NGHIÊN CỨU ĐẶC ĐIỂM CHẨN ĐOÁN HÌNH ẢNH Ở BỆNH NHÂN GLÔCÔM GÓC MỞ THIẾU NIÊN

Abstract

Purpose: To describe the imaging characteristics of patients with juvenile open-angle glaucoma (JOAG). Patients and Methods: A cross-sectional descriptive study was conducted on patients diagnosed with JOAG at the Vietnam National Eye Hospital from June to December 2025. Results: The study was conducted on 67 eyes from 34 patients. The mean central corneal thickness (CCT) was 538.33 ± 40.62 µm, with most eyes belonging to the thin and normal corneal groups. Anterior chamber angle findings: The mean scleral spur angle (SSA) was 61.21 ± 7.31°, and the mean angle opening distance at 500 µm (AOD-500) was 0.33 ± 0.10 mm². A hyperreflective membrane overlying the trabecular meshwork was observed in 29.9% of eyes. Schlemm’s canal was visualized at the 3 o’clock or 9 o’clock position in 58.2% of eyes. Optic nerve and retinal nerve fiber layer (RNFL): Mean global RNFL thickness was 74.75 ± 18.26 µm; inferior: 87.22 ± 28.40 µm, superior: 90.73 ± 28.79 µm, nasal: 63.13 ± 14.25 µm, temporal: 58.28 ± 17.53 µm. Mean optic disc area was 2.26 ± 0.45 mm², neuroretinal rim area 0.88 ± 0.33 mm², and cup volume 0.68 ± 0.46 mm³. Mean cup-to-disc (C/D) ratio was 0.76 ± 0.11, and the mean vertical C/D ratio was 0.73 ± 0.12.Visual field parameters:Mean deviation (MD): -7.68 ± 8.93 dB; pattern standard deviation (PSD): 4.62 ± 3.51 dB.There was a statistically significant correlation between pre-treatment intraocular pressure (IOP) and the following factors: visibility of Schlemm’s canal at the anatomical position, optic disc condition, and visual field defects (p < 0.05).No statistically significant correlation was observed between pre-treatment IOP and central corneal thickness, anterior chamber angle parameters, hyperreflective membrane over the trabecular meshwork.No significant association was found between Schlemm’s canal visibility and the presence of a hyperreflective membrane. Conclusion: Juvenile open-angle glaucoma represents a heterogeneous group of disorders. In addition to clinically significant findings, imaging modalities have greatly contributed to understanding the pathogenesis and characteristic optic disc damage. Anterior segment OCT findings demonstrate the persistence of mesenchymal remnants (manifested as a hyperreflective membrane) accompanied by the absence of Schlemm’s canal, suggesting outflow obstruction located within the anterior chamber angle and anterior to the canal. In other cases, when the trabecular meshwork is not identifiable on gonioscopy, Schlemm’s canal is often absent on OCT as well, indicating canal hypoplasia as a cause of elevated intraocular pressure.