Figure 1.

(A) Retinal nerve fibre layer thickness evaluated by optical coherence tomography in optic neuropathy and control subjects. Average retinal nerve fibre layer (RNFL) thicknesses of temporal, superior, nasal and inferior quadrants are shown for control, LHON and DOA subjects. Retinal nerve fibre layer thickness was significantly lower in optic neuropathy subjects compared with controls in each quadrant. There were no statistical differences between LHON and DOA subjects except for superior retinal nerve fibre layer thickness, which was significantly lower in LHON subjects (P = 0.037). The average retinal nerve fibre layer thickness was 97.3 μm ± 8.4 in controls, 52 μm ± 9 in LHON and 59.3 μm ± 5.8 in DOA subjects. (B) Melatonin suppression test results in control and optic neuropathy subjects. Box plots of melatonin plasma levels at the four sampling times (00:30, 01:30, 02:30, 03:30 am) are shown for the baseline (dark grey) and light suppression (light grey) nights in control (CTRLs; left panel) and optic neuropathy (right panel) subjects. In the control group, a significant difference in melatonin plasma levels between the baseline and the test night was evident for the third (P = 0.000008) and fourth samples (P = 0.00015); this difference was also evident in optic neuropathy subjects for the third (P = 0.0018) and fourth (P = 0.0046) samples. Asterisks indicate these significant differences. (C) Melatonin suppression scores for controls and optic neuropathy subjects. Box plots of control-adjusted melatonin suppression score (caMSS), suppression rate and absolute difference (%) scores are shown for control (dark grey) and optic neuropathy (ON; light grey) subjects in the left, middle and right panels, respectively. No statistical differences were evident between groups, demonstrating similar magnitude of light-induced melatonin suppression.