[Correlation between photoreceptor layer and visual acuity in eyes with persistent cystoid macular edema secondary to branch retinal vein occlusion].

OBJECTIVE: To study the correlation of visual acuity and photoreceptor in eyes with persistent cystoid macular edema associated with branch retinal vein occlusion (BRVO).

METHODS: It was a retrospective case series study.Medical records of 41 patients (41 eyes) with persistent cystoid macular edema secondary to BRVO diagnosed in Department of Ophthalmology, Peking Union Medical College Hospital from January 2008 to January 2010 were studied retrospectively. On the images obtained by spectral-domain OCT, the thickness of foveal neurosensory retina and photoreceptor layer that was beneath the foveal cystoid spaces, and the transverse length and height of foveal cystoid spaces were measured. The status of the junction between inner and outer segments of the photoreceptors (IS-OS) in the fovea was also assessed. The correlations between the parameters above and visual acuity were analyzed.

RESULTS: The average foveal neurosensory thickness was (484.71 ± 131.86) µm, the photoreceptor layer thickness was (92.04 ± 45.53) µm and the size of foveal cavity was 772.59 µm × 362.17 µm. By the Spearman's rank correlation analysis, among the parameters above, only photoreceptor layer thickness showed correlation with logMAR visual acuity (r = -0.373, P = 0.016), while other parameters showed no correlation with logMAR visual acuity. Cases were classified as three groups according to the status of IS-OS layer: continuous group (8 cases), discontinuous group (19 cases) and interrupted group (14 cases). LogMAR visual acuity in these eyes with an interrupted IS-OS line in the fovea was significantly worse than that in eyes with a continuous or discontinuous IS-OS line (P = 0.030 and 0.003, respectively). There was no statistical difference between continuous and discontinuous group (P = 0.750).

CONCLUSIONS: In patients with persistent cystoid macular edema associated with BRVO, the thickness of the foveal photoreceptor layer are positively associated with visual acuity, and the eyes without IS-OS layer have worse visual acuity than eyes with IS-OS layer.