Abstract
Purpose :
Global myopia incidence is rising, making myopia management research crucial. Current spectacle options include the use of spherical and aspheric lenslets which introduce peripheral myopic defocus. Sub-elements (SE), such as modified axicons (mA) and modified light swords (mLS), designed with extended depth of focus (EDOF) features have the potential to improve the visual performance offered with current options. P.A.U.S.E.® (Phase Alteration Utilising Sub Elements) spectacles with mA and mLS were designed and fabricated. This work assesses EDOF of these novel spectacles through schematic optical modelling and in-vitro evaluation and ascertains if the two methods are correlated.
Methods :
OpticStudio (OS, ANSYS, USA) was utilized to model the optical performance of P.A.U.S.E.® and Single Vision (SV) spectacles. OS's built-in routines were employed to derive the modulation transfer function (MTF) values. An in-vitro evaluation was performed using a bench-top Model Eye (ME) with a 3-mm pupil capturing point spread function (PSF) and USAF target images. PSFs were post-processed through a Fast Fourier Transform to obtain the corresponding MTF of low to medium spatial frequencies (SF), 25 to 50 Cyc/mm. Two different threshold MTF values (0.1 and 0.2) were used to derive a dioptric EDOF range. USAF images were post-processed using custom routines to yield Michelson's contrast levels for different SFs and vergences.
Results :
Optical modelling demonstrated an increase in EDOF ranges of up to 0.75 D and 1.00 D for SE, mA and mLS, respectively, which is an increase of 84% and over 100% compared to SV measures. In-vitro results mirrored the optical modelling findings, demonstrating an increase in EDOF ranges of up to 2.00 D and 1.75 D for SE, mA and mLS, respectively, which is an increase of 73% and 64% compared to SV measures. Michelson contrast measures using USAF target further substantiated these in-vitro findings with qualified support.
Conclusions :
Optical modelling coupled with in-vitro ME results confirm that EDOF is achievable with SEs configured with mA and mLS, compared to SV. The findings from schematic modelling and bench-top evaluation were in good concordance. Further clinical evaluation assessing the utility of EDOF-based SE in spectacles to improve visual performance over current myopia management solutions is underway.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.