Abstract
Purpose: :
We describe in detail the procedure we used for identifying the most suitable candidates to receive the Argus II retinal prosthesis system.
Methods: :
In order to identify patients who could benefit the most from the Argus II epiretinal implant, we performed a screening as follows:1) First phone interview: we verified that the patients met a few basic criteria: adult (25 years old or older); severe to profound outer retinal degeneration; some residual light perception; previous history of useful form vision.We then asked if they had other associated diseases (e.g., retinal detachment, glaucoma, etc.), if they ever had ophthalmic surgery and if they suffered from Usher’s Syndrome (hearing loss associated).More general questions were then asked about their past and present school and work activities (to understand their educational level and learning speed), as well as questions about their general health status (cardio-vascular problems, neurological disorders, etc.)2) In-clinic screening: the patients pre-selected via the phone interview underwent a more comprehensive screening at the hospital: eye examination (visual acuity, intraocular tone, state of the conjunctiva, cornea, lens, presence of nystagmus, ocular motility, fundus examination), Goldmann visual field, OCT, Fluorescein Angiography, Fundus Photos, ultrasonic A-Scan, Photo Flash Test, Landolt C, Square localization, Direction of Motion, Grating Visual Acuity.Consensus within medical team members: once the first two steps of screening were completed, we reviewed all the medical and psychophysical results to assess the best candidates
Results: :
From an initial list of 119 patients, all suffering from Retinitis Pigmentosa at different stages, 15 blind candidates were selected for thorough in-clinic screening. From the comparative results of these tests, 13/15 patients were found eligible to receive an Argus II implant..
Conclusions: :
This is the first time we standardized a series of medical and psychophysical tests, widely accepted by the community and readily available in any eye hospital, for assessing retinal implant candidates. Results suggest that our selection process could quickly become a de facto standard in the field. Tests are fast (2h/patient), easy to perform, well tolerated by the patients, and with a clear outcome. The number of eligible patients is high with respect to to the total screened patients.
Keywords: retinal degenerations: hereditary • space and scene perception • perception