MT-ND4 and Leber hereditary optic neuropathy: A landmark phase 3 trial of AAV2-ND4 (lenadogene nolparvovec) in LHON showed that a single intraocular injection led to clinically meaningful vision improvement in a subset of patients, and intriguingly even the contralateral sham-treated eyes showed some delayed improvement, suggesting inter-eye transfer of vector or protein [29].