Abstract
Purpose :
Dilation drops are frequently used when imaging with an adaptive optics scanning laser ophthalmoscope (AOSLO) to paralyse accommodation and enlarge the pupil. Although this improves and maintains image quality, it causes inconvenience for the participant and requires prescription and medical supervision. Here we evaluate the feasibility of imaging without pupil dilation and with visual stimulation over extended periods and at different visual fields.
Methods :
Experiments were performed using a custom-built AOSLO (830 nm imaging; 930 nm wavefront sensing). An oscillating stimulus with a full-field sinusoidal intensity modulation at 98% contrast was presented from a projector through a Badal system. In each trial, an additional static fixation cross was displayed at four degrees angular separation from the imaging scan patch in one of the four visual fields. The participant fixated on the cross over a 5-second image acquisition period from the AOSLO. 20 trials, 5 for each visual field were grouped in a block, and each participant completed 5 blocks, lasting ~1.5 hours in total. Six healthy participants within the age of 20-28 years participated in the study, 5 of which had normal visual acuity, and one with -2.0 diopters myopia. Rooms lights were turned off during experiments, and between blocks all participants except one took a 2-minute break in a lighted room. Coefficients of variation (CoV) were used to assess the image quality of raw retinal images. Each visual field was considered independently and the mean CoV and standard error of the mean (SEM) was calculated (i) over blocks for each participant (within-participant, n=5) and (ii) over participants (between-participant, n=6). To quantify the variation in image quality the normalised SEM, defined by the SEM over mean, was used.
Results :
The maximum within-participant normalised SEM for each field was 2.97% nasal, 4.01% superior, 4.17% temporal, 4.90% inferior; and the between-participant normalised SEM was 3.73% nasal, 3.82% superior, 2.44% temporal, 1.13% inferior.
Conclusions :
Our results show that over a 1.5-hour period, the variation in image quality between blocks from a given participant is comparable to that between participants, showing good promise for imaging using an AOSLO with no pupil dilation over extended periods.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.