EARLY CONJUNCTIVAL CHANGES FOLLOWING TREATMENT WITH METIPRANOLOL AND PRESERVATIVES ARE NOT REVERSIBLE WITH DEXAMETHASONE

Background: Topical medication for the treatment of glaucoma alters th e cellular and extracellular composition of the superficial and deep c onjunctival layers. We sought to determine whether, after short-term u se of metipranolol with preservatives, subsequent application of stero ids or metipranolol without preservatives affects these conjunctival c hanges. Methods: Rabbits received topical metipranolol over a period o f 6 months. For the following 2 months, one group received metipranolo l without preservatives, and another group steroids. For controls, ani mals were treated with preservatives only or metipranolol with preserv atives forb months. Superior bulbar conjunctiva was examined by light microscopy, immunohistochemistry, and transmission electron microscopy . Results: On light microscopic and immunohistochemical examination of conjunctival specimens from all groups, there was an increase of sube pithelial collagen deposition in all treated groups. Treatment with st eroids or preservative-free metipranolol did not alter the initial eff ects, By electron microscopy, additional extracellular matrix changes were seen as well as degenerative changes of tissue fibroblasts. a Con clusion: The animal model used was able reliably to produce conjunctiv al changes following antiglaucomatous therapy. The changes seen were e arly changes, because there was no increase of inflammatory cells. Ste roids did not significantly affect the changes. The beneficial effect of steroids used prior to glaucoma surgery remains controversial.