Abstract
Purpose :
Chronotype—whether an individual is a morning lark or a night owl—serves as a behavioral indicator of their underlying circadian rhythms. While genome-wide association studies have identified chronotype-related variants expressed in the retina, there is limited epidemiological evidence linking chronotype to retinal morphology. This study examines the association between chronotype and retinal layer thicknesses using data from UK Biobank.
Methods :
Participants who had completed a touchscreen questionnaire on sleep patterns and had quality-controlled optical coherence tomography (OCT) data from the baseline assessment were included in this analysis. Self-reported chronotype was categorized into four types: "extreme morningness", "moderate morningness", "moderate eveningness" and "extreme eveningness." OCT parameters included thicknesses of the macular retinal nerve fiber layer (mRNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer (INL), the inner nuclear layer-external limiting membrane (INL-ELM), the inner nuclear layer-retinal pigment epithelium (INL-RPE), the external limiting membrane-inner segment outer segment (ELM-ISOS), the inner segment outer segment-retinal pigment epithelium (ISOS-RPE), and the retinal pigment epithelium (RPE). Multivariable linear regression was used to model associations, adjusting for sociodemographic, lifestyle, systemic, and ocular confounding factors.
Results :
Data from 34528 participants with a mean age of 57 years were analyzed. The distribution of chronotypes was as follows: extreme morningness (n=9171; 27%), moderate morningness (n=12346; 36%), moderate eveningness (n=9743; 28%), and extreme eveningness (n=3268; 9%). The extreme eveningness group had significantly thinner INL (β -0.07; 95% confidence interval [CI] -0.11 to -0.03; P<0.001), INL-ELM (β -0.07; 95% CI -0.11 to -0.03; P<0.001), INL-RPE (β -0.07; 95% CI -0.11 to -0.03; P<0.001), ELM-ISOS (β -0.09; 95% CI -0.13 to -0.05; P=1.5e-6), and RPE thicknesses (β -0.07; 95% CI -0.11 to -0.03; P=0.001) compared to the extreme morningness group. No statistically significant associations were observed for mRNFL and GCIPL thicknesses.
Conclusions :
Eveningness is associated with thinner INL and outer retinal layer thicknesses, but not with mRNFL or GCIPL. The potential bidirectional interaction between circadian biology and retinal photoreceptors warrants further investigation, and causality remains unclear.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.