Elliott H. Sohn, Benjamin C. Chaon, Douglas A. Jabs, James C. Folk

To compare the long-term outcomes of peripheral retinal cryoablation to conventional treatment for active pars planitis. Retrospective, interventional, comparative case series. Review at a single institution was conducted to compare the effect of cryotherapy to eyes with pars planitis to those receiving conventional therapy (topical, regionally injected or oral corticosteroid therapy). Best-corrected visual acuity (VA), complications, resolution of cystoid macular edema (CME), anterior chamber and vitreous inflammation were assessed. One hundred thirty-six eyes were treated conventionally, 50 eyes were treated with cryotherapy. Median follow-up was 60.8 months (range 8.1-223.1 months) in the cryotherapy group and 45.0 months (range 3.1-339.0 months) in the controls. There were no significant differences in baseline VA, anterior chamber and vitreous inflammation, presence of CME, and prior use of regional corticosteroid injections. VA improved over time in the cryotherapy group (slope of -0.0018 logMAR-units-per-month; p=0.023) but declined in the controls (slope of +0.0011 logMAR-units-per-month; p=0.023). Kaplan-Meier survival estimates demonstrated faster times to resolution of anterior chamber cell, vitreous cell, and CME in the cryotherapy-treated eyes. Hazard ratios of remission (adjusted for confounding factors) for vitreous cell and CME for those treated with cryotherapy compared to controls were 4.73 (95% confidence interval 1.63,13.63; p=0.004) and 6.85 (95% 1.06,44.78; p=0.044), respectively. No ocular complications were identified in the cryotherapy group. These data suggest that peripheral retinal cryoablation therapy is an effective treatment for active pars planitis and may be better than conventional regional corticosteroid injections and oral corticosteroid therapy for induction of remission.