Histologic Study after 5-Fluorouracil Injection into the Bleb in Ahmed Valve Implanted Rabbit Eyes

PURPOSE: To study the effect of the 5-fluorouracil (5-FU) injection into the bleb after the Ahmed glaucoma valve implant in rabbits. METHODS: Ahmed valve was implanted in normal 10 rabbits without previous ophthalmic history. In 4 of 10 rabbits, 5-FU (50 mg/ml, 0.1ml) was injected into filtering bleb in every two weeks for two times at postoperative 1 month and others were followed up as a control group. We obtained histological findings in 2 rabbis of control group at postoperative 1 month. In the control group and 5-FU injected 4 rabbit eyes, each 2 rabbit eyes were enucleated at postoperative 3 months and 6 months in both groups. The dissected bleb was examined through light microscopy with hematoxyline and eosin (H and E) stain and Masson-Trichrome (M-T) stain, and electron microscopy. RESULTS: The bleb was relatively avascular on gross and histological examination in the 5-FU injected group, and collagen fibers of the 5-FU injected group were less compact than that of the control group at postopeative 3 months. The number of inflammatory cells, fibroblasts and capillaris in outer layer was decreased in the 5-FU injected group. Under the electron microscopic examination, the density of collagen fibers was decreased and the space among them was widened. This change was more prominent in the 5-FU injected group. CONCLUSIONS: We found that the histological changes of blebs were made by the influx of aqueous humor through the Ahmed glaucoma valve and more stimulated by injection of 5-FU into the bleb after implantation of Ahmed glaucoma valve in a rabbit model.

Surgical results of Vitrectomy for Diabetic Macular Heterotopia

PURPOSE: This study aimed to investigate visual prognosis and postoperative complications of vitrectomies for macular heterotopia, and compare it with that of tractional macular detachment. METHODS: Medical records of 10 eyes which had undergone pars plana vitrectomy for diabetic macular heterotopia and 21 eyes which for diabetic tractional macular detachment in the 202 patients who had been diagnosed as proliferative diabetic retinopathy at Pusan Paik hospital from January, 1995 to december, 1998 were reviewed to study their clinical features, complications, visual outcome. RESULTS: Final postoperative improved visual acuity was documented in 70% of patients with macular heterotopia and 38% of patients with tractional macular detachment (P>0.05). Postoperative vitreous hemorrhage and cataract developed in 20% and 10% of patients with macular heterotopia and 19% and 10% of patients with tractinal macular detachment. Patients with macular heterotopia experienced retinal detachment and macular hole. Patients with tractional macular detachment experienced increased IOP, neovascular glaucoma and phthisis. CONCLUSIONS: Although we could not revealed statistical significance, the surgical results of vitrectomy for diabetic macular heterotopia was better than that of diabetic tractional macular detachment and in the view of vision and complications, diabetic macular heterotopia was more favorable.