SUNDAY 10TH SEPTEMBER
The morphology of uveoscleral outflow pathway
PURPOSE: To specify the anterior chamber source of uveoscleral outflow. SETTING: Regional T.I. Eroshevsky Ophthalmic Hospital, State Medical University, Samara, Russian Federation. METHODS: We performed perfusion of human cadaver eyes with India ink suspension through clear corneal tunnel. Lamellar scleral dissection revealed the ciliary muscle surface. We observed the character and volume of suprachoroidal fluid in different pressure conditions. After formaldehyde fixation we performed further dissection of trabecular meshwork and ciliary muscle with subsequent preparation of flat specimens of different layers of trabecular meshwork as well as histological sections for light microscopy. RESULTS: Unexpectedly voluminous flow of India inc-stained fluid was observed after the ciliary muscle exposure. Histological research revealed numerous ink particles in the trabecular meshwork and between the ciliary muscle bundles. No inc particles were found in the iris root. Human trabecular meshwork was found consisting of 6 definite layers instead of 4 generally considered. These layers differ from each other both in structure and connections. Most of the trabeculae appears to continue directly into the ciliary muscle bundles, and therefore, should be considered as the uveal ones. CONCLUSION: Aqueous drainage from anterior chamber appears to be entirely trabecular with two components: trans-trabecular (usually considered as trabecular outflow) and para-trabecular (uveoscleral). Sufficient pathway for uveoscleral outflow may be represented by inter-trabecular slits continued directly into the spaces between the ciliary muscle bundles.
A. Zolotaryov, E. Karlova, G. Nikolayeva, RUSSIA