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

Area of Science:

• Ophthalmology
• Retinal Imaging
• Genetics

Background:

• Cystoid macular edema (CME) is a frequent complication in retinitis pigmentosa (RP).
• The underlying pathophysiology of CME in RP remains poorly understood.
• Swept-source (SS) OCT angiography (OCTA) offers novel insights into macular vascular changes.

Purpose of the Study:

• To investigate the pathophysiologic mechanisms of CME formation in retinitis pigmentosa (RP).
• To correlate structural and vascular abnormalities with CME using SS-OCTA.
• To explore genotype-specific prevalence of CME in RP.

Main Methods:

• Retrospective cross-sectional study of 70 patients with molecularly confirmed RP.
• Multimodal imaging including SS-OCT and SS-OCTA (PLEX Elite 9000).
• Semiautomated analysis of images using ImageJ to assess structural and vascular features.

Main Results:

• 31% of RP patients exhibited CME, with prevalence varying by genotype (RPGR: 10%, USH2A: 36%, RHO: 48%).
• Strong spatial overlap (97%) was found between CME and preserved external limiting membrane (ELM).
• Significant spatial overlap (83%) existed between CME and deep capillary plexus (DCP) flow loss.

Conclusions:

• CME is common in RP, with prevalence influenced by genetic mutations.
• Impaired fluid clearance at the DCP level is a likely shared mechanism for CME in RP.
• Strong correlation between DCP flow loss and ELM preservation suggests a common pathophysiologic pathway.