Table 1.

Summary of enzymatic substances used in vitreoretinal procedures13

Enzymes	Characteristics	Action point	Assumed safe dose	Indications
Plasmin	Non-specific protease	– Lamin	0.4 IU	– PVD induction
		– Fibronectin		– Macular hole
				– Diabetic macular edema
Hyaluronidase	Specific enzyme	– Hyaluronate	10, 20 IU	– Synchysis with partial PVD
				– Non-absorbable hemorrhages to the vitreous
Dispase	Non-specific protease	– Collagen type IV	0.1–5 U	– PVD induction
		– Fibronectin		– Macular pucker
				– PVR
Chondroitinase	Specific enzyme	– Chondroitin sulfate	20–10,000 U	– PVD induction
				– Epiretinal membranes
				– Macular hole
Collagenase	Specific enzyme	– Collagen	12–24 U	– Easier removal of proliferative fibrous membranes
Urokinase	Specific enzyme	– Plasminogen	1,000 IU	– PVD induction
TPA	Specific enzyme	– Peptide bond	25–50 mg/mL	– Eases PVD
		– Arginine 560-valine 561 of plasminogen		– Intravitreal hemorrhage
				– Subretinal hemorrhage
				– CRVO (central retinal vein occlusion)

Abbreviations: PVD, posterior vitreous detachment; PVR, posterior vitreoretinal proliferations; TPA, tissue plasminogen activator.