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

Simmerer C, Morakis M, Gomez-Perez L, Liu A, Durr NJ
arXiv 2024 [Preprint]

Abstract
Access to eye care can be expanded with high-throughput, easy-to-use, and portable diagnostic tools. Phase-mask encoded imaging could improve these aspects of the fundus camera by enabling computational refocusing without any moving parts. This approach circumvents the need to adjust lenses to compensate for accommodation or refractive errors. We developed a computational fundus camera by introducing a holographic diffuser at the conjugate plane to the ocular pupil, resulting in a laterally shift-invariant point-spread function. We demonstrate computational refocusing of a model eye fundus over a large range of defocus errors (up to ±12D). We also show computationally-refocused color in vivo human fundus images with a ≥35-degree field-of-view (FOV). This technology could eventually be combined with the wavefront-sensing capabilities of phase-mask encoded imaging to create a compact ophthalmic imaging system that simultaneously captures a fundus image and performs aberrometry.