Symptoms of amaurosis Leber. The main symptoms are: absence of central vision, unregistered or abnormal subnormal ERG, nystagmus. Diagnosis of congenital amaurosis of Leber is very difficult, because the symptoms found in patients: strabismus, keratoconus, high grade hypermetropia, neurological and neuromuscular disorders, hearing loss, mental retardation, may be in other systemic diseases..