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Henri Lorach, Jenny Wang, Dae Yeong Lee, Roopa Dalal, Philip Huie, Daniel V Palanker; Retinal safety of near infrared radiation in photovoltaic restoration of sight. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3726. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Photovoltaic restoration of sight requires intense near infrared (NIR) light to effectively stimulate retinal neurons. We assess the retinal safety of such irradiation in the rabbit eye with and without the presence of a retinal implant.
Retinal damage threshold was determined in pigmented rabbits exposed to 880nm laser radiation. A computational model of the rabbit eye was used to assess the temperature increase with and without the subretinal silicon implant. The model was validated by comparison of the computed temperature with (a) previously published experimental data in pigmented rabbits and (b) with the damage thresholds in intact and in implanted rabbits.
In pigmented rabbits, the 50% probability (ED50) of retinal damage during 100s long exposures with 1.2mm diameter beam occurred at 175mW. According to computational model of the rabbit eye, it corresponded to the temperature rise of 12.5°C, matching the published data. In presence of an implant, the same temperature rise was expected at 78mW of power. In implanted animals, no visible damage was observed up to 60mW, and ED50 corresponded to 71mW. In the normal use conditions of the photovoltaic subretinal prosthesis (5mW/mm2, 5ms, 40Hz), the retinal temperature rise is not expected to exceed 0.43°C.
The NIR light intensity required for activation of the photovoltaic retinal prosthesis is well within the safety limits for chronic use (< 1°C).
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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