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

Objectives: 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.

Methods: 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.

Results: 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.

Conclusions: 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.