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[Enzymatically induced posterior vitreous detachment in proliferative diabetic vitreoretinopathy]
Background:
Complete detachment of the posterior vitreous cortex is an important aim in the treatment of proliferative diabetic vitreoretinopathy (PDVR). Today a posterior vitreous detachment (PVD) can only be achieved during vitrectomy. A randomized pilot study was started to evaluate wether intravitreally injected TPA is sufficient to induce a PVD in diabetic eyes.
Patients And Methods:
Eight weeks prior to vitrectomy because of proliferative diabetic vitreoretinopathy (non-clearing haemorrhage, fibrovascular proliferations) 20 eyes which had an attached vitreous received a cryopexy of the peripheral retina. In 11 eyes that had been selected at random 10 micrograms of recombinant tissue plasminogen activator were injected midvitreally 24 hrs later. A newly formed PVD was assessed by means of biomicroscopy or ultrasound.
Results:
A newly formed partial (n = 3) or complete (n = 7) PVD was found in 10 of 11 TPA-treated eyes versus one partial detached vitreous in the control group. In 3 younger patients PVD developed exclusively after TPA-injection. We did not observe severe changes of the ERG, decrease of visual acuity, severe new vitreous haemorrhages or opacities of the lens. In 3 eyes (2 eyes of the control group) a circumscribed retinal detachment developed during the follow-up period.
Conclusions:
The described technique can be used in diabetics without severe side effects. It facilitates the removal of the vitreous cortex and may be a valuable adjunct to the surgical management of PDVR. Unlike other proteases TPA is available for clinical use through recombinant DNA technology which allows standardized enzymatic activities, steril and non-infectious conditions.