The subject of our investigations is the question: is there an increased risk of infection with eyes operated on keratoprostheses made with hydrophilic soft plastic material (HEMA)? Our first step was an analysis of the normal conjunctival spectrum of microorganism of our rabbits, operated and nonoperated. Then we made exploratory punctures of the anterior chamber of 7 eyes submitted to implantations of HEMA keratoprostheses. During a period of 10 days this puncture exudate was incubated in a culture medium. In 6 out of 7 cases, even after 10 days of incubation, no microorganisms were found. In one case after 72 hours of incubation, a poor growth of a staphylococcus was observed. It can be assumed that in this case the microorganism entered the anterior chamber during the puncture procedure. The results of these investigations confirm the calculation that the "pores" of hydrophilic plastic material are too small for penetration of microorganism.