Cystoid Macular Edema in Retinitis Pigmentosa: Pathophysiologic Insight Using Swept-Source OCT and Angiography

Cystoid macular edema (CME) is relatively common in patients with retinitis pigmentosa (RP), but its pathophysiology is poorly understood. This study aims to provide insight into pathophysiologic mechanisms of CME formation using swept-source (SS) OCT angiography (OCTA).

Retrospective cross-sectional study at a tertiary referral center.

Seventy consecutive patients with molecularly confirmed RP (associated with RHO, USH2A, or RPGR) with and without CME.

All patients underwent complete ophthalmic examination with multimodal imaging, including SS-OCT with SS-OCTA (PLEX Elite 9000). Images were then analyzed in a semiautomated fashion using ImageJ.

Structural and vascular abnormalities seen on SS-OCT and SS-OCTA in patients with RP, and spatial overlap between CME areas, vascular flow loss in the deep capillary plexus (DCP), and preserved external limiting membrane (ELM) and ellipsoid zone (EZ).

One hundred twenty-nine eyes from 70 patients (mean age 37 years, range 6 to 78) with molecularly confirmed RP were included. The mean best-corrected visual acuity measured 0.35 logarithm of the minimum angle of resolution (range -0.12 to 2.7). Overall, 31% of patients had CME (10% in RPGR, 36% in USH2A, 48% in RHO). There was a strong correlation between regions of CME and ELM preservation (97% spatial overlap overall) as well as DCP flow loss (83% spatial overlap). There was moderate correlation between regions of CME and EZ preservation (66% spatial overlap).

Cystoid macular edema is relatively common in RP, with different prevalence depending on genotype. There is strong spatial overlap between areas of DCP loss and ELM preservation regardless of genotype, suggesting a shared mechanism of impaired fluid clearance at the level of the DCP.

The author has no/the authors have no proprietary or commercial interest in any materials discussed in this article.