To the Editor.
—Threshold stage III (TS III) has been defined as 5 contiguous clock hours of stage III retinopathy of prematurity (ROP) in zone 1 or 2 in the presence of disease. The Multicenter Trial of Cryotherapy for ROP (CRYO-ROP) has shown that treatment of TS III reduces the incidence of unfavorable outcome by 46%.1 Other investigators suggested that laser photocoagulation is effective in the treatment of ROP, although these studies used different delivery systems, treated at different stages, and varied in their outcome criteria.2 McNamara et al3 presented evidence of successful treatment of TS III ROP with the binocular indirect laser delivery system at the 1990 Annual Scientific Meeting of The Retina Society. Landers et al4 reported a regressive response of TS III ROP with indirect laser photocoagulation in an eye considered at risk for complications from cryotherapy. We report preliminary results on 12 eyes
Iverson DA, Trese MT, Orgel IK, Williams GA. Laser Photocoagulation for Threshold Retinopathy of Prematurity. Arch Ophthalmol. 1991;109(10):1342-1343. doi:10.1001/archopht.1991.01080100022007