Refractive outcomes, corneal haze and endothelial cell loss after myopic photorefractive keratectomy in an Asian population: The Singapore Armed Forces' experience.

IMPORTANCE: This study reports outcomes of myopic photorefractive keratectomy (PRK) in a mainly ethnic Chinese population in Singapore. BACKGROUND: To assess the incidence and associations of corneal haze and endothelial cell count (ECC) loss up to 12 months after PRK. DESIGN: This was a retrospective case series conducted in a tertiary eye centre. PARTICIPANTS: A total of 158 patients (309 eyes) with a mean age of 22.1 ± 3.4 years were included. The majority was Chinese (97.4%) and male (97.4%). Mean preoperative spherical equivalent was -3.33 ± 1.15 D. METHODS: Eyes were categorized based on postoperative haze severity. A multivariate analysis adjusting for age and use of intraoperative mitomycin-C (MMC), preoperative sphere and cylinder was performed. MAIN OUTCOME MEASURES: Refractive outcomes and corneal haze 3 and 12 months after PRK were assessed. ECC measurements were obtained before PRK and at variable periods postoperatively. RESULTS: At 12 months, overall efficacy index was 0.98, and safety index was 1.09. Eight (2.5%) eyes underwent enhancement surgery. An analysis was performed on 295 eyes that did not undergo enhancement and had complete clinical data, which demonstrated a decrease in the incidence of haze from 38.2% at 3 months to 9.3% at 12 months. Higher myopia was associated with increased haze severity at 3 months (OR, 1.36; P = .005). Higher astigmatism was associated with increased haze severity at 3 (OR, 1.65; P = .018) and 12 months (OR, 2.32; P = .015). Intraoperative MMC was not associated with haze severity or ECC loss. CONCLUSIONS AND RELEVANCE: Myopia and astigmatism were associated with increased corneal haze severity. Intraoperative MMC did not accelerate ECC loss. Overall, PRK is effective, predictable and safe in Asian eyes.

Proof-of Concept that an Acute Trophic Factors Intervention After Spinal Cord Injury Provides an Adequate Niche for Neuroprotection, Recruitment of Nestin-Expressing Progenitors and Regeneration.

Trophic factor treatment has been shown to improve the recovery of brain and spinal cord injury (SCI). In this study, we examined the effects of TSC1 (a combination of insulin-like growth factor 1 and transferrin) 4 and 8 h after SCI at the thoracic segment level (T12) in nestin-GFP transgenic mice. TSC1 treatment for 4 and 8 h increased the number of nestin-expressing cells around the lesion site and prevented Wallerian degeneration. Treatment with TSC1 for 4 h significantly increased heat shock protein (HSP)-32 and HSP-70 expression 1 and 2 mm from lesion site (both, caudal and rostral). Conversely, the number of HSP-32 positive cells decreased after an 8-h TSC1 treatment, although it was still higher than in both, non-treated SCI and intact spinal cord animals. Furthermore, TSC1 increased NG2 expressing cell numbers and preserved most axons intact, facilitating remyelination and repair. These results support our hypothesis that TSC1 is an effective treatment for cell and tissue neuroprotection after SCI. An early intervention is crucial to prevent secondary damage of the injured SC and, in particular, to prevent Wallerian degeneration.

1-year results of combined half-dose photodynamic therapy and ranibizumab for polypoidal choroidal vasculopathy.

BACKGROUND: To evaluate the efficacy and safety of half-dose photodynamic therapy (PDT combined with ranibizumab for polypoidal choroidal vasculopathy (PCV). PCV is commonly treated with a combination of anti-vascular endothelial growth factor and standard-dose photodynamic therapy (PDT). Choroidal ischemia and visual loss can be resulted from the standard-dose PDT. Half-dose PDT has proved to produce similar results and safety profile in treating central serous chorioretinopathy. Half-dose PDT may offer an alternative for PCV cases where the damage to choroidal vasculature maybe less. Here, we report the efficacy of treating PCV cases with combination of ranibizumab and half-dose PDT. METHODS: In this prospective, non-comparative, interventional case series, 19 treatment-naive eyes were treated with combined half-dose PDT and ranibizumab. All subjects were followed up for 12 months with measurement of best-corrected visual acuity (BCVA), central foveal thickness (CFT) by optical coherence tomography. Indocyanine green angiogram (ICG) was performed every 3-monthly, and subjects assessed in terms of polyp regression rates, changes in vision and central foveal thickness, need to repeat half-dose PDT. Subgroup analysis was performed based on ICG features. RESULTS: The mean logMAR BCVA improved from 0.64 at baseline to 0.41 at 12 months. The mean CFT improved from 459.6 mum at baseline to 384.2 mum at 12 months. The difference between baseline BCVA and CFT and that at 12 months were statistically significant (both P = 0.03). Polyp regression rate after one half-dose PDT was 42.1 %. This was 61.5 % in the polyp-only group, while that in the branching-vascular-network (BVN) group was 0 % (P = < 0.01). CONCLUSION: Half-dose PDT combined with intravitreal ranibizumab was able to induce high polyp regression rate in PCV cases that had one single polyp.

Correlation of structural and electrophysiological changes in the retina of young high myopes.

PURPOSE: Despite a high prevalence of myopia among young East Asian adults, there is a lack of data on the myopic retina structure-function relationship in this group. We examined the association between optical coherence tomography (OCT) and electroretinogram (ERG) measurements in highly myopic young Asian adults to provide this information and also determined if OCT can be used as an alternative screening tool to assess retinal function in young myopic adults. METHODS: This was a prospective study comprising young adults aged between 18 and 25 years with spherical equivalent refraction of worse than -6.00 D. A comprehensive ophthalmic examination comprising fundus examination and grading, ocular biometry, time-domain OCT (fovea, macular and retinal nerve fibre layer thickness) and ERG (full field and multifocal) were performed for all the eyes. RESULTS: A total of 32 eyes (mean spherical equivalent ± standard deviation -10.17 ± 1.51 D, mean age 23.8 ± 1.3 years) were included. None of the eyes showed visible myopic retinopathy and the central retina thickness of all eyes was classified as within the normal range. Full-field ERG amplitude and multifocal ERG P1 amplitudes in the outer rings (R3-R5) were, however, inversely associated with axial length. The multifocal ERG P1 amplitudes were also positively correlated with mean retinal nerve fibre layer thickness in R2, 4, 5 rings and outer macular thickness in R 2-5 rings. CONCLUSION: These findings suggest that full field ERG changes may precede fundus and OCT changes in highly myopic young adults. Although there was some correlation between multifocal ERG amplitudes with OCT outer macular and retinal nerve fibre layer thickness, the OCT may not be useful as a retinal function screening tool, being within normal limits in all eyes. Further longitudinal studies are required to determine how the relationship between ERG and OCT will evolve over time.

Choroidal thickness in relation to hypercholesterolemia on enhanced depth imaging optical coherence tomography.

PURPOSE: To investigate the relationship of hypercholesterolemia and choroidal thickness in normal healthy volunteers. METHOD: This was a cross-sectional observational study. Volunteers with no ocular abnormalities were examined using enhanced depth imaging optical coherence tomography. Choroidal and retinal thicknesses were measured at the fovea, and at 4 different locations 1 mm superior, inferior, temporal, and nasal to the fovea. Subjects were further divided into those with hypercholesterolemia (Group 1) and normal control subjects (Group 2) for subgroup analysis regarding the effect of hypercholesterolemia on choroidal thickness. Subjects with hypertension and diabetes were excluded. RESULTS: A total of 322 eyes of 161 subjects were studied. Mean age was 59.9 years (range, 24-84 years). The mean subfoveal choroidal thickness was 261 ± 98.7 µm. Mean subfoveal choroidal thickness negatively correlated with age (r = -0.326; P = 0.001). The mean serum total cholesterol was 5.02 ± 0.98 mmol/L. In Group 1, it was 5.65 ± 1.15 mmol/L, while in Group 2, it was 4.72 ± 0.73 mmol/L. The difference was statistically significant (P = 0.003). Subjects in Group 1 tended to be older and have worse vision, although the difference did not reach statistical significance. The mean subfoveal choroidal thickness in Group 1 was 306 ± 111 µm, while that in Group 2 was 258 ± 97 µm. The difference was statistically significant (P = 0.041). The same difference was also found at the 1 mm nasal (P = 0.041) and 1 mm superior (P = 0.040). CONCLUSION: The subfoveal choroidal thickness was found to be significantly higher in subjects with hypercholesterolemia. This has to be taken into account when analyzing choroidal thickness.

Higher order aberrations and visual function in a young Asian population of high myopes.

Purpose: To examine the associations between higher order aberrations (HOAs), visual performance, demographics, and ocular characteristics in a young Asian population with high myopia. Methods: This was a retrospective review of military pre-enlistees conducted between March 2014 to September 2018. Visual acuity and contrast sensitivity were tested under photopic, mesopic and simulated night conditions. Ocular, corneal and internal HOAs were measured with a Hartmann-Shack wavefront aberrometer (KR-1W, Topcon Co., Tokyo, Japan). Results: 522 eyes of 263 consecutive subjects with severe high myopia (defined as spherical equivalent refraction [SER] ≤ -10.00D) in at least one eye, and high myopia (SER ≤ -6.00D) in the fellow eye, [mean (SD) SER -11.85 (2.03D)] were analysed. The mean (SD) age of subjects was 18.5 (1.6) years. Chinese eyes had significantly greater internal total HOA root-mean-square (RMS) compared to Malay eyes [mean difference (SD) 0.0246 (0.007) µm, p < 0.001). More negative SER was associated with greater ocular total HOA (p = 0.038), primary coma (p = 0.003) and tetrafoil (p = 0.025) RMS, as well as more positive ocular (p = 0.003) and internal primary spherical aberration (p = 0.009). Greater ocular total HOAs was associated with reduced visual acuity in simulated night conditions and low contrast, decreased contrast sensitivity under mesopic and simulated night conditions (all p < 0.05). Conclusions: Greater HOAs were associated with Chinese ethnicity and more negative SER in a young Asian population with high myopia. Greater HOAs were associated with poorer visual performance in low luminance and reduced contrast conditions.

Variability in Grading Diabetic Retinopathy Using Retinal Photography and Its Comparison with an Automated Deep Learning Diabetic Retinopathy Screening Software.

BACKGROUND: Diabetic retinopathy (DR) screening using colour retinal photographs is cost-effective and time-efficient. In real-world clinical settings, DR severity is frequently graded by individuals of different expertise levels. We aim to determine the agreement in DR severity grading between human graders of varying expertise and an automated deep learning DR screening software (ADLS). METHODS: Using the International Clinical DR Disease Severity Scale, two hundred macula-centred fundus photographs were graded by retinal specialists, ophthalmology residents, family medicine physicians, medical students, and the ADLS. Based on referral urgency, referral grading was divided into no referral, non-urgent referral, and urgent referral to an ophthalmologist. Inter-observer and intra-group variations were analysed using Gwet's agreement coefficient, and the performance of ADLS was evaluated using sensitivity and specificity. RESULTS: The agreement coefficient for inter-observer and intra-group variability ranged from fair to very good, and moderate to good, respectively. The ADLS showed a high area under curve of 0.879, 0.714, and 0.836 for non-referable DR, non-urgent referable DR, and urgent referable DR, respectively, with varying sensitivity and specificity values. CONCLUSION: Inter-observer and intra-group agreements among human graders vary widely, but ADLS is a reliable and reasonably sensitive tool for mass screening to detect referable DR and urgent referable DR.

Strategies for endogenous spinal cord repair: HPMA hydrogel to recruit migrating endogenous stem cells.

Injury to the spinal cord disrupts ascending and descending axonal pathways and causes tissue damage with a subsequent limited cellular regeneration. Successful treatment would encompass the restoration of the cytoarchitecture, homeostasis and function all in dear need. Transplantation-based treatments using exogenous cells are the most favoured approach. Yet, with the advent of the stem cell concept and continuous progress in the field it became clear that the endogenous potential for repair is greater than previously thought. As an alternative to neural grafting, we and other researchers have aimed at understanding what are the elements needed for a successful repair with self progenitors that would give rise to the cell types needed to restore function of the central nervous system. Some studies involve both scaffolds and cell grafts. Here we describe studies on spinal cord repair using what we call "endogenous tissue engineering for regenerative medicine". The approach involves a hydrogel that mimics the natural milieu where endogenous pre-existing and newly formed cells populate the gel progressively allowing for the integration of CNS self populations leading to a successful recovery of function. Highlight aspects learned from this type of studies are that: Endogenous reconstruction of the injured spinal cord is possible by using the adequate support. The contribution of nestin-expressing progenitors to spinal cord regeneration is continuous and substantial both, in the reconstructed segment as well as, along the distal and caudal segments of the reconstructed spinal cord. Most of these cells appear to have been in a quiescent state until the injury occurred and only a small fraction of these neural progenitors was produced via cell proliferation. The hydrogel combined with exercise was necessary and sufficient to restore locomotor function in cats that underwent spinal transaction followed by reconstructive surgery. This recovery of function was first seen 28 days after surgery and continued to improve for at least 21 months. Therefore, endogenous pre-existing and newly formed cells populated the gel scaffold established contact with the non injured tissue and lead to recovery of function.

Trophic factors are essential for the survival of grafted oligodendrocyte progenitors and for neuroprotection after perinatal excitotoxicity.

The consequences of neonatal white matter injury are devastating and represent a major societal problem as currently there is no cure. Prematurity, low weight birth and maternal pre-natal infection are the most frequent causes of acquired myelin deficiency in the human neonate leading to cerebral palsy and cognitive impairment. In the developing brain, oligodendrocyte (OL) maturation occurs perinatally, and immature OLs are particularly vulnerable. Cell replacement therapy is often considered a viable option to replace progenitors that die due to glutamate excitotoxicity. We previously reported directed specification and mobilization of endogenous committed and uncommitted neural progenitors by the combination of transferrin and insulin growth factor 1 (TSC1). Here, considering cell replacement and integration as therapeutic goals, we examined if OL progenitors (OLPs) grafted into the brain parenchyma of mice that were subjected to an excitotoxic insult could rescue white matter injury. For that purpose, we used a well-established model of glutamate excitotoxic injury. Four-day-old mice received a single intraparenchymal injection of the glutamate receptor agonist N-methyl-D-aspartate alone or in conjunction with TSC1 in the presence or absence of OLPs grafted into the brain parenchyma. Energetics and expression of stress proteins and OL developmental specific markers were examined. A comparison of the proteomic profile per treatment was also ascertained. We found that OLPs did not survive in the excitotoxic environment when grafted alone. In contrast, when combined with TSC1, survival and integration of grafted OLPs was observed. Further, energy metabolism in OLPs was significantly increased by N-methyl-D-aspartate and modulated by TSC1. The proteomic profile after the various treatments showed elevated ubiquitination and stress/heat shock protein 90 in response to N-methyl-D-aspartate. These changes were reversed in the presence of TSC1 and ubiquitination was decreased. The results obtained in this pre-clinical study indicate that the use of a combinatorial intervention including both trophic support and healthy OLPs constitutes a promising approach for long-term survival and successful graft integration. We established optimal conditioning of the host brain environment to promote long-term survival and integration of grafted OLPs into an inflamed neonate host brain. Experimental procedures were performed under the United States Public Health Service Guide for the Care and Use of Laboratory Animals and were approved by the Institutional Animal Care Committee at (UCLA) (ARC #1992-034-61) on July 1, 2010.

Diabetic Macular Edema Management in Asian Population: Expert Panel Consensus Guidelines.

PURPOSE: The aim of this consensus article was to provide comprehensive recommendations in the management of diabetic macular edema (DME) by reviewing recent clinical evidence. DESIGN: A questionnaire containing 47 questions was developed which encompassed clinical scenarios such as treatment response to anti-vascular endothelial growth factor and steroid, treatment side effects, as well as cost and compliance/reimbursement in the management of DME using a Dephi questionnaire as guide. METHODS: An expert panel of 12 retinal specialists from Singapore, Malaysia, Philippines, India and Vietnam responded to this questionnaire on two separate occasions. The first round responses were compiled, analyzed and discussed in a round table discussion where a consensus was sought through voting. Consensus was considered achieved, when 9 of the 12 panellists (75%) agreed on a recommendation. RESULTS: The DME patients were initially profiled based on their response to treatment, and the terms target response, adequate response, nonresponse, and inadequate response were defined. The panellists arrived at a consensus on various aspects of DME treatment such as need for classification of patients before treatment, first-line treatment options, appropriate time to switch between treatment modalities, and steroid-related side effects based on which recommendations were derived, and a treatment algorithm was developed. CONCLUSIONS: This consensus article provides comprehensive, evidence-based treatment guidelines in the management of DME in Asian population. In addition, it also provides recommendations on other aspects of DME management such as steroid treatment for stable glaucoma patients, management of intraocular pressure rise, and recommendations for cataract development.

Evolving Practice Patterns in Singapore's Public Sector Ophthalmology Centers During the COVID-19 Pandemic.

Coronavirus disease 19 (COVID-19) was first reported in Wuhan, China, in December 2019, and has since become a global pandemic. Singapore was one of the first countries outside of China to be affected and reported its first case in January 2020. Strategies that were deployed successfully during the 2003 outbreak of severe acute respiratory syndrome have had to evolve to contain this novel coronavirus. Like the rest of the health care services in Singapore, the practice of ophthalmology has also had to adapt to this rapidly changing crisis. This article discusses the measures put in place by the 3 largest ophthalmology centers in Singapore's public sector in response to COVID-19, and the challenges of providing eye care in the face of stringent infection control directives, staff redeployments and "social distancing." The recently imposed "circuit breaker," effectively a partial lockdown of the country, has further limited our work to only the most essential of services. Our staff are also increasingly part of frontline efforts in the screening and care of patients with COVID-19. However, this crisis has also been an opportunity to push ahead with innovative practices and given momentum to the use of teleophthalmology and other digital technologies. Amidst this uncertainty, our centers are already planning for how ophthalmology in Singapore will be practiced in this next stage of the COVID-19 pandemic, and beyond.

Systemic Factors Associated with Treatment Response in Diabetic Macular Edema.

PURPOSE: To identify systemic factors that may influence the response to anti-VEGF therapy in patients with diabetic macular edema (DME). METHODS: 35 patients undergoing anti-VEGF injections for centre-involving DME were studied in this prospective observational study. The primary outcome was change in macular thickness one month after treatment, measured using spectral-domain optical coherence tomography (OCT). At baseline, information on various systemic factors was collected including glycosylated hemoglobin (HbA1c), serum VEGF levels, lipid profile and markers of renal function, and blood pressure. Thirty-three of the 35 patients were included in this study. Nonparametric statistical tests were used for the analysis of the data in view of the nonnormal distribution of the outcome variables. Multivariate analysis was performed using logistic regression. Stata 12.1 software was used for the analysis. Main Outcome Measures. Reduction in macular central subfield thickness (on spectral-domain OCT) and change in logMAR visual acuity at one month after injection. RESULTS: Lower HbA1c levels (7% or less) were significantly associated with greater reduction in central macular subfield thickness at one month after injection of bevacizumab or ranibizumab on both univariate analysis (p=0.012) and multivariate analysis (p=0.012) and multivariate analysis (. CONCLUSIONS: Better glycemic control is associated with a greater reduction in central macular thickness after the first injection of bevacizumab or ranibizumab in diabetic macular edema. Patients with high levels of HbA1c and poor response to anti-VEGF may benefit from strict control of their blood glucose.

Clinical spectrum, treatment and outcomes of uveal melanoma in a tertiary centre.

INTRODUCTION: We aimed to describe the clinical characteristics, diagnostic challenges, treatment patterns and outcomes of uveal melanoma (UM) in a tertiary care centre. METHODS: This is a retrospective case series of 11 consecutive patients with UM who were managed in a tertiary referral centre between 2002 and 2017. Epidemiological, clinical, pathological and radiological characteristics were reviewed. Classification of choroidal melanoma as small, medium or large was based on the criteria established by the Collaborative Ocular Melanoma Study. RESULTS: Mean age at presentation was 42.9 (range 27‒67) years. In 7 (64%) patients, a definitive diagnosis of UM was made after a mean follow-up period of 6.4 (range 1‒17) months. There were one, six and four patients with small-, medium- and large-sized choroidal melanomas, respectively. Treatment was enucleation in 5 (45.5%) patients, plaque brachytherapy in 4 (36.4%) patients, transpupillary thermotherapy in 1 (9.1%) patient, and observation in 1 (9.1%) patient. Median follow-up was 29 months. Metastatic disease developed in 5 (45.5%) patients at the mean age of 46.6 (range 38‒56) years, with median overall survival of 20 months. Genetic mutations in three patients were monosomy 3 (n = 2), and gain of 3q and 8q (n = 1). CONCLUSION: Our study supports the finding that UM in Chinese and Asian Indian patients presents at a younger age than in Caucasians. Although it is rare, ophthalmologists should remain mindful of this life-threatening disease. We propose establishing a national and regional registry for ocular tumours with genetic information to characterise the disease spectrum in Southeast Asia.

Retinal-detachment repair and vitreous-like-body reformation via a thermogelling polymer endotamponade.

Internal-tamponade agents are crucial surgical adjuncts in vitreoretinal surgery. Clinically used endotamponade agents act through buoyancy forces, yet can result in prolonged post-operative positioning, temporary loss of vision, raised intra-ocular pressure, cataract formation or the need for additional removal surgery. Here, we describe a thermogelling polymer that provides an internal tamponade effect through surface tension and swelling counter-forces. We tested the long-term biocompatibility of the polymer endotamponade in rabbit vitrectomy models, and its surgical efficacy and biocompatibility in a non-human primate retinal-detachment model. We also show that, while the thermogel biodegrades during the three months following surgery, it promotes the reformation of a vitreous-like body that mimics the biophysical properties of the natural vitreous. The thermogelling endotamponade might serve as a long-term vitreous substitute.

Peripheral retinal changes in highly myopic young Asian eyes.

PURPOSE: To determine the type and prevalence of peripheral retinal changes and its relationship with axial length (AL) in a population of young Asian adult males. METHODS: This was a cross-sectional study of male subjects aged between 19 and 25 years old. High myopes [spherical equivalent refraction, (SER) < -6.00 D] were recruited and underwent further ocular investigations including dilated retinal photography and binocular indirect ophthalmoscopy by two trained ophthalmologists. The frequency of peripheral retinal changes within high myopes was correlated with axial length and also compared with a group of emmetropes (SER between -0.50 D and +1.00 D). RESULTS: A total of 593 high myopes and 156 emmetropes were recruited. White without pressure (WWOP; n = 458, 46.5%) and lattice degeneration (LD; n = 109, 14.6%) were the commonest findings, and their prevalence was significantly higher among high myopes (LD, 16.9% versus 5.8%; WWOP, 57.2% versus 5.8%; both p < 0.001). Among high myopes, temporal LD was more common (71%) and 35% had more than one area in the same eye. Increasing AL was associated with LD (odds ratio 1.28, p = 0.01) and retinal holes (odd's ratio 1.44, p = 0.02) on multivariate analysis. CONCLUSION: White without pressure (WWOP) and LD were the commonest peripheral retinal changes. One-third of high myopes with LD had more than one area in the same eye. Increasing AL was associated with LD and retinal holes. Studies in older adults should be conducted to develop clinical guidelines for the management of high myopes.

Comparison of central corneal thickness measurements by visante anterior segment optical coherence tomography with ultrasound pachymetry.

PURPOSE: To compare the measurement of the central corneal thickness (CCT) by Visante (Carl Zeiss Meditec, Dublin, California, USA) anterior segment optical coherence tomography (AS-OCT) with ultrasound pachymetry. DESIGN: Population-based, cross-sectional study. METHODS: Participants were part of a population-based study of 3280 Malay subjects aged 40 to 80 years in Singapore. Ultrasound pachmetry of CCT was performed on all participants and approximately 10% underwent further evaluation with AS-OCT. RESULTS: Two hundred and eighty-five consecutive subjects were included, with a mean age of 57.9 (+/- 10.8) years. CCT as measured by ultrasound pachymetry was highly correlated with the equivalent AS-OCT reading (The Pearson correlation coefficient = 0.93, P < .001). However, Bland-Altman analysis showed that CCT as measured by ultrasound pachymetry was significantly higher by 16.5 +/- 11.7 microm (limits of agreement -6.1 to 39.1, P < .001). CONCLUSIONS: CCT measured by Visante AS-OCT was highly correlated with that from ultrasound pachymetry. However, CCT readings by Visante AS-OCT were consistently less than that of ultrasound pachymetry.

Relationship between Myopia Severity and Macular Retinal Thickness on Visual Performance under Different Lighting Conditions.

OBJECTIVE: To evaluate the relationship between both spherical equivalent (SE) and retinal thickness (RT) on best-corrected visual acuity (BCVA) among young Asian adult men under photopic, mesopic, and simulated night-vision goggle (NVG) lighting conditions. DESIGN: Community-based cross-sectional study. PARTICIPANTS: Total of 698 myopic and 148 emmetropic subjects. METHODS: All participants underwent a complete ophthalmic examination and color fundus photography. BCVA and subjective refraction were assessed under standardized photopic, mesopic, and simulated NVG lighting conditions. Retinal thickness in various Early Treatment Diabetic Retinopathy Study (ETDRS) subfields was measured using spectral-domain OCT using a standardized protocol. Univariate and multiple linear regression analyses were performed to assess the relationship between BCVA and both SE and RT. MAIN OUTCOME MEASURES: Relationship between BCVA and both SE and RT. RESULTS: The mean age of all subjects was 21.1 years, with mean SE of -8.44 diopter (D) among the myopic subjects (range, -3.75 D to -23.0 D) and +0.10 among the emmetropic subjects (range, -0.49 D to +1.00 D). BCVA worsened progressively with increasing myopia under all lighting conditions (standardized coefficient -0.581 under photopic conditions, P < 0.001). RT was thickest among participants with LogMAR VA ≤0.00, and became thinner in the groups including those with VA >0.00 to ≤0.10 and >0.10 (mean inner subfield RT: 342.7 µm vs. 338.1 µm vs. 331.0 µm, respectively, P < 0.001) under all lighting conditions. When multiple linear regression was performed, higher degrees of myopia and decreasing RT were associated with reduced BCVA (all P < 0.05). For each diopter increase in myopia, mean BCVA decreased by 0.01 LogMAR in photopic conditions and 0.02 LogMAR in mesopic conditions (both P < 0.001). The mean BCVA reduced by 0.05 LogMAR (P = 0.003) and 0.04 LogMAR (P = 0.037), under photopic and scotopic lighting conditions respectively, for each 100-µm decrease in RT. CONCLUSIONS: Both the severity of myopia and macular RT independently affect visual performance under photopic, mesopic, and simulated NVG conditions.

Choroidal thickness does not predict visual acuity in young high myopes.

PURPOSE: To investigate the influence of choroidal thickness (CT) on visual acuity (VA) in young persons with extremely high myopia. METHODS: We conducted a case-control study of young men with extremely high myopia and controls with emmetropia recruited from a mandatory medical eye review for employment purposes. Retinal and choroidal imaging was performed using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). RESULTS: We included 105 extremely high myopic subjects with spherical equivalent (SE) -10 dioptre (D) or worse and 50 emmetropic subjects with SE less than 0.5 D. The mean SE was -11.56 ± 2.04 D (range, -10 to -23 D) for myopic group and 0.14 ± 0.25 D for emmetropic group. The mean age of included myopic and emmetropic subjects was 21.51 ± 1.22 years and 21.96 ± 0.89 years, respectively. In the univariate analysis, subfoveal CT was significantly associated with best-corrected visual acuity (BCVA) (ß = -0.039, p = 0.015). However, in the multiple linear regression analysis, after adjusting for SE and presence of any pathological myopia lesions such as posterior staphyloma, lacquer cracks or chorioretinal atrophy, subfoveal CT was not independently associated with BCVA (p = 0.937). CONCLUSION: Extremely high myopic eyes had thinner choroid, but CT was not an independent predictor of VA. Other factors related to myopia are likely responsible for the diminished VA in young extremely high myopic eyes.