Abstract
Purpose :
Optical coherence tomography optoretinography (OCT-ORG) is an emerging imaging modality that evaluates retinal function. However, numerous studies have been conducted with dedicated OCT systems. This study aims to demonstrate the feasibility of OCT-ORG using a commercially available OCT with modification limited to software only, not hardware.
Methods :
OCT images were recorded from a rabbit using spectral-domain (SD) OCT (Mirante, Nidek) with customized software. The SD-OCT system operates at a wavelength of 880 nm with 85 kHz A-scan rate. A blue laser centered at 488 nm from a scanning laser ophthalmoscope (SLO) was used for light stimulation. Each stimulus had a power of 150 μW and a duration of 0.7 seconds, aiming to achieve 1.5% bleach. Prior to the measurements, a healthy pigmented rabbit was given general anesthesia and a muscle relaxant, fitted with a contact lens, and dark-adapted for 20 minutes. The rabbit was dark-adapted for 5 minutes between each measurement. Post-recording, ORG signals from photoreceptors between the inner and outer segment (IS/OS) junction and retinal pigment epithelium (RPE) were computed using phase-based analysis with an optimized Knox–Thompson method. The ORG signals were recorded three times each, with and without stimulus. Student’s t-test was used to calculate statistical analysis between conditions.
Results :
Figure 1 shows the ORG signals. The mean photoreceptor elongation ± standard error of the mean (SEM) converted from phase difference Δφ to the optical path length (OPL) and statistical significance were measured at 1, 2, and 3 seconds post-stimulus. At these intervals, the elongation was 16.4±11.9 nm (without stimulus) and 55.4±4.41 nm (with stimulus) at 1 second (p<0.05), 24.4±21.2 nm and 81.3±8.02 nm at 2 seconds (p=0.066), and 15.4±14.4 nm and 69.7±8.42 nm at 3 seconds (p<0.05), respectively.
Conclusions :
This study demonstrates the feasibility of OCT-ORG using a commercially available OCT device. This advancement validates the method’s effectiveness but also contributes to the potential for clinical implementation.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.