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T. Hamanaka, K. Kasahara, T. Takemura; Pathological Study of Primary Angle Closure Glaucoma Treated by Different Surgery. Invest. Ophthalmol. Vis. Sci. 2010;51(13):631.
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Iridotomy (LI) and lensectomy combined with intraocular lens implantation (LILI) are the basic treatment for primary angle closure glaucoma (PACG), however, the reasons for the persistence of high IOP after LI, and residual glaucoma after LILI have not yet been clarified. We have studied the histological changes of outflow routes using trabeculectomy (TLE) specimens in patients with PACG and tried to clarify these questions.
Materials and Methods: :
Each TLE specimen from 28 eyes of 24 patients was divided into three pieces and processed for light microscopy for immunohistochemical staining of CD 68 as a marker for macrophages, thrombomodulin and CD 34 as a marker for endothelium of the Schlemm canal (SC), D2-40 as a marker for trabecular cells (TC, accepted IOVS 2009) and for transmission electron microscopy.
The eyes were divided into three groups, group A: 8 eyes with combined surgery of TLE and LILI without previous surgery, group B: 14 eyes with combined surgery of TLE and LILI after failed iridotomy, group C: 6 eyes with TLE because IOP was not controlled after LILI. Loss of TC, degenerated TC, negative staining with D2-40 and fusion of the trabecular beams in the posterior parts of trabecular meshwork, and disappearance of the spaces of juxta-canalicular tissue (JCT) with infiltration of melanocytes and swelling of TC were common findings in all groups. Occlusion or narrowing of SC (less than 150µm) was observed in 4 eyes of group B (29%, three eyes with acute attack) and 3 eyes in group C (50%, no eyes had any acute attack). CD 68-positive cells were observed in three eyes with acute attack in group A (13%) and B (14%) and three eyes without acute attack in group C (67%).
Occlusion of SC may be caused by underperfusion of aqueous outflow in JCT. Occlusion of SC or macrophage infiltration, which may be caused by remnants of the lens cortex after LILI, may be the main reason for residual glaucoma. Persistence of trabecular-iris contact may cause the degeneration and disappearance of TC in the posterior part of trabecular meshwork resulting in the fusion of trabecular beams and also occlusion of SC.
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