The effect of peripheral defocus on axial growth and modulation of refractive error in hyperopes

Abstract

Purpose: To establish whether axial growth and refractive error can be modulated in hyperopic children by imposing relative peripheral hyperopic defocus using multifocal soft contact lenses. Methods: A prospective controlled study with hyperopic participants allocated to a control or test group. Control group participants were corrected with single vision spectacles and changes to axial length and refractive error were followed for 3 years. For the test group, axial growth and post-cycloplegic refractive error were observed with participants wearing single vision spectacles for the first 6 months of the trial and then corrected with centre-near multifocal soft contact lenses with a 2.00 D add for 2 years. The central ‘near’ portion of the contact lens corrected distance refractive error while the ‘distance’ portion imposed hyperopic defocus. Participants reverted to single vision spectacles for the final 6 months of the study. Results: Twenty-two participants, mean age 11.13 years (SD 1.72) (range 8.33-13.92), completed the trial. Axial length did not change during the first 6 months in either group (P = 1.000). Axial growth across the 2-year intervention period was 0.17 mm (SEM 0.04) (P < 0.0005) in the test group versus 0.06 mm (SEM 0.07) (P = 0.677) in the control group. Axial length was invariant during the final 6 months in either group (P = 1.000). Refractive error was stable during the first 6 months in both groups (P = 1.000). Refractive error change across the 2-year intervention period was -0.26 D (SEM 0.14) (P = 0.375) in the test group versus -0.01 D (SEM 0.09) (P = 1.000) in the control group. Neither the test (P=1.000) nor control (P=0.628) group demonstrated a change in refractive error during the final 6 months. Conclusions:  The rate of axial growth can be accelerated in children with hyperopia using centre-near multifocal soft contact lenses.