Optical coherence tomography of macular edema in retinal vein occlusion

Abstract

Objective To observe the images characteristics of optic coherence tomography (OCT) on macular edema in retinal vein occlusion (RVO), and to explore the application value of Fourier-domain (FD)OCT in RVO macular edema. Methods The clinical data of 91 RVO patients (92 eyes) were retrospectively analyzed. All patients received examinations of best corrected visual acuity (BCVA), direct or indirect ophthalmoscope, slit lamp ophthalmoscope, and 60 patients (60 eyes)also underwent fundus fluorescein angiography. There were 35 patients (35 eyes) with central retinal vein occlusion (CRVO) and 56 patients (57 eyes) with branch retinal vein occlusion (BRVO). The type and involved layer of macular edema, and subtle structure changes of the outer retina were observed through the horizontal and vertical scanning lines through the foveal under the model of 5 Line Raster. The foveal thickness (FT), height of serous retinal detachment, width and height of foveal cystoid spaces and thickness of foveal photoreceptor layer were measure manually. The central fovea thickness (CFT), volume (V) and average thickness (AT) were collected from the OCT readings. Further analysis was focused on different type of the edema, characteristics of OCT images and the relationship between the different type of the edema and vision. Results The manifestation of macular edema was variable by OCT scanning, and can be categorized into diffuse edema (sponge-like thickening of the retina with reduced reflectivity) 12 patients ( 12 eyes, 13.0% ), cystoid edema (multi-cyst-like space in the neuro-retina separated by tissue column) 21 patients (21 eyes, 22.8%) and serous retinal detachment (separation of neuro-retina and retinal pigment epithelium by space with low reflectivity) 37 patients (37 eyes, 40. 2%) and mixed edema(mix of the above several edema form) 58 patients (59 eyes, 64.1 %). The edema can happen at different layers of the neuro-retina, including outer nuclear layer/outer plexiform layer (ONL/OPL) in 92 patients (92 eyes, 100. 0%), inner nuclear layer (INL) in 68 patients (68 eyes, 74.2%) and ganglion cell layer (GCL) in 23 patients (23 eyes, 25.0%).Statistic analysis revealed that BCVA was related to the integrity of IS/OS (r=3. 778 6, P=0. 000), ELM (r=4.462 2, P= 0. 000 ) and FT (r=-0.4513, P=0. 000 ), but not related to CFT (r=0.269 7, P=0.121), V(r=0.0528, P= 0. 054 ) and AT (r=0.0608, P=0.075). Conclusion he manifestation of macular edema associated with RVO is variable. FD-OCT can demonstrate its fine details, and some changes are related to visual acuity. Therefore, the value of quantitative analysis in these patients needs further confirmation. Key words: Macular edema/diagnosis; Retinal vein occlusion/diagnosis; Tomography, optical coherence