Handheld Adaptive Optics Scanning Laser Ophthalmoscope for in vivo Photoreceptor Imaging of Supine Adults and Neonates

Abstract

Purpose : Visualization of individual photoreceptors close to the fovea with the current generation of large footprint tabletop adaptive optics (AO) scanning laser ophthalmoscope (SLO) systems is largely limited to upright, cooperative patients. We describe a handheld AOSLO (HAOSLO) system that utilizes a light and compact AO framework and custom optics and mechanics to achieve photoreceptor visualization in supine adults and neonates during examination under anesthesia (EUA).

Methods : A compact deformable mirror (DM) with 69 actuators and a 10.5 mm pupil diameter was used as the adaptive element to correct for wavefront distortions. The handheld probe, weighing less than 400 grams, permitted a 1.4° x 1.6° field of view and 2.5 µm lateral resolution at a speed of 8.3 frames per second with a beam diameter of 6 mm at the eye. Optical aberrations were corrected without a wavefront sensor by using a third order Zernike basis stochastic parallel gradient descent algorithm to maximize the mean intensity of the acquired image. To improve the convergence time, downsampling was applied to the acquired image during sensorless correction to increase the iteration rate to 41.5 Hz.

Results : The handheld probe was calibrated and used to acquire retinal images of multiple dilated, supine, healthy human adult volunteers. Additionally, the fellow eye of a neonate with unilateral persistent retinal vasculature, congenital caratact, aphakia, and tractional/rhegmatogenous retinal detachment was imaged during an EUA. High-resolution retinal images visualizing the photoreceptor mosaic in the adult and child were acquired (Figure 1).

Conclusions : We have demonstrated the first HAOSLO system and have tested it to achieve photoreceptor visualization in supine healthy adults and neonates. The use of this technology may provide a compact solution for photoreceptor imaging near the fovea in neonates and young children.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. a) Photograph of HAOSLO in handheld use. The handheld probe has a form factor of 10.3 x 5.3 x 11.2 cm. b) 1.0° field of view retinal image (single frame) acquired with the probe after sensorless AO correction on a dark-adapted adult volunteer at a location 1.2° temporal to the fovea. c) 0.75° field of view retinal image (single frame) acquired from neonate during EUA. Scale bar: 0.25°.