Purpose
To determine whether soft contact lenses with
positive spherical aberration (+SA) can slow
myopia progression.
Methods
Eligible subjects (N = 127, primarily Asian) aged 8 to 11 years were randomized to wear either control (spherical design) or test (with +SA) soft daily disposable contact lenses for a minimum of 1 and up to 2 years (treatment phase). Subjects from the initial cohorts (N = 82) were then followed for an additional 1.5 years while wearing a marketed spherical daily disposable contact lens (withdrawal phase).
Axial length and spherical equivalent cycloplegic autorefraction (SECAR) were measured at baseline and every 6 months in both phases.
Results
During the first year of treatment, lens type (test vs. control) had a statistically significant impact on axial elongation (p = 0.0409). Eyes wearing test lenses increased in length by 0.11 (65.3%) and 0.14 (38.6%) mm less than eyes wearing control soft lenses at 6 and 12 months, respectively (p < 0.05 at both time points). The principal control of axial elongation occurred during the first 6 months. Spherical equivalent cycloplegic autorefraction change from baseline was significantly less in the test cohort than the control cohort by 0.21D (54.0%) at 6 months (p < 0.05) but not at 12 months (0.14D, p > 0.05). Lens type was not overall a significant factor affecting refractive error change (p = 0.0677). After ceasing treatment, neither the rate of axial elongation nor change in SECAR was significantly different between the initial two cohorts.
Conclusions
The
soft contact lens with +SA slowed axial growth of the eye, although this did not translate into a sustained statistically significant effect on SECAR. The majority of the treatment effect occurred in the initial 6 months of wear. No evidence of rebound effect was observed after ceasing treatment.
