AI‑generated visualization of retinal cones.
Adaptive optics retinal imaging achieves some of the highest‑resolution views of the living human eye, yet still struggles with a surprisingly basic problem: precise fixation and light delivery to the retina.
Researchers at the Miller Lab, Indiana University School of Optometry, have developed a compact, fully integrated fixation–stimulus channel designed to enhance the precision and reliability of functional adaptive optics (AO) retinal imaging. Their system addresses two critical challenges in AO ophthalmoscopy: precise control of eye fixation and delivery of spectrally pure, well‑timed visual stimuli.
Why fixation control matters in AO retinal imaging
AO retinal imaging enables cellular‑level visualization of the living human eye using modalities such as flood illumination, scanning laser ophthalmoscopy (SLO), and optical coherence tomography (OCT). However, the small field of view and high magnification inherent to AO make experiments highly sensitive to fixation errors and stimulus variability.
A fixation–stimulus channel built from stock components
To overcome this issue and improve accessibility, the researchers designed a fixation–stimulus channel built from stock components that combines wide‑field gaze steering with high‑performance stimulus delivery. The fixation subsystem provides a large steering range, low distortion, extended working distance, and refractive error correction, enabling stable imaging even in far peripheral retinal regions.
Optimized stimulus delivery for optoretinography
The stimulus subsystem, enabled by a SuperK white light laser, is optimized for functional imaging by optoretinography (ORG), which measures light‑evoked responses of individual cone photoreceptors. Powered by a broadband supercontinuum laser and acousto‑optic tunable filtering, the system delivers short, high‑intensity, spectrally pure flashes across the visible spectrum with fast wavelength switching and excellent beam uniformity. Multi‑stage filtering suppresses spectral sidelobes, improving the robustness of cone classification and spectral sensitivity measures.
Together, the integrated design delivers a high-efficiency fixation and stimulus solution for functional AO ophthalmoscopy, while serving as a practical, open-source template for other AO laboratories.
Get all the details in the case story and white paper.
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