Therapeutic outcomes of cryotherapy versus transpupillary diode laser photocoagulation for threshold retinopathy of prematurity

Abstract

Introduction: We undertook this study to compare the clinical outcomes in patients treated for threshold retinopathy of prematurity (ROP) with transpupillary diode laser photocoagulation versus transscleral cryotherapy. Methods: A retrospective chart review was performed of patients treated for threshold ROP at our institution between 1988 and 1997. Cryotherapy was used to treat patients before 1992, and diode laser was used thereafter. One hundred fifteen eyes of 63 patients underwent cryotherapy, and 130 eyes of 70 patients underwent laser treatment. Because strong concordance exists between fellow eyes treated for ROP, statistical analysis was done for right eye outcomes only. Demographics, short-term complications, and treatment parameters were compared on the entire cohort of patients. Structural outcomes were compared between a group of 79 cryotreated eyes (39 OD, 40 OS) and a group of 113 laser-treated eyes (56 OD, 57 OS). Mean cycloplegic refraction was compared between a group of 38 cryotreated eyes (18 OD, 20 OS) and a group of 90 laser-treated eyes (46 OD, 44 OS). Visual acuity for preverbal and nonverbal children was estimated and converted to a Snellen visual acuity equivalent. Geometric mean visual acuity was then compared between a group of 44 cryotreated eyes (22 OD, 22 OS) and a group of 92 laser-treated eyes (47 OD, 45 OS). Patients were included in each outcome analysis if adequate documentation was present in the patient record. Results: Demographics and short-term complications were not significantly different between the 2 groups. In the statistical group, 22 of 39 right eyes (56.4%) in the cryotherapy group versus 49 of 56 right eyes (87.5%) in the laser group had resolution of ROP after treatment ( P = .0008). Mean spherical equivalent cycloplegic refraction at 12 months of age and over the follow-up period was not significantly different between the cryotherapy and laser groups. Estimated geometric mean visual acuity in the cryotherapy group was 20/103 and in the laser group was 20/49 at 12 months of age ( P = .0099). Conclusions: Diode laser photocoagulation was associated with a better long-term structural outcome and visual acuity compared with cryotherapy for the treatment of threshold ROP. Refractive error was not significantly different between the 2 groups over an equivalent follow-up period. (J AAPOS 1999;4:234-40)