Purpose: To examine the spherical equivalent of refractive errors in preterm children with threshold retinopathy of prematurity treated with cryotherapy or laser. Patients and Method: A group of 14 one-year-old children (selected from 761 preterm children born at the Hospital São Paulo of the Universidade Federal de São Paulo between 1988 and 1998) with stage 3 threshold retinopathy of prematurity treated with cryotherapy or laser photocoagulation was enrolled in the study and the spherical equivalent under cycloplegia was analyzed. Statistical analysis of the results was performed using Wilcoxon and Mann-Whitney tests. Results: 64.3% of the patients developed myopia. Of the patients who were treated with cryotherapy 80% showed high myopia and 20% low hyperopia. The mean of the spherical equivalent was --3.10 D in the right and --3.25 D in the left eye. There was no statistically significant difference between the two eyes regarding the refractive outcome. Concerning patients treated with laser, 55.6% showed myopia of which 20% was high myopia and 80% low myopia; 11.1% showed no refractive error and 33.3% developed low hyperopia. The mean of the spherical equivalent was --0.58 D in the right eye and --0.83 D in the left eye. A statistically significant diference was found between the two eyes. The correlation of refractive results in both groups of patients showed an increase in the amount of high degree myopia in patients treated with cryotherapy (P<0.05). Conclusions: Myopia is a frequent finding in children treated for retinopathy of prematurity. Myopia not only is more frequent but it appears with higher degrees in children treated with cryotherapy as compared with those treated with laser.
Retinopathy; Prematurity; Cryotherapy; Laser