Abstract
Purpose :
This study investigated the changes in short-term axial length (AxL) and vision performance during exposure to simulated optical designs with coaxial and non-coaxial plus power lenslets, induced by adaptive optics (AO).
Methods :
An optical design with multiple lenslets of plus power (0.79 mm in diameter at pupil plane) distributed evenly over its optical zone (40% fill factor) was created through a spatial light modulator AO system. Between the plus power lenslets, the remaining optical area (60%) was optimally focussed for distance vision. Two types of plus power zones were tested; (i) coaxial, where lenslets created a single focal point (+10 D) in front of the retina on the optical axis, and (ii) non-coaxial, where lenslets created multiple focal points (+10 D) in front of the retina, with the central ray of each lenslet directed to the fovea. Six healthy young with normal vision subjects participated in the study. Subjects watched a movie through the AO system and AxL was measured with a Lenstar LS-900 biometer before, at 20 mins and after 40 mins exposure to the test designs. VA was tested with high-contrast tumbling E letters displayed on a micro-display in the AO system and contrast sensitivity (CS) was tested with an E letter target (0.5 logMAR) that was controlled by a QUEST algorithm.
Results :
At the end of 40 mins, coaxial and non-coaxial designs caused a significant and similar reduction in axial length compared to baseline (-5.7 ± 3.6 vs -8.3 ± 6.2 µm respectively, both p < 0.05) (Figure 1). The optical design with coaxial plus power lenslets caused a larger loss of VA of 0.15 ± 0.04 logMAR compared to the design with non-coaxial plus power lenslets with 0.07 ± 0.05 logMAR loss (t =3.2, p <0.05) (Figure 2). A greater loss of CS was also found with the coaxial plus power zones causing a loss of 0.08 ± 0.02 of Weber contrast compared to the non-coaxial design, with a CS loss of 0.03 ± 0.02. (t =4.8, p <0.005).
Conclusions :
Optical designs utilizing non-coaxial plus power lenslets were found to produce similar shortening effects on short-term axial length, while causing a smaller loss in visual performance than designs using conventional coaxial plus power lenslets.
This is a 2021 ARVO Annual Meeting abstract.