The 360° circumferential opening of Schlemm's canal in normal individuals detected by enhanced depth imaging optical coherence tomography

Abstract

We aimed to observe the opening status and morphological parameters of Schlemm's canal (SC) in normal eyes using enhanced depth imaging optical coherence tomography (EDI-OCT). Consecutive EDI-OCT scans were used to examine the right eye of 20 normal individuals. EDI-OCT was performed clockwise for 8 regions (at the 12:00, 1:30, 3:00, 4:30, 6:00, 7:30, 9:00 and 10:30 o’clock positions). Image processing and analysis in java software was used to measure the area, perimeter, and diameter of SC. Twenty-one serial scans of each region were evaluated and a total of 168 images were included in the analyses of each eye. The SC was detected in 100.0% of the sections. The distribution of individual measurements of SC was highly variable. The mean values of SC size significantly differed among the different clock-face positions. The mean values of the area, perimeter, and diameter of SC in the 9:00 o’clock position were the lowest, and those at the 7:30 o’clock position were the highest (P < .05). There was no obvious association between intraocular pressure and SC size at any clock position. Although SC tends to open circumferentially in normal individuals, the distribution of individual measurements is highly variable. Morphological manifestation of SC measured by EDI-OCT is a useful way to evaluate the circumferential opening status of SC.

Acute Effects of Intraocular Pressure-Induced Changes in Schlemm's Canal Morphology on Outflow Facility in Healthy Human Eyes

“…TIA500 of the nasal point was calculated, and it was found to be slightly decreased at T0, but there were no significant differences from the baseline to T4, which implies the stable structure of the anterior chamber in the nasal region. In our previous study, we observed that SC lumen tends to open circumferentially in normal individuals by EDI-OCT. 38 Further research is required to determine the correlation of circumferential of SC and the outflow facility using advanced equipment and methods.…”

Iridocorneal angle imaging of a human donor eye by spectral-domain optical coherence tomography

“…Imaging of the TM geometry has been widely investigated in clinical studies because this is usually the impeded site leading to reduced ocular outflow and glaucoma development [22][23][24][25][26][27][28][29][30] . The AS-OCT systems have also been used to measure the SC cross-sectional areas in healthy and glaucomatous patients [31][32][33][34][35][36] , or to study the SC morphological changes in response to different IOPs 37 and glaucoma treatments [38][39][40][41][42] .…”