Wherever Kiyo Sato-Viacrucis goes, the blackbirds fly with her.

Thousands of Sacramento preschool and kindergarten children know her as the "Blackbird Lady."

Youngsters in Alaska and Hawaii, in schools from California to Maine, know the blackbirds of the 53-year-old public health nurse who is revolutionizing the ordinary eye examintion for little children.

Recently at the picturesque frame, 110-year-old Edward Kelley School in Sacramento, the Japanese-American nurse gathered preschoolers around her in a circle as she always does when giving her eye tests.

"I'm going to tell you a story. This is my friend, the blackbird," she began as she held up an 8 3/4-inch square white cardboard in the middle of which was a 3 1/2-by-4 1/4-inch stylized blackbird's beak headed upward.

"He goes up, up, up in the sky," the nurse said, turning the card so that the blackbirdhs beak headed upward.

"Then he goes down, down, down to the ground to get a big fat worm," she explained, showing the bird in a nose dive.

Mrs. Sato-Viacrucis held the card sideways to show the bird flying to the right, then reversed the card to show the bird flying to the left as she told how the blackbird flew out to sea. Then flew back to land again.

As she told her story she asked the boys and girls from time to time to point the direction the blackbird was flying.

The children got into the spirit of the flying bird, waved their arms and meneuvered them like a blackbird in flight.

After the story session, the children one by one were called into a room where the nurse gave her Blackbird Screening System eye test.

Mrs. Sate-Viacrucis sat on a chair 20 feet from the child being tested. The child was given a pair of cardboard screening spectacles with a flip-out lens for each eye.

On one of the black flip-out lenses is printed, "I Just Had My Eyes Checded" -- a souvenir for the yoiungster to take home.

The nurse flashed the Blackbird cards, and the boy or girl motioned with a hand and arm the direction the blackbird was flying. The smallest blackbird on the cards measures only 1-2 by 3-8 inches, and correct identification indicates 20-20 vision.

In the testing, if a child misses the direction the bird is flying a nurse's aide duly notes the boy's or girl's restricted visual ability.

"I had given the traditional Pointing E or Snellen E Chart eye test for years," Mrs. Sato-Viacruczs explained. "It consists of the letter E in four different positions.

"The trouble other school nurses and I have always had when testing with the letter E is that many of the preschoolers don't have the E in their background.

"The little childeren have a short attention span. Many do not relate to the E"

One day five years ago, Mrs. Sato-Viacrucis got the idea of doctoring the E to make it look like a bird in flight. That was the birth of her Blackbird Vision Screening System.

The children all relate to birds in flight. The nurse's story session eliminates the tedious task of teaching boys and girls the positions of the E.

In the past with the E, many youngsters were confused and a large percentage test because they were unable to comprehend the various positions of the E.

Now 98 percent of the children readily understand the different flight patterns of the blackbird.

Leading ophtalmologists have endorsed Mrs. Sato-Viacrucis' system.

She had her Blackbird system copyrighted three years ago, borrowed $2,000 from her brother and had the Blackbird Vision Screening System kit she designed printed.

The kits, which sell for $29.95 include six cardboard cards of various sizes, 25 screening spectacles with flipout lenses, the blackbird story and instructions. Additional cardboard spectacles may be ordered.