Purpose
Limited data exists comparing the central to peripheral retinal ischemia in retinal vascular disease. In this study, we quantitatively compare the extent of non-perfusion in the central 45 degrees to the remaining 200 degrees of angiographically visible retina in Central retinal vein occlusion (CRVO), Branch retinal vein occlusion (BRVO), Hemiretinal vein occlusion (HRVO) and Diabetic retinopathy (DR).
Methods
95 eyes presenting with retinal vascular pathology to a single retina specialist between August 2008 and August 2014 were randomly selected in a retrospective manner. All patients underwent wide-field retinal imaging, including fundus photography and fluorescein angiography (FA) using the Optos 200 Tx system (Optos plc, Scotland, UK). ImageJ 1.43 software was used to calculate the central areas of non-perfusion (defined as central 45 degrees) and peripheral areas of non-perfusion (defined as the area beyond 45 degrees). Non-perfusion was defined as dull/dark sections of the FA occurring in the mid-phase of the test and not attributable to blockage from blood and/or pigment and/or hard exudate. T-test and linear regression were used to analyze the data.
Results
The sample included 18 eyes with CRVO, BRVO or HRVO and 64 eyes with DR. 3 eyes were excluded due to previous panretinal photocoagualation and 10 due to poor visualization. The extent of central non-perfusion averaged 9%±11% (range: 0-46%) for all pathologies combined. Similarly, the average extent of peripheral non-perfusion averaged 9%±12% (range: 0-51%). These results demonstrated no significant statistical differences between the percent central and peripheral non-perfusion areas for both groups (p=0.52 and 0.53, respectively). Linear regression between peripheral and central non-perfusion areas were statistically significant (p<0.05) for both groups.
Conclusions
Our data demonstrate a linear relationship between peripheral and central areas of non-perfusion. Nevertheless, viewing in isolation misses nearly 42% of the total non-perfusion areas. This data is critical not only to guide therapeutic options but will also serve as a gauge for the clinical applicability of medical practices not using wide field retinal imaging.