Refractive and biometrical characteristics of children with retinopathy of prematurity who received laser photocoagulation or intravitreal ranibizumab injection

Purpose To investigate the refractive and biometrical developments of children with retinopathy of prematurity (ROP) who received laser photocoagulation (LP) or intravitreal ranibizumab injection as treatment. Methods This case-control study involved cases with Zone II Stage 3 ROP. Fourteen children (28 eyes) who received single LP were included in the laser group, and 14 children (27 eyes) who received single intravitreal ranibizumab injection were included in the injection group. The mean age at operation was 37.00 +/- 1.72 and 36.36 +/- 1.66 weeks for the laser and injection groups, respectively (P=0.161), and refraction measurements and biometry were performed at the mean age of 5.00 +/- 1.63 and 5.00 +/- 0.94 years for the laser and injection groups, respectively (P=1.000). Spherical equivalent (SE) after mydriatic refraction and best corrected visual acuity (BCVA) were measured by refraction test. Central corneal thickness (CCT), anterior corneal surface curvature and curvature radius, anterior chamber depth (ACD), lens thickness (LT) and axial length (AL) were measured by biometry using the IOL Master700 biometric instrument (Carl Zeiss Meditec AG). The biometrical images were reanalysed using a self-developed program in MATLAB (R2016a, MathWorks, Inc.) to obtain additional eye parameters, including the curvatures of the posterior cornea and the anterior and posterior surfaces of the lens. SPSS (V.23.0) was used for statistical analysis. Independent sample t test was used to compare the eyeball biological and refractive state measures of the two groups, and Pearson correlation coefficient was used to evaluate the correlation between SE and the biological parameters. Results Cornea-related parameters: CCT (0.54 +/- 0.04mm vs 0.55 +/- 0.02mm, >0.05), anterior corneal surface curvature radius (7.56 +/- 0.26 mm vs 7.67 +/- 0.43mm, >0.05) and posterior corneal surface curvature radius (6.82 +/- 0.27mm vs 6.79 +/- 0.42mm, >0.05). ACD (3.21 +/- 0.25mm vs 3.22 +/- 0.19mm, >0.05). Lens-related parameters: anterior lens surface curvature radius (10.04 +/- 0.89mm vs 9.82 +/- 1.08mm, >0.05), posterior lens surface curvature radius (5.49 +/- 0.55mm vs 5.92 +/- 0.73mm, <0.05) and LT (3.80 +/- 0.14mm vs 3.59 +/- 0.16mm, <0.05). AL (21.82 +/- 1.07 vs 22.68 +/- 1.61, <0.05). Parameters related to refractive state: SE (-2.43 +/- 3.56 vs -0.53 +/- 3.12, <0.05) and BCVA (log MAR, 0.17 +/- 0.14 vs 0.21 +/- 0.18, >0.05). The SE of children in the laser group was positively correlated with LT (=0.438, <0.05), negatively correlated with ACD (=-0.437, <0.05) and had no significant correlation with other eyeball biological indicators (>0.05). The SE of children in the injection group was negatively correlated with AL (=-0.537, <0.05), positively correlated with CCT (=0.455, <0.05) and had no significant correlation with other eyeball biological indicators (>0.05). Conclusion LP and intravitreal ranibizumab injection as ROP treatments produce myopic refraction with increased degree of myopia in children who received LP than in children who received ranibizumab injection. The increased myopia after LP is due to the increases in LT and posterior lens curvature and a shallow ACD.