Wide-Field Sensorless Adaptive Optics Optical Coherence Tomography for Enhanced Visualization of the Retinal Periphery

Abstract

Purpose : To enhance the visualization of anatomical and pathological features in the peripheral retina for ophthalmic and neurologic diseases using Optical Coherence Tomography (OCT).

Methods : A 100 kHz swept-source OCT engine with a custom adaptive optics wide field-of-view sample arm was used in this work. The sample arm was designed and modeled in Zemax (Zemax, LLC) to conjugate two 10mm galvanometers, a deformable mirror (Imagine Optic, Inc), and the pupil plane of the eye. Intensity-based sensorless adaptive optics (SAO) optimization was used to estimate and correct wavefront aberrations, allowing for a more compact lens-based sample arm to be engineered. Using custom C++/CUDA software, the deformable mirror could be updated every other B-scan for 1024 A-scans/B-scan, allowing a full B-scan to be acquired between each new mirror shape.

Results : The wide-field sample arm achieved a field-of-view >70°, corresponding to >20mm in adult subjects. The peak sensitivity of the sample arm was 101dB with an axial resolution of 7.16μm and a -6dB range of 4.49mm. The imaging system was capable of acquiring continuous wide fields-of-view or smaller SAO corrected high-resolution patches (Fig. 1). SAO optimization improved the brightness and resolution, with correction of the wavefront stabilizing within 5-10 seconds. SAO was especially important when imaging higher retinal eccentricities. Healthy and pathological eyes were imaged in consenting adults in accordance with the Duke University Institutional Review Board.

Conclusions : Sensorless adaptive optics aided in visualizing the anatomic features of the peripheral retina. Improving both signal intensity and resolution may prove essential for evaluating peripheral pathologies as sufficient resolution and brightness could not be achieved without adaptive optics. The wide-field sample arm could acquire both full fundus OCT images as well as smaller high-resolution patches.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

(left) Wide field-of-view summed volume projection (top) and B-scan (bottom) OCT images acquired in a single continuous scan. The colored dashes correspond to the location of small patches within the context of wide-field scans. (middle) High-resolution peripheral B-scan images with (top) and without (bottom) SAO applied. (right) Images highlighting the benefits of SAO, including increased brightness and better resolved features, such as blood vessels and ELM (yellow arrows).