Abstract
Purpose: :
To investigate histopathologically whether irreversible change of the outflow routes occurs in primary angle closure glaucoma.
Methods: :
Twenty-two trabeculectomy specimens from 22 patients with primary open angle closure glaucoma were used in this study. Each specimen was dissected into three pieces and the center of dissected block was processed for immunohistochemical study of CD 68 to detecting macrophages or monocytes, and thrombomodulin to detect the Schlemm canal using light microscopy. The remaining two blocks from each specimen were processed for transmission electron microscopy.
Results: :
Five eyes which had suffered an acute attack and the remaining 17 eyes had chronic angle closure glaucoma without acute attack. Previous surgeries before trabeculectomy were iridotomy (16), phacoemulsification and intraocular lens implantation (4) and goniosynechiolysis (1). Trabeculectomy was performed in the area of the peripheral anterior synechia (PAS) or trabecular-iris contact in 19 eyes and in the open angle area in 3 eyes. Visual field defects ranged from stage 0 to 6 in the Aulhorn-Greve classification (A-G).Occlusion of the Schlemm canal was observed in four eyes with advanced visual field defects (one eye: stage 3, 3 eyes: stage 6). A large number of pigmented cells were observed in the trabecular meshwork not only in eyes in the advanced stage but also in the early stage of A-G. Juxta-canalicular connective tissue (JCT) became compact with swollen trabecular cells in ten eyes in which trabeculectomy was performed at the PAS or trabecular-iris contact. CD-positive cells were observed in eyes with an acute attack and previous cataract surgery.
Conclusions: :
Occlusion of the Schlemm canal may be an irreversible change to the outflow routes. Swelling of the trabecular cells in JCT may result from no aqueous flow and this change may be reversible if aqueous humor starts to flow again by releasing PAS or trabecular-iris contact. Long persistence of PAS or trabecular-iris contact may be a risk of occlusion of the Schlemm canal.
Keywords: pathology: human • trabecular meshwork