[Biocompatibility of polyvinylalcohol gel as a vitreous substitute]

Polyvinylacohol (PVA) gel cross linked by gamma irradiation was assessed as a possible vitreous substitute. In our previous, reports, elevation of intraocular pressure and inflammatory changes in the vitreous cavity after operation were observed in some of the experimental animals. Four types of PVA gel (sol) were produced by a newly refined method. We improved the gel systhesis process to remove the monomer and contamination. Colored rabbits were used for this experiment. Vitreous replacement was performed after vitrectomy. This was followed clinically by ophthalmoscopy, tonometry, fundus photography, electroretinogram, chemotaxis, and laser-flare-cell-metering. Histopathological examination by light microscopy was performed after 3 months. PVA gel has good biocompatibility in the vitreous cavity, and gel with a network similar to that of the vitreous body showed the best biocompatibility. Although it is necessary to investigate the biocompatibility over the long term and to evaluate the tamponade effect, PVA gel will be a bood candidate for a vitreous substitute.