Visual Diagnosis: Sudden-Onset Decreased Vision In A Healthy Teenage Boy

1. Claudia Teles-Silva, MD* 2. Ana Reis-Melo, MD* 3. Joana Rodrigues Araujo, MD† 4. Mafalda Sampaio, MD* 5. Margarida Tavares, MD* 1. *Paediatrics Department and 2. †Ophthalmology Department, Centro Hospitalar Sao Joao, Porto, Portugal A 17-year-old healthy boy is admitted to the emergency department with sudden-onset decreased vision in his left eye. It is not associated with redness of the eye or ophthalmoparesis. In the previous 2 weeks, the patient has fully recovered from an upper respiratory tract infection with fever, myalgia, and cervical lymphadenopathy. He does not wear contact lenses, and there is no history of trauma. The adolescent has had no previous hospital admissions or surgeries. He has complete immunization according to the national vaccination program. He is institutionalized due to poor social support but spends weekends at his parents’ home in northern Portugal. The parents live in a rural zone, where he reports occasional contact with dogs and an unvaccinated young cat. There is no travel history outside of Portugal in the previous year. On physical examination he appears well. He has no fever, and his blood pressure is normal. There are no skin lesions and no cervical or axillary adenopathy. The neurologic examination findings are also normal. On ophthalmologic examination his visual acuity is 10 of 10 in the right eye and 3 of 10 in the left eye. His pupils are equal, round, and reactive to light, without a relative afferent pupillary defect, also known as Marcus Gunn pupil (an anomaly of pupils that respond differently to light shone in 1 eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve). Dilated funduscopic examination of the left eye reveals sectoral disc edema inferiorly with suspected subretinal fluid in the nasal macula. Ocular coherence tomography reveals sectoral optic disc edema …