Long-term biometric optic components of diode laser-treated threshold retinopathy of prematurity at 9 years of age.

PURPOSE: To assess quantitatively the biometric optic components and its relationship with refractive status in preterm school children with diode laser-treated threshold retinopathy of prematurity (ROP).

METHODS: A prospective, cross-sectional study in which ultrasound biometric measurement of optic components and cycloplegic refraction were performed on 24 consecutive preterm children with diode laser-treated threshold ROP at the age of 9 years. The study results were compared with 1021 age-matched full-term control children from a national survey.

RESULTS: The eyes with laser-treated ROP showed statistically significantly thicker lens (3.94 versus 3.39 mm), steeper vertical corneal curvature (7.47 versus 7.67 mm) and shallower anterior chamber depth (ACD) (2.91 versus 3.58 mm) than age-matched full-term controls, but no difference in axial length (23.32 versus 23.24 mm). The laser-treated eyes had a mean spherical equivalent (SE) of -4.49 D compared with mean SE of -0.44 D in controls. Of 46 eyes studied, 93% of eyes were myopic and 28.3% with high myopia (<-6.0 D) compared with the 32% prevalence of myopia in controls. In preterm children, younger gestational age tended to correlate with shallower ACD (r = 0.352) and thicker lens (r = -0.298); lower birth weight tended to correlate with shallower ACD (r = 0.372) and steeper cornea (r = 0.360).

CONCLUSIONS: There were higher prevalence and greater magnitude of myopia in preterm children. The significantly thicker lens, steeper corneal curvature and shallower anterior chamber depth are the major factors contributing to the development of myopia in preterm school children with laser-treated threshold ROP.