A case report of atypical optic neuritis.

Optic neuritis is a severe blinding ocular disease, and identifying its etiology is crucial for selecting appropriate treatment strategies and evaluating patient prognosis. This paper reports the clinical data of a patient initially presenting with unilateral visual decline who was ultimately diagnosed with bilateral atypical optic neuritis. The patient was a 40-year-old male who presented with decreased vision in the left eye for 2 weeks. Fundus examination at admission revealed bilateral optic disc edema, leading to a diagnosis of bilateral atypical optic neuritis. Systemic examination showed a positive Treponema pallidum particle agglutination test. After a series of serological and cerebrospinal fluid examinations for syphilis, syphilitic optic neuritis was excluded. The patient showed a poor response to conventional treatment for optic neuritis. Further comprehensive brain and ocular examinations were performed. After excluding multiple possible causes of optic neuritis, mitochondrial gene testing ultimately confirmed the diagnosis of Leber hereditary optic neuropathy (LHON). For young male patients presenting with acute vision loss, bilateral involvement, and typical fundus findings, etiological investigation should be emphasized, particularly the application of genetic testing, to achieve early diagnosis and timely treatment.