According to the National Association of School Nurses, only 45 percent of the nation's public schools have a full-time on-site nurse.

CNN: Are school nurses disappearing?

Backing VSP's request for a Supreme Court hearing are three national charities, all partners in Sight for Students--Prevent Blindness America, the National Association of School Nurses and the National Council of La Raza (a Hispanic anti-poverty group).

FORBES: Supreme Court Question: What's A Charity?

But by the time she left school nursing in 2005, "there were children in the majority of classrooms" with the disorder, said Schoessler, who now works at the National Association of School Nurses in Silver Spring, Md.

NPR: Study: Food, Skin Allergies Increasing In Children