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Abstract #6619 Published in IGR 4-1
Outflow facilities through Descemet's membrane in rabbits
Spiegel D; Schefthaler M; Kobuch KGraefe's Archive for Clinical and Experimental Ophthalmology 2002; 240: 111-113
BACKGROUND: The outflow pathway in viscocanalostomy, a new procedure in glaucoma surgery, is unclear; however, outflow through Descemet's membrane has been postulated. This study evaluates outflow rates through Descemet's membrane at different intraocular pressure (IOP) levels in rabbits. METHODS: Fifty-one Descemet's membranes without endothelium from enucleated rabbit eyes were installed in a double-ring system, the Minuth sheet. Difference IOP levels (20, 25, 30, 40, 50 mmHg) were applied to one side of the system. The system was filled with balanced salt solution. The total amount of fluid percolating through Descemet's membrane was measured after 12 hours. Based on this, flow rates were calculated. The area of Descemet's membrane was 6.9 mm2. RESULTS: At a pressure of 20 mmHg, the flow rate was less than 0.003 μl/min. At pressures above 30 mmHg, flow rates ranged from 0.04-0.15 μl/min, with a mean of 0.09 μl/min. To achieve pressure control at high pressures, an area of at least 150 mm2 of Descemet's membrane would be needed. CONCLUSIONS: Descemet's membrane provides good outflow resistance in rabbit eyes. Based on these results, for pressure control by outflow through Descemet's membrane only, at least the whole cornea area would be needed. If the same is true of humans, additional outflow sources would be necessary in cases of viscocanalostomy.
Dr. D. Spiegel, Department of Ophthalmology, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany. Spiegel@eye-regensburg.de
Classification:
2.5 Meshwork (Part of: 2 Anatomical structures in glaucoma)
5 Experimental glaucoma; animal models
12.8.3 Non-perforating (Part of: 12 Surgical treatment > 12.8 Filtering surgery)