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Abstract #15361 Published in IGR 1-3
Localised retinal nerve fibre layer defects in chronic experimental high pressure glaucoma in rhesus monkeys
Jonas JB; Hayreh SSBritish Journal of Ophthalmology 1999; 83: 1291-1295
AIM: To evaluate prospectively in an experimental model of chronic high pressure glaucoma whether the concept of a mainly diffuse pattern of optic nerve damage holds true for high pressure glaucoma. METHODS: The study comprised nine eyes of nine rhesus monkeys (Macaca mulatta) with a mean age of 17.7 (SD 3.1) years (range, 13-23 years). Experimental glaucoma was produced by multiple applications of argon laser to the trabecular meshwork. Applanation tonometry was regularly performed and fundus photographs, which were taken serially, were used for retinal nerve fiber layer (RNFL) assessment and morphometric optic disc analysis. Six monkeys, in which arterial hypertension and atherosclerosis had additionally been induced several years before elevation of intraocular pressure, did not show any sign of diffuse loss or localized defects of the RNFL before initiation of glaucoma. RESULTS: Compared with the same eyes at baseline, localized RNFL defects had developed in eight (89%) eyes. It included all three eyes (100%) of the monkeys without arterial hypertension/arteriosclerosis, and five of the six monkeys (83%) with arterial hypertension/arteriosclerosis. Four eyes had multiple localized RNFL defects. In all eyes, diffuse RNFL loss was additionally present. CONCLUSIONS: Besides diffuse loss of RNFL, localized RNFL defects were present in almost all eyes of monkeys with chronic experimental high pressure glaucoma. Challenging the concept that a mostly diffuse type of optic neuropathy occurs in high pressure glaucoma, the results suggest that, in high pressure glaucoma, at least a mixture of localized and diffuse pattern of optic nerve damage prevails.
Dr. J.B. Jonas, University Eye Hospital, Schwabachanlage 6, 91054 Erlangen; Germany
Classification:
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
5 Experimental glaucoma; animal models
