Abstract
Purpose :
To investigate potential associations between single retinal layer thickness and cognitive impairment.
Methods :
Participants of the population-based cross-sectional Beijing Eye Study 2011 without any retinal or optic nerve disease underwent a series of ocular examinations including spectral-domain OCT. Using a multiple-surface method, the retina in the macula OCT cube scans was automatically segmented into 9 layers, the from retinal nerve fiber layer (RNFL) to the retinal pigment epithelium and Bruch’s membrane (RPE/BM) complex (Figure 1). Cognitive function was evaluated using the Mini-mental Statement Examination (MMSE). A MMSE score ≤ 26 was defined as cognitive impairment. Multivariable regression models were used to analyze associations between retinal thickness and cognitive function.
Results :
The study included 2035 eyes (2035 participants; 56.9% women; mean age: 61.4 ± 8.4 years; mean axial length: 23.09 ± 0.84 mm). After adjusting correlated parameters including age, gender, axial length, education level, best corrected visual acuity and subfoveal choroid thickness, a lower cognitive function score was related with a thinner inner plexiform layer (IPL) (P=0.03, correlation coefficient: 0.04), thinner outer nuclear layer and external limiting membrane (ONL/ELM) (P=0.005, correlation coefficient: 0.02). For every unit decrease in the MMSE score, a mean decrease of 25µm and 50µm was detected for the thickness of the IPL and ONL/ELM, respectively. Stratified by sex, the association with a thinner IPL was found only for women (P=0.008), while the association with a thinner ONL/EML thinning was found only for men (P=0.011) (Figure 2). As compared with cognitively normal participants, those classified as cognitively impaired had a significantly thinner IPL (38.2±3.4 mm versus 38.5±3.3mm, P = 0.02, Odds ratio: 1.05 (1.01, 1.08)), while their ONL/ELM showed no significant difference (P=0.247). RNFL thickness was not related with the cognitive score (P=0.09) nor the presence of cognitive impairment (P=0.711) in multivariate analysis.
Conclusions :
A thinner IPL and ONL/ELM was associated with a lower cognitive function score in an elderly Chinese population. Further studies may explore associations the eye and the brain, addressing the question whether the retina might serve for detecting biomarkers for screening neurodegenerative diseases.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.