Abstract
Purpose: :
To examine the intensity and biocompatibility of Teflon-coated platinum iridium wires that can be used in several visual prosthesis systems that we have developed.
Methods: :
Scanning electron microscopy was used to examine the surface of the wires where they were grasped with a vitreoretinal forceps and the damage was graded on a scale of 0 to 3. Three types of wires were used for this study. Platinum iridium wires with diameters of 50 µm were coated with Teflon (total diameters, 68 and 100 µm), or with Parylene (total diameter, 70 µm). Electroretinography (ERG) was performed and the implicit times and amplitudes of a-and b-waves were compared at baseline and 1 week after the insertion of a total of 20 mm of 68-µm Teflon wires into rabbit eyes (n=4) to study the biocompatibility.
Results: :
In no cases was the full thickness of the coating of any wires damaged. The mean damage grades for the 68- and 100-µm Teflon wires or the 70-µm Parylene wire were 1.67, 1.0, and 0, respectively. The damage grade for the Teflon wires was significantly (p<0.01) higher than for the Parylene wire. There were no statistical differences in any ERG component between baseline and 1 week after the wires were implanted.
Conclusions: :
The Teflon-coated wires were damaged more than the Parylene-coated wire, suggesting that they should be handled with caution. Teflon-coated platinum iridium may be highly biocompatible in the eyes.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques