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. Author manuscript; available in PMC: 2021 Jul 21.
Published in final edited form as: Prog Retin Eye Res. 2020 Nov 17;83:100917. doi: 10.1016/j.preteyeres.2020.100917

Fig. 11. Conduits cross Schlemm’s canal to hinged collector channel flaps.

Fig. 11.

(A) Scanning electron microscopy image after Schlemm’s canal (SC) dilation with viscoelastic and fixation. The inner wall of SC rests against several layers of adjacent collapsed trabecular meshwork (TM) lamellae. Nuclear bulges of endothelial cells are visible along the SC inner wall. A Schlemm’s canal inlet valve arises from SC inner wall endothelium and crosses SC to the external wall. The lumen of the inlet valve is continuous with the juxtacanalicular space of the TM. The SC inlet valve lumen thus provides a conduit for aqueous passage from the juxtacanalicular space to SC. (B) Anterior segment of the eye perfused with 500 nm green fluorescent microspheres followed by Schlemm’s canal dilation with viscoelastic. Confocal microscopy labeling is with DAPI (blue) for nuclei and CD31 (red) for vascular endothelium. The CD31 label identifies continuity of SC inner wall and SC inlet valve endothelial surfaces. Microspheres fill the intertrabecular spaces. A Schlemm’s canal inlet valve labeled with CD31 originates from SC inner wall endothelium and crosses SC to a collector channel entrance (CCE). Microspheres fill the SC inlet valve lumen from its origin at SC inner wall to its attachment at a CCE at SC external wall. Passage of microspheres provides evidence that the SC inlet valves can function as a conduit for aqueous. (C) Confocal microscopy - native fluorescence, SC viscoelastic dilation. An SC inlet valve initially forms a funnel (FNL) arising from the TM, develops a cylindrical conduit area, then attaches to the tip of a hinged collagen flap (HCF) at SC external wall. A Schlemm’ canal inlet valve has a direct opening to SC (OTC). The OTC is adjacent to a CCE at the entrance to a circumferential deep scleral plexus (CDSP). Tissue source: Primates, Macaca nemestrina. From Johnstone Glaucoma Lab, University of Washington.