A group of Japanese researchers has found out why eyes develop signs of pollen allergy so quickly after exposure to pollens.

A Juntendo University research group led by associate professor Ando Tomoaki published the results of their study in the International science journal JCI insight.

Pollinosis is caused when an allergen in pollen shells makes its way through the eyes and into the body. The mechanism of the rapid transport of the allergen had been unclear, as eyes were supposed to be protected by a mucous membrane.

The researchers separated the allergen from pollen shells. After exposing mice to the allergen and the shells, they made microscopic observations of the mice's reactions.

They observed goblet cells on the surface of the eyes rapidly took in a substantial amount of the allergen upon exposure to the shells and delivered them to immune cells.

They also saw little intake of the allergen when mice were exposed only to the allergen.

They have concluded that the mechanism explains why signs of pollinosis manifest rapidly after exposure to pollens.

Ando says a closer study of the mechanism could lead to the development of new treatments for pollinosis.