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Maria Kolic, Elizabeth Baglin, Samuel A Titchener, Carla J Abbott, Kiera A Young, Myra McGuinness, Rosie C.H Dawkins, Daniel Chiu, Jonathan Yeoh, Janine Walker, William G Kentler, Nick Barnes, Matthew A Petoe, Lauren N Ayton, Chi D Luu, Penelope J Allen; A 44 channel suprachoroidal retinal prosthesis: initial functional vision results.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4986. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
The 44 channel (44Ch) suprachoroidal retinal prosthesis is a second-generation bionic eye implant that follows on from a proof of concept study conducted between 2012 and 2014 (NCT01603576). The 44Ch implant is designed to provide artificial vision (phosphenes) to recipients with end stage retinitis pigmentosa (RP). We aimed to compare the performance of activities of daily living (ADL) and orientation and mobility (OM) tasks, pre-implant and post activation of the device.
The 44Ch supra choroidal retinal prosthesis was successfully implanted unilaterally in four participants with advanced RP, between February and August 2018. After a period of vision rehabilitation training, participants were assessed on three tasks; table-top search (TTS), doorway detection (DWD) and obstacle avoidance (OA). Assessment time points were; prior to implantation (baseline, BL) and post device activation, week 17 (W17) and week 20 (W20). The performance was compared between device on and off for each participant using Wilcoxon’s matched-pairs signed rank test, for DWD and OA and the McNemar’s exact test for TTS.
To date, ADL and O&M data were only available on the first 2 recipients (P1, male, 39 years and P2, female, 66 years). In TTS, P1 performed more accurately in reaching for the object with device on than device off at W17 (p=0.030) and W20 (p < 0.001) but P2 showed no difference in accuracy at any time points (p ≥ 0.225). In DWD, P1 navigated to and touched the door significantly more often with device on than device off (W17 p=0.016, W20, p=0.005) but P2 showed no difference in accuracy (W17 and W20, p=1.000) albeit correct head orientation toward the door was demonstrated. On OA, more seeded obstacles were detected with device on compared to off for P1 (W17 p=0.004, W20 p=0.007) and for P2 (W17 p=0.008, W20 p=0.005). The median number of collisions with seeded obstacles was less with device on compared to device off but only for P1 at W17 (p=0.019) but not at W20 (p=0.087) or P2 (W17 p=0.151, W20 p=0.347).
The initial data for the 44Ch suprachoroidal retinal prosthesis indicate the device has the capability to improve functional vision for people with profound vision loss from RP. Further training and familiarisation of visual input generated by the device could improve performance with the device.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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