Purpose: To develop a method of imaging the retina using wide-field fluorescein angiography and use this method to investigate the areas of perfusion abnormalities in patients treated with ranibizumab for central retinal vein occlusion.
Methods: Cross-sectional analysis of patients recruited to a prospective study. Patients in a prospective study of ranibizumab for central retinal vein occlusion were imaged with wide-field angiography. Fluorescein angiograms taken with the Optos P200 Scanning Laser Ophthalmoscope were obtained of the posterior portion of the eye and of the periphery through ocular steering. Resultant images of the periphery were registered to the posterior image using thin-plate spline warping. A transformation was used to measure the retinal surface area. Perfusion characteristics were compared with injection frequencies and protocol refraction visual acuity measurements.
Results: Of 22 patients imaged, 7 would be classified as nonperfused by the Central Retinal Vein Occlusion Study (CVOS) angiographic criteria. However, all patients showed confluent areas of nonperfusion in the retinal periphery ranging in size from 16 disk areas to 242 disk areas. The areas of peripheral nonperfusion were not significantly different in the Central Retinal Vein Occlusion Study-perfused group versus nonperfused group. The area of peripheral nonperfusion was not correlated with the number of injections (r = -0.13, P = 0.58), but was inversely correlated with visual acuity (r = -0.52, P = 0.013). Blood vessels at the border of the peripheral nonperfusion did not show signs of neovascular growth or profuse leakage.
Conclusion: Angiographic mapping of the retina is possible using image-processing techniques with wide-field images. Eyes with central retinal vein occlusion develop widespread peripheral vascular obliteration in regions that are difficult to image with conventional fundus cameras. These nonperfused areas may have important implications for visual function.