Effect of acute-phase retinopathy of prematurity on grating acuity development in the very low birth weight infant. The Cryotherapy for Retinopathy of Prematurity Cooperative Group.

Purpose: To examine the development of grating acuity in four groups of eyes in the Multicenter Study of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP): eyes with no ROP; eyes with less-than-prethreshold ROP; eyes with prethreshold ROP; and eyes with threshold ROP that were randomized to serve as controls (not treated with cryotherapy).

Methods: Subjects were 1398 children with birth weights < 1251 g whose acute-phase ROP was documented as part of the CRYO-ROP study. Monocular grating acuity was measured using the Teller acuity card procedure when children reached 1, 2, 3 1/2, and 4 1/2 years of age.

Results: Eyes in the no-ROP and less-than-prethreshold groups showed nearly identical acuity development. Eyes with prethreshold ROP showed mean acuity similar to the no-ROP group at 1 and 2 years, but slightly below the no-ROP group at 3 1/2 and 4 1/2 years. Only 50% of eyes in the threshold untreated ROP group had measurable acuity. These eyes showed mean acuity scores that were approximately 1 octave below those of the no-ROP group at all four test ages. When data from eyes with ROP residua or other ocular abnormalities, and data from eyes of children who were unable to pass the study developmental screening items, were excluded, acuity development was similar among groups.

Conclusions: Mild (less-than-prethreshold) ROP has no effect on the development of grating acuity in children between 1 and 4 1/2 years of age. Moderate (prethreshold) ROP is associated with reduced acuity at 3 1/2 and 4 1/2 years. In general, severe (threshold untreated) ROP results in moderate to severe reductions in acuity at all ages between 1 and 4 1/2 years. However, a small number of children with severe ROP show normal acuity development.