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J. Chen, L. Snebold, M. Kenney, J. Brookman, J.F. Rizzo, III, Boston Retinal Implant; A Modified Method for Ab Externo, Sub–Retinal Prosthetic Implantation . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3190.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a more well–controlled method to implant a relatively large electrode array into the sub–retinal space.
Fourteen eyes of Yucatan miniature pigs were studied under inhalation anesthesia. To control excessive bleeding, "controlled" hypotension (30 – 45mmHg) was maintained by IV nitroprusside. A partial thickness scleral flap (up to 8 x 6 mm) was dissected 5 mm posterior to the limbus super–temporally. To lower intra–ocular pressure, significant vitrectomy was performed in all eyes, and anterior chamber paracentesis was performed in two eyes. Then, scleral fibers were shaved away to expose the choroid; a choroidectomy was made by tenting the choroid with a forceps and removing the tissue with a scissors. In 4 eyes, Healon was injected through a choroidotomy into the sub–retinal space to separate the choroid and retina. An inactive, gold–wired polyimide strip was placed onto the retina and the scleral flap was sutured.
In 4 eyes, the surgery failed because of a significant choroidal hemorrhage and retinal tear. In 7 eyes, a large area of retina (> 6 x 3 mm) was exposed and an array was successfully implanted in 5 of these eyes (In the other 2 eyes, an area of retina was exposed but the eye collapsed thereafter because of marked ocular hypotonia). In 3 eyes, the area of exposed retina was not large enough for the 1.5 mm wide electrode array.
More work is needed to develop this technique, but this procedure is a viable alternative method for prosthetic implantation because this procedure is more controlled (i.e. the retina and array can be easily visualized at the same time) and less invasive (i.e. it does not require making a retinotomy and creating a retinal bleb) than our current method.
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