Absolute sensitivity of the electroretinogram and of the optic nerve action potential in the perfused feline eye.
OBJECTIVE
To assess and characterize the electroretinogram (ERG) and the optic nerve response (ONR) at threshold stimulus intensity in the isolated perfused cat eye.


METHODS
Eyes were enucleated from deeply anesthetized adult cats and arterially perfused with oxygenated serum-enriched tissue culture medium. Light stimuli of 20- to 400- msec duration from a xenon arc source, attenuated down to threshold intensities by neutral density filters, were delivered via a modified fundus camera in full dark adaptation. Vitreal ERGs and ONRs were amplified, digitized, averaged and analyzed using LabVIEW for Windows software.


RESULTS
The threshold intensities in log scot q/deg(2) per second for the negative scotopic threshold response (STR), for the ERG b-wave, and for the ONR were at 2.87+/-0.35, 3.53+/-0.35 and 1.78+/-0.48, respectively.


CONCLUSIONS
The in vitro perfused mammalian eye preparation exhibits remarkably low thresholds for the ERG and particularly for the ONR near the intensity required for the human psychophysical threshold.
Kuze
Manami
M
Department of Ophthalmology, Mie University School of Medicine, Mie Prefecture, Japan. m-kaze@clin.medic.mie-u.ac.jp
Niemeyer
Günter
G
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002415:Cats / Q000502:physiology*; D004596:Electroretinography; D009900:Optic Nerve / Q000502:physiology*; D010477:Perfusion; D010775:Photic Stimulation; D012684:Sensory Thresholds