Corneal anesthesia is a rare condition, therefore its diagnosis is frequently impaired or it is not noticed during the anterior segment examination. Case report of a 18-year-old patient referred to our Corneal and External Disease Department who complained of dry eye symptoms and with a suspicion of Sjögren's syndrome. She had amblyopia of the right eye, consequence of corneal leucoma over the visual axis secondary to a fingernail traumatism inflicted by herself in childhood. On the ophthalmologic examination corneal sensitivity was absent in both eyes. Severe dry eye and breakup time less than four seconds. Diagnosis of congenital corneal anesthesia was established, secondary to trigeminal anesthesia found on neurological evaluation of facial sensitivity. She also showed sudden movements of the chin which evidenced sensorial pathology of the trigeminal nerve. The general ophthalmologist and specially anterior segment specialists must perform tests for corneal sensitivity during the routine eye examination.