Abstract
PURPOSE. To validate the ability of visible-light optical coherence tomography (vis-OCT) in imaging the full Schlemm’s canal (SC) and its surrounding limbal vascular network in mice in vivo through a compound circumlimbal scan. METHODS. We developed an anterior segment vis-OCT system and a compound circumlimbal scanning method, which montages eight rotated raster scans. We calibrated the circumlimbal scan geometry using a three-dimensional printed phantom eyeball before imaging wild-type C57BL/6J mice. We measured SC size by segmenting SC cross sections from vis-OCT B-scan images and imaged the limbal microvascular network using vis-OCT angiography (vis-OCTA). To introduce changes in SC size, we used a manometer to adjust the intraocular pressure (IOP) to different levels. To create additional optical scattering contrast to enhance SC imaging, we surgically increased the episcleral venous pressure (EVP) and caused blood reflux into SC. RESULTS. Using the compound circumlimbal scan, our anterior segment vis-OCT noninvasively imaged the full SC and limbal microvascular network in mouse for the first time. We observed an average 123% increase in SC volume when we decreased the IOP by 10 mm Hg from the baseline IOP of 7 to 10 mm Hg and an average 72% decrease in SC volume when the IOP level was elevated by 10 mm Hg from the baseline IOP. We also observed location-dependent SC size responses to IOP changes. Blood reflux caused by increased EVP enabled vis-OCTA to directly visualize SC, which matched well with the segmented SC. CONCLUSIONS. Vis-OCT and vis-OCTA can accurately image the entire SC and limbal microvascular network in vivo using the compound circumlimbal scan. Vis-OCT is also able to quantitatively measure SC responses to changing IOP levels.
Original language | English (US) |
---|---|
Article number | 2761682 |
Journal | Investigative Ophthalmology and Visual Science |
Volume | 61 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2020 |
Funding
Supported in part by National Institutes of Health grants R01EY026078, DP3DK108248, R01EY029121, R01EY028304, R44EY026466, P30 EY016665, and T32EY25202; a Cornew Innovation Award from the Chemistry of Life Processes Institute at Northwestern University; the National Science Foundation Graduate Research Fellowship 1000260620 (LB); and RPB Stein Innovation Award, an award from RPB to the Department of Ophthalmology, University of Wisconsin-Madison (NS). The authors thank Pieter Norden and Benjamin Thomson for helpful discussions. Supported in part by National Institutes of Health grants R01EY026078, DP3DK108248, R01EY029121, R01EY028304, R44EY026466, P30 EY016665, and T32EY25202; a Cornew Innovation Award from the Chemistry of Life Processes Institute at Northwestern University; the National Science Foundation Graduate Research Fellowship 1000260620 (LB); and RPB Stein Innovation Award, an award from RPB to the Department of Ophthalmology, University of Wisconsin-Madison (NS).
Keywords
- Angiography
- Optical coherence tomography
- Schlemm’s canal
ASJC Scopus subject areas
- Ophthalmology
- Sensory Systems
- Cellular and Molecular Neuroscience