Retinal blood flow levels measured by Laser Speckle Flowgraphy in central retinal vein occlusion as a predictive factor for ischemia and visual loss

Abstract

Purpose: To investigate the prognosis factor for ischemia and decline in visual acuity after intravitreal bevacizumab injections (IVB) for macular edema (ME) secondary to central retinal vein occlusion (CRVO).

Methods: Thirty-one patients (31 eyes) being treated with IVB (1.25 mg/0.05 ml) for secondary ME of CRVO were examined. The patients did not have other ocular conditions that could affect retinal blood flow. They were classified according to fluorescein angiography into non- ischemic type or ischemic type. LSFG analyses of retinal blood flow levels were based on examinations of the mean blur rate (MBR) at the major vessels of the optic disc. We evaluated the rate of MBR (affected eye/ fellow eye×100, %).

Results: At the last visit, of 31 eyes, 25 (80.6%) were classified as non-ischemic types and 6 (19.4%) were classified as ischemic type. Before the first IVB, the mean logMAR visual acuity was 0.60+/-0.35% in non-ischemic group, and 1.56+/-0.58% in ischemic group, in non-ischemic group of visual acuity was significantly better than in ischemic group (P=0.00002). Before the first IVB, the mean rate of MBR was 59.8+/-23.2% in non-ischemic group, and 31.6+/-6.5% in ischemic group, in non-ischemic group of the rate of MBR was significantly greater than in ischemic group (P=0.004). Multiple linear regression analysis showed the logMAR visual acuity after the first IVB significantly correlated to the logMAR visual acuity at the last visit (Standardized coefficients: 0.67, P=0.000…). The rate of MBR after the first IVB significantly correlated to the rate of MBR to fellow eye of affected eye at the last visit (Standardized coefficients: 0.53, P=0.0016).

Conclusions: Even though the background for CRVO pathology can vary, LSFG may be useful to evaluate the degree of ischemia. The logMAR visual acuity and the rate of MBR to fellow eye of affected eye can be predictive factors in CRVO patients treated with IVB.

Keywords: 749 vascular occlusion/vascular occlusive disease • 572 ischemia • 700 retinal neovascularization