Visual evoked potentials to infrared stimulation in normal cats and rats

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Neuroscience

Background:

• Retinal degenerative diseases lack effective treatments, driving the development of retinal prosthetics.
• The subretinal approach utilizes photodiodes in a silicon chip to generate electrical currents.
• Near-infrared (NIR) light stimuli have been used to differentiate implant responses from native retinal activity.

Purpose of the Study:

• To investigate the sensitivity of the native retina to NIR light.
• To re-evaluate the interpretation of electrophysiological responses to NIR stimuli in the context of subretinal implants.

Main Methods:

• Recording evoked potentials over the visual cortex in response to NIR light stimuli.
• Comparing responses under different retinal conditions, specifically dark-adapted states.

Main Results:

• The native retina exhibits unappreciated sensitivity to NIR light, particularly under dark-adapted conditions.
• This sensitivity can confound the interpretation of electrophysiological data used to assess subretinal implant function.
• Previously assumed characteristics of implant-mediated responses may be influenced by native retinal activity.

Conclusions:

• The sensitivity of the native retina to NIR light must be considered when evaluating subretinal prosthetic implants.
• Current methods for distinguishing implant-generated signals from native retinal activity may require revision.
• Further research is needed to refine testing protocols for retinal prosthetics.