Structural changes of the retina in retinal vein occlusion - Imaging and quantification with optical coherence tomography

Background and objective: To evaluate the potential of optical coherence tomography (OCT) for imaging and quantifying structural changes in the retinal architecture following venous occlusive disease. Patients and methods: We studied 20 patients with retinal venous occlusive disease: 5 patients suffered from branch retinal vein occlusion (BRVO), and 15 from central retinal vein occlusion (CRVO). Patients with CRVO were studied within 72 hours after the first onset of symptoms. Patients were examined by OCT after a complete ophthalmologic examination including fluorescein angiography. A standard set of linear scans through the center of fixation and individual scans over areas of special interest were performed. Scans were qualitatively evaluated and quantitative measurements were performed on single A-scans at 5 locations of linear scans. Measurements were taken in the center of fixation, at the foveal rim, and at the edge of the scan. We measured total retinal thickness, thickness of cystoid spaces, and thickness of the highly reflective outer band. Results: OCT produced detailed images of retinal thickening, intra- and subretinal hemorrhage, intra- and subretinal fluid accumulation, and formation of intraretinal cystoid spaces. Quantitative evaluation revealed a mean central retinal thickness of 274 +/- 181 mum (72-760 mum) in patients with central retinal vein occlusion. Visual acuity did not correlate with central or extrafoveal retinal thickness. Conclusion: Optical coherence tomography is a useful imaging technique for studying changes of retinal architecture following venous occlusive disease. Even minor changes like localized subretinal fluid accumulation or beginning epiretinal membrane formation can be visualized in detail. In contrast to other diseases like diabetic maculopathy, quantitative assessment of macular thickness does not correlate to visual acuity. Nevertheless, because of detailed imaging, OCT might become a useful tool in the follow-up and treatment of individual patients.