Retinal Vessel Diameter in Asymmetrical Age–Related Macular Degeneration

Abstract

Abstract: : Purpose: There is evidence to suggest that the alternation of retinal blood flow might play a role in the development of choroidal neovascularisation (CNV) in patients with age–related macular degeneration (AMD). Previous studies had shown that the retinal vessel diameters are similar in both eyes. A pilot study was performed to calculate retinal vessel size and assess whether there is significant asymmetry in retinal vessel diameters in patients with asymmetrical AMD, i.e. CNV in one eye. Methods: Computer–assisted grading (similar to the Wisconsin system) was performed from a digital fundal image centered on the disc to determine the average diameter of retinal arterioles and venules and their ratio in asymmetrical AMD patients. The macula area was cropped in order to mask the recording observers. Results: From the 34 patients that were included in this pilot study, the mean arteriole to venule (A/V) ratio were 0.76 in the CNV eye and 0.71 in the fellow eye. This increased ratio is mostly due to an increase of arteriole diameter. This result was not statistically significant but shows a clear trend. If this trend is real, we would need 128 patients to reach statistically significant at p<0.01. Conclusions:: It appears that the retinal arteriole diameter is increased with an increased A/V ratio in eye with CNV. It is uncertain whether this is a primary or secondary effect.

Keywords: age-related macular degeneration • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: risk factor assessment