In vivo fundus imaging and computational refocusing with a diffuser-based fundus camera

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, reducing hardware complexity and cost. Although phase mask-based imaging has been demonstrated in a model eye, this approach has not been shown in vivo.

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 in vivo fundus.

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 $\ge \pm 10$ diopters of defocus error. The device was tested for ocular safety, and a human imaging pilot study was performed.

The device captured and digitally refocused color human fundus images. The field of view was $\ge 35\mathrm{deg}$ , and resolution was 7.7 to 9.6 line pairs per millimeter.

We present the first in vivo diffuser-based fundus images, demonstrating the feasibility of computational imaging for ocular diagnostics.