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Visual field extent not reduced much by early treatment of ROP

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Treating high-risk retinopathy of prematurity (ROP) early, before threshold severity is reached, preserves peripheral vision with relatively little reduction in visual field extent. That’s according to a report from the Early Treatment for Retinopathy of Prematurity (ETROP) Cooperative Group, published in the Archives of Ophthalmology for February.

Dr. Graham E. Quinn, with the Children’s Hospital of Philadelphia, Pennsylvania, and colleagues explain that treatment of ROP currently involves ablation of the avascular peripheral retina. The ETROP study “was designed to test the hypothesis that treatment of eyes with high-risk prethreshold ROP would improve visual acuity outcomes compared with outcomes obtained when treatment was delayed until threshold severity was reached.”

The current report describes results of visual field measurements in 370 surviving study participants at age 6 years.

Overall, the mean visual field extent was greater in eyes that had been treated early than in those managed conventionally. This was partially due to fewer blind eyes in the early treatment group (9.0%) than in the conventional management group (14.9%), the researchers found.

In eyes with preserved vision, early treatment produced a small (2.3%-7.5%) reduction in visual field extent, according to the report. This was statistically significant only along the superonasal meridian compared with eyes treated conventionally

From the outset, the investigators were concerned that early treatment could cause substantial visual field loss in eyes with high-risk prethreshold disease in zone I, the central zone of the retina, compared with more peripheral zone II. However, they observed a minimal field loss difference with early treatment between high-risk zone I eyes compared with high-risk zone II eyes.

Summing up, the authors write, “It is reassuring and surprising that earlier treatment has no effect on visual field extent, particularly given the substantial number of eyes with zone I disease in this study.”

They do note however, that eyes with less severe disease (type 2 ROP), did not benefit from early treatment, supporting an observational approach with treatment if progression occurs.

Arch Ophthalmol. 2011;129:127-132