• Clostridiopeptidase A digested pre-retinal cicatricial tissue without causing morphological alteration of normal retina during a 30-minute incubation in the rabbit. Light and transmission electron microscopy were used to determine effects on the inner limiting membrane and retinal ganglion and Müller's cells and to evaluate enzyme digestion of pre-retinal scarring. Removal of the injected collagenase by vitrectomy resulted in normal electroretinograms and retinal morphology 48 hours postoperatively. If the enzyme was left in the eye for 24 hours, lens opacities, partial erosion of the inner limiting membrane, and extensive hemorrhage resulted. The specificity of action of the collagenase is due to the high degree of purity of the enzyme used and a substantial biochemical difference between scar collagen and basement membrane collagen. The injection of purified collagenase capable of digesting vitreal scar tissue while leaving the retina undamaged could represent a new approach to vitrectomy, specifically to facilitate certain cases of membranectomy.
Moorhead LC, Redburn DA, Kirkpatrick DS, Kretzer F. Bacterial CollagenaseProposed Adjunct to Vitrectomy With Membranectomy. Arch Ophthalmol. 1980;98(10):1829-1839. doi:10.1001/archopht.1980.01020040681018