Functional and structural neuroretinal disorders in HIV Controllers. Prospective cohort study.

OBJECTIVE: To estimate the prevalence and cumulative incidence of neuro-retinal-disorders (NRD) in HIV-controllers. DESIGN: Prospective, single-centre, cohort study of people living with HIV (PLWH): elite-controllers, long-term-non-progressors and early diagnosed. METHODS: The study compared "HIV-controllers" (including elite-controllers and long-term-non-progressors), who were not on antiretroviral therapy (ART), and "HIV-treatment" (HIV-infected subjects with a recent diagnosis and on ART). A matched cohort of "non-HIV subjects" was created. NRD was defined as at least one altered (not normal) ophthalmological parameter (functional or structural). Functional (visual acuity, contrast sensitivity, chromatic vision, visual field) and structural parameters (ganglion cells, macular nerve fibre layer, peripapillary nerve fibre layers, vascular calibre) as well as quality of life (Medical Outcomes Study-HIV Short Form-30) were assessed. RESULTS: Between March 2012 and November 2015, the study included all HIV-controllers (16 elite-controllers, 1 long-term-non-progressor), 11 HIV-treatment and 16 non-HIV. Prevalence of NRD at baseline was 88.2% (15/17, 95% CI: 65.7%-96.7%), 90.9% (10/11, 95% CI: 62.3%-98.4%) and 56.3% (9/16, 95% CI: 33.2%-76.9%), respectively. Cumulative incidence at 3 years was 50% (1/2), 100% (1/1) and 33.3% (2/6), respectively. None of the participants manifested ocular clinical symptoms. Three years later, prevalence of NRD was 92.3% (12/13, 95% CI: 66.7%-98.6%), 75% (6/8, 95% CI: 40.9%-92.9%) and 50.0% (7/14, 95% CI: 26.8%-73.2%), respectively. Contrast sensitivity and structural parameters were globally the most affected among PLWH. Quality of life (total score) [median (interquartile range)] at baseline and 3 years was 82 (71-89) and 74 (63.5-79.25) in HIV-controllers and 80 (73-88) and 88 (83-92) in HIV-treatment. CONCLUSIONS: HIV-controllers and those individuals on ART presented a higher percentage of NRD than non-HIV. Our results suggest that NRD could be a biomarker of ocular aging among PLWH.

A hybrid model for the detection of retinal disorders using artificial intelligence techniques.

The prevalence of vision impairment is increasing at an alarming rate. The goal of the study was to create an automated method that uses optical coherence tomography (OCT) to classify retinal disorders into four categories: choroidal neovascularization, diabetic macular edema, drusen, and normal cases. This study proposed a new framework that combines machine learning and deep learning-based techniques. The utilized classifiers were support vector machine (SVM), K-nearest neighbor (K-NN), decision tree (DT), and ensemble model (EM). A feature extractor, the InceptionV3 convolutional neural network, was also employed. The performance of the models was evaluated against nine criteria using a dataset of 18000 OCT images. For the SVM, K-NN, DT, and EM classifiers, the analysis exhibited state-of-the-art performance, with classification accuracies of 99.43%, 99.54%, 97.98%, and 99.31%, respectively. A promising methodology has been introduced for the automatic identification and classification of retinal disorders, leading to reduced human error and saved time.

ROS-responsive charge reversal mesoporous silica nanoparticles as promising drug delivery system for neovascular retinal diseases.

Intravitreal injection of biodegradable implant drug carriers shows promise in reducing the injection frequency for neovascular retinal diseases. However, current intravitreal ocular devices have limitations in adjusting drug release rates for individual patients, thereby affecting treatment effectiveness. Accordingly, we developed mesoporous silica nanoparticles (MSNs) featuring a surface that reverse its charge in response to reactive oxygen species (ROS) for efficient delivery of humanin peptide (HN) to retinal epithelial cells (ARPE-19). The MSN core, designed with a pore size of 2.8 nm, ensures a high HN loading capacity 64.4% (w/w). We fine-tuned the external surface of the MSNs by incorporating 20% Acetyl-L-arginine (Ar) to create a partial positive charge, while 80% conjugated thioketal (TK) methoxy polyethylene glycol (mPEG) act as ROS gatekeeper. Ex vivo experiments using bovine eyes revealed the immobilization of Ar-MSNs-TK-PEG (mean zeta potential: 2 mV) in the negatively charged vitreous. However, oxidative stress reversed the surface charge to -25 mV by mPEG loss, facilitating the diffusion of the nanoparticles impeded with HN. In vitro studies showed that ARPE-19 cells effectively internalize HN-loaded Ar-MSNs-TK, subsequently releasing the peptide, which offered protection against oxidative stress-induced apoptosis, as evidenced by reduced TUNEL and caspase3 activation. The inhibition of retinal neovascularization was further validated in an in vivo oxygen-induced retinopathy (OIR) mouse model.

Exploring the impact of Choroideremia on women with phenotypic and/or genotypic evidence of disease: insights from a global survey.

INTRODUCTION: Choroideremia (CHM) is an X-linked inherited retinal disease mostly affecting males. However, women with phenotypic and/or genotypic evidence of CHM may develop degenerative visual disability with advancing age. Our objective was to determine the visual impacts of phenotypic and/or genotypic evidence of CHM in women and its associated psychosocial burden and influence on activities of daily living (ADLs). METHODS: We conducted an international cross-sectional survey from April to December 2022 using an e-questionnaire distributed through not-for-profit stakeholder organizations and social media plat-forms. RESULTS: With a total of 55 respondents (n = 55), most women with phenotypic and/or genotypic evidence of CHM (76%) reported a change in their visual acuity. When assessing its impact on ADLs, Pearson's correlation coefficient showed a negative correlation between driving (p = 0.046) and mobility capabil-ities (0.046) with the respondent's age. More than half of women reported being afraid, anxious, and stressed, with women below the age of 50 years old reporting a significantly higher level of distress and hopelessness (p = 0.003), anxiety (p = 0.00007), issues with relaxing (p = 0.025), and negative personal thoughts (p = 0.042). CONCLUSION: Overall, this survey outlines both physical and psychological burden of being a woman with phenotypic and/or genotypic evidence of CHM. Given the limited clinical research in females affected by CHM, this patient-centered survey is a crucial advocacy tool for these individuals.

Acquired Vitelliform Lesions in Intermediate Age-Related Macular Degeneration: A Cross Sectional Study.

PURPOSE: This study aims to define the characteristics of acquired vitelliform lesions (AVLs) in patients with intermediate age-related macular degeneration (iAMD). DESIGN: Retrospective, observational, cross sectional study. SUBJECTS: This study included 217 eyes with AVLs associated with iAMD, and an equivalent number of control patients. METHODS: OCT scans were evaluated for qualitative and quantitative parameters at both the eye and lesion level. Eye-level parameters included the presence of: hyporeflective core drusen, intraretinal hyperreflective foci (IHRF), subretinal drusenoid deposits, macular pachyvessels, central retinal thickness, and central choroidal thickness. Lesion-level qualitative parameters included the presence of ellipsoid zone (EZ) and external limiting membrane disruption overlying the AVL, IHRF overlying the AVL, AVL overlying drusen, pachyvessels under the AVL, a solid core within AVL, and AVL location. Lesion-level quantitative characteristics included AVL height and width, AVL distance from the fovea, and sub-AVL choroidal thickness. MAIN OUTCOME MEASURES: The primary outcomes assessed included the frequency of IHRF, the presence of macular pachyvessels, central choroidal thickness, and the dimensions (both height and width) of AVLs. RESULTS: Comparing the AVL and control groups, the frequency of IHRF (AVL: 49.3% vs. control: 26.3%) and macular pachyvessels (37.3% vs. 6.9%) was significantly higher in the AVL case group, and the central choroidal thickness (256.8 ± 88 µm vs. 207.1± 45 µm) was thicker in the AVL group. Acquired vitelliform lesions located over drusen, with overlying IHRF, or situated subfoveally, and AVL lesions with EZ disruption were found to have a greater lesion height and width compared with AVL lesions lacking these characteristics (P value < 0.001 for all). Additionally, a significant negative correlation was observed between the distance from the fovea and AVL height (Spearman rho: -0.19, P = 0.002) and width (Spearman rho: -0.30, P = 0.001). CONCLUSIONS: This study represents the largest reported cohort of AVL lesions associated with iAMD. Novel findings include the higher frequency of pachyvessels in addition to the presence of a thicker choroid in these eyes, as well as the greater height and width of AVL closer to the foveal center. These findings may offer insights into pathophysiologic mechanisms underlying the development of AVL. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Epigenetic Switches in Retinal Homeostasis and Target for Drug Development.

Retinal homeostasis, a tightly regulated process maintaining the functional integrity of the retina, is vital for visual function. Emerging research has unveiled the critical role of epigenetic regulation in controlling gene expression patterns during retinal development, maintenance, and response to mutational loads and injuries. Epigenetic switches, including DNA methylation, histone modifications, and non-coding RNAs, play pivotal roles in orchestrating retinal gene expression and cellular responses through various intracellular, extracellular, and environmental modulators. This review compiles the current knowledge on epigenetic switches in retinal homeostasis, providing a deeper understanding of their impact on retinal structural integrity and function and using them as potential targets for therapeutic interventions.

Quantitative microvascular analysis in different stages of retinitis pigmentosa using optical coherence tomography angiography.

As retinitis pigmentosa (RP) is chronic and progressive, the chronological sequence of microvascular changes is important for understanding its pathophysiology. We aimed to investigate retinal and choroidal microvascular changes according to the RP stages. The stages of RP were classified into three stages according to the integrity and width of the inner segment ellipsoid zone: early, ≥ 2500 µm; moderate, < 2500 µm; advanced, absence. Using optical coherence tomography angiography, quantitative microvascular parameters were analyzed. In total, 91 eyes from 49 patients were included. For the superficial capillary plexus (SCP) and deep capillary plexus (DCP), perfusion densities (PDs) in the early stage (SCP: 37.32 ± 8.11%; DCP: 21.19 ± 9.15%) were greater than those in moderate (SCP: 34.16 ± 6.65%, P = 0.011; DCP: 15.67 ± 8.85%, P = 0.031) and advanced stages (SCP: 33.71 ± 9.02%, P = 0.030; DCP: 12.83 ± 6.29%, P < 0.001). The choroidal vascularity index in the early stage (0.58 ± 0.03) was greater than those in the moderate (0.57 ± 0.02, P = 0.017) and advanced stage (0.56 ± 0.02, P = 0.033). The area and perimeter of foveal avascular zone (FAZ) in advanced stage (0.44 ± 0.26 mm2, 2.96 ± 0.86 mm, respectively) were larger than those in early (0.26 ± 0.11 mm2, P = 0.020; 2.19 ± 0.53 mm, P = 0.006, respectively) and moderate stage (0.28 ± 0.13 mm2, P = 0.043; 2.24 ± 0.67 mm, P = 0.013, respectively). During RP disease progression, retinal and choroidal microvascular vessel density decreases in the early stage, followed by FAZ enlargement in the advanced stage.

Ranibizumab Biosimilars in Treating Retinal Disorders: A Cost-Effective Revolution?

Ranibizumab, is a humanized, monoclonal antibody fragment that binds and inactivates vascular endothelial growth factor-A (VEGF-A) and VEGF-B. One of the main indications for an intravitreal treatment with ranibizumab is age-related macular degeneration (AMD), which is a retinal disease with a high worldwide socioeconomic impact. Biosimilars constitute biological products that demonstrate similar pharmacodynamic and pharmacokinetic characteristics with a reference product, as well as comparable clinical efficacy, safety and immunogenicity. Since the approval of the first biosimilar Razumab, there has been a variety of new biosimilars available on the market. They offer the advantage of the same good clinical and safety results at a better price. All Ranibizumab biosimilars that have gained approval were tested in double masked Phase 3 clinical studies. The use of Ranibizumab biosimilars in neovascular AMD is well reported in the bibliography. Nevertheless, over the last few years, there is a tendency of using biosimilars in other retinal diseases like retinopathy of prematurity (ROP), diabetic macular edema (DME) or polypoidal choroidal vasculopathy (PCV). In conclusion, ranibizumab biosimilars offer a promising avenue for the management of retinal diseases, especially in countries with lower socioeconomic status, where there is lack of availability of innovator ranibizumab. However, further research is required to fully explore their efficacy, safety, and long-term outcomes in a plethora of retinal diseases.

A new computer-aided diagnosis tool based on deep learning methods for automatic detection of retinal disorders from OCT images.

PURPOSE: Early detection of retinal disorders using optical coherence tomography (OCT) images can prevent vision loss. Since manual screening can be time-consuming, tedious, and fallible, we present a reliable computer-aided diagnosis (CAD) software based on deep learning. Also, we made efforts to increase the interpretability of the deep learning methods, overcome their vague and black box nature, and also understand their behavior in the diagnosis. METHODS: We propose a novel method to improve the interpretability of the used deep neural network by embedding the rich semantic information of abnormal areas based on the ophthalmologists' interpretations and medical descriptions in the OCT images. Finally, we trained the classification network on a small subset of the online publicly available University of California San Diego (UCSD) dataset with an overall of 29,800 OCT images. RESULTS: The experimental results on the 1000 test OCT images show that the proposed method achieves the overall precision, accuracy, sensitivity, and f1-score of 97.6%, 97.6%, 97.6%, and 97.59%, respectively. Also, the heat map images provide a clear region of interest which indicates that the interpretability of the proposed method is increased dramatically. CONCLUSION: The proposed software can help ophthalmologists in providing a second opinion to make a decision, and primitive automated diagnoses of retinal diseases and even it can be used as a screening tool, in eye clinics. Also, the improvement of the interpretability of the proposed method causes to increase in the model generalization, and therefore, it will work properly on a wide range of other OCT datasets.

Pattern electroretinography response in amblyopic adults.

INTRODUCTION: Amblyopia is generally a unilateral disorder, defined by at least a difference of two lines of visual acuity between both eyes with the best-corrected visual acuity, a decrease in contrast sensitivity, and a decrease in stereopsis. Pattern electroretinogram (PERG) is a noninvasive technique that provides a retinal biopotential and is a highly sensitive indicator of changes in the macular area. Our aim was to evaluate if there are differences in the retinal response of an amblyopic eye compared with a normal eye (NE). METHODS: We evaluated twenty-four adult volunteers, twelve amblyopes (mean 43.42 ± 12.72 years old), and twelve subjects with NE (mean 35.58 ± 12.85 years old). None of the subjects in the two groups had comorbidities. A complete optometric examination was performed including parameters such as visual acuity (VA) by far and near with ETDRS chart, eye alignment with cover test, and evaluation of retinal cells response with PERG. RESULTS: The refractive error found in the NE group of subjects had a mean of - 0.95 ± 1.65D, while the amblyopic group showed a mean of - 2.03 ± 4.29D. The VA in amblyopic eyes had a mean of 0.38 ± 0.20 logMAR. Analyzing PERG data, we observed significant differences in the P50-N95 amplitudes of the amblyopic group compared with the NE group (p < 0.0001-amblyopic eye vs. NE; p = 0.039-fellow eye vs. NE). DISCUSSION: These findings suggest that amblyopic patients may also present other impairments beyond the visual cortex. PERGs seem to be an important complementary examination in the diagnosis of other impairments in amblyopia.

Changes in Metamorphopsia in Patients Undergoing Treatment for Vitreoretinal Disorders.

PURPOSE: To quantify and compare the severity of metamorphopsia in patients undergoing vitrectomy for vitreoretinal disorders. METHODS: Data were collected evaluated from 319 patients with vitreoretinal disorders, including epiretinal membrane (ERM), macular hole (MH), cystoid macular edema with branch retinal vein occlusion (BRVO-CME), CME with central retinal vein occlusion (CRVO), diabetic macular edema (DME), macula-off rhegmatogenous retinal detachment (M-off RD), and macula-on RD (M-on RD). Metamorphopsia was recorded with the M-CHARTS preoperatively and at 3 and 6 months postoperatively. RESULTS: Preoperative and 6-month postoperative metamorphopsia scores were 0.69 ± 0.50 and 0.50 ± 0.52, respectively. Before surgery, 94% of patients presented with metamorphopsia (score ≥0.2). Preoperative metamorphopsia scores were significantly correlated with postoperative metamorphopsia scores (r = 0.378, p < 0.0001). Preoperative metamorphopsia score was significantly higher for ERM (0.89) than for DME (0.51). Vitrectomy significantly improved metamorphopsia in ERM and MH but not in the other disorders. In contrast, treatment improved visual acuity for all disorders except CRVO-CME and M-on RD. CONCLUSION: This quantitative study indicated that metamorphopsia is present in most patients undergoing surgery for vitreoretinal diseases and is most severe in ERM. In these patients, vitrectomy improved visual acuity but not metamorphopsia.

Multimodal and longitudinal evaluation of novel phenotype-genotype correlation of CLN3 isolated retinal degeneration in an hispanic female with heterozygous mutations c.944dup and c.1305C>G.

BACKGROUND: Inherited retinal disorders (IRDs) are a complex group of heritable diseases which are characterized by rod, cone, retinal pigment epithelium, or optic nerve dysfunction. Recently, mutations in CLN3 have also been associated with isolated IRDs. Herein, a case with heterozygous CLN3 variations that had not been previously linked to a CLN3-isolated retinal degeneration (CLN3IRD) phenotype in a Hispanic female and its multimodal imaging findings across a 10-year follow-up are presented. MATERIAL AND METHODS: An observational, prospective, case report on a hispanic female with CLN3IRD is presented. Patients underwent genetic testing and color fundus photography (CFC) and autofluorescence (FAF), fluorescein angiography (FA), Spectral domain optical coherence tomography (OCT) of the macular area, electroretinogram (ERG) and 30-2 visual field examination through automated perimetry. RESULTS: A female, aged 24, affected by CLN3IRD phenotype from c.944dup and c.1305C>G compound heterozygous variants, presented with bilateral hypopigmentary changes in the macular area of OU with that corresponded to hyporautofluorescent deposits in the macular area on FAF. An atrophic maculopathy was evident on structural OCT, and FA disclosed a symmetrical macular hyperflourescence with staining in the early and late stages in OU. Humphrey visual field testing showed a marked reduction of the central visual field in OU. Electrophysiological testing revealed an ERG with markedly decreased a and b waves in OU. In ten years follow up developed of bone spiculae in the midperipheral retina. CONCLUSIONS: We reported a patient with a novel CLN3IRD severe phenotype associated with the variants c.944dup and c.1305C>G, which had previously only been associated with JCNL.

Early pigment spot segmentation and classification from iris cellular image analysis with explainable deep learning and multiclass support vector machine.

Globally, retinal disorders impact thousands of individuals. Early diagnosis and treatment of these anomalies might halt their development and prevent many people from developing preventable blindness. Iris spot segmentation is critical due to acquiring iris cellular images that suffer from the off-angle iris, noise, and specular reflection. Most currently used iris segmentation techniques are based on edge data and noncellular images. The size of the pigment patches on the surface of the iris increases with eye syndrome. In addition, iris images taken in uncooperative settings frequently have negative noise, making it difficult to segment them precisely. The traditional diagnosis processes are costly and time consuming since they require highly qualified personnel and have strict environments. This paper presents an explainable deep learning model integrated with a multiclass support vector machine to analyze iris cellular images for early pigment spot segmentation and classification. Three benchmark datasets MILE, UPOL, and Eyes SUB were used in the experiments to test the proposed methodology. The experimental results are compared on standard metrics, demonstrating that the proposed model outperformed the methods reported in the literature regarding classification errors. Additionally, it is observed that the proposed parameters are highly effective in locating the micro pigment spots on the iris surfaces.

Clinical, biochemical and molecular analysis in a cohort of individuals with gyrate atrophy.

BACKGROUND: Gyrate atrophy of the choroid and retina is a rare autosomal recessive metabolic disorder caused by biallelic variants in the OAT gene, encoding the enzyme ornithine δ-aminotransferase. Impaired enzymatic activity leads to systemic hyperornithinaemia, which in turn underlies progressive chorioretinal degeneration. In this study, we describe the clinical and molecular findings in a cohort of individuals with gyrate atrophy. METHODS: Study participants were recruited through a tertiary UK clinical ophthalmic genetic service. All cases had a biochemical and molecular diagnosis of gyrate atrophy. Retrospective phenotypic and biochemical data were collected using electronic healthcare records. RESULTS: 18 affected individuals from 12 families (8 male, 10 female) met the study inclusion criteria. The median age at diagnosis was 8 years (range 10 months - 33 years) and all cases had hyperornithinaemia (median: 800 micromoles/L; range: 458-1244 micromoles/L). Common features at presentation included high myopia (10/18) and nyctalopia (5/18). Ophthalmic findings were present in all study participants who were above the age of 6 years. One third of patients had co-existing macular oedema and two thirds developed pre-senile cataracts. Compliance with dietary modifications was suboptimal in most cases. A subset of participants had extraocular features including a trend towards reduced fat-free mass and developmental delay. CONCLUSIONS: Our findings highlight the importance of multidisciplinary care in families with gyrate atrophy. Secondary ophthalmic complications such as macular oedema and cataract formation are common. Management of affected individuals remains challenging due to the highly restrictive nature of the recommended diet and the limited evidence-base for current strategies.

Systematic review and meta-analysis of childhood visual impairment in the Eastern Mediterranean Region.

Background: Childhood visual impairment has a significant effect on social life, educational performance, and professional choices, and can lead to poverty. Aims: To review the prevalence and causes of visual impairment among children aged 5-17 years in the Eastern Mediterranean Region (EMR). Methods: This study was conducted in 2021 using the Preferred Reporting Items for Systematic reviews and Meta- Analyses (PRISMA) method. We searched Google Scholar, PubMed, Web of Science, Scopus, Index Medicus for the Eastern Mediterranean Region, and Medline for studies published between January 2000 and April 2020. The articles included were epidemiological studies of prevalence and causes of childhood visual impairment published in peer-reviewed journals. Results: Of the 12 705 articles screened, 23 from 9 countries met the inclusion criteria. The pooled prevalence of uncorrected, presenting, and best-corrected childhood visual impairment was 11.57%, 8.34% and 1.21%, respectively. The most common causes of childhood visual impairment were refractive error (51.89%), amblyopia (11.15%), retinal disorders (3.90%), corneal opacity (3.0%), and cataract (1.88%). There was a highly significant heterogeneity between the studies (P < 0.0001). Conclusion: The prevalence of visual impairment among children in the EMR was high, and the leading causes were uncorrected refractive error and amblyopia, which were avoidable. Access to eyecare services may help improve early diagnosis and treatment of preventable causes of childhood visual impairment.

Progressive Cone-Rod Dystrophy and RPE Dysfunction in Mitfmi/+ Mice.

Mutations in the mouse microphthalmia-associated transcription factor (Mitf) gene affect retinal pigment epithelium (RPE) differentiation and development and can lead to hypopigmentation, microphthalmia, deafness, and blindness. For instance, an association has been established between loss-of-function mutations in the mouse Mitf gene and a variety of human retinal diseases, including Waardenburg type 2 and Tietz syndromes. Although there is evidence showing that mice with the homozygous Mitfmi mutation manifest microphthalmia and osteopetrosis, there are limited or no data on the effects of the heterozygous condition in the eye. Mitf mice can therefore be regarded as an important model system for the study of human disease. Thus, we characterized Mitfmi/+ mice at 1, 3, 12, and 18 months old in comparison with age-matched wild-type mice. The light- and dark-adapted electroretinogram (ERG) recordings showed progressive cone-rod dystrophy in Mitfmi/+ mice. The RPE response was reduced in the mutant in all age groups studied. Progressive loss of pigmentation was found in Mitfmi/+ mice. Histological retinal sections revealed evidence of retinal degeneration in Mitfmi/+ mice at older ages. For the first time, we report a mouse model of progressive cone-rod dystrophy and RPE dysfunction with a mutation in the Mitf gene.

Ribbon Synapses and Retinal Disease: Review.

Synaptic ribbons are presynaptic protein complexes that are believed to be important for the transmission of sensory information in the visual system. Ribbons are selectively associated with those synapses where graded changes in membrane potential drive continuous neurotransmitter release. Defective synaptic transmission can arise as a result of the mutagenesis of a single ribbon component. Visual diseases that stem from malfunctions in the presynaptic molecular machinery of ribbon synapses in the retina are rare. In this review, we provide an overview of synaptopathies that give rise to retinal malfunction and our present understanding of the mechanisms that underlie their pathogenesis and discuss muscular dystrophies that exhibit ribbon synapse involvement in the pathology.

Electronic medical records driven big data analytics in retinal diseases, report number 1: non-oncological retinal diseases in children and adolescents in India.

PURPOSE: To describe the spectrum and demographic distribution of non-oncological retinal diseases in children and adolescents presenting to a multi-tier ophthalmic hospital network in India. METHODS: This is a cross-sectional hospital-based retrospective study over nine years (March 2011-March 2020) from a pyramidal eye care network in India. The analysis included 477,954 new patients (0-21 years), collected from an International Classification of Diseases (ICD) coded electronic medical record (EMR) system. Patients with a clinical diagnosis of retinal disease (non-oncological) in at least one eye were included. Age-wise distribution of these diseases in children and adolescents was analysed. RESULTS: In the study, 8.44% (n = 40,341) of new patients were diagnosed with non-oncological retinal pathology in at least one eye. The age group-specific distribution of retinal diseases was 47.4%, 11. 8%, 5.9%, 5.9%, 6.4%, 7.6% in infants (< 1 year), toddlers (1-2 years), early childhood (3-5 years), middle childhood (6-11 years), early adolescents (12-18 years) and late adolescents (18-21 years), respectively. 60% were male, and 70% had bilateral disease. The mean age was 9.46 ± 7.52 years. The common retinal disorders were retinopathy of prematurity (ROP, 30.5%), retinal dystrophy (19.5%; most commonly, retinitis pigmentosa), and retinal detachment (16.4%). Four-fifth of the eyes had moderate to severe visual impairment. Nearly one-sixth of patients needed low vision and rehabilitative services, and about 1 in 10 patients required surgical intervention (n = 5960, 8.6%). CONCLUSION AND RELEVANCE: About 1 in 10 children and adolescents seeking eye care in our cohort had non-oncological retinal diseases; the common ones were ROP (in infants) and retinitis pigmentosa (in adolescents). This information would help future strategic planning of eye health care in the institution in pediatric and adolescent age groups.

A novel homozygous missense substitution p.Thr313Ile in the PDE6B gene underlies autosomal recessive retinitis pigmentosa in a consanguineous Pakistani family.

BACKGROUND: Retinitis pigmentosa (RP) is one of the most frequent hereditary retinal diseases that often starts with night blindness and eventually leads to legal blindness. Our study aimed to identify the underlying genetic cause of autosomal recessive retinitis pigmentosa (arRP) in a consanguineous Pakistani family. METHODS: Following a detailed ophthalmological examination of the patients by an ophthalmologist, whole-exome sequencing was performed on the proband's DNA to delineate the genetic cause of RP in the family. In-depth computational methods, in-silico analysis, and familial co-segregation study were performed for variant detection and validation. RESULTS: We studied an inbred Pakistani family with two siblings affected by retinitis pigmentosa. The proband, a 32 years old female, was clinically diagnosed with RP at the age of 6 years. A classical night blindness symptom was reported in the proband since her early childhood. OCT report showed a major reduction in the outer nuclear layer and the ellipsoid zone width, leading to the progression of the disease. Exome sequencing revealed a novel homozygous missense mutation (c.938C > T;p.Thr313Ile) in exon 12 of the PDE6B gene. The mutation p.Thr313Ile co-segregated with RP phenotype in the family. The altered residue (p.Thr313) was super conserved evolutionarily across different vertebrate species, and all available in silico tools classified the mutation as highly pathogenic. CONCLUSION: We present a novel homozygous pathogenic mutation in the PDE6B gene as the underlying cause of arRP in a consanguineous Pakistani family. Our findings highlight the importance of missense mutations in the PDE6B gene and expand the known mutational repertoire of PDE6B-related RP.

Inherited retinal disorders: a genotype-phenotype correlation in an Indian cohort and the importance of genetic testing and genetic counselling.

PURPOSE: Recent advances in sequencing technologies have enabled radical and rapid progress in the genetic diagnosis of inherited retinal disorders (IRDs). Although the list of gene variations continues to grow, it lacks the genetic etiology of ethnic groups like South Asians. Differences in racial backgrounds and consanguinity add to genetic heterogeneity and phenotypic overlaps. METHODS: This retrospective study includes documented data from the Gen-Eye clinic from years 2014 to 2019. Medical records and pedigrees of 591 IRD patients of Indian origin and genetic reports of 117 probands were reviewed. Genotype-phenotype correlations were performed to classify as correlating, non-correlating and unsolved cases. RESULTS: Among the 591 patients, we observed a higher prevalence of clinically diagnosed retinitis pigmentosa (38.9%) followed by unspecified diagnoses (28.5%). Consanguinity was reported to be high (55.6%) in this cohort. Among the variants identified in 117 probands, 36.4% of variants were pathogenic, 19.2% were likely pathogenic, and 44.4% were of uncertain significance. Among the pathogenic and likely pathogenic variants, autosomal recessive inheritance showed higher prevalence. About 35% (41/117) of cases showed genotype-phenotype correlation. Within the correlating cases, retinitis pigmentosa and Stargardt disease were predominant. Novel variants identified in RP, Stargardt, and LCA are reported here. CONCLUSION: This first-of-a-kind report on an Indian cohort contributes to existing knowledge and expansion of variant databases, presenting relevant and plausible novel variants. Phenotypic overlap and variability lead to a differential diagnosis and hence a clear genotype-phenotype correlation helps in precise clinical confirmation. The study also emphasizes the importance of genetic counselling and testing for personalized vision care in a tertiary eye hospital.