Abstract
Abstract: :
Purpose:To compare the characteristics of pores in the inner wall of Schlemm's canal in glaucomatous and normal eyes, accounting for the effects of fixation conditions. Methods:Outflow facility was measured in enucleated glaucomatous human eyes. Eyes were fixed under constant flow conditions, microdissected to expose the inner wall of Schlemm's canal, and prepared for scanning electron microscopy (SEM). The density and diameter of the two subpopulations of pores, intracellular and intercellular (or "border") pores in the inner wall were measured. Data were compared to previous studies on normal eyes and also in glaucomatous eyes where fixation conditions were not as well controlled. Results:Glaucomatous eyes had less than one fifth the number of pores that normal eyes do, after accounting for the influence of volume of fixative perfused through the eyes. The density of intracellular pores and the diameter of these pores correlated with the density and diameter of the border pores, respectively. Conclusion:The density of both border pores and intracellular pores are increased by fixation in a similar fashion. Both classes of pores are reduced in POAG. If pores are physiological structures, the elevated IOP characteristic of POAG may be quantitatively explained by a decreased porosity of the inner wall endothelium.
Keywords: 503 outflow: trabecular meshwork • 472 microscopy: electron microscopy