We retrospectively reviewed electronic medical records of all participants who had undergone an AS-OCT examination (Visante OCT, version 3.0; Carl Zeiss Meditec, Dublin, CA, USA) under controlled room lighting conditions (0.5 cd/m2) from the ongoing Asan Glaucoma Progression Study. All participants initially underwent a complete ophthalmic examination, including a review of medical history, measurement of best-corrected visual acuity, measurement of manifest refraction, slit-lamp biomicroscopy, Goldmann applanation tonometry, gonioscopy, funduscopic examination, stereoscopic optic disc photography, retinal nerve fiber layer photography, and a visual field test (Humphrey field analyzer; Swedish Interactive Threshold Algorithm 24-2; Carl Zeiss Meditec, Jena, Germany). We excluded the following patients: those with acute angle closure, phacomorphic glaucoma, or phagocytic glaucoma; patients with a history of ophthalmic surgery, including laser peripheral iridotomy, implantable Collamer lens insertion, anterior chamber lens implantation, penetrating keratoplasty, cataract surgery, or vitrectomy; patients with secondary glaucoma, including neovascular or uveitic glaucoma; and those with anterior chamber or corneal abnormalities, including iridocorneal synechiae and high iris insertion, iridocorneal syndrome, or keratoconus. If a participant had undergone multiple AS-OCT examinations, the highest-quality image, defined as showing good visibility of the scleral spur, was selected for analysis. Both eyes of the same patient were included if eligible. A 0° to 180° scan acquired in anterior segment quad mode with a size of 1200 × 1500 pixels (height by width) was center cropped to create a 512-pixel × 1024-pixel image, which was then resized to 256 × 512 pixels and a grayscale color mode. As a result, 2111 eyes of 1261 patients were included in this analysis.
All procedures conformed to the Declaration of Helsinki, and this study was approved by the institutional review board of the Asan Medical Center, University of Ulsan, Seoul, Korea. The requirement for informed consent was waived due to the study's retrospective design.