Retinal adaptive optics imaging with a pyramid wavefront sensor.

Elisabeth Brunner,Muhammad Faizan Shirazi,Rainer Leitgeb,Christoph K Hitzenberger,Julia Shatokhina,Wolfgang Drexler,Ronny Ramlau,Andreas Pollreisz,Michael Pircher

doi:10.1364/boe.438915

Abstract

The pyramid wavefront sensor (P-WFS) has replaced the Shack-Hartmann (SH-) WFS as the sensor of choice for high-performance adaptive optics (AO) systems in astronomy. Many advantages of the P-WFS, such as its adjustable pupil sampling and superior sensitivity, are potentially of great benefit for AO-supported imaging in ophthalmology as well. However, so far no high quality ophthalmic AO imaging was achieved using this novel sensor. Usually, a P-WFS requires modulation and high precision optics that lead to high complexity and costs of the sensor. These factors limit the competitiveness of the P-WFS with respect to other WFS devices for AO correction in visual science. Here, we present a cost-effective realization of AO correction with a non-modulated P-WFS based on standard components and apply this technique to human retinal in vivo imaging using optical coherence tomography (OCT). P-WFS based high quality AO imaging was successfully performed in 5 healthy subjects and smallest retinal cells such as central foveal cone photoreceptors are visualized. The robustness and versatility of the sensor is demonstrated in the model eye under various conditions and in vivo by high-resolution imaging of other structures in the retina using standard and extended fields of view. As a quality benchmark, the performance of conventional SH-WFS based AO was used and successfully met. This work may trigger a paradigm shift with respect to the wavefront sensor of choice for AO in ophthalmic imaging.

Highlights

With the rise of adaptive optics (AO), the potential of high resolution optical imaging has been unlocked for several applications including astronomy [1], microscopy [2] and ophthalmology [3]
As a test scenario to demonstrate the repeatability of high performance ophthalmic AO with the pyramid wavefront sensor (P-wavefront sensor (WFS)), we have chosen AO-optical coherence tomography (OCT) imaging of the photoreceptor layer at a small field of view (FoV) of 1° x 1° in the central fovea of 5 healthy subjects with large pupil diameters > 6
In the presented data set, single cone photoreceptors can be visualized in the fovea centralis in both the en-face and B-scan image (Fig. 5(b) + (c)) demonstrating the excellent AO correction quality obtained with the P-WFS

Summary

Introduction

With the rise of adaptive optics (AO), the potential of high resolution optical imaging has been unlocked for several applications including astronomy [1], microscopy [2] and ophthalmology [3]. With the resulting imaging capabilities of these instruments, various cell types such as cone photoreceptors [4, 7], rod photoreceptors [8, 9], retinal pigment epithelium (RPE) cells [10, 11], ganglion cells [12] and more have been identified in the retina from data captured in vivo. These works have revolutionized the imaging options of the living retina, and first commercialization of AO supported instruments for improved diagnostics and treatment control have been realized. A blur effect equivalent to that obtained by a dynamic modulation can be obtained without using any moving part

Methods

Results

Conclusion