Figure 1: Procedures of the optic coherence tomography (OCT) volumes. This is the right eye of patient #20. Before surgery, a horizontal OCT volume (A) and a vertical OCT volume (B) are used to scan the macular hole (MH). On post-operative visits, both OCT volumes were used to scan the macula in the “follow-up” mode (C and D). Each OCT volume contains 131 B-scan lines (from No. 1/131 to 131/131). The numbering sequence is upward in the horizontal volume (A and C) and leftward in the vertical volume (B and D). E, F and G: Three consecutive B-scans show serial changes of the neurosensory retina from interruption to continuity. The retina becomes continuous in the B-scan No. 79/131 (F). The B-scan No. 78/131 shows an MH (E) and the B-scan No. 80/131 shows a continuous retina (G). As a result, the B-scan No. 79/131 was determined to pass through the superior boundary of the MH. H, I and J: CRT is the smallest distance from internal limiting membrane to Bruch's membrane. CRT in the B-scan No. 50/131 (H), 51/131 (I), and 52/131 (J) is 224, 211, and 215 μm, respectively. Other B-scans of the same OCT volume have greater CRT. Hence the B-scan No. 52/131 was determined to pass through the foveal pit. In the right eye of patient #20, the B-scans No. 79/131, 45/131, 41/131, and 81/131 pass through the superior, inferior, nasal, and temporal MH boundaries. The horizontal B-scan No. 62/131 [(79+45)/2] and vertical B-scan No. 61/131 [(41+81)/2] were determined to pass through the MH center. On the postoperative visit of 12 months, the horizontal B-scan No. 69/131 and vertical B-scan No. 51/131 were determined to pass through the foveal pit. Since spacing between adjacent B-scans was 12 μm, foveal pit moved superiorly by 84 μm [(69–62)× 12 μm] and moved nasally by 120 μm [(61–51)× 12 μm].