Thankfully, this is not how our peepers actually work.
"Wearing glasses will not make your eyes worse," says Michael J. Duerr, an optometrist in Rochester Hills, Michigan. "Your actual prescription is based on the anatomy of the eye: the front curve of the cornea, the refractive power of the intraocular lens, and the length of the eyeball." And peering through spectacles won't change that anatomy, Duerr says. "Wearing glasses or soft contact lenses will not change what your required prescription is."
But when you take off your glasses, the world seems blurrier than you remember. Does this indicate that you "need" your glasses more now than you did before you got them? Not necessarily. That change probably just means you're getting used to seeing things clearly, according to the American Academy of Opthamology. Now that you know what the world is supposed to look like, it's hard to go back—even if you thought your vision was fine before.
It's true that you may find yourself needing stronger and stronger prescriptions as the years go on, but again: This isn't a result of wearing glasses. Our vision deteriorates as we get older, and chances are, you'll need to upgrade your prescription from time to time.
That brings us to another interesting worry: Some people fear that wearing an incorrect or outdated prescription can cause their eyesight to get worse. This is also a myth, at least in the case of adults—two studies found that incorrect prescriptions did slightly increase the progression of myopia, or nearsightedness, in children.
In addition, the special glasses given to children with crossed eyes or a lazy eye can actually change them—but in a good way. These aids help straighten the eye. The real harm comes from not using them, according to the Opthamology Department at Mayo Clinic Health System in La Crosse, Wisconsin: "Not wearing such glasses may lead to permanently defective vision."
But don't fear wearing glasses: There's no evidence that the correct prescription will worsen eyesight in children or adults. As long as you stick with your annual or bi-annual checkups, you shouldn't have anything to worry about. Wear your specs whenever you need them, and enjoy the privilege of seeing clearly.
