Because malaria is so common in Africa, children may have an incidental malaria infection whilst actually having another life-threatening illness. This can confuse the diagnosis in an unconscious child. Doctors hope that widespread use of eye examination could greatly reduce the number of children dying from this major childhood killer.

A study has shown that changes to the retina were the only clinical sign or laboratory test which could distinguish between patients who actually died from cerebral malaria and those with another cause of death.

"Over a million people a year die from malaria, and most of these are African children," explains Dr Nick Beare of the St Paul's Eye Unit, Liverpool. "Death is usually caused by cerebral malaria, a severe complication of malaria in which the Plasmodium falciparum malaria parasite causes infection of the capillaries that flow through the tissues of the brain, affecting the brain and central nervous system. This can lead to convulsions, coma and death."

Cerebral malaria is accompanied by changes in the retina, the light-sensitive tissue at the back of the eye. These changes, known as malarial retinopathy, include white, opaque patches, whitening of the infected blood vessels, bleeding into the retina and swelling of the optic nerve, the nerve that transmits visual signals to the brain. The first two of these signs are unique to severe malaria, and not seen in any other disease.

"In cerebral malaria, the eye acts as a window onto the brain, providing valuable information for the doctors caring for the patients," says Dr Beare. "Our research demonstrates that the detection of malarial retinopathy can identify those children at most risk of death. Diagnosis requires special training in eye examination, but is relatively straightforward and cost effective, which is essential in resource-poor settings such as Africa."; Source: Wellcome Trust