Background: With the establishment of laser photocoagulation as a standard treatment modality for prethreshold retinopathy of prematurity (ROP), a dramatic reduction of cases with ROP blindness and severe visual impairment have been reported. In the same time, high refractive errors, a common complication in ROP cases and especially in ROP treated infants, have become the main cause of visual and often severe visual impairment.
Aim: The purpose of our study was to analyse the long-term refractive status in children at 3.5 years after laser-treatment for type 1 prethreshold ROP.
Patients and methods: A retrospective, one centre study of refractive status of 18 children with laser-treated type 1 prethreshold ROP was conducted. The refraction after cycloplegia with 1% cyclopentolate was measured at a mean age of 3.56 years (SD ± 0.34). Hyperopia was subdivided into two groups - low hyperopia (SE < +5.0 D) and high hyperopia (SE ≥ +5.0 D). Myopia was classified as myopia (SE ≥ -0.25D) and high myopia (SE ≥ -5.0 D). Astigmatism was divided into low astigmatism (plus CD ≥ +1.0 D) and high astigmatism (plus CD ≥ +2.0 D).
Results: Thirty-three eyes of 18 children were recruited in the study. Three eyes were excluded because of unfavourable anatomical results. The mean gestational age at birth was 27.3 weeks (24-31 weeks, SD ± 1.78), and the mean birth weight - 928.9 g (550-1500 g, SD ± 252.8). The mean spherical equivalent for the whole group was -1.82 D and ranged from -9.00 D to +4.50 D (SD ± 3.48). Hyperopia was observed in 12 (36.4%) eyes. Myopic refraction had 21 (63.6%) eyes. Astigmatism was detected in 18 (54.5%) eyes. Anisometropia had 3 (16.7%) children. Six children (33.4%) had strabismus (4 esotropia; 2 exotropia).
Conclusion: High per cent of treated infants for vision-threatening ROP have visual significant refractive errors and strabismus that can cause serious visual impairment if not treated properly and on time.
Keywords: Laser treatment; ROP; Refraction.