Collagen gels: design for a vitreous replace- ment.

Clear, stable gels have been prepared from purified tropocollagen from calf skin; the collagen was solubilized with a proteolytic enzyme (Proctase) and stabilized by ultraviolet irradiation under nitrogen. These gels are clear, possess altered immunologic reactivity, and have properties of an ideal vitreous replacement. Implantations in rabbit and monkey eyes appear to be well tolerated, remain clear, and gradually disappear in about 2 months.