Correlation of retinopathy of prematurity in fellow eyes in the cryotherapy for retinopathy of prematurity study. The Cryotherapy for Retinopathy of Prematurity Cooperative Group
G. E. Quinn, V. Dobson, A. Biglan, J. Evans, D. Plotsky and R. J. Hardy
Division of Pediatric Ophthalmology, Children's Hospital of Philadelphia, USA.
OBJECTIVE: To examine the similarity of extent (sectors) and severity
(stage) of acute-phase retinopathy of prematurity (ROP) between fellow eyes
and the concordance of cicatricial outcomes at age 1 year of eyes that did
not develop threshold disease. METHODS: Four thousand ninety-nine infants
with birth weights of less than 1251 g who participated in a natural
history segment of the Cryotherapy for Retinopathy study underwent biweekly
eye examinations from 4 to 6 weeks after birth until retinal vasculature
was complete or until ROP regressed or reached threshold severity. Eyes
were categorized as follows: (1) no ROP, (2) less than prethreshold ROP,
(3) prethreshold ROP, (4) threshold ROP, and (5) unable to determine. The
presence and stage of ROP residua in fellow eyes were evaluated at 12
months. RESULTS: Acute-phase ROP status between 32 and 42 weeks
postconceptional age showed a high degree of correspondence between fellow
eyes in severity (stage) and location (zone) of ROP, presence of plus
disease, and sectors of stage 3 retinopathy. More variability between eyes
was seen when cicatricial status at age 1 year was examined. This higher
variability was evident even though results from patients with threshold
ROP (many of whom underwent cryotherapy) were excluded. CONCLUSION: The
usual course of ROP during its acute phase is for fellow eyes to be very
similar in ROP status. However, asymmetry between eyes is not unusual in
eyes with posterior pole residua of ROP.
