Sleep Regularity and Age-Related Eye Diseases: Prospective Analyses with Retinal Imaging and Multimorbidity Assessment in the UK Biobank.

Sleep regularity, a key circadian dimension of sleep health, has been linked to cardiometabolic and neurodegenerative outcomes, yet its relevance to ocular ageing remains unclear. The retina is a metabolically active, circadian-regulated neural tissue, suggesting that irregular sleep may contribute to the development of age-related eye diseases. We studied 78,839 adults in the UK Biobank. Sleep regularity was quantified using the Sleep Regularity Index (SRI). Associations with age-related macular degeneration (AMD), cataract, glaucoma, retinal vein occlusion (RVO), and diabetic retinopathy (DR) were examined using Cox models, restricted cubic splines, subgroup analyses, and propensity-score matching. Retinal structural and vascular metrics were additionally evaluated. Nomogram models integrating SRI with clinical risk factors were developed. Lower SRI was consistently associated with higher risks of AMD (HR=0.87), cataract (HR=0.95), and glaucoma (HR=0.89), with clear dose-response patterns; no robust associations were found for RVO or DR. Higher SRI correlated with greater macular, retinal ganglion cell (RGC), and retinal nerve fiber layer (RNFL) thicknesses, and with more favourable retinal vascular geometry. Incorporating SRI improved prediction performance for AMD, cataract, and glaucoma (AUC 0.72-0.74). SRI also declined markedly with increasing ocular multimorbidity. Sleep regularity was consistently associated with major age-related eye diseases, ocular multimorbidity, and retinal structural and vascular characteristics. These findings highlight sleep regularity as a clinically relevant behavioural correlate of ocular ageing and a potential adjunctive marker for prevention-oriented risk stratification.