The Cone Optoretinogram as a Function of Retinal Eccentricity

Adaptive optics scanning laser ophthalmoscopy optoretinography quantifies cellular function in the living retina by measuring the <i>en face</i> intensity change in cone photoreceptors due to visual stimulation. To fulfill the potential of optoretinography as a biomarker for assessing function in disease, we require normative optoretinographic measurements across the retina. Here we provide such measurements. We use a custom adaptive optics scanning laser ophthalmoscope to investigate cone optoretinogram (ORG) amplitudes across retinal eccentricity in five normal-sighted participants. For this purpose, we aggregated signals across cones in each measurement (~1° by 1° patch) to provide a measurement we call the population ORG. Average population ORG amplitudes decreased with increasing eccentricity for all participants, although there were individual differences in the detailed pattern of the decrease. ORG amplitudes were correlated with the thickness of the outer retina as measured using clinical OCT, which also decreases with eccentricity. Characterizing the population cone ORG as a function of eccentricity in normal-sighted participants is an important step towards establishing norms that will allow it to be used as a biomarker for assessing photoreceptor function in retinal disease.