Looking directly at the sun without protection can result in permanent damage to the retina after just a short time. But even sunglasses cannot protect the eyes from an eclipse, regardless of how dark they are, warns optometrist Sandy Wenzel.
"It just isn't sufficient. To watch an eclipse, one must wear the special glasses with specially designed filters. These meet certain ISO standards. People also need to be careful when buying cheap glasses online, as they may not meet the standards."
People often underestimate the strength of the sun's rays because "the retina does not have any pain receptors." Often, one only notices an eye injury when it's too late. "It's common to only notice damage when the retina has been burned or otherwise damaged, when it's much too late."
Wenzel says in no circumstances should anyone try to look directly at the sun without adequate protection.
What do we need to look for when buying eclipse glasses?
The best places to purchase eclipse glasses are opticians', says Wenzel. The proper glasses have very dark filters, "specially made to look at the sun directly." Particular care should be taken when putting the glasses on children, to ensure they fit properly. The eclipse glasses are all one size, says Wenzel, so her advice is to secure the glasses with an elastic on a child to ensure they only look through the filter foil.
What are the alternatives to glasses?
If you can't get hold of any eclipse glasses, one alternative to make your own pinhole camera. "You can take a big piece of cardboard and make a small hole in it, then when you hold it up to the sun, it can reflect off a white surface, like paper, and that will allow you to see the crescent of the eclipse without looking directly at it." But even with such alternatives it's important to ensure you do not like directly at the sun, advises Wenzel.
