In vivo depth-resolved morphological analysis of compound eye dioptric system using full-field optical coherence tomography

Abstract

Presence of a range of insects with different shape, size, and structural morphology of compound eye reveals the diverse pathways adopted by the nature striving to develop a flawless vision under given set of constraints. Exploration of various compound eyes allows researchers to understand better the various stages of visual system development in insects. By far, the most frequently used techniques for the investigation of structural morphology of a compound eye are scanning electron microscopy, transmission electron microscopy, microcomputed tomography, and histology. The nature of implementation of these techniques restricts in vivo studies, and also the requirements for a complicated and costly setup put limitations on its availability at small research facilities. Despite the widespread acceptance of the optical coherence tomography (OCT) as a standard tool for the various ophthalmological investigations, reports on compound eye study using OCT are uncommon. We demonstrate the application of a full-field OCT (FF-OCT) system for depth-resolved structural imaging and morphological analysis of the compound eye dioptric system. We report the application of a time-domain FF-OCT system for depth-resolved en face and three dimensional in vivo imaging of dragonfly’s prominent compound eye with resolutions of 2.8 and 7.2 μm in lateral and axial directions, respectively. The study shows the effectiveness of the FF-OCT approach for label-free and rapid structural morphology analysis of compound eyes. The results have been compared with the histology results reported in literature.