Abstract
Purpose: :
Near-infrared light, outside the absorption range of the photoreceptors, was used to optically monitor retinal activity in response to a well-defined visual stimulus.
Methods: :
The measurements were carried out with the Retinal Function Imager (RFI) (Optical Imaging, Ltd.). The RFI measures activity-dependent functional signals in retinal image series recorded at chosen wavelengths. We measured changes in retinal reflectance during short and long trials with two visual stimulus test patterns and blank as a control. The two stimuli are either single flash or train of flashes at 4-30Hz while recording in infrared from eyes of anesthetized monkeys.
Results: :
Imaging the intact retina of anesthetized macaque monkey in vivo, we found a new functional signal localized to the axonal arches of the retinal ganglion cells emanating from the activated retinal area. Other intrinsic signals differing in temporal and spatial characteristics as well as their polarity were also observed.
Conclusions: :
Assessing the status of the axon arcades non-invasively might provide a new objective indicator for retinal diseases, particularly glaucoma.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • ganglion cells