A Fluorescem Angiographic Study of Patients with Pars Planitis and Peripheral Exudation (snowbanking) before and after Cryopexy

Abstract

Transconjunctival cryopexy of the vitreous base is clinically effective in patients with steroid nonresponsive pars planitis who have peripheral neovascularization. Cryoablation of the region previously has been thought to eliminate the areas of permeable neovascular tissue, thus removing the focus of exudation. The authors report the first study of patients with refractory pars planitis in which fluorescein angiography of the inferior pars plana snowbanks was performed both before and after cryopexy of the vitreous base. Twelve consecutive phakic eyes with pars planitis and prominent peripheral snowbanks had fluorescein angiograms of the pars plana. Clinical involvement was graded on the basis of visual acuity, levels of vitreous inflammation and cystoid macular edema, and on the extent of peripheral snowbanking. Transconjunctival cryopexy of the vitreous base was performed. Fluorescein angiography of the pars plana snowbanks was repeated 2 months after the procedure, and clinical involvement again was graded. Early hyperfluorescence with late leakage was present in all eyes and was limited to the area of the pars plana snowbanks. After cryopexy of the vitreous base, all eyes demonstrated hypofluorescence and diminution of late-phase dye leakage in the treated areas. Eighty-three percent of all eyes demonstrated clinical improvement, consistent with previously reported studies. Cryopexy of the vitreous base decreases peripheral exudation in patients with refractory pars planitis and snowbanking. This suggests that elimination of peripheral neovascular tissue may be directly related to clinical improvement in these patients.