Abstract
Purpose: :
To determine whether retinal vascular tortuosity associated with age-related macular degeneration (AMD).
Methods: :
The Singapore Malay Eye Study (SiMES) is a population-based eye survey including 3,280 (78.7% response) persons aged 40 to 80 years. Retinal vascular tortuosity was measured quantitatively from digital photographs using a computer-assisted program. Retinal vascular tortuosity was derived as the integral of the curvature square along the path of the vessel then normalized by the total path length. Arteriolar and venular tortuosity measures were analyzed separately. Measurements from right eyes were used, unless the parameter studied was ungradable, when left eye measurements were used. Early and late AMD signs were graded from retinal photographs at a central reading centre using the modified Wisconsin AMD scale. Data on major cardiovascular risk factors and blood pressure were self-reported.
Results: :
Of the 3,280 participants, 2,904 had photographs that were gradable for both AMD and retinal vascular tortuosity. AMD was present in 157 subjects (142 with early and 15 with late AMD). After adjusting for age and gender, eyes with increased retinal venular tortuosity (0.029 vs 0.027, p=0.011) were more likely to have early AMD signs. This association remained significant after further adjustment for systolic blood pressure, current smoking, hypertension, diabetes, HbA1c, and retinal arteriolar caliber (0.030 vs 0.028, p=0.027). Arteriolar tortuosity was not associated with AMD.
Conclusions: :
Increased retinal venular tortuosity was associated with AMD prevalence. These data suggest that at early AMD stage, subtle changes in retinal vascular geometry may be present.
Keywords: age-related macular degeneration • image processing • retina