Published in:
01-10-2019 | Original Paper
Assessment of Schlemm’s canal in acute primary angle closure: an anterior segment optical coherence tomography study
Published in: International Ophthalmology | Issue 10/2019
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Purpose
To image and quantitatively evaluate the Schlemm’s canal (SC) dimensions in the eyes with acute primary angle closure (APAC) with anterior segment optical coherence tomography (AS-OCT), and compare it with the SC measurements taken after the control of intraocular pressure (IOP) and in the normal age-matched controls.
Materials and methods
Seventeen eyes of 14 patients with the newly diagnosed APAC and 59 age-matched normal subjects underwent AS-OCT to image SC. SC cross-sectional area, SC meridional and coronal diameters were measured in the temporal and nasal regions at 3 and 9 o’clock position. After laser iridotomy and control of the IOP, all SC parameters were measured again at a week later, in APAC eyes. Intrasession intraobserver reliability of the SC measurements was assessed with intraclass correlation coefficient.
Results
Mean SC-SCA (10,600 ± 2691 µm2), SC meridional (682 ± 125 µm) and coronal diameters (21.2 ± 8.2 µm) showed a significant increase in the APAC eyes at presentation, when compared to the SC parameters measured at a week later (6499 ± 1754 µm2, 450 ± 169 µm and 15.75 ± 8.6 µm, p = < 0.0001, < 0.0001 and 0.01, respectively) and in the normal controls (7192 ± 1022 µm2, 499.2 ± 179.8 µm, 15.43 ± 4.35 µm, p = 0.02, < 0.0001, 0.01, respectively). There was no difference in the measured SC parameters between the normal controls and APAC eyes, when the parameters were measured at a week, after resolution of the acute attack (all p > 0.05).
Conclusion
A significant expansion of SC was observed in the APAC eyes at presentation, when compared to the normal controls and after the acute attack resolved. SC parameters may provide a useful research tool for evaluating morphological changes in the SC in APAC eyes, during an acute attack.