Visual impairment and blindness due to retinitis pigmentosa in India: 15-year follow-up of the Andhra Pradesh Eye Disease Study cohort

Purpose: To assess the incidence, visual impairment, and blindness due to retinitis pigmentosa (RP) in a rural southern Indian cohort. Methods: This is a population?based longitudinal cohort study of participants with RP from the Andhra Pradesh Eye Disease Study (APEDS) cohorts I and III, respectively. The study included participants with RP of APEDS I who were followed until APEDS III. Their demographic data along with ocular features, fundus photographs, and visual fields (Humphrey) were collected. Descriptive statistics using mean ± standard deviation with interquartile range (IQR) were calculated. The main outcome measures were RP incidence, visual impairment, and blindness as per the World Health Organization (WHO) definitions. Results: At baseline (APEDS I), 7771 participants residing in three rural areas were examined. There were nine participants with RP with a mean age at baseline of 47.33 ± 10.89 years (IQR: 39–55). There was a male preponderance (6:3), and the mean best?corrected visual acuity (BCVA) of 18 eyes from nine participants with RP was 1.2 ± 0.72 logarithm of minimum angle of resolution (logMAR; IQR: 0.7–1.6). Over a mean follow?up duration of 15 years, 5395/7771 (69.4%) were re?examined, which included seven RP participants from APEDS 1. Additionally, two new participants with RP were identified; so, the overall incidence was 370/ million in 15 years (24.7/million per year). The mean BCVA of 14 eyes of seven participants with RP who were re?examined in APEDS III was 2.17 ± 0.56 logMAR (IQR: 1.8–2.6), and five of these seven participants with RP developed incident blindness during the follow?up period. Conclusion: RP is a prevalent disease in southern India that warrants appropriate strategies to prevent this condition.

Phenotypic variations in ocular features among siblings with oculocutaneous albinism

Purpose: To assess the clinical profiles, presenting ocular features, and variations in the phenotypic features in siblings with oculocutaneous albinism (OCA). Methods: Electronic medical records of consecutive siblings diagnosed with albinism from January 2016 to December 2020 were reviewed to identify the affected siblings. The variations in their phenotypic characteristics were studied. Results: Significant variations were observed in the clinical features between the siblings (n = 42). A difference of >2 lines in visual acuity was observed in 50% (n = 21) of the sibling pairs. Compound hyperopic astigmatism was the commonest refractive error. The refractive status was different in 80.95% (n = 34) pairs. Although individually strabismus and abnormal head posture were observed in one?third and one?fourth of individual children, respectively, both siblings with similar strabismus were seen in only 16.67% (n = 7) and with a similar abnormal head posture in 13.33% (n = 5). Nystagmus was the most consistent finding across these siblings with a similar nature of horizontal jerk or pendular in 65% of sibling pairs. Conclusion: This study observed significant variations in phenotypic presentations among siblings with OCA. Such differences in clinical manifestations and severity would be helpful in appropriate counseling of these families as the need for rehabilitation services is likely to vary across siblings

Changing trends in the prevalence of blindness and visual impairment in a rural district of India: Systematic observations over a decade.

Context: Globally, limited data are available on changing trends of blindness from a single region. Aims: To report the changing trends in the prevalence of blindness, visual impairment (VI), and visual outcomes of cataract surgery in a rural district of Andhra Pradesh, India, over period of one decade. Settings and Design: Rural setting; cross-sectional study. Materials and Methods: Using a validated Rapid Assessment of Cataract Surgical Services (RACSS) method, population-based, cross-sectional survey was done in a rural district in the state of Andhra Pradesh, India. Two-stage sampling procedure was used to select participants ≥50 years of age. Further, a comparative analysis was done with participants ≥50 years from the previously concluded Andhra Pradesh Eye Disease Study (APEDS) study, who belonged to the same district. Statistical Analysis: Done using 11th version of Stata. Results: Using RACSS, 2160/2300 (93.9%) participants were examined as compared with the APEDS dataset (n=521). Age and sex adjusted prevalence of blindness in RACSS and APEDS was 8% (95% CI, 6.9–9.1%) and 11% (95% CI, 8.3–13.7%), while that of VI was 13.6% (95% CI, 12.2–15.1%) and 40.3% (95% CI, 36.1–44.5%), respectively. Cataract was the major cause of blindness in both the studies. There was a significant reduction in blindness following cataract surgery as observed through RACSS (17.3%; 95% CI, 13.5–21.8%) compared with APEDS (34%; 95% CI, 20.9–49.3%). Conclusion: There was a significant reduction in prevalence of blindness and VI in this rural district of India over a decade.

Complex genetic mechanisms in glaucoma: An overview.

Glaucomas comprise a group of hereditary optic neuropathies characterized by progressive and irreversible visual field loss and damage to the optic nerve head. It is a complex disease with multiple molecular mechanisms underlying its pathogenesis. Genetic heterogeneity is the hallmark of all glaucomas and multiple chromosomal loci have been linked to the disease, but only a few genes have been characterized, viz. myocilin (MYOC), optineurin (OPTN), WDR36 and neurotrophin-4 (NTF4) in primary open angle glaucoma (POAG) and CYP1B1 and LTBP2 in congenital and developmental glaucomas. Case-control-based association studies on candidate genes involved in different stages of glaucoma pathophysiology have indicated a very limited involvement. The complex mechanisms leading to glaucoma pathogenesis indicate that it could be attributed to multiple genes with varying magnitudes of effect. In this review, we provide an appraisal of the various efforts in unraveling the molecular mystery in glaucoma and also some future directions based on the available scientific knowledge and technological developments.

Single-nucleotide polymorphisms in peroxisome proliferator-activated receptor γ and their association with plasma levels of resistin and the metabolic syndrome in a South Indian population.

Studies on the association of the Pro12Ala and C1431T polymorphisms of PPARγ with diabetes and obesity have revealed extensive population-dependent variations. However, association of these polymorphisms with the metabolic syndrome and its individual components has not been well investigated in the Indian population. The Indian population harbours the maximum number of diabetics in the world who are thus more susceptible to metabolic disorders. We screened a South Indian population (N = 699) for a possible association of these polymorphisms with the metabolic syndrome (MS) and type 2 diabetes. We also investigated the correlation of these two single-nucleotide polymorphisms (SNPs) with plasma resistin levels. The C1431T SNP was associated with higher levels of plasma resistin (P = 0.017). Furthermore, C1431T was associated with resistin in different tertiles. Prevalence of the ‘Pro-C’ haplotype decreased with increasing tertiles of resistin (84.1% to 75.4%, P = 0.037). Plasma resistin levels were not found to be associated with MS and type 2 diabetes. These results point to a likely association of plasma resistin levels with PPARγ polymorphisms in the Indian population.