Influence of refractive error and axial length on retinal vessel geometric characteristics.
OBJECTIVE
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. Spherical equivalent refraction was assessed using an autokeratorefractometer and subjective refraction. AL retinal vascular caliber, tortuosity, and branching characteristics were quantified from retinal fundus photographs using a semiautomated computer-assisted program according to a standardized protocol.


RESULTS
In multivariate analyses adjusting for age, sex, education, smoking, blood pressure, diabetes status, and antihypertensive 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.


CONCLUSIONS
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.
Lim
Laurence Shen
LS
Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
Cheung
Carol Yim-lui
CY
Lin
Xiaoyu
X
Mitchell
Paul
P
Wong
Tien Yin
TY
Mei-Saw
Seang
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001160:Arterioles / Q000473:pathology; D044466:Asian People; D058452:Axial Length, Eye / Q000503:physiopathology*; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology; D012171:Retinal Vessels / Q000473:pathology*; D012846:Singapore; D014699:Venules / Q000473:pathology
D000959:Antihypertensive Agents