Quantitative evaluation of dissociated optic nerve fibre layer (DONFL) following idiopathic macular hole surgery

To quantitatively evaluate concentric macular dark spots (CMDS) on spectral-domain optical coherence tomography (SD-OCT) to determine the morphological characteristics of dissociated optic nerve fibre layer (DONFL) following the performance of internal limiting membrane (ILM) peeling in patients with full-thickness idiopathic macular hole (IMH) closure.

Retrospective study on patients who underwent a vitrectomy with ILM peeling procedure. BCVA, cross-sectional OCT scans, and three-dimensional reconstructions of en face OCT scans were analysed preoperatively, at 2, 6, 12 months post-operatively. A novel image analysis technique was used to automatically measure DONFL logical properties through the radius, area, the nerve fibre layer dissociation index (NFLDI), and depth of the CMDS.

53 eyes of 51 patients were included, and the mean follow-up was 11.53 ± 6.26 months. CMDS was found in 46 (86.79%) eyes within 2 months after ILM peeling and 50 (94.34%) eyes within 6 months after ILM peeling. CMDS concentrated on the temporal side of the macula in all 50 eyes (100%) at first detection. The area, NFLDI, and depth of CMDS in four quadrants developed significantly during the postoperative 6 months (p < 0.05), and then these changes slowed down and remained unchanged 12 months post-operatively. The morphological changes in the temporal quadrant were significantly greater than those in other quadrants at 2, 6, 12 months (all p < 0.05) post-operatively.

CMDS mostly appeared and concentrated on the temporal side of the macula in IMHs within two months after ILM peeling and progressed within 6 months and remained unchanged after 12 months.