Purpose
The purposes of this study were to characterize the correlation between transient intrinsic optical signals (IOSs) and electrophysiological kinetics in the retina, and to validate in vivo confocal IOS mapping of localized retinal dysfunction.
Methods
A rapid line-scan ophthalmoscope was employed to conduct in vivo confocal-IOS imaging of frog (Rana Pipiens) retinas. This imaging system provided cellular spatial-resolution and millisecond temporal-resolution. Dynamic spatiotemporal filtering was integrated to reject signal contamination of hemodynamic changes on fast IOS imaging. Comparative IOS and electroretinography (ERG) measurements were conducted to investigate the physiological mechanism of confocal-IOS. Laser-injured frog eyes were employed to validate the potential of confocal-IOS mapping of localized retinal dysfunctions.
Results
Comparative IOS and ERG experiments revealed a close correlation between the confocal-IOS and retinal ERG a-wave, which has been widely used to evaluate photoreceptor function. IOS imaging of laser-injured frog eyes indicated that the confocal-IOS could unambiguously detect localized (30 µm) functional lesions in the retina before a morphological abnormality is detectable (Fig. 1).
Conclusions
The confocal-IOS predominantly results from retinal photoreceptors, and promises a method for concurrent morphological and functional assessment of the retina (Fig. 1). We anticipate that confocal-IOS imaging can provide applications in early detection of age-related macular degeneration, retinitis pigmentosa and other retinal diseases that can cause pathological changes in the photoreceptors.
Keywords: 508 electrophysiology: non-clinical •
648 photoreceptors •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)