OR217
   
 

Influence of Refractive Error and Axial Length on Retinal Vessel Geometric Characteristics

1. Laurence Lim¹
2. Carol Cheung¹
3. Xiaoyu Lim²
4. Paul Mitchell³
5. Tien Yin Wong¹
6. Seang Mei Saw1,2

¹Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
²Department of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore
³Centre for Vision Research, University of Sydney, NSW, Australia

Purpose: To evaluate the influence of refractive error and axial length (AL) on retinal vascular network geometry measurements in an adult Asian population

Methods: This was a population-based, cross-sectional study on 2882 persons with diabetes in the Singapore Malay Eye Study (SiMES). Spherical equivalent refraction (SE) was assessed using an autokeratorefractometer and subjective refraction. AL was measured by IOL Master. Retinal vascular caliber, tortuosity, and branching characteristics were quantified from retinal fundus photographs using a semi-automated computer-assisted program according to a standardized protocol.

Results: In multivariate analyses adjusting for age, gender, education, smoking, blood pressure, diabetes status, and anti-hypertensive medication use, longer AL and more myopic refraction were associated with narrower retinal arterioles and venules,(p ≤ 0.001 for all) and less tortuous (straighter) arterioles,(p < 0.001 for both). Longer AL and more myopic refraction were also associated with increased branching coefficients in both arterioles (p < 0.001 for both) and venules.(p = 0.02 and p < 0.001 respectively). Longer AL and more myopic refraction were associated with more acute branching angles in arterioles (p < 0.001 for both) but not venules.

Conclusion: Myopic refractive errors and longer AL are associated with narrower retinal arterioles and venules, less tortuous arterioles, and increased branching coefficients in both arterioles and venules. These findings provide insights into ocular blood flow in myopia, and also suggest that future studies evaluating these retinal parameters should account for the influence of AL and refractive error.


 
RANZCO