Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep.

Severe visual impairment can result from retinal degenerative diseases such as retinitis pigmentosa, which lead to photoreceptor cell death. These pathologies result in extensive neural and glial remodelling, with survival of excitable retinal neurons that can be electrically stimulated to elicit visual percepts and restore a form of useful vision. The Phoenix99 Bionic Eye is a fully implantable visual prosthesis, designed to stimulate the retina from the suprachoroidal space. In the current study, nine passive devices were implanted in an ovine model from two days to three months. The impact of the intervention and implant stability were assessed using indirect ophthalmoscopy, infrared imaging, and optical coherence tomography to establish the safety profile of the surgery and the device. The biocompatibility of the device was evaluated using histopathological analysis of the tissue surrounding the electrode array, with a focus on the health of the retinal cells required to convey signals to the brain. Appropriate stability of the electrode array was demonstrated, and histological analysis shows that the fibrotic and inflammatory response to the array was mild. Promising evidence of the safety and potential of the Phoenix99 Bionic Eye to restore a sense of vision to the severely visually impaired was obtained.

Safety and biocompatibility of a bionic eye: Imaging, intraocular pressure, and histology data.

The data presented here are related and supplementary data to the research article "Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep" [1]. In Eggenberger et al., nine sheep of the Suffolk (N=2) and Dorper (N=7) breeds were implanted in the left eye with an electrically inactive, suprachoroidal retinal stimulator (Bionic Eye) for durations of up to 100 days. The surgical safety, implant stability and device biocompatibility were assessed. Intraocular pressure measurements, indirect and infrared ophthalmoscopy and optical coherence tomography were performed at fixed time points to evaluate the clinical effects of the surgery and device implantation. Post-mortem eye tissue collection and histology was performed to measure the effects of the intervention at the cellular level. The data, including a comprehensive collection of fundus, infrared, optical coherence tomography and histology images can be used as a reference for comparison with other research, for example, active retinal stimulators. Furthermore, these data can be used to evaluate the suitability of the sheep model, in particular Dorper sheep, for future research.

Overnight orthokeratology lens wear can inhibit the central stromal edema response.

PURPOSE: To investigate the overnight corneal edema response during overnight orthokeratology (OK). METHODS: Eighteen young adult myopic subjects wore reverse-geometry lenses in Boston XO material (nominal Dk/t 46 x 10(-9) cm.mL O2/s.mL.mmHg) on an overnight wearing schedule for 1 month. Another 10 subjects wore conventional rigid gas-permeable (GP) lenses of similar Dk/t in one eye only, on an identical schedule. Corneal stromal thicknesses in the center, midperiphery, and periphery were measured by optical pachometry in the morning after lens removal, after 1, 4, 10, and 30 nights of wear. Changes from baseline for OK, GP and no-lens eyes were compared by repeated-measures ANOVA and protected post hoc t-tests. RESULTS: The central stroma swelled significantly less in OK than in GP eyes (P < 0.001, ANOVA), and less than with no lens wear (P < 0.001, ANOVA) throughout the study. Overnight edema levels consistent with Dk/t were found on day 1 in the midperiphery (3.5 mm from apex) and periphery (5.0 mm) with both OK and GP lenses. The overnight edema response decreased significantly through the study with both lens types. Recovery to baseline stromal thickness during the day was demonstrated for GP eyes and for OK eyes in the central and peripheral cornea. CONCLUSIONS: Overnight wear of reverse-geometry OK lenses inhibited the central stromal edema response. Overnight edema levels consistent with Dk/t were found in the corneal midperiphery and periphery. Adaptation of the edema response occurred with continuing overnight lens wear. The results suggest that central pressure exerted by the flat-fitting base curve of the OK lens acts locally as a "clamp" to inhibit overnight central corneal swelling.