Symmetry Analysis for Detecting Early Glaucomatous Changes in Ocular Hypertension Using Optical Coherence Tomography

摘要

Thirty-three consecutive ocular-hypertensive patients (33 eyes), 25 normal volunteers (25 eyes), and 35 open-angle glaucoma patients (35 eyes) were enrolled in this study. Circular OCT scans were obtained using a diameter of 3.4 mm around the optic disc. RNFL thickness was measured, and a symmetry analysis was performed using symmetry ratios. To calculate the symmetry ratios, the circle was divided into the superior and inferior hemiretina. The superior hemiretina was further subdivided into three (area I, temporal 45°; area II, superior 90°; and area III, nasal 45°) or five (with areas 1–5, each spanning 36°) zones. The symmetry ratios were defined as the ratios comparing the RNFL thickness within each of the zones with that in the analogous zone in the inferior hemiretina.