The study was done to characterise the pRNFL thickness changes in patients with LHON having m.11778G>A (MT-ND4) mutation.

This retrospective cross-sectional study included 221 eyes from patients with LHON (n=145)—classified into seven groups according to disease duration and 52 eyes from healthy controls (n=26).

Results Within 3 months of onset, the temporal pRNFL thickness decreased significantly, whereas the remaining quadrants and the average pRNFL thickness initially increased. The temporal quadrant (p<0.01) and average pRNFL thickness (p=0.02) significantly decreased at 3–6 months. Excluding that in the nasal quadrant (p=0.93), pRNFL thickness significantly decreased in all other quadrants at 6–9 months. At 9–12 months, the average and individual quadrant pRNFL thicknesses continued to decrease. Compared with 12–24 months, the pRNFL thickness was thinner at 24–60 months and >60 months.

The study concluded that the pRNFL thickness initially increased and then decreased, corresponding to the retinal ganglion cell swelling and apoptosis. pRNFL thinning first occurred in the temporal quadrant, followed by the inferior and superior quadrants, and finally, the nasal quadrant. pRNFL continued to thin slowly in some quadrants even after 60 months.

Reference: https://bjo.bmj.com/content/early/2020/08/29/bjophthalmol-2020-316573