Purpose : Adaptive-optics-based visual simulation is a useful tool in different areas of clinical ophthalmology. However, current commercial instruments are monocular and the most thorough binocular testing can only be performed with bulky laboratory prototypes. In this context, the aim of this work was to develop a compact binocular instrument suitable for clinical environments and able to deal with a wide variety of patients, including those with abnormal eye’s optics.
Methods : The new binocular device has been adapted from a commercial monocular version (VAO, Voptica SL, Murcia, Spain). Both eyes’ pupils were fit into the Hartmann-Shack (HS) wavefront sensor and liquid crystal on silicon (LCoS) phase modulator, for measurement and manipulation of ocular aberrations. Conversely, the stimulus generator was replaced by two HD screens, one for each eye, for stimulus presentation and psychophysics, including stereo-acuity tests. Additionally, a single intensity modulator was included for generating artificial pupils in both eyes, and a single tunable lens for correction of defocus. A pupil camera monitoring both eyes and a periscopic system allows controlling eye separation and tilt for precise patient’s positioning. The whole system is mounted in a relatively compact housing similar to standard ophthalmic equipment. GPU-based processing of the HS images allows for simultaneous measurements in real time for both eyes.
Results : The dynamic range of the device was determined by measuring and inducing aberrations in artificial eyes and in a group of highly-aberrated volunteers, adding trial lenses in some cases to increase ammetropia. By using the tunable lens to roughly compensate for defocus, the instrument successfully copes, both for measuring and correcting, with a range of +/-15D in spherical equivalent, +/-6D in cylinder and at least 1µm in all high-order aberrations over a 4.5-mm diameter pupil. The use of the device was easy both for operators and subjects.
Conclusions : A compact Binocular Visual Adaptive Optics simulator has been developed allowing clinical visual testing under controlled optical conditions in both eyes. The instrument has a high dynamic range much increased with respect to the current commercially available monocular device, and it may be used to better understand the relationship between optics and visual performance in patients with highly aberrated eyes (e.g., keratoconus).
This abstract was presented (poster) at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.