Noninvasive Imaging and Measurement of Accommodation Using Dual-Channel SD-OCT

Abstract

Purpose: To investigate the feasibility and practicality of real-time noninvasive imaging and measurement of ocular accommodation (0–5D with one diopter step) using dual-channel, dual-focus spectral domain optical coherence tomography (SD-OCT).Materials and Methods: A custom-built, dual-channel, dual-focus SD-OCT was used to image the anterior segment, including the cornea, iris, and anterior and posterior lens surfaces. Three consecutive measurements were taken in each accommodative session for each subject. Changes in ocular dimensions during accommodation were calculated based on the acquired SD-OCT images. A Friedman test was used to test sensitivity of ocular dimension changes per diopter of accommodation.Results: With accommodation, anterior chamber depth (ACD), curvature radius of both anterior (RAL) and posterior (RPL) lens surfaces, and pupil diameter (PD) decreased significantly, whereas lens thickness (LT) increased significantly (p < 0.05, Friedman test). Ocular dimensions tended to change according to the increasing of accommodative stimulus, as did a backward movement of the posterior lens surface.Conclusions: SD-OCT, via extended imaging depth through a dual-channel, dual-focus approach, is a feasible and practical modality for noninvasive imaging and measurement of ocular accommodation.