Refractive Errors and Strabismus in Premature Asian Infants With and Without Retinopathy of Prematurity

JTS Theng, TY Wong, Y Ling
Correspondence: Julian Theng

ABSTRACT
Aim In Caucasian populations, premature infants with retinopathy of prematurity (ROP) have been reported to have higher risks of developing refractive errors and strabimus. The purpose of this study is to evaluate the rate of these complications in Asian premature infants with and without ROP.
Methods A retrospective case review of all premature infants referred to the Singapore National Eye Centre for ophthalmology screening. These included all neonates born earlier than 34 weeks gestational age and less than 1500 grams in birth weight. Standardized ophthalmology examinations including cycloplegic refraction and fundus examination at regular intervals were performed to determine the presence of ROP, refractive errors, squints and other ocular abnormalities until the patients were 3 years old.
Results During 1991 to 1993, a total of 113 neonates were reviewed. Of these, 16 (14.2%) developed ROP. The risk of ROP was higher with lower birth weights and earlier gestational ages. At 1-year follow-up, the rate of myopia was 33.3% in babies with ROP compared to 3.7% in babies with no ROP (p < 0.001). The higher rates of myopia in babies with ROP remained with longer follow-up (33.3% and 25% in ROP group versus 3.4% and 3.8% in no ROP group, at 2 and 3 years respectively). There was no difference in rates of astigmatism or hyperopia throughout the 3 years. At 1 year follow-up, the rate of strabismus was 20% in the ROP group compared to 4.9% in the no ROP group (p = 0.07). However, this difference in rates of strabismus was not significant at 2 and 3 years of follow-up.
Conclusion Premature babies with ROP had higher rates of myopia and strabismus than those without ROP. Long-term follow-up of these babies is important for early detection and treatment of these ocular problems.

Keywords: ROP, myopia, astigmatism, strabismus, amblyopia
Singapore Med J 2000; 41(8): 393-397