Leber’s Hereditary Optic Neuropathy Following Unilateral Syphilitic Optic Neuritis

Abstract

This report describes a case of Leber’s hereditary optic neuropathy (LHON) following unilateral syphilitic optic neuritis. A 31-year-old man presented with a four-day history of decreased vision in his left eye. At the initial visit, the patient’s best corrected visual acuity (BCVA) was 1.2 and 0.02 in the right and left eye, respectively, along with a relative afferent pupillary defect in the left eye. Goldmann visual field testing revealed a central absolute scotoma and an enlarged blind spot in the left eye. Serological testing confirmed syphilis with rapid plasma reagin positivity. The patient was diagnosed with syphilitic optic neuritis and treated with intravenous penicillin G (24 million units daily) for two weeks. After two weeks of therapy, his left BCVA improved to 0.4 after two months. However, five months later, despite completing syphilis treatment, the patient developed acute painless visual loss in both eyes. His BCVA decreased to 0.8 and 0.05 in the right and left eyes, respectively. Goldmann visual field testing revealed a central absolute scotoma and an enlarged blind spot in both eyes. After two weeks, BCVA progressively declined to 0.4 in the right and 0.04 in the left eye. Furthermore, Goldmann visual field testing revealed an enlarged central absolute scotoma and blind spot in both eyes. Six months after the initial examination, his BCVA was counting fingers and 0.02 in the right and left eye, respectively. The optic discs appeared diffusely pale in both eyes. Genetic testing for LHON revealed a pathologic mtDNA 11778 point mutation. This case underscores the importance of considering the possibility of LHON if acute or subacute vision loss occurs subsequently or simultaneously in both eyes and remains unresponsive to treatment.