Retinal Vascular Dilation to Flicker Light is Reduced in patient with Retinal Vein Occlusion

Abstract

Purpose: To analyze dynamics of retinal vessel dilation response to flicker light in patients with retinal vein occlusion (RVO).

Methods: Ten patients with RVO were consecutively included and compared to 10 age and sex matched healthy controls (age 55.4 ± 9.1 years and 54.1 ± 7.5 years, respectively, p = 0.88 ; 8 males and 8 males, respectively p = 0.96). The retinal vascular response to flicker light stimulation was assessed in each participant using the Dynamic Vessel Analyzer (DVA, IMEDOS, Jena, Germany). Relative dilations of selected arteriole and venule segments during flicker stimulation and resting diameters were measured automatically. Maximum vessel dilation was calculated as the percentage increase in vessel diameter relative to 50 sec baseline after 20 sec of flicker stimulation and non-ficker period for 80 sec. Three consecutive measurement cycles were averaged. Mean values for RVO patients and healthy controls were compared using Mann Whitney test.

Results: In RVO patients, the mean diameter of arterial vessels studied was 110.50 ± 20.11μm; maximum arterial dilations during flicker stimulation was 2.07 ± 1.62%. The mean dimeter of venous vessels studied was 150.80 ± 36.62μm; maximum venous dilations was 1.88 ± 0.94%. In healthy controls, the mean diameter of arterial vessels studied was 108.20 ± 12.88μm; maximum arterial dilations during flicker stimulation was significantly higher than RVO patients (4.33 ± 0.88%, p = 0.005). The mean diameter of venous vessels studied was 136.2 ± 16.71μm; maximum venous dilations was significantly higher than RVO patients (4.89 ± 2.30%, p = 0.004).

Conclusions: Retinal vascular dilation during flicker stimulation is reduced in patients with RVO. Interestingly, a significant reduction could be demonstrated in both venous and arterial vessels. Whether the above described changes in vascular dynamics could be involved in the development of different retinal signs related to RVO remain to be clarified by further studies.

Keywords: 550 imaging/image analysis: clinical • 749 vascular occlusion/vascular occlusive disease