Transcellular Aqueous Humor Outflow: A Theoretical and Experimental Study
When the aqueous humor passed through the transcellular channels of the inner wall endothelium of Schlemm’s canal the flow was estimated to be very slow and viscous (Reynolds’ number about 10-3). It was found to be accurate to treat this extreme flow situation with conventional hydrodynamic formulae without specific corrections. Four different principal configurations of the transcellular channels were investigated. The theoretical calculations yielded results in good agreement with those obtained from the experimental model studies. Where deviations occurred they were probably explained by a radial flow component, which was not incorporated in the theoretical formulae applied. A spherical channel configuration was considered most similar to the in vivo situation and this yielded experimental resistance values half those of previously applied theoretical methods. Using previous morphological data the present results indicated that less than 5% of the total resistance to aqueous humor outflow was located in the inner wall endothelium in normal human eyes, and about 10% in cynomolgus monkey eyes at normal intraocular pressure.
KeywordsAqueous Humor Cone Angle Pore Radius Trabecular Meshwork Radial Flow
Unable to display preview. Download preview PDF.
- Eriksson, A.: Flow investigations at extremely low Reynolds’ number, applied to the eye. Report AE-975 (in Swedish), the Aeronautical Research Institute of Sweden, Bromma (1974)Google Scholar
- Svedbergh, B.: Aspects of the aqueous humor drainage. Functional ultrastructure of Schlemm’s canal, the trabecular meshwork and the corneal endothelium at different intraocular pressures. Acta Univ. Upsal. 256, 1–71 (1976a)Google Scholar
- Svedbergh, B.: Effects of intraocular pressure on the pores of the inner wall of Schlemm’s canal: a scanning electron microscopic study. In: The Structure of the Eye III (Yamada, E. & Mishima, S., ed.), pp. 127–135. Tokyo: Japanese Journal of Ophthalmology (1976b)Google Scholar