Evaluating Human Rod Photoreceptor Function Using Pixelwise Intensity-Based Optoretinography

Area of Science:

• Ophthalmology
• Cellular Biology
• Medical Imaging

Background:

• Over 50 inherited retinal diseases exist, often marked by early rod photoreceptor dysfunction.
• The optoretinogram (ORG) is an emerging assay for detecting cellular optical changes in response to stimuli.
• Rod photoreceptors are crucial for vision, and their early functional loss is key in many retinal diseases.

Purpose of the Study:

• To investigate the feasibility of obtaining intensity-based optoretinograms (iORGs) from rod photoreceptors.
• To explore the necessity of individual rod identification for waveform extraction.
• To analyze rod iORG morphology and compare it with cone iORGs.

Main Methods:

• Utilized an adaptive optics scanning laser ophthalmoscope to acquire iORGs from rod photoreceptors.
• Examined the impact of individual rod identification on waveform extraction.
• Analyzed the root mean square (RMS) morphology of rod iORGs.

Main Results:

• Rod iORG RMS waveforms exhibited slower implicit times and lower amplitudes compared to cone iORGs.
• Similar iORG RMS metrics were achieved whether using only identified rod locations or all rod-containing pixels.
• Rod optoretinograms are feasible even when rod photoreceptors are not fully resolved.

Conclusions:

• Obtaining rod optoretinograms is simplified by not requiring individual rod counting.
• This method enhances practicality and scalability for evaluating rod function in larger populations and diseased retinas.
• The approach broadens the clinical applicability of optoretinography for retinal disease diagnosis and monitoring.