Abstract
Purpose: :
Preterm children, particularly children born before 28 weeks post-conception and weighing less than 1000 g, are at high risk for myopia. The optical components involved in the development of myopia in preterm children are not clearly understood. We evaluated the refractive error and optical components in eyes of preterm children in order to determine which optical components may be responsible for myopia development, and whether these components differ between children who had spontaneous regression of retinopathy of prematurity versus regression following laser ablation of the peripheral retina.
Methods: :
Cycloplegic refraction was obtained from 55 preterm children born at 23-28 weeks post-conception; 30 of the preterm children had received laser treatment. The optical components of the eyes of a subset of these children were measured with a LENSTAR® optical biometer to compare axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and radii of corneal curvature among fullterm (avg age=8.7 y; n=17), preterm (avg age=9.5 y; n=11), and preterm+laser (avg age=9.3 y; n=6) treated children. All eyes had normal appearing posterior poles.
Results: :
The refractive errors of both preterm groups were significantly more myopic than previously published age-matched fullterm children (p<0.001; Zadnick et al., OVS 2003). The refractive errors of preterm+laser children were significantly more myopic than preterm children (p=0.007). Subset analysis demonstrated that both preterm and preterm+laser children had shorter ALs (p<0.008) and increased corneal curvature (p<0.04) compared to fullterm children. In addition, preterm+laser children had decreased ACD and increased LT compared to fullterm children (p<0.001) and preterm children (p<0.007). Even the two children who developed high myopia ≥5.00D had ALs shorter than fullterm children. There were no significant differences in CCT among groups.
Conclusions: :
Unlike fullterm children with school-age axial myopia, preterm infants (especially those who have had laser treatment) have short axial lengths, shallow anterior chambers, thick lenses and steep corneal curvatures, consistent with arrested anterior segment development.
Keywords: retinopathy of prematurity • myopia • refraction