Disc torsion and vertical disc tilt are related to subfoveal scleral thickness in open-angle glaucoma patients with myopia

Abstract

PURPOSE. To find out the characteristics of optic disc morphology in glaucomatous eyes and to evaluate related ocular factors, including the scleral thickness measured from swept-source optical coherence tomography (OCT). METHODS. We compared disc torsion and tilt between 180 normal controls and 180 patients with open-angle glaucoma, matched according to age and axial length based on propensity scores. In a subset of 63 glaucoma and matched control eyes with high myopia, swept-source OCT images of the optic nerve head obtained. The disc ovality and torsion degree were measured from disc photographs, and tilt degree was measured from cross-sectional images of the optic nerve head using swept-source OCT. Scleral thickness was measured from sweptsource OCT images at the subfoveal point and 1000 lm away superiorly, inferiorly, temporally, and nasally from the subfoveal point. RESULTS. The degree of disc tilt and torsion was significantly different between glaucoma (9.3 ± 6.3° and 28.2 ± 19.8°, respectively) and control eyes (6.2 ± 4.1° and 14.1± 8.0°, respectively) with similar axial length. The thickness of the inferior sclera and the superiorinferior difference were significantly different between control and glaucomatous eyes with high myopia (P < 0.001 and P = 0.031). The thickness of the inferior sclera and the superiorinferior difference were significantly related to the disc tilt (P = 0.034 for inferior sclera and P = 0.001 for superior-inferior difference) and torsion (P < 0.001 and P < 0.001, respectively) in glaucomatous eyes with high myopia. CONCLUSIONS. Disc tilt and torsion were prominent features of glaucomatous eyes when compared to normal controls with similar axial length and were significantly related to the thickness of the inferior sclera in glaucomatous eyes with myopia.