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Abstract #6550 Published in IGR 3-2
Glaucoma filtration surgery using amniotic membrane transplantation
Barton K; Budenz DL; Khaw PT; Tseng SCGInvestigative Ophthalmology and Visual Science 2001; 42: 1762-1768
PURPOSE: To investigate the potential use of amniotic membrane transplantation (AMT) in the construction of glaucoma filtering blebs. METHODS: Twenty-four albino rabbits underwent glaucoma filtration surgery in one eye. In alternate cases, the conjunctival flap was replaced with AMT. Postoperative examination data were grouped into three time points. Six animals with AMT and six filtration surgery-controls were euthanatized at each of two postoperative time points, and tissue was obtained for histological examination. Conjunctival biopsies were explanted for estimation of fibroblast outgrowth. RESULTS: Bleb formation was observed in all eyes, and amniotic membranes were epithelialized after 11.2 ± 2.48 (mean ± SD) days. Throughout the study, intraocular pressure (IOPs) were significantly lower in operated than in unoperated fellow eyes. Between postoperative days 11 and 16 (the middle time point), the percentage IOP reduction in AMT eyes was significantly greater than in filtration surgery controls (p = 0.014), although not at other time points. Filtration surgery survival was significantly longer in the AMT group (22.3 ± 3.8 days; mean ± SE) than in 'no AMT' controls (14.0 ± 1.6 days; p = 0.035). In tissue culture, significantly less fibroblast outgrowth occurred from AMT explants when compared with unoperated conjunctiva (p = 0.01) between postoperative days 3 and 9 (the early time point). AMTs were intact on histological examinations after 14 days, but were associated with considerable granulomatous inflammation. After 26 days, the ocular surfaces remained clinically intact, but lysis of AMT was noted histologically. CONCLUSIONS: AMT exhibits potential as an alternative tissue to conjunctiva in the construction of glaucoma filtration blebs. The healing response, as demonstrated by fibroblast outgrowth, is retarded when compared with conventional conjunctival closure. The improvement in bleb survival must be weighed against the potential for complications related to delayed healing. In rabbits, human amniotic membrane elicited a late xenograft reaction, leading to granulomatous inflammation and dissolution of the membrane.
Mr K. Barton, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK. keith1barton@cs.com
Classification:
12.8.5 Other (Part of: 12 Surgical treatment > 12.8 Filtering surgery)
