Introduction. Leber's hereditary optic neuropathy (LHON) typically affects young adults with a higher prevalence in men, but can ultimately occur at any age and also in women. LHON is caused by point mutations in the mitochondrial DNA. Classically, LHON presents as a subacute unilateral loss of visual acuity, dyschromatopsia in the red-green axis and a central or centrocecal scotoma. The contralateral eye usually develops similar symptoms within 3 - 6 months of onset of the disease. Case outline. A 55-year-old male patient presented to a neurologist 20 days after the onset of vision loss. The patient was admitted as an emergency to The Clinic for the Eye Disease due to a sudden vision loss in both eyes. The best corrected visual acuity in both eyes was 4/60. The IOP on both eyes was normal. Oedema of the optic nerve head was found on the right eye and a disc with blurred borders was seen on the left eye. During hospitalisation several consultative examinations and diagnostic procedures were performed, together with blood laboratory and visual field perimetry. Genetic testing for LHON as well as antibodies to AQ4, immunoserology, virology, and lumbal puncture have been performed. VEP and ultrasound examination were performed as well. Conclusion. In our patient, the presence of a heteroplasmic mutation m.11778 G> A (MT-ND4) in mitochondrial DNA analyzed from a peripheral blood sample was shown. In the available literature, this is the first documented LHON case demonstrating complete restitution of visual acuity in both eyes with LHON.