Abstract
Purpose : Adaptive optics (AO) based visual simulation is a promising technique used in clinical ophthalmology for vision testing, evaluation and outcome optimization. The current clinical instruments are very useful but either are bulky tabletop systems or are only limited to the correction/simulation of defocus. We propose a wearable head-mounted adaptive optics visual simulator, which looks like a typical virtual reality headset, to measure and simulate a variety of aberrations’ patterns in real-time.
Methods : The head-mounted instrument is adapted from a commercial desk-top AO visual simulator (VAO, Voptica SL, Murcia, Spain). The miniature optical components and path folding mechanism are used to achieve small device footprints. A custom Hartmann-Shack (HS) wavefront sensor and Liquid Crystal on Silicon Spatial Light Modulator (LCoS-SLM) wavefront manipulator are respectively used to measure and induce the aberration corrections. A HD micro-display is used as stimuli screen to display visual acuity (VA) charts and/or to perform any other psychophysical tests. Moreover, the customized device enclosures and component mounts are designed, and 3D printed in-house to achieve wearable form-factor. The head-mounted unit is tethered to the processing unit and operated via a dedicated software to perform the desired measurements.
Results : The developed prototype was tested by adding trial lenses and measuring and simulating their corrections. Moreover, a preliminary testing was performed with a small group of volunteers. The measurement result showed linear relationship between induced and measured for defocus up to ±7D and astigmatism up to ±5D. The Modulation Transfer Function (MTF) analysis of the visual correction showed the post-correction visual resolution of up to 35 cycles/degree. The subjective assessment of defocus showed coherency between HS measurements and post-correction VA.
Conclusions : A head-mounted adaptive optics visual simulator is developed to allow personalized visual evaluation and simulation. The instrument provides wavefront aberration measurement and correction features in a single wearable form-factor. Further developments and design refinements can improve the weight and size distribution and overall device ergonomics and the binocular application. The instrument can increase the patients’ comfort and would allow the use under natural viewing conditions to adapt correction strategies to normal visual behavior.
This abstract was presented (oral) at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.
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