97th DOG Annual Meeting 1999
P593
THE RETINA IMPLANT-PROJECT (EPI-RET):
QUANTITATIVE ANALYSIS OF BIOMECHANICAL FEATURES OF DIVERSE METHODS FOR INTRAOCULAR FIXATION OF IMPLANTS
S. Taneri, F. P. Bollmann, C. E. Uhlig, S. Kupich, H. Gerding
Background: Stable epiretinal fixation of intraocular structures causing as little tissue damage as possible is a challenging task within the Retina Implant-Project. This in vitro study examines the biomechanical features of several mechanical methods at nearly static conditions for the fixating of such intraocular implants in a quantitative way.
Material and methods: A special experimental layout has been constructed for precisely and continuously measuring force and resulting displacement (resolution: <100 µm) simultaneously obtaining a force-translation-diagram. The apparatus consists of 4 force transducers (range: <0.1N, <1N, <2.5N, <10N; resolution: 0.01% of full scale force) and a frictionless (<0.01N) displacement sensor based on the Hall effect connected via an analog amplifier and an A/D conversion card to an IBM pentium PC clone running DasyLab 3.0 (Ms-Windows 95) for data acquisition. A micromanipulator was used for pushing/pulling different conventional retinal tacks as well as our own tacks with elastic properties into/out of sclera of various species (rabbit, macaque, porcine and human). Points of entrance were examined using light or scanning electron microscopy.
Results and Conclusion: While conventional retinal tacks have a varying resistance to being pulled out, our novel hybrid-tacks (metal and plastic material) pierce sclera at significantly smaller force causing less tissue damage as seen in microscopy. Their explantation does not lead to tearing of the surrounding tissue thus making implantation reversible.
Sponsored by BMBF(KZ: 01IN501) within the EPI-RET-consortium
Dept. of Ophthalmology, Univ. of Münster, Domagkstr. 15, 48129 Münster, Germany
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