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arXiv · 1710.10508

High-Resolution, Three-Dimensional Reconstruction of the Outflow Tract Demonstrates Segmental Differences in Cleared Eyes

Susannah Waxman·Ralitsa T. Loewen·Yalong Dang·Simon C. Watkins·Alan M. Watson·Nils A. Loewen
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Abstract

Purpose: The rate of conventional aqueous humor outflow is the highest nasally. We hypothesized that this is reflected in regionally different outflow structures and analyzed the entire limbus by high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM). Methods: We perfused pig eyes by anterior chamber cannulation with eight lectin-fluorophore conjugates, followed by optical clearance with benzyl alcohol benzyl benzoate (BABB). RSCM and an advanced analysis software (Imaris) were used to reconstruct a three-dimensional, whole-specimen rendering of the perilimbal outflow structures. We performed morphometric analyses of the outflow tract from the level of the trabecular meshwork (TM) to the scleral vascular plexus (SVP). Results: Except for pigmented structures, BABB cleared the entire eye. Rhodamine-conjugated Glycine max agglutinin (soybean, SBA) labeled the outflow tract evenly and retained fluorescence for months. RSCM produced terabyte-sized files allowing for in silico dissection of outflow tract vessel at a high resolution and in 3D. Networks of interconnected lumina were traced from the TM to downstream drainage structures. The collector channel (CC) volumes were ten times smaller than the receiving SVP vessels, the largest of which were in the inferior limbus. Proximal CC diameters were up to four times the size of distal diameters and more elliptical at their proximal ends. The largest CCs were found in the superonasal and inferonasal quadrants where the highest outflow occurs. Conclusions: RSCM of cleared eyes enabled high-resolution, volumetric analysis of the outflow tract. The proximal structures had greater diameters nasally while the SVP was larger in the inferior limbus.

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Susannah Waxman, Ralitsa T. Loewen, Yalong Dang, Simon C. Watkins, Alan M. Watson, Nils A. Loewen. 2017-10-28. High-Resolution, Three-Dimensional Reconstruction of the Outflow Tract Demonstrates Segmental Differences in Cleared Eyes. https://arxiv.org/abs/1710.10508

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