Abstract
Purpose :
Short term changes in ocular axial length (AL) due to choroid thickness may serve as a biomarker for future changes in eye growth and myopia development. This study investigated short term changes in AL in response to optical aberration profiles designed to induce various amounts of optical anisotropy in the peripheral retina.
Methods :
An adaptive optics vision simulator (AOVS) was used to induce 5 optical test conditions (TCs), while subjects viewed a visual stimulus (5 deg of visual angle) for 30 minutes in white light and with natural pupils. Simultaneously, AL measurements were acquired in 10 minute intervals with a Lenstar LS900 biometer. The study was performed monocularly (left eye) in 10 subjects (age: 29±4) with normal vision (baseline refractive error -0.78±1.19 D, range: -2.75 to +0.50 D). The three novel optical designs evaluated in this study consisted of a 4.0 mm diameter central plano optical zone, and a peripheral optical zone segmented into 4 identical quadrants containing peripheral positive defocus (TC1), peripheral astigmatism and coma (TC2), and a combination of peripheral positive defocus, astigmatism, and coma (TC3). TC1-3 were designed to provide the peripheral retina with radially elongated optical anisotropy (TC1), zero optical anisotropy with astigmatism and coma correction (TC2), and zero optical anisotropy with an overcorrection of defocus (TC3). Two control TCs were included in the study: distance-corrected plano and a concentric, center-far, multiring bifocal (BF).
Results :
After 30 minutes of viewing, the resultant mean change in AL for TC1, TC2 and TC3 was -13±6, -4±8, -6±9 μm, respectively, whereas for the control conditions was -2±5 (plano) and -7±10 μm (BF). TC1 was the only condition with a significant reduction in AL compared to plano (p = 0.013) and a correlation to baseline AL (r = -0.59).
Conclusions :
The optical design with the strongest potential for controlling myopia progression consisted of peripheral positive defocus (TC1), intended to provide the average myopic eye with radially elongated peripheral optical anisotropy. While more work is required to elucidate the underlying mechanisms encoding the optical cues for myopia control, it is worth noting the AOVS’ visual stimulus subtended a small visual angle, thereby isolating the effect of the optical designs to mechanisms of the central retina.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.