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Xin et al.'s case report demonstrated the use of a novel swept-source optical coherence tomography (OCT) probe to visualize collector channel entrances ex vivo. Their side-viewing OCT probe (outer diameter, 0.15 mm) was contained within a biocompatible fluorinated ethylene-propylene tube (outer diameter, 0.25 mm). When inserted into the Schlemm's canal of a human cadaver eye, the probe provided a cross-sectional OCT image of collector channel entrances. When placed next to the trabecular meshwork in the anterior chamber, the OCT probe visualized both Schlemm's canal and collector channel entrances.
In newer glaucoma surgeries targeting the iridocorneal angle and Schlemm's canal, real-time intraoperative evaluation of the Schlemm's canal and collector channels using this OCT probe may be helpful in selecting the target area to improve surgical outcomes. Visualization of Schlemm's canal and collector channel en-trances from the anterior chamber may be most useful clinically, as it makes the OCT probe much easier to use and decreases surgical time substantially compared to inserting the probe into Schlemm's canal. Additionally, as the authors mentioned, this OCT probe can potentially be used to evaluate in vivo dynamic structural changes in the Schlemm's canal and collector channels in response to intraocular pressure changes.
The outer diameter (0.25 mm) of this novel OCT probe is the same as that of a canaloplasty catheter (iTrack™, iScience Interven-tional, Menlo Park, CA). Therefore, the OCT probe can potentially achieve a similar effect as canaloplasty when inserted into the Schlemm's canal for visualization of the conventional aqueous outflow pathway. However, if it is inserted into Schlemm's canal, it will likely alter the anatomy of surrounding microstructures including collector channels and their en-trances.
Since this is a prototype device, better resolution and clearer visualization with increased signal-to-noise ratio are needed for future clinical application of this technology. The authors are also encouraged to provide more in vivo quantitative data regarding human aqueous outflow pathway in dynamic settings in the future.