Pre-term birth exposes infants to a host of potential developmental challenges, vision included. While retinopathy of prematurity (ROP) is one of the leading causes of blindness and visual impairment worldwide, refractive error and binocular vision disorders are also common in premature infants with or without ROP. While ROP is actively screened for in premature newborns, the less dire refractive error may not be.

A recent study found more visual impairment in healthy controls than in their premature counterparts. The prospective study included a case group of 90 premature children (62 with and 28 without ROP during infancy) and 90 healthy controls.

In children five to six years old, the researchers noted that 26.7% of patients and 48.9% of controls had visual impairment. Between the case and control groups, they observed different amounts of amblyopia (3.3%, 12.2%), strabismus (6.7%, 6.7%) and refractive errors (16.7%, 30%). There were no significant correlations in any of these variables between groups, but strabismus before six years of age was determined to be a risk factor for amblyopia. There was also a significant association between refractive errors and amblyopia. While children with ROP had more severe refractive errors than those without (22.6% vs. 3.6%), there was no significant association between ROP and visual impairment.

The investigators reported that 90% of patients and 78.9% of controls had a visual acuity greater than 0.9 in the right eye, with no significant correlation. In the left eye, there was a significant correlation between the 94.4% of patients and 81.1% of controls who had a visual acuity greater than 0.9.

“The relatively low incidence of visual impairment in the children in the case group, all of whom were premature, with or without ROP, may indicate timely treatment and neonatal follow-up,” the study authors concluded in their paper. Their findings support pediatric vision exams and patient/family education on visual impairment.