; IC del 95%: ­0,10 a 0,03) o las SVL subcorregidas (DM 0,05 mm; IC del 95%: ­0,01 a 0,11) reduzcan la longitud axial. A los dos años, en 21 estudios (4169 participantes), la mediana del cambio en la longitud axial de los controles fue de 0,56 mm. Las siguientes intervenciones podrían reducir la elongación axial en comparación con los controles: atropina a dosis alta (DM ­0,47 mm; IC del 95%: ­0,61 a ­0,34), atropina a dosis media (DM ­0,33 mm; IC del 95%: ­0,46 a ­0,20), ortoqueratología (DM ­0,28 mm; IC del 95%: ­0,38 a ­0,19), atropina a dosis baja (DM ­0,16 mm; IC del 95%: ­0,20 a ­0,12), MFSCL (DM ­0,15 mm; IC del 95%: ­0,19 a ­0,12) y gafas multifocales (DM ­0,07 mm; IC del 95%: ­0,12 a ­0,03). Las PPSL podrían reducir la progresión (DM ­0,20 mm; IC del 95%: ­0,45 a 0,05), pero los resultados no fueron consistentes. Se encontró poca o ninguna evidencia de que las SVL subcorregidas (DM ­0,01 mm; IC del 95%: ­0,06 a 0,03) o las RGP (DM 0,03 mm; IC del 95%: ­0,05 a 0,12) reduzcan la longitud axial. No hubo evidencia concluyente sobre si el abandono del tratamiento aumenta la progresión de la miopía. Los eventos adversos y la adherencia al tratamiento no se comunicaron de forma consistente, y solo un estudio informó sobre la calidad de vida. Ningún estudio proporcionó información sobre intervenciones ambientales que informaran sobre la progresión en niños con miopía y ninguna evaluación económica analizó intervenciones para el control de la miopía en niños. CONCLUSIONES DE LOS AUTORES: La mayoría de los estudios compararon tratamientos farmacológicos y ópticos para enlentecer la progresión de la miopía con un comparador inactivo. Los efectos al año demostraron que estas intervenciones podrían ralentizar el cambio refractivo y reducir el alargamiento axial, aunque a menudo los resultados fueron heterogéneos. El conjunto de evidencia disponible a los dos o tres años fue más escaso, y persiste la incertidumbre sobre el efecto sostenido de estas intervenciones. Se necesitan estudios a más largo plazo y de mejor calidad que comparen las intervenciones para el control de la miopía utilizadas solas o en combinación, así como métodos mejorados de seguimiento y notificación de los efectos adversos.

Influence of location, season and time of day on the spectral composition of ambient light: Investigation for application in myopia.

PURPOSE: Given the possible role of spectral composition of light and myopia, this study aimed at investigating the variation in the spectral composition of ambient light in different (a) outdoor/indoor locations, (b) time of a day and (c) seasons. METHODS: The spectral power distribution (SPD), categorised into short (380-500 nm), middle (505-565 nm) and long wavelengths (625-780 nm), was recorded using a handheld spectrometer at three outdoor locations ('open playground', 'under shade of tree' and 'canopy') and three indoor locations ('room with multiple windows', 'closed room' and 'closed corridor'). Readings were taken at five different time points (3-h intervals between 6:30 and 18:00 hours) on two days, each during the summer and monsoon seasons. RESULTS: The overall median SPD (IQR [25th-75th percentile] W/nm/m2 ) across the three outdoor locations (0.11 [0.09, 0.12]) was 157 times higher than that of the indoor locations (0.0007 [0.0001, 0.001]). Considerable locational, diurnal and seasonal variation was observed in the distribution of the median SPD value, with the highest value being recorded in the 'open playground' (0.27 [0.21, 0.28]) followed by 'under shade of tree' (0.083 [0.074, 0.09]), 'canopy' (0.014 [0.012, 0.015]) and 'room with multiple windows' (0.023 [0.015, 0.028]). The relative percentage composition of short, middle and long wavelengths was similar in both the outdoor and indoor locations, with the proportion of middle wavelengths significantly higher (p < 0.01) than short and long wavelengths in all the locations, except 'canopy'. CONCLUSION: Irrespective of variation in SPD values with location, time, day and season, outdoor locations always exhibited significantly higher spectral power than indoor locations. The relative percentage composition of short, middle and long wavelengths of light was similar across all locations. These findings establish a foundation for future research to understand the relationship between spectral power and the development of myopia.

Development and validation of a 'MyLyt' wearable light tracking device.

PURPOSE: We developed a clip-on light tracker (MyLyt) for estimating light exposure in real time. This study aimed at validating and investigating the feasibility of using MyLyt in children and adults. METHOD: The study was conducted in two phases. Phase 1 involved validation against a factory-calibrated digital lux meter in three separate conditions: controlled environmental set-up, outdoors and indoors where intra-test (two measurements by the same tracker), inter-test (measurements among trackers) and inter-device (MyLyt tracker and lux meter) validations were conducted. Phase 2 involved a feasibility study where MyLyt was used in a real-world setting by 21 adults and 8 children. Participants were asked to log their real-time movements in an 'activity diary', which were correlated with the lux levels measured by the tracker. RESULTS: A strong positive correlation and non-significant difference in the recorded mean illuminance levels were observed during intra-test (inter-class correlation: 1.00, p = 0.99), inter-test (0.91-1.00, p > 0.15) and inter-device (0.91-1.00, p > 0.56) validation in all three testing conditions (p > 0.49), except the indoor location. While the lux level measured by MyLyt was significantly higher than that of the lux meter (p < 0.01) in the indoor locations, differences were minimal and clinically insignificant. A Bland-Altman plot showed a minimal mean difference (95% limits of agreement) between the MyLyt tracker and lux meter in all three conditions (controlled environmental set-up: 641 [-949, 2230], outdoor: 74 [-2772, 2920] and indoor: -35 [-151, 80] lux). Phase 2 validation showed an expected illuminance level against the corresponding location with high sensitivity (97.8%) and specificity (99%) to accurately differentiate between outdoor and indoor locations. CONCLUSION: The MyLyt tracker showed good repeatability, strong correlation and comparable values with the lux meter in the three tested conditions, making it suitable for tracking light exposure patterns for both research and clinical purposes.

Refractive development in individuals with ocular and oculocutaneous albinism.

PURPOSE: Albinism is known to disrupt emmetropisation in animal models. However, it is not clear if the same effect is seen in humans. This study aimed to investigate the refractive profile in individuals diagnosed with ocular albinism (OA) and oculocutaneous albinism (OCA) based on a large dataset. METHODS: Required data from 618 individuals (61% males and 39% females) diagnosed with albinism were exported from the eyeSmart electronic medical records of L V Prasad Eye Institute. Overall, there were 112 (18%) individuals diagnosed with OA and 506 (82%) with OCA. Based on the spherical equivalent refraction (SER), individuals were classified as emmetropes, myopes, and hyperopes. RESULTS: The overall spherical equivalent refraction of the individuals ranged from -25.00D to + 12.00D with a median + 0.25D (-2.00 to + 2.25 D). The proportion of individuals with albinism (combined OA, OCA) having hyperopia and myopia (overall: N = 282;45.6% vs. N = 245;39.6%) were similar (p = 0.18), and the least were with emmetropia (overall: N = 91;14.7%). Across all the age groups (0-10, 11-20, 21-30, > 30 years), the frequency of hyperopes and myopes was significantly higher (p < 0.05) compared to emmetropes. Both high degrees of hyperopia and myopia were found in individuals diagnosed with OA and OCA. Irrespective of the albinism type, with-the-rule (70%) astigmatism was the most prevalent compared to other types of astigmatism. The frequency of with-the-rule astigmatism was significantly high in the presence of nystagmus compared to individuals with no nystagmus in both OA (75% vs 25%, p = 0.01) and OCA (77% vs 23%, p = 0.014) groups. CONCLUSION: The presence of both high hyperopia and high myopia and very few numbers with emmetropia across all age groups indicates disrupted normal refractive development in individuals with albinism. With-the-rule astigmatism and nystagmus may result in meridional degradation of the retinal image leading to impairment of normal emmetropisation process in individuals with albinism.

Time spent outdoors as an intervention for myopia prevention and control in children: an overview of systematic reviews.

PURPOSE: Outdoor light exposure is considered a safe and effective strategy to reduce myopia development and aligns with existing public health initiatives to promote healthier lifestyles in children. However, it is unclear whether this strategy reduces myopia progression in eyes that are already myopic. This study aims to conduct an overview of systematic reviews (SRs) reporting time spent outdoors as a strategy to prevent myopia or slow its progression in children. METHODS: We searched the Cochrane Library, EMBASE, MEDLINE and CINAHL from inception to 1 November 2020 to identify SRs that evaluated the association between outdoor light exposure and myopia development or progression in children. Outcomes included incident myopia, prevalent myopia and change in spherical equivalent refraction (SER) and axial length (AL) to evaluate annual rates of myopia progression. The methodological quality and risk of bias of included SRs were assessed using the AMSTAR-2 and ROBIS tools, respectively. RESULTS: Seven SRs were identified, which included data from 47 primary studies with 63,920 participants. Pooled estimates (risk or odds ratios) consistently demonstrated that time outdoors was associated with a reduction in prevalence and incidence of myopia. In terms of slowing progression in eyes that were already myopic, the reported annual reductions in SER and AL from baseline were small (0.13-0.17 D) and regarded as clinically insignificant. Methodological quality assessment using AMSTAR-2 found that all reviews had one or more critical flaws and the ROBIS tool identified a low risk of bias in only two of the included SRs. CONCLUSION: This overview found that increased exposure to outdoor light reduces myopia development. However, based on annual change in SER and AL, there is insufficient evidence for a clinically significant effect on myopia progression. The poor methodological quality and inconsistent reporting of the included systematic reviews reduce confidence in the estimates of effect.

Short-Term Exposure to Blue Light Shows an Inhibitory Effect on Axial Elongation in Human Eyes Independent of Defocus.

Purpose: Given the potential role of light and its wavelength on ocular growth, we investigated the effect of short-term exposure to the red, green, and blue light on ocular biometry in the presence and absence of lens-induced defocus in humans. Methods: Twenty-five young adults were exposed to blue (460 nm), green (521 nm), red (623 nm), and white light conditions for 1-hour each on 4 separate experimental sessions conducted on 4 different days. In each light condition, hyperopic defocus (3D) was induced to the right eye with the fellow eye experiencing no defocus. Axial length and choroidal thickness were measured before and immediately after the light exposure with a non-contact biometer. Results: Axial length increased from baseline after red light (mean difference ± standard error in the defocussed eye and non-defocussed eye = 11.2 ± 2 µm and 6.4 ± 2.3 µm, P < 0.001 and P < 0.01, respectively) and green light exposure (9.2 ± 3 µm and 7.0 ± 2.5 µm, P < 0.001 and P < 0.001) with a significant decrease in choroidal thickness (P < 0.05, both red and green light) after 1-hour of exposure. Blue light exposure resulted in a reduction in axial length in both the eyes (-8.0 ± 3 µm, P < 0.001 in the defocussed eye and -6.0 ± 3 µm, P = 0.11 in the non-defocused eye) with no significant changes in the choroidal thickness. Conclusions: Exposure to red and green light resulted in axial elongation, and blue light resulted in inhibition of axial elongation in human eyes. Impact of such specific wavelength exposure on children and its application in myopia control need to be explored.

Do rectus muscle parameters vary between emmetropes and myopes?

PURPOSE: This study investigated the thickness, area, and insertion site of the medial (MR) and lateral (LR) rectus muscles in individuals with emmetropia and different degrees of myopia. METHODS: Swept-source optical coherence tomography images of the MR and LR muscles in 80 participants including emmetropes (spherical equivalent refractive error [SER] ±0.50 D, N = 14) and myopes (≤ -0.75 D, N = 66), were analysed. Custom-designed, semi-automated software was used to measure parameters such as insertion distance from limbus, muscle thickness at every 1 mm interval to 3 mm periphery and muscle area from insertion site to 3 mm. RESULTS: The median (Q1, Q3) SER error and axial length were -6.00 D (-13.25, -2.12) and 25.78 mm (23.78, 28.61), respectively. The MR was significantly thinner (mean ± SE: 137.7 ± 8.9 vs. 159.7 ± 8.9 µm, p < 0.01) and occupied less area than the LR (0.35 ± 0.01 vs. 0.42 ± 0.01 mm2 , respectively, p < 0.01). The thickness of the MR gradually increased from the insertion site to a 3 mm peripheral eccentric location (106.5 3.8 µm at 1 mm, 135.5 ± 4.5 µm at 2 mm and 156.1 ± 5.9 µm at 3 mm, p < 0.01). The overall median thickness of the MR was significantly less in myopes (129 µm [111.5, 152.2]) than emmetropes (158.1 [134.3, 167.7] µm, p = 0.03). However, no such trend was seen in the LR muscle. Muscle area and insertion distance were not different between emmetropes and myopes in both horizontal rectus muscles. CONCLUSION: Unlike the LR, the parameters of the MR (thin and occupying less area) show significant association with myopia. While the key finding of this study indicates the possible association of MR parameters with myopia, the clinical relevance of this finding and its role in myopiogenesis/progression needs to be investigated further.

Ambient light level varies with different locations and environmental conditions: Potential to impact myopia.

PURPOSE: Considering that time spent outdoors is protective for myopia, we investigated how ambient light levels reaching the eye varies across 9 outdoor and 4 indoor locations in 5 different environmental conditions. METHODS: Illuminance (lux) was recorded using a lux meter under conditions of weather (sunny/cloudy), time of a day (7:00,10:00,13:00, and 16:00 hours), seasons (summer/winter), and sun protection (hat and cap) in outdoor and indoor locations. Nine outdoor locations were "open playground", "under a translucent artificial-shade", "under a porch facing east", "under a porch facing south", "under a big tree", "between three buildings", "within 4 buildings", and "canopy". As a ninth outdoor location, "Under a glass bowl" in the outdoor location was used as a simulation for "glass classroom model" and measurement was taken at the floor level only to determine in overall the illuminance conditions with glass covered on all sides. The 4 indoor locations included "room with multiple large windows", "room with combination light source", "room with multiple artificial lights", and "room with single artificial light". RESULTS: The overall median illuminance level (median; Q1-Q3) recorded in 9 outdoor locations was 8 times higher than that of all indoor locations (1175;197-5400 lux vs. 179;50-333 lux). Highest illuminance in outdoor locations was recorded in "open playground" (9300;4100-16825 lux), followed by "under a translucent artificial shade (8180;4200-13300 lux) and the lowest in "within 4 buildings" (11;6-20 lux). Illuminance under 'Canopy', 'between three buildings' and 'within four buildings' was similar to that of indoor locations (<1000 lux). Time of the day, weather, season, sensor position and using sun protection did not alter illuminance to change from high to low level (>1000 to <1000 lux). Among indoor locations, illuminance in "room with multiple large windows" crossed 1000 lux at a specific time points on both sunny and cloudy days. CONCLUSIONS: Illuminance levels in outdoors and indoors varied with location type, but not with other conditions. Given the variation in illuminance in different locations, and the impact it may have on myopia control, appropriate detailed recommendations seems necessary while suggesting time outdoors as an anti-myopia strategy to ensure desired outcomes.

Quantitative corneal neural imaging using in vivo confocal microscopy in cases of congenital corneal anesthesia: A prospective analysis and clinical correlation.

Purpose: Congenital corneal anesthesia (CCA) is a rare clinical entity that poses a diagnostic dilemma, particularly in the pediatric age group with very little literature on this. Accurate initial diagnosis, evaluation, early identification of risk factors, aggressive systemic workup, and appropriate therapy are paramount to prevent visual loss due to long-term complications of corneal anesthesia. The purpose of the study was to estimate and compare the corneal neural architecture using real time, in vivo confocal microscopy (IVCM) in patients with CCA as against a control population. Methods: This was a retrospective nonconsecutive, comparative clinical case series in a tertiary hospital in South India from June 2015 to December 2018. Methods: IVCM was accomplished in cooperative children in whom central cornea was relatively clear. The clearest three to five images from each eye were selected, and the nerves were analyzed for length, thickness, density, dichotomous pattern, and beading. Statistical analysis was done using Origin v7.0 (Origin Lab Corporation, Northampton, MA, USA). Results: In total, 15 eyes of 11 cases and 20 eyes of 10 controls were imaged. Measurements on corneal nerve density showed a significant difference (P = 0.0005), cases having a lower mean (3.85 ± 1.38 mm per mm2) compared to the controls (6.74 ± 1.75 mm per mm2). Measurements on corneal nerve length (P = 0.28), thickness (P = 0.45), and presence of beading (P = 0.97) and dichotomous pattern (P = 0.07) did not reveal a significant difference between cases and controls. Conclusion: There is a strong relationship between the functional loss (absent corneal sensation) and anatomical decrease (reduced subbasal nerve density) of corneal nerves in congenital corneal anaesthesia.

Anterior Sclera Undergoes Thinning with Increasing Degree of Myopia.

Purpose: Considering that ocular expansion is associated with scleral thinning, this study investigated variation in scleral thickness (anterior scleral thickness [AST] and posterior scleral thickness [PST]) in different meridians across emmetropes and a wide range of myopes. Methods: A total of 95 participants (mean age, 24 ± 4 years) including emmetropes (spherical equivalent refractive error, ±0.75 diopters [D]; n = 20) and myopes (-1.00 to -27.25 D; n = 75) underwent ocular imaging with swept-source optical coherence tomography. All the images were analyzed using semiautomated custom-designed software to determine scleral thickness in 1-mm intervals. AST was estimated from limbus to 5 mm (n = 95), and PST from fovea to 5 mm (n = 25; high myopes only) along the horizontal and vertical meridian. Results: The median spherical equivalent refractive error and axial length were -4.25 D (IQR, -12.50 to -1.00 D) and 25 mm (IQR, 23.72-28.35 mm), respectively. The anterior sclera was thinnest in the superior and thickest in the inferior region (475.3 ± 19.0 vs. 605.9 ± 18.6 µm; P < 0.001). The inferior AST alone decreased significantly with increasing magnitude of myopia (r = 0.27; P = 0.008). There were no differences in AST between nasal and temporal meridians (583.24 ± 15.00 vs. 587.09 ± 27.00 µm; P > 0.05). The mean subfoveal PST for the subset of high myopes was 251.7 ± 12.0 µm which was thinner than mean AST along all the meridians by more than 45%. The averaged scleral thickness peripheral to fovea (1-5 mm) was similar along different meridians (P > 0.05). Conclusions: The relative significant thinning of the anterior sclera along the inferior meridian with increasing degree of myopia compared with the other three meridians indicates the potential role of AST, especially in the inferior meridian, to act as a marker for myopia progression.

Outcomes of therapeutic penetrating keratoplasty in 198 eyes with fungal keratitis.

Purpose: To study the outcomes of therapeutic penetrating keratoplasty in fungal keratitis. Methods: This retrospective, observational, interventional case series involved an audit of 198 consecutive eyes that underwent therapeutic penetrating keratoplasty (ThPK) for fungal keratitis at L V Prasad Eye Institute between January 2008 and December 2010 was performed. The data on demographics, clinical characteristics, intraoperative, and late postoperative complications were noted. The primary outcome measure was eradication of infection and postoperative anatomical success. Secondary outcome measures were graft survival, risk factors, clinical features, and management of recurrent fungal keratitis post ThPK. Results: Mean follow-up after ThPK was 24 ± 17 months. A total of 178 (89.9%) eyes had complete eradication of fungal infection, whereas 20 (10.1%) eyes developed recurrence. Anatomical restoration was achieved in majority of cases (192 eyes; 97%). Larger infiltrate size was associated with a higher risk of recurrence of infection. The median graft survival rate was 5.9 months. The graft survival was better for grafts <8 mm versus those with >8 mm (P = 0.026) and not found significantly related to the species of fungus. Twenty-seven eyes underwent re-grafting: penetrating keratoplasty in 14 eyes, and Descemet's stripping endothelial keratoplasty in 13 eyes. Conclusion: As larger infiltrate prior to therapeutic keratoplasty had much higher risk of recurrences; timely surgical intervention should be considered in cases not responding to medical therapy. Alternative strategies of management of postoperative inflammation need to be considered to prevent graft failures.

Corneal Endothelial Cell Density in Uveal Coloboma Associated With Microcornea.

PURPOSE: To evaluate the relationship between endothelial cell density (ECD) and mean corneal diameter (MCD) in eyes with uveal coloboma associated with microcornea. METHODS: Corneal endothelial cell imaging was performed using specular microscopy on 22 eyes of 18 subjects diagnosed with uveal coloboma associated with microcornea. The MCD was noted as the average of horizontal and vertical corneal diameters, which were measured using the ruler tool of the slit-lamp biomicroscope and Castroviejo calipers. RESULTS: Mean age of the study subjects was 29.7 ± 10.4 years (range, 14-46 years). The MCD was 7.3 ± 1.1 mm (range, 4.9-9 mm). Mean ECD (3436 ± 316.2 cells/mm) of the study subjects was significantly (P < 0.0001) higher than the mean ECD (2761.8 ± 140.9 cells/mm) of age-matched (range, 10-40 years) normal eyes with no ocular pathology. The pleomorphism and polymegathism were comparable between the 2 groups. Regression analysis showed that MCD had a significant negative (R = -0.55; P = 0.02) relationship with ECD. CONCLUSIONS: Eyes with congenital uveal coloboma associated with microcornea have increased ECD. Increased ECD may be partly due to a reduced posterior corneal surface area in microcornea.

Patterns of posterior ocular complications in myopic eyes of Indian population.

This is a retrospective study aimed to investigate the patterns of myopic fundus complications in Indian children and young adults. Electronic medical records of 29,592 patients, aged 10-40 years, who visited L V Prasad Eye Institute between 1st January to 31st December 2016 were analysed in the study. Data such as age, gender, refractive error and various pathologic lesions of posterior globe were considered for analysis. Among all the patients with different types of refractive errors, myopia was found in 47.4%, high myopia in 6.8% and pathologic myopia in 2.2%. There was no trend of the increased prevalence of pathologic myopia with increasing age, except for a significant difference between the children aged 10-15 years (2.7%) and those aged more than 15 years (>4%). . Although, the overall pattern of pathologic lesions was similar across different grades of myopia (2.5% in low myopes vs. 2.2% in severe myopes), lesions like staphyloma and retinal detachment increased with increasing degree of myopia. The proportion of pathologic lesions across different grades of myopia suggests the necessity for careful peripheral fundus examinations irrespective of the degree of myopia for better management and prognostic purposes.