Prevalence and Risk Factors of Cystoid Macular Edema in Patients With Retinitis Pigmentosa in the United States: IRIS Registry Analysis

Purpose: To investigate the prevalence and characteristics of cystoid macular edema (CME) in patients with retinitis pigmentosa (RP) in the United States. Methods: A retrospective cohort study was performed of patients with RP in the IRIS Registry (2013-2023). The association between clinical characteristics and CME was analyzed using multivariate logistic regression. Results: Among 50 219 patients with RP, 8495 (16.9% of eyes) had CME. Patients with CME were slightly younger (median age, 56 years) compared with those without CME (median age, 58 years; P < .001). Ocular comorbidities and procedures were more common in RP eyes with CME than in those without, including epiretinal membrane (ERM) (39% vs 15%), vitreomacular traction (VMT) (7.5% vs 1.6%), diabetic retinopathy (8% vs 3.9%), retinal vein occlusion (4.8% vs 0.4%), cataract surgery (20% vs 17%), Nd:YAG capsulotomy (11% vs 9%), and pars plana vitrectomy (2.1% vs 0.9%) (all P < .001). On multivariate analysis, the odds of CME increased with observation time and decreased with age. History of ERM or VMT conferred significantly higher odds of CME (odds ratio [OR], 3.01, 95% CI, 2.85-3.18 vs OR, 2.49, 95% CI, 2.18-2.84 in those with no ERM or VMT). Eyes undergoing cataract surgery or vitrectomy also had higher CME risk (OR, 1.18, 95% CI, 1.10-1.27; OR, 1.66, 95% CI, 1.36-2.03). Visual acuity at diagnosis and 2 years later was worse in eyes with CME compared with those without CME (median, 0.3 logMAR vs 0.18 logMAR; P < .001). Conclusions: CME is a frequent complication in patients with RP and is associated with younger age, longer observation, and coexisting ocular conditions. Careful monitoring of high-risk patients is critical for timely detection and management.