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N Alteheld, MA Vobig, G Marzella, H Berk, R Shojaei, U Heimann, S Held, P Walter, KU Bartz-Schmidt; The Intraocular Vision Aid (IoVA) . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4170.
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Purpose: Intraocular miniaturized image transmission systems are developed to restore vision in patients with irreversible destruction of the anterior ocular segment (i.e. chemical burns, explosion trauma, trachoma) and high risk for corneal transplantation, provided that the posterior ocular segment is intact. The complete system consists of a CMOS-camera, a transmitter - both integrated into a spectacle frame - and an intraocular display in conjunction with a miniaturized compound optical system. The transmission of images and energy to the intraocular display is wireless. Biocomaptibilty testing included toxicity tests of the implanted materials and an evaluation of the effects of light and temperature on retinal function. An in-vivo study was conducted using pigmented rabbits. Methods: Material toxicity: After lensectomy "dummies" with silicone encapsulation were implanted into the capsular bag (n=4). Six months follow-up comprised clinical examinations and recording of the electroretinogram (ERG) and visually evoked potentials (VEP). Temperature effects: Lensectomy was performed (n=6). A resistor integrated into an intraocular lens was implanted. A temperature sensor was inserted into the vitreous cavity to record preretinal temperature. ERG and VEP elicited by bright flash stimulation were recorded continously during alteration of preretinal temperature for 3 hours. Light effects: Rabbits were exposed to LED light (external source / intraocular LED) for 24 hours. ERG and VEP were recorded continuously. A histological examination was performed in all animals after the experiment. Results: All implanted materials were well tolerated during 6 months follow up. No significant functional or histological alterations were found. Tolerable energy doses could be defined for electrically active intraocular implants. Conclusion: Biocompatibility tests give encouraging results concerning the feasibility of intraocular miniaturized image transmission systems.
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