Eye problems can develop silently, stealing away sight before a person realizes something is wrong.

The National Society to Prevent Blindness publishes a "Home Eye Test for Adults" to make people more aware of their eyes and of the need to have regular eye examinations.

"Most eye conditions, such as macular degeneration which affects the central part of the retina responsible for fine vision , diabetes and glaucoma, are successfully treated if detected early," said Dr. Martin Ehrenberg, ophthalmologist and medical director of the society.

The test is divided into four parts: distance vision, macular degeneration, near vision and glaucoma risk. "In our daily lives, we use both of our eyes," Ehrenberg said. "Unless we individually test each eye, it is very possible that severe visual impairment in one of the two eyes can go unnoticed completely, because one eye is taking over for the other."

Nearly half a million people in the United States are legally blind, according to Ehrenberg, and an estimated 47,000 will become blind each year. He recommends people with no eye problems to have their eyes checked once a year. People with diabetes should have an eye examination every six months.

For a copy of the home eye test, write: Department HETA, National Society to Prevent Blindness, 79 Madison Ave., New York, N.Y. 10016, and enclose $1. Home tests for preschool children are available free.