Impact of chronic kidney disease on the incidence of visual impairment and age-related eye diseases in a multi-ethnic Asian population.

Background: The kidney and eye share common metabolic and vascular risk factors, and chronic kidney disease (CKD) has been associated with the prevalence of visual impairment (VI). In this study, we examined the association of CKD with incident VI and major age-related eye diseases, including cataract, age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma, in a multi-ethnic Asian population. Methods: We analysed data from 6486 Chinese, Malay, and Indian adults aged 40-80 years who participated in the Singapore Epidemiology of Eye Diseases study at baseline (2004-11) and six-year follow-up visit (2011-17) and were free of VI and the respective eye diseases at baseline. We defined CKD (n = 564; 8.7%) as an estimated glomerular filtration rate (eGFR)<60 ml/min/1.73 m2, and categorised the severity of CKD into stages G1-G5. Eye examinations included refraction, slit-lamp examinations, and retinal imaging. We defined incident VI as best-corrected visual acuity <20/40 in the better eye. Eye diseases examined included cataract, AMD, retinopathy, including DR in those with diabetes and glaucoma. We examined associations between CKD, VI, and eye diseases using multivariable logistic regression models adjusted for age, gender, ethnicity, diabetes, and hypertension status, presenting the results as odds ratios (ORs) and 95% confidence intervals (CIs). Results: CKD participants had a higher incidence of any VI (14.3% vs. 3.3%; P < 0.001), any AMD (8.0% vs. 5.4%; P < 0.001), and cataracts (65.1% vs. 40.8%; P < 0.001) than non-CKD participants. VI incidence increased with CKD severity in G1-G2 (3.3%), G3a (13.5%), and G3b-G5 (16.3%) (P < 0.001). In multivariable models, CKD was associated with incident VI (OR = 1.47; 95% CI = 1.03-2.10) and moderate/worse DR (OR = 2.62; 95% CI = 1.35-5.10). Conclusions: Our results suggest that the presence of CKD increases the risk and severity of VI and eye diseases in Asian adults. Our findings highlight the importance of regular eye exams for CKD patients to reduce the risk of VI.