Abstract
Purpose :
Retinal blood flow is reduced in patients with vascular occlusions and can be quantified by comparing blood flow between the affected eye and the fellow eye. In this prospective study, we describe short- and long-term changes in retinal blood flow in patients with unilateral central retinal vein occlusions (CRVOs).
Methods :
The eyes of patients with acute, less than 1 month old (n = 8), and chronic, greater than 2 years old (n = 18), unilateral CRVOs were imaged using laser-speckle flowgraphy at the optic nerve head. For each patient, the relative blood flow (RBF) was calculated by dividing the mean blur rate of the occluded eye by the mean blur rate of the unaffected fellow eye. Patients with follow-up measurements (n =11) were used to compare the change in RBF within 6 months in acute and chronic CRVOs. Additionally, the RBF in CRVO patients was compared to control subjects without any ocular disease (n = 18). RBF measurements were also compared to visual acuity and central macular thickness obtained at the time of measurement as well as to the number of injections each patient required after measurement. Data was analyzed using the Wilcoxon Rank Sum Test.
Results :
Eyes with acute CRVO showed a reduction in relative blood flow of 33% (SE: 15%, p < 0.001), compared to 27% (SE: 11%, p < 0.001) in eyes with chronic CRVO. There was a significant difference in the average 6-month change in RBF between acute and chronic CRVOs, with acute eyes increasing by 9.7% and chronic eyes decreasing by 1.2% (SE: 5%, p < 0.01).
Conclusions :
CRVOs can cause a marked reduction in blood flow that persists for years. Eyes with acute CRVOs are more likely than chronic CRVOs to experience increased perfusion over time, which may be correlated with improved functional and anatomical outcomes. These results also highlight the need for animal models of CRVOs to consider the long-term complications that can arise from chronic reductions in retinal blood flow.
This is a 2021 ARVO Annual Meeting abstract.