The incidence of recurrent
vitreous hemorrhage of proliferative
diabetic retinopathy following posterior
vitrectomy ranges from 29% to 75% in reported series. Fluid-gas exchange and vitreous cavity lavage are the popular methods of treating this kind of recurrent
hemorrhage. The fluid-gas exchange cannot offer clear vision immediately after the procedure. To improve the function of the classic vitreous cavity lavage, we designed a volume homeostatic fluid-fluid exchanger - Chen's I/A device.
Tissue plasminogen activator (t-PA) is a
protease that preferentially converts
fibrin-bound
plasminogen to the active
proteolytic enzyme,
plasmin. It has been clinically and experimentally proven effective in lysis of postvitrectomy
blood clot and
fibrin formation. When the
blood clot is formed in the vitreous cavity,
intravitreal injection of t-PA can convert
plasminogen to
plasmin and remove the clot. From July 1999 to January 2000, ten eyes of postvitrectomy diabetic
vitreous hemorrhage (PDVH) were collected. In each case, 4 days after
intravitreal injection (IVI) of t-PA (30 microg), vitreous cavity lavage was performed with Chen's I/A device. Of these cases, 8 eyes (80%) experienced an immediate clearing of the vitreous cavity. Early complications included anterior hyaloid fibrovascular proliferation (2 eyes) and postoperative intraocular pressure elevation (3 eyes). On the basis of the results of this study, our conclusion is that volume homeostatic vitreous cavity lavage, combined with
intravitreal injection of t-PA, is an excellent method for treatment of postvitrectomy diabetic
vitreous hemorrhage but, in cases of PDVH with iris rubeosis, the advantage of this procedure is uncertain.