OPTICAL IMPLICATIONS OF MYOPIA CONTROL CONTACT LENSES: ACCOMMODATION, RETINAL DEFOCUS AND THE EFFECTS OF PROLONGED ELECTRONIC DEVICE USE ON CHILDREN'S EYES

Abstract

This doctoral research advances the field of optical corrections for myopia control by introducing and validating novel optical measurement technologies and evaluating their application in myopia management strategies. Specifically, the dissertation first focuses on the validation of a high-resolution pyramidal wavefront sensing aberrometer, demonstrating its sensitivity (approximately four-times greater than available techniques) when quantifying the complex optics of myopia control lenses, such as dual-focus (DF) contact lenses (CLs).

Next, using a novel zone-wise analysis technique, the impact of DF CLs on inducing myopic defocus was examined in a cohort of young adult myopes who habitually had large lags of accommodation compared to those with more accurate accommodation. The study systematically assessed the shift in refractive state introduced by these lenses during accommodation both when viewing on- and off-axis. The results indicate that DF CLs do not significantly affect the individual’s accommodative behavior when compared to single vision CLs. The results also indicated that the treatment zone of DF CLs effectively replaced the hyperopic defocus commonly found in eyes corrected with single vision lenses with myopic defocus. The magnitude of this myopic introduction depended on individuals’ habitual accommodative responses. Specifically, individuals with higher accommodative lags experienced less myopic defocus.

The dissertation further extends the investigation to the effects of 1 hour sustained near viewing of electronic devices on accommodative responses and retinal defocus in myopic children wearing DF CLs and emmetropic children wearing no CL correction. A significant increase in hyperopic defocus over time was evident in both groups. The treatment zones of DF CLs lenses provided myopic defocus which reduced in magnitude at later time points. These insights emphasize the need for personalized approaches in myopia management, considering individual accommodative behaviors and visual habits in the digital age.