$\textit{In vivo}$ fundus imaging and computational refocusing with a diffuser-based fundus camera

TL;DR

This study introduces a novel diffuser-based fundus camera capable of in vivo imaging and digital refocusing, potentially enhancing diagnostic capabilities with a simple, phase mask-based approach that requires no moving parts.

Contribution

The paper demonstrates the first in vivo use of a diffuser-based fundus camera with computational refocusing, expanding the potential for accessible and high-throughput eye diagnostics.

Findings

Captured and digitally refocused color fundus images in vivo

Achieved a field of view of at least 35 degrees

Resolution ranged from 7.7 to 9.6 line pairs per mm

Abstract

Significance: Access to diagnostic eye care could be expanded with high-throughput and easy-to-use tools. Phase mask-based imaging may improve the fundus camera by enabling computational refocusing with no moving parts. While phase mask-based imaging has been demonstrated in a model eye, this approach has not been shown $\textit{in vivo}$. Aim: A computational fundus camera was designed, constructed, and evaluated with the goal of determining the feasibility and performance of phase mask-based computational imaging of the $\textit{in vivo}$ fundus. Approach: A holographic diffuser was introduced in a modified commercial fundus camera at a plane conjugate to the ocular pupil, resulting in a linear and shift-invariant point spread function that varies with refractive error. The image could be digitally refocused across a range of $\geq\pm$ 10 diopters of defocus error. The device was tested for ocular safety, and a human imaging pilot study was performed. Results: The device captured and digitally refocused color human fundus images. The field of view was $\geq$35 degrees and resolution was 7.7-9.6 line pairs per mm. Conclusions: We present the first $\textit{in vivo}$ diffuser-based fundus images, demonstrating the feasibility of computational imaging for ocular diagnostics.