Optical modelling of a supplementary tunable air-spaced goggle lens for rodent eye imaging.

Elie De Lestrange-Anginieur,Qiushi Ren,Xiaoyun Jiang,William H Merigan

doi:10.1371/journal.pone.0181111

Abstract

Aberration variations severely degrade retinal imaging in small animal eyes. Previously, the approach of a goggle lens with a matching corneal index was proposed to overcome the on-axis resolution limit of static imaging systems, which allows the use of the full eye pupil. But this technique didn’t address the problem of the large power variation, and the ensuing aberration on and off-axis, when dealing with small animal eyes. In this study, we present the concept of a tunable goggle lens, designed to compensate individual ocular aberration for different rodent eye powers. Ray tracing evidences that lens-fitted goggles permit, not only to adjust individual eyes power, but also to surpass conventional adaptive correction technique over large viewing angle, provided a minimum use of two spaced liquids. We believe that the overlooked advantage of the 3D lens function is a seminal finding for further technological advancements in widefield retinal imaging.

Highlights

Imaging of the rodent eye has received particular attention in the context of fundus disease
Our result confirms the potential of refractive index matching in the rodent eye, showing that the use of a multilayer artificial cornea can assist a higher resolution correction
It is expected that imaging of the cellular structures with a designed goggle lens could be a significant improvement over imaging of the uncorrected rodent eyes at large pupil

Summary

Introduction

Imaging of the rodent eye has received particular attention in the context of fundus disease. In silico modeling of a supplementary tunable air-spaced goggle lens for rodent eye imaging aberration, the authors demonstrate that the immersion of the cornea in a suitable liquid (i.e. saline water) could allow a substantial improvement in retinal images, resulting in a larger optical throughput with increased resolution on axis. The realization of a separate corrective unit in the contact probe brought a strong stabilization of the eye [8, 10] It afforded to spatially extend the artificial cornea beyond the restrictive physical limit of a lens-fitted contact lens (i.e. having ordinarily lighter weight). We demonstrate that the use of an air-space liquid lens, serving as an artificial cornea, could present a significant potential to enhance wide-angle retinal images (%20deg) of the rodent eye, and complement indirect imaging techniques. The concept is demonstrated using optical modeling software, not demonstrating a real (physical) lens system, there may well be manufacturing considerations that need to be taken into account before instantiation can be realized

Methods

Mismatched index approach

A supplementary goggle lens for enhanced wide-angle resolution

Findings

Discussion & conclusion