SBS may be misdiagnosed, underdiagnosed, and overdiagnosed, and caregivers may lie or be unaware of the mechanism of injury. Commonly, there are no externally visible signs of the condition. Examination by an experienced ophthalmologist is often critical in diagnosing shaken baby syndrome, as particular forms of ocular bleeding have been claimed to be quite characteristic, although the scientific basis for such claims seems weak at best. Magnetic resonance imaging may also depict retinal hemorrhaging; this may occasionally be useful if an ophthalmologist examination is delayed or unavailable. Conditions that are often excluded by clinicians include hydrocephalus, sudden infant death syndrome (SIDS), seizure disorders, and infectious or congenital diseases like meningitis and metabolic disorders. CT scanning and magnetic resonance imaging are used to diagnose the condition. Conditions that may accompany SBS include bone fractures, injury to the cervical spine (in the neck), retinal bleeding, cerebral bleed or atrophy, hydrocephalus, and papilledema (swelling of the optic disc).