Laser photocoagulation (810 nm diode) for threshold retinopathy of prematurity: a prospective randomized pilot study of treatment to ridge and avascular retina versus avascular retina alone.

The purpose of this study was to compare the structural outcome of laser treatment to avascular retina and ridge versus laser treatment to avascular retina alone in cases with threshold retinopathy of prematurity (ROP). A prospective, randomized, interventional, comparative study of consecutive cases referred to a single tertiary center was considered here. 50 infants with bilateral symmetrical threshold ROP were recruited into this study over a period of 3 years. Threshold ROP was defined as per CRYO-ROP study. Perinatal history details for all patients including significant maternal history were recorded. One eye of each patient was randomized (Microsoft Excel 2000) to one of the two treatment groups--laser treatment to avascular retina (Group A) or laser treatment to avascular retina and ridge (Group B). Laser treatment was performed with a 810 nm diode laser (Iris Medical Instruments, Inc. Mountain View, CA, USA). Treatment was continued until regression of ROP. Structural outcome was assessed at a minimum follow-up of 6 months and was considered favorable or unfavorable as per the CRYO-ROP study criteria. An unfavorable outcome consisted of either (1) a retinal fold involving the macula; (2) any retinal detachment involving zone 1; or (3) a retrolental mass that obscured visualization of the posterior pole. Secondary outcome measures included the difference in time to regression of ROP and complications of treatment between the two treatment groups. 100 eyes of 50 infants received laser photocoagulation for threshold ROP after randomization (50 eyes in each group). Of these 50 infants, 20 (40%) were female and 30 (60%) were male. A significant proportion of the children (46%) were conceived as twins. The average birth weight was 1360 ± 326 g (range 750-2200 g). The mean gestational age at birth was 30.72 ± 1.6 weeks (range 26-36 weeks). Zone I disease was present in 14 (14%) eyes and zone II in the remaining 86 eyes (86%). Threshold stage retinopathy (CRYO-ROP criteria) extending 360° (12 clock hours) was present in 21 infants (42%), 5 contiguous clock hours of stage 3+ in 14 infants (28%) and intermediate range in the remaining 15 infants (30%). At 6 months follow-up, 3 eyes (6%) in group A and 1 eye (2%) in group B had an adverse structural outcome; however, the time to regression of retinopathy 2.98 ± 1.5 weeks in group A and 3.12 ± 1.1 in group B (P = 0.889) and the rate of complications such as retinal hemorrhage, 3 eyes in group A and 4 eyes in group B, was comparable. Zone I eyes showed equal incidence of favorable anatomical outcome (85.7%) in each group. Laser treatment to ridge was found to be safe and effective in the treatment of threshold ROP in this short-term pilot study; however, it needs to be ascertained whether this treatment has long-term advantages over conventional laser treatment to avascular retina, as well as the long-term benefits of treatment to ridge.

RCT Entities:   Population Interventions Outcomes