Publications by authors named "D A X Nayagam"
Purpose: To assess the feasibility of a second-generation (44-channel) suprachoroidal retinal prosthesis for provision of functional vision in recipients with end-stage retinitis pigmentosa (RP) over 2.7 years.
Design: Prospective, single-arm, unmasked interventional clinical trial.
Article Synopsis
- Extraocular electrical stimulation can protect retinal cells but currently relies on patients frequently setting up external electrodes, which is inconvenient.
- A new minimally-invasive implant has been developed to provide a reliable method for chronic electrical stimulation of the retina, aimed at improving patient adherence to treatment.
- In a study with adult felines, the device showed surgical and stimulation safety with no adverse effects, stable electrode performance, and no significant changes to retinal health, suggesting it could be a viable long-term solution.
Purpose: Accurate mapping of phosphene locations from visual prostheses is vital to encode spatial information. This process may involve the subject pointing to evoked phosphene locations with their finger. Here, we demonstrate phosphene mapping for a retinal implant using eye movements and compare it with retinotopic electrode positions and previous results using conventional finger-based mapping.
View Article and Find Full Text PDFPurpose: To report the long-term observations of the electrode-tissue interface and perceptual stability in humans after chronic stimulation with a 44-channel suprachoroidal retinal implant.
Methods: Four subjects (S1-4) with end-stage retinitis pigmentosa received the implant unilaterally (NCT03406416). Electrode impedances, electrode-retina distance (measured using optical coherence tomography imaging), and perceptual thresholds were monitored up to 181 weeks after implantation as the subjects used the prosthesis in the laboratory and in daily life.
Objective: Long-term electroencephalogram (EEG) recordings can aid diagnosis and management of various neurological conditions such as epilepsy. In this study we characterize the safety and stability of a clinical grade ring electrode arrays by analyzing EEG recordings, fluoroscopy, and computed tomography (CT) imaging with long-term implantation and histopathological tissue response.
Approach: Seven animals were chronically implanted with EEG recording array consisting of four electrode contacts.