Abstract
Purpose :
Increased resistance within the conventional outflow pathways (including the trabecular meshwork, Schlemm’s Canal (SC), and distal outflow pathways) is the leading and only modifiable risk factor for glaucoma. It is documented that flow within the conventional outflow pathway is segmental and that glaucoma surgery can improve circumferential flow. We developed a robotic visible-light optical coherence tomography (vis-OCT) for imaging the entire conventional outflow pathways and investigated its segmental anatomical differences.
Methods :
We developed a robotic anterior segment vis-OCT to image the conventional outflow pathways circumferentially (360 degrees) in mouse eyes at an angle perpendicular to the limbus. Furthermore, we developed protocols for automatic pupil and corneal alignment before and during acquisition. We reconstructed the anatomy of the entire outflow pathways and limbal vasculature in five wild-type C57BL/6J mice. We measured segmental patterns in SC volume, SC dimensions, collector channel density, and vascular density. Following baseline anatomical measurements, we applied topical 1% pilocarpine and observed segmental alterations in changes in SC morphology.
Results :
We observed segmental differences in SC morphology and volume unique to each eye. On average, the largest quadrant had 2.13 ± 0.41 times the volume of the smallest quadrant. Upon pilocarpine administration, SC volume increased in all quadrants. However, the volume increase was uneven, with the largest quadrant increasing in volume by 83.94% and the smallest quadrant by 5.06%.
Conclusions :
There are segmental differences in the structure and functional response of the conventional outflow pathway to pilocarpine administration in vivo. This suggests that our robotic anterior-segment OCT has the potential to study the development of segmental behavior of the conventional outflow pathway in vivo.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.