Intrinsic signal optoretinography of dark adaptation kinetics

TL;DR

This study introduces a noninvasive functional OCT method to monitor dark adaptation in vivo, revealing morphological and signal changes in photoreceptors, which could enable early diagnosis of retinal diseases.

Contribution

The paper demonstrates the use of intrinsic signal optoretinography with functional OCT to assess dark adaptation kinetics in vivo, providing new insights into photoreceptor physiology.

Findings

Shortening of the outer retina observed during dark adaptation

Morphological changes in cone and rod interdigitation zones

Reduction in intrinsic signal amplitude at photoreceptor inner segments

Abstract

Delayed dark adaptation due to impaired rod photoreceptor homeostasis has been reported as the earliest symptom of eye diseases such as age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. Objective measurement of dark adaptation can facilitate early diagnosis to enable prompt intervention to prevent vision losses. However, there is a lack of noninvasive methods capable of spatiotemporal monitoring of photoreceptor changes during dark adaptation. Here we demonstrate functional optical coherence tomography (OCT) for in vivo intrinsic signal optoretinography (ORG) of dark adaptation kinetics in the C57BL/6J mouse retina. Functional OCT revealed a shortening of the outer retina, a morphological change in the cone and rod photoreceptor interdigitation zone, and a reduction in intrinsic signal amplitude at the photoreceptor inner segment ellipsoid. A strong positive correlation between morphophysiological activities was also confirmed. Functional OCT of dark adaptation kinetics promises a method for rapid ORG assessment of physiological integrity of retinal photoreceptors.