By Rajat N. Agrawal, M.D.
Patients with advanced Retinitis Pigmentosa (RP) and Age-related
Macular Degeneration (AMD) have limited treatment options at this time.
Treatments like Vitamin A therapy for RP and laser and newer anti-VEGF
injections for AMD are currently being advised, but they are not much
help in advanced condition of these diseases. Stem cells treatment, gene
therapy and retinal transplantation are not yet ready for clinical
practice.
Artificial Retinal Implant Project is currently focused on restoring
sight to such patients. Our group, along with Second Sight Medical
Products based in Sylmar, CA, has successfully implanted a 16-electrode
ARGUS-I® device in 6 patients with advanced RP, with encouraging
results. In 2007, a clinical trial was begun with a 60-electrode
ARGUS-II® device in a multicentric trial that is spread around the
United States, Europe and Mexico. So far, 19 patients have been
implanted with the device.
A routine retinal surgery is performed to implant the device in the
eye. The device incorporates a coil placed on the surface of the eye,
with an array of electrodes being placed on the surface of the retina. A
coil on the glasses worn by the patient wirelessly communicates with
the secondary coil on the eye. A video camera on the glasses digitizes
the image and sends the information via a microprocessor to the implant.
Specific stimulation of the electrodes allows for visual perception by
the patient in the form of spots of light, described as “phosphenes.”
We are also in development of a 1000-electrode device that is likely
to give better visual benefit to patients, with a possible increase in
visual field. Although many advances have been made in the field of
artificial retina, with encouraging results from clinical trials so far,
the reality of a commercially available device is still a few years
away.
For more information, please contact Rajat N. Agrawal, M.D., Doheny
Eye Institute, University of Southern California, Los Angeles,
California, ragrawal@doheny.org, (323) 442-6776.
About Dr. Agrawal
Rajat N. Agrawal, M.D., is an Ophthalmologist and a Vitreo-Retinal
Surgeon. He is currently Asst. Professor of Clinical Ophthalmology,
Director of the Center for Retinal Degenerative Diseases, Study Director
of the Artificial Retina Implant Project, and Co-Director of
Intraocular Implants at the Doheny Eye Institute, University of Southern
California, Los Angeles, California.
Dr. Agrawal received his Medical degree (MBBS) from Government
Medical College, Nagpur, India, followed by an Ophthalmology residency
in Mumbai, India, and certification by the National Board
(Ophthalmology). He underwent Fellowship training in Vitreo-Retinal
Diseases and Surgery at the Medical Research Foundation (Sankara
Nethralaya), Chennai, India, and worked at a Consultant Vitreo-Retinal
Surgeon for more than 7 years, involved in clinical care, research and
teaching and training retina fellows and residents. He was later invited
to the Chinese University of Hong Kong, and by the Government of the
Commonwealth of Bahamas to teach and train local ophthalmologists in
retinal surgical techniques.
Dr. Agrawal was later recruited into the Doheny Eye Institute in Los
Angeles in 2003, where he is currently based. In addition to the routine
clinical work, he is significantly involved in the Artificial Retinal
Implant project, which aims at perfecting a complex artificial retinal
device that will allow patients with advanced retinitis pigmentosa and
age-related macular degeneration see again. In addition, he is also
involved in developing techniques for using stem cells in retinal
degenerative disorders, development of nano-drug delivery devices,
surgical instrumentation and newer surgical techniques.