Cystoid macular edema in retinitis pigmentosa patients without associated macular thickening

Purpose: To describe the occurrence of cystoid macular edema (CME) in the setting of central foveal thickness (CFT) under 250μm as measured by optical coherence tomography (OCT) in patients with retinitis pigmentosa (RP). Methods: Stratus OCT was used to measure CFT in a total of 90 eyes from 46 patients with RP. Cross-sectional OCT images were also evaluated for CME, which was defined as cystoid changes in the macula seen on at least two linear scans. Results: CME was identified in 13 of the 46 patients or in 22 of 90 eyes by OCT. In eyes with macular edema, CFT ranged from 224 to 718μm (mean=339±137μm). In eyes without macular edema, CFT ranged from 99 to 273μm (mean= 184±40μm). Bilateral CME occurred in 9 of 13 patients (69%). CFT was considered "normal" in 7 of the 22 eyes (32%) with CME. Two patients had bilateral CME with normal CFTs, under 250μm. Conclusion: We demonstrate the occurrence of CME in RP patients without associated thickening, which has not been described. This concept likely is applicable to other diseases with retinal thinning.