Childhood versus early-teenage onset Leber's hereditary optic neuropathy: visual prognosis and capacity for recovery.

Objective: In Leber's hereditary optic neuropathy (LHON) in children and teenagers, the influence of age on visual prognosis has not yet been investigated.

Methods: Patients from the mitoNET registry with LHON onset at age 4-16 years with at least 4 years of follow-up without treatment were included. Visual acuity (VA) at baseline, lowest VA ever recorded (nadir) and VA at end of follow-up were compared between childhood onset (ChO, ≤12 years of age) and early-teenage onset (eTO; 13-16 years).

Results: Out of 231 patients with LHON, 19 met the inclusion criteria (8.2%). There were 11 patients in the ChO and 8 patients in the eTO group. Mean age at onset was 8.6 (SD 2.1) years (ChO) and 15.4 (SD 0.7) years (eTO) (p<0.00001). Follow-up was mean 184 (SD 129) months (ChO) and 119 (SD 78) months (eTO) (p=0.22). Baseline VA was similar between both groups in better (p=0.96) and worse eyes (p=0.54). In worse eyes, both groups deteriorated similarly (p=0.79) until nadir and showed similar recovery until end of follow-up (p=0.38). In better eyes, both groups deteriorated similarly (p=0.16) until nadir. From nadir until end of follow-up, better eyes in the ChO group showed a significantly better recovery (-0.35 (SD 0.36) vs -0.01 (SD 0.06) logMAR; p=0.02) than eTO eyes.

Conclusion: Visual prognosis of LHON in children is much more favourable in cases of childhood onset (≤12 years of age) as compared with teenage onset (13-16 years), mostly due to better recovery from nadir in childhood onset.