An 18-year-old healthy man was evaluated in the eye emergency room for acute progressive painless vision loss in both eyes. First was affected a right eye and a six days later, left eye was affected too. Best-corrected visual acuity was 20/800 right eye and 20/300 left eye with a right afferent pupillary defect. Eye movements were full. Slit-lamp exam showed temporal pallor in both optic nerves. Orbit and brain MRI showed T2 hyperintensity of the chiasm bilaterally, the right optic nerve orbital segment, and left optic nerve prechiasmatic segment with subtle postcontrast enhancement of the right optic nerve intraorbital segment. Patient was followed and genetic test showed LHON mutation for 11778 ND4 gene. In mean time, another patient came in the clinic with similar symptoms. This was a cousin of the first patient. Best-corrected visual acuity was 20/400 right eye and 20/800 left eye without afferent pupillary defect. Slit-lamp exam showed temporal pallor in both optic nerves. The findings were suggestive of LHON. Genetic test is suggested.
Presentation Date: 04/30/2020
Issue Date: 08/01/2020