Bethesda, Md. - May is Health Vision Month and Dr. Henry Wiley at the National Eye Institute says the best way to check in on eye health isn't just to see if things are getting blurry. It's to get a dilated eye exam.

"A lot of sight-threatening conditions don't present a lot of warning signs or symptoms before they reach a stage where they really can become a problem for the eyes and for vision," Wiley says.

Wiley says it's a good idea for everyone to have a dilated eye examination and has a simple way to determine whether it is time for one.

"Boiling that down, if it's been a while since you've had a comprehensive dilated eye examination, then think about putting it on the calendar," Wiley says. "If you've had one recently but you're not sure whether you're due for another, then I would recommend talking to your existing health care team -- your primary care physician or your current eye doctor."

But Wiley says the recommended frequency of those exams changes from person to person.

"The frequency of screening is really going to depend on how old you are, what underlying medical conditions you have, what your family history is," he says. "And other factors as well."

Wiley says a dilated eye exam is the best way for a doctor to get a look inside a patient's eyeball and can prevent vision problems.

"For a number of conditions, we're adept at catching early stages of these conditions many times before they present with symptoms or problems," he says. "We're better at treating those conditions if we get to them at that point."