JMIR Publications

ABSTRACT

Background:

Retinitis pigmentosa (RP) is an incurable, degenerative retinal condition causing progressive sight loss, impacting significantly on patients’ quality of life. The Argus® II Retinal Prosthesis is a surgically implanted medical device which delivers electrical stimulation to the retina. It is intended to produce a form of artificial vision to blind people with severe to profound RP by stimulating remaining viable retinal cells to induce visual perception. This study has been initiated by NHS England’s Commissioning through Evaluation programme and funded through the UK’s National Institute of Health Research

Objective:

To assess the impact of the Argus II device on patient’s daily activities and quality of life.

Methods:

This protocol is a prospective, single arm, open-label, mixed methods study on 10 consecutive participants receiving the Argus II device. Patient representatives have played an integral role in the design of the study. Eligibility criteria include ultra-low vision in both eyes as a result of end-stage RP and a willingness and capacity to complete the post-implantation rehabilitation programme. Participants will be interviewed by independent researchers at baseline and 12 months later using a semi-structured, in-depth approach, alongside validated questionnaires (Impact of Vision Impairment Very Low Vision, EQ-5D-5L and EQ-VAS, and Hospital Anxiety and Depression Scale) and a bespoke device-related questionnaire which includes questions about users’ experiences with the procedure, the device, and rehabilitation. The impact of the device on patients’ functional vision and activities of daily living will be assessed by vision rehabilitation specialists using a set of tests measured on an ordinal scale (e.g. ability to locate objects and avoid obstacles). Clinical outcomes include full-field stimulus light threshold, square localization, direction of motion, grating visual acuity, Landolt-C, procedural success and adverse events. Qualitative and quantitative outcomes will be linked on a single database to enable individual participant measures to be considered in toto, comparing baseline to final review.

Results:

Ethics approval has been obtained and funding has been awarded. The manufacturer recently withdrew the Argus II device from sale in the UK, therefore the study is not going ahead at this time.

Conclusions:

The mixed method approach provides a rich and in-depth assessment of the impact of the device on participants’ quality of life. Despite the work not going ahead, publication of this publicly-funded protocol is important for researchers planning similar work.