A clinicopathologic correlative study of noncontact transscleral Nd:YAG cyclophotocoagulation.

We studied the histopathologic changes of three eyes enucleated two weeks, eight weeks, and 17 months, respectively, after noncontact Nd:YAG cyclophotocoagulation. The histologic findings at two weeks were destruction of the nonpigmented and pigmented ciliary body epithelium, occlusion of the capillaries of the ciliary processes, and ciliary body stromal necrosis in the region of the processes. Hyperplasia of the pigmented and nonpigmented epithelium, fibrosis and near total atrophy of the ciliary processes, and partial atrophy of the ciliary muscles were present at eight weeks and 17 months. We concluded that application of treatment 1.0 to 1.5 mm posterior to the corneoscleral limbus selectively destroys the pars plicata, and that, histologically, the mechanism for reducing intraocular pressure appears to be destruction of ciliary processes with reduction of aqueous formation.