GALNS and vitreous hemorrhage: Glycosidic enzymes (hyaluronidases and a chondroitinase) have previously been tested in animal models for pharmacological vitreolysis without reported adverse effects,37, 38, 39 and a highly purified ovine hyaluronidase, Vitrase (ISTA Pharmaceuticals, California, USA) has been used in a clinical trial aiming to aid the dispersion of vitreous hemorrhage.40