Jd. Weiland et al., Understanding the origin of visual percepts elicited by electrical stimulation of the human retina, GR ARCH CL, 237(12), 1999, pp. 1007-1013
Citations number
22
Categorie Soggetti
Optalmology
Journal title
GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY
Background: The success of a retinal prosthesis for patients with outer ret
inal degeneration (ORD) depends on the ability to electrically stimulate re
tinal cells other than photoreceptors. Experiments were undertaken in human
volunteers to ascertain whether electrical stimulation of cells other than
photoreceptors will result in the perception of light.
Methods: In two subjects, two areas of laser damage (argon green and krypto
n red) were created in an eve scheduled for exenteration due to recurrent c
ancer near the eye. In the operating room prior to exenteration, under loca
l anesthesia, a hand-held stimulating device was inserted via the pars plan
a and positioned over the damaged areas and normal retina. Subjects' psycho
physical responses to electrical stimulation wore recorded.
Results: In both subjects, electrical stimulation produced the following pe
rceptions. Normal retina: dark oval (subject 1), dark half-moon (subject 2)
; krypton red laser-treated retina: small, white light (both subjects); arg
on green laser-treated retina: thin thread (subject I), thin hook (subject
2). Histologic evaluation of the krypton red-treated retina showed damage c
onfined to the outer retinal layers, while the argon green-treated area evi
nced damage to both the outer and the inner nuclear layers.
Conclusion: The perception produced by electrical stimulation was dependent
on the retinal cells present. Electrical stimulation of the krypton red-ab
lated area best simulated the electrically elicited visual perceptions of o
ur blind, ORD patients, suggesting that the site of stimulation in blind pa
tients is the inner retinal neurons.