Feature

A Starry-Eyed Gaze: NASA Technology Improves Vision Screening
02.24.09
 
Anisometropia is a condition in which the eyes have unequal refractive power.

Shown here, anisometropia is a condition in which a patient's eyes have unequal refractive power. If not caught early enough, anisometropia can cause amblyopia, or lazy eye. Image Credit: Vision Research Corporation

Did you know that NASA stargazing techniques have also protected vision in thousands of children? It's a definite case where "foresight” has helped improve "farsight."

In the 1980s, scientists at NASA's Marshall Space Flight Center shed a new light on vision testing. Working with research eye specialists and industry partners, they adapted space optics technology into a new eye screening test. The result was a technique called photorefraction. During this process, a beam of light shines into a patient's eyes, bends inside, then reflects an image back to a camera. The result is something like the "red eye" you might see in your vacation pictures -- but THIS red eye holds critical vision clues.

You've heard of having stars in your eyes, but what about moons? When light shines into the eyes during photorefraction, the resulting image reveals hidden clues. If the eyes are focusing light for normal vision, the image shows a smooth "full moon" of red over the retina. If the eyes have abnormalities, the image changes. Farsightedness reflects a bright half moon over the top of the pupil. In nearsightedness, the light reflects as a brighter crescent moon in the bottom half of the eye. Other potential problems also show distinct patterns of reflection.

Photorefraction doesn't replace a professional eye exam. Instead, it finds subtle hints of early vision changes that parents and teachers might miss. Common childhood vision problems include nearsightedness, farsightedness, astigmatism, corneal irregularities, alignment errors, and amblyopia, or "lazy eye."

Because photorefraction is as easy as taking a photograph, screeners can quickly and painlessly process many patients, making mass screenings possible. It also has advantages over a traditional eye chart test. Here's why. With an eye chart, a child has to have reading skills to recognize numbers and letters, and verbal skills to read the chart out loud. In contrast, photorefraction can even be used on babies.

Does the process work? Here's an example to help you decide. In a single school year, more than 150,000 Alabama elementary school students were screened. Over 3,000 had early indications of amblyopia -- the leading cause of preventable blindness in children. Left untreated after age seven, it can cause permanent vision loss. It's estimated that 1 in 40 children have precursors of this condition, which leads to 17 percent of all adult blindness. Early detection leads to early correction.

Since the inception of photorefraction, hundreds of thousands of children have been treated for eye problems that might have gone unnoticed, leading to blindness and decreased quality of life. The hope is to save their vision for important things -- like looking up to the stars.

> Read the entire story in Spinoff 2008