Treatment for central retinal vein occlusion (CRVO) remains disappointing despite recently proposed intraocular surgical techniques.^1,2 We previously introduced the use of intravitreal tissue plasminogen activator (TPA) for acute central retinal vein occlusion in 1999.³ Numerous investigators have confirmed its safety and suggested that it may have a beneficial role in the treatment of acute central retinal vein occlusion.^4–7 Although some studies in rabbits suggest the rabbit retina is not permeable to TPA, investigators found the porcine retina was, in fact, permeable to TPA.^8,9 Our clinical experience with intravitreal TPA in humans with CRVO and large submacular haemorrhages strongly suggests that intravitreal TPA does cross the …