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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. 16. Synchronous lumen dimension changes of Schlemm’s canal and collector channels.

Fig. 16.

(A) Representative 3-D reconstruction of the entire length of a limbal Schlemm’s canal (SC) region obtained from stitching five tangential sections together. The image plane is perpendicular to the canal circumference. The SC inlet valves appear as structures spanning between the walls of SC (yellow arrows). Purple and green arrows show collector channel ostia (CCO). Blue arrows show entrances of circumferentially oriented deep scleral plexus. Asterisks mark septa that divide SC from the circumferentially oriented deep scleral plexus (CDSP) parallel to SC. The tilted section shows different levels in the height of SC, thus exhibiting differing relationships. (B) Representative two-dimensional (2-D) structural OCT and scanning electron microscopy (SEM) images from the limbal region of an eye. (a) OCT image with the cannula inside SC (arrow). (b) At a location, ~150 μm away from the cannula tip before infusion of perfusate to raise pressure. Arrows identify SC as a potential space with no lumen, (c) shows the maximally dilated appearance at the same location resulting from a bolus of aqueous. Images (d) and (e) are representative SEM images from the limbal region. The SEM and OCT images mirror each other in illustrating the structural features of the outflow system. Original SEM images: 337× magnification. The image in (d) shows a collector channel entrance or ostia (CCO). A septum present at the CCO is attached to the TM by a Schlemm’s canal inlet valve, which is labeled here as a cylindrical crossing structure (CAS). Image (e) is the adjacent section from the same segment showing the transition from the region of a CCO in (d) to the circumferentially oriented deep scleral plexus (CDSP). The CDSP is labeled as a collector channel in (d), (e), (f) because publication of these figures was before recognition of CDSP as unique entities. The image in (f) is a 2× enlargement of (c). CM, ciliary muscle. (C) Enlarged view of (f) in image (B) identifying the location of measurements in D. (D) Progressive increase in the height of SC, CC, and CAS with time during SC filling with a bolus of aqueous from a reservoir. SC (black curve), CC (red curve), Schlemm’s canal inlet valves (here labeled as CAS) (blue curve). Tissue source: Primates, Macaca nemestrina. From Hariri S, Pressure dependent TM motion with high-resolution OCT, J Biomed Opt 19,106013 1–10601311, 2014. Video - Linked TM and CC Motion 1-s2.0-S1350946220300896-mmc5.mp4.