First Author: D.Guven TURKEY
Co Author(s): M. Demir D. Ozcan S. Tiryaki Demir H. Kacar S. Cevher
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Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA, USA) is a surgically implantable device designed to provide artificial vision to patients with outer retinal degenerative diseases basically RP. Our aim is to present the clinical and imaging characteristics of two patients before and after Argus II retinal prosthesis implantation.
Our hospital has been certified and announced as a centre for implantation in Turkey in 2014. More than 450 RP patients were evaluated for candidacy, and suitable 2 RP patients received the implant 14 and 3 months ago.
First patient was a 58 years-old male with end-stage RP. His vision was light perception bilaterally for 5 years.He was phakic with axial length of 23.13mm, and intraocular pressure(IOP) of 18mmHg. He received prosthesis implantation simultaneously with phacoemulsification and intraocular lens implantation. Second patient was a 36 years old male RP with only light perception. He was pseudophakic with an axial length of 24.95mm and IOP of 12 mmHg. The patients were evaluated before and after the prosthesis implantation by detailed ophthalmological examination, anterior and posterior segment photography and SD-optical coherence tomography. Fitting for identification of electrical stimulation threshold levels were done 2 weeks after the surgery. Rehabilitation sessions started after the first month.
During and after the implantation no adverse effect was encountered intraocularly or extraocularly. All 60 electrodes were functional in both patients. The system was actively used at least 2.5-5 hours /day. The electrode arrays remained stable over the macula and in contact with the retina. In the first patient after 9 months there were a few cystic spaces seen in the retina under the array and some fibrous strands on the retina. This patient could identify black letters on white and write his name. He could recognize black figures on white, identify black numbers on white, sort the numbers, place the numbers of the clock hours and the hour hands correctly. Second patient who was very eager to use the system, especially had increased comfort during walking alone, avoiding obstacles outside home when the system was active. Light perception did not change in any of the patients when the system was inactive.
Retinal prosthesis are devices that induce artificial vision by delivering electrical stimulation to the retina epiretinally, subretinally or suprachoroidally. Both of our patients showed a continuous vision-related improvement in the performance of several real-life tasks. The system was found to be effective in increasing self-confidence.