Abstract
Purpose :
To use the opponent dual-detector spectral drive model of emmetropization (Gawne, Optical Society of America Fall Vision Meeting abstract, 2019) to examine the potential effectiveness of dual-focus lenses with chromatic filters to magnify longitudinal chromatic aberration (LCA) for myopia control.
Methods :
Using data from northern tree shrews (small diurnal mammals closely related to primates), we have developed an opponent dual detector spectral model for how the eye could make use of longitudinal chromatic aberration (LCA) to guide emmetropization. The model provides a target refraction and a gain toward that target. We have simulated the potential effectiveness for myopia control of dual-focal lenses (plano and +2 D regions) in which the plano region transmits long (“red”) wavelengths and the +2 region transmits short (“blue”) wavelengths (see Fig.1). For simplicity, we assumed the transmission of each filter changed from 100% to 0% at a specific "spectral crossover" wavelength. For each crossover wavelength, we calculated the estimated hyperopic bias in diopters, and the increase in the gain of the emmetropization mechanism.
Results :
At a spectral crossover of 478 nm, the gain to restore emmetropia from –3 D of myopic defocus was 36% greater than compared to a plano standard lens, and the bias towards hyperopia was 1.0 D. As the crossover wavelength increased, the gain to restore emmetropia from –3 D of myopic defocus decreased, and the hyperopic bias increased, until by 598 nm the hyperopic bias was 1.75 D and the gain to restore emmetropia at –3D of myopic defocus was normal.
Conclusions :
In principal, dual-spectrum dual-focal lenses, using modest differences in optical power between the different zones, could both shift the target of the emmetropization mechanism to a more hyperopic point, and also increase the gain away from myopia by boosting the LCA drive signal to the emmetropization mechanism. These results suggest that testing this lens design in animal models might be indicated.
This is a 2020 ARVO Annual Meeting abstract.