Abstract
Purpose: :
To quantify retinal non-perfusion as an index for ischemia in patients with branch retinal vein occlusion (BRVO). To correlate ischemic index values with the presence of neovascularization and macular edema in BRVO.
Methods: :
An imaging database of ultra wide-field angiograms performed at a single academic institution was searched for patients with a diagnosis of BRVO. Images from 25 patients with BRVO not previously treated with focal macular laser, scatter photocoagulation or intravitreal pharmacotherapy were graded for the presence of non-perfusion, neovascularization and macular edema. Image analysis software was used to quantitatively measure areas of non-perfusion and to calculate a retinal ischemic index defined as total area of non-perfusion divided by total area of retina visualized. Statistical analysis was performed to determine the sensitivity and specificity of various degrees of non-perfusion for the presence of neovascularization and macular edema. A chart review (average follow-up time 16 months) was performed for all patients for the development of macular edema or neovascularization.
Results: :
Ultra wide-field angiograms from 25 eyes of 25 patients were analyzed with a diagnosis of BRVO. Non-perfusion was visualized and quantified in all patients and an ischemic index was generated for each patient. Neovascularization and macular edema were seen in 28% and 80% of patients, respectively. Ischemic index values ranged from 0.1% to 30%. An ischemic index of 7% was 100% sensitive and 83% specific for the presence of neovascularization and 50% sensitive and 100% specific for macular edema. Increasing ischemic index for all patients was significantly associated with neovascularization (p < 0.01). Increasing inschemic index for patients with major BRVO was significantly associated with macular edema (p =0.028)
Conclusions: :
Retinal ischemia following branch retinal vein occlusion can be quantified utilizing ultra wide-field fluorescein angiography. A retinal ischemic index may help risk stratify patients with BRVO for the development of neovascularization and macular edema.
Keywords: vascular occlusion/vascular occlusive disease • imaging/image analysis: clinical • ischemia