Refractive Growth of the Crystalline Lens in the Infant Aphakia Treatment Study

Objective: To compare the rate of refractive growth (RRG3) of the crystalline lens ("lens") versus the eye excluding the lens ("globe") for the fellow, noncataractous eyes of participants in the Infant Aphakia Treatment Study.

Design: Retrospective cohort study.

Subjects: A total of 114 children who had unilateral cataract surgery as infants were recruited. Biometric and refraction data were obtained from the normal eyes at surgery and at 1, 5, and 10 years. Subjects were included if complete data (axial length [AL], corneal power, and refraction) were available at surgery and at 10 years of age.

Methods: At surgery and at 1, 5, and 10 years, AL, corneal power, and cycloplegic refraction were measured in the normal eyes. For each eye, the RRG3 was defined by linear regression of refraction at the intraocular lens (IOL) plane against log₁₀ (age + 0.6 years). The RRG3 for the globe was based on IOL power for emmetropia; the RRG3 for the lens was based on IOL power calculated to give the observed refractions. Intraocular lens powers were calculated with the Holladay 1 formula. The means were compared with a paired 2-tailed t test, and linear regression was used to look for a correlation between RRG3 of the lens globe.

Main outcome measures: The RRG3 of the lens and globe.

Results: Complete data were available for 107 normal eyes. The mean RRG3 of the lenses was -12.0 ± 2.5 diopters (D) and the mean RRG3 of the globes was -14.1 ± 2.7 D (P < 0.001). The RRG3 of the lens correlated with the RRG3 of the globe (R ² = 0.25, P < 0.001).

Conclusions: The RRG3 was 2 D more negative in globes compared with lenses in normal eyes. Globes with a greater rate of growth tended to have lenses with a greater rate of growth.