In reply
For years, the Multicenter Trial of Cryotherapy for ROP investigators have devoted countless hours to studying the relation between stage 3 ROP and eventual outcome. The risk for an unfavorable outcome depends on multiple variables, only one of which is the extent of stage 3 disease. A more posterior location (zone) of ROP and the presence of plus disease are important indexes of ROP severity. Rapidity of disease progression is also significant.1The requested subgrouping of fundus outcome data shows no significant difference in the rate of occurrence of unfavorable outcome (P=.65) across the 4 clock hours of ROP. The lowest rate of unfavorable fundus outcome, 6.1%, was for eyes with 4 clock hours of stage 3 ROP, and the highest rate, 15.7%, was for eyes with 3 clock hours.In response to Dr Hindle, there is probably no perfect way to ensure against adverse outcomes