Figure 1 Section of lamina cribrosa illustrating lamina cribrosa thickness (LCT) measurement. LCT was defined as the measurement from the first collagenous plate to the point where myelinated axons became visible, delineated by “X”. The area was arbitrarily divided into four sections (a–d), about 100 μm thick, for measurement of cribrosal beam thickness. Magnification 10×. a, anterior; b, mid‐anterior; c, mid‐posterior; d, posterior.