Jan. 24, 2001 — The last solar eclipse of the millennium occurred Christmas Day last year. But did the thousands who viewed this rare celestial event stop to think about possible damage to their eyes?

Actually, that damage may be more limited than is popularly thought, according to new research. But although total blindness may be rare after eclipse-gazing, it’s still best to be cautious, experts tell WebMD.

Samuel Wong, MD, and colleagues from the Leicester Royal Infirmary in Leicester, England, studied 45 patients after they observed an August 1999 solar eclipse. Although none of the patients who looked directly at the eclipse was totally blinded, 40 of them experienced discomfort or had visual disturbances or changes within the eye. Only five patients had no evidence of eye damage.

Nevertheless, the damage done to the eye can be severe enough to affect daily activities, according to the study, published in the British medical journal The Lancet.

Media warnings of possible eye damage when viewing eclipses may have made the observers more cautious, researchers postulate, resulting in less visual impairment than might otherwise have taken place. But while the researchers praised the media for these public health warnings, other eye experts have different opinions.

“This study shows that the fear-mongering that seems to accompany many of the warnings that are broadcast and printed about upcoming solar eclipses really isn’t necessary,” says Ralph Chou, MSc, OD, associate professor of optometry at the University of Waterloo in Ontario. “When public health authorities make their announcements, they overdo it and then it causes all sorts of panic.”

Frederick L. Ferris, MD, disagrees.

“I don’t know how you could overemphasize this too much,” says Ferris, an ophthalmologist with the National Eye Institute, in Bethesda, Md. “If you look at a solar eclipse and lose vision from it, there’s not much that can be done about that,” he tells WebMD. “It seems to me the warning is appropriate.”

“There is not enough information in the media about safe viewing of an eclipse,” agrees Joan W. Miller, MD, associate professor of ophthalmology at Harvard Medical School’s Massachusetts Eye and Ear Infirmary in Boston. “It’s so sad — you only get two eyes. … If you’re going to view an eclipse, make yourself a pinhole device and look at the phenomenon indirectly. Basically, look at the shadow.”

Which is not bad advice when it comes to looking at the sun at anytime, most experts say. “Some patients can be left with some kind of visual change that doesn’t come back,” Miller says.

While the lure of an eclipse or any bright light can be hard to deny, Ferris says the solution to protecting your eyes is simple: “Don’t look at extremely bright lights. If it hurts when you look, it probably isn’t a good idea.”

Ferris hasn’t seen any eye injuries as a result of the December eclipse.

“But if people who viewed it have trouble reading because a very central part of their vision appears blurry or blank, while the rest of their vision is clear,” this could indicate a problem, he says. Vision can come back to some degree, but the damage is generally permanent.