Late-Onset Leber Hereditary Optic Neuropathy: A Report of a Case and Review of the Literature.

Leber hereditary optic neuropathy (LHON) constitutes a mitochondrial disorder characterized by subacute, bilateral central vision impairment, secondary to mitochondrial DNA (mtDNA) mutations. These mutations compromise Complex I, subsequently precipitating the degeneration of retinal ganglion cells (RGCs). While traditionally manifesting in young males, contemporary literature has documented a small number of cases of late-onset presentation. Numerous studies have suggested the existence of a distinct clinical phenotype, particularly concerning the funduscopic features of the optic disc. Elucidating this atypical manifestation is paramount to preclude diagnostic inaccuracies and to refine therapeutic intervention. In this context, we describe the case of a 70-year-old male presenting with progressive bilateral vision loss and diffuse thinning of the ganglion cell complex on optical coherence tomography (OCT), notably lacking the hyperaemic phase typical of younger patients. Genetic analysis confirmed the homoplasmic m.14484T>C mutation; however, despite the traditionally favourable prognosis associated with this variant, the patient progressed to permanent optic atrophy with no functional recovery. By reporting this case of late-onset LHON and providing a comprehensive review of clinical cases documented in recent literature, our objective is to ascertain whether late-onset presentation endows this clinical entity with additional distinguishing characteristics.