If you're one of the 41 million Americans who wear contact lenses, you're at risk for a condition that could lead to blindness—and it's almost entirely your fault.
Corneal neovascularization is when the cornea, the transparent tissue covering each eye, gets deprived of oxygen from being covered up all day by a sight-enhancing slip of plastic. Starved for air, the cornea enacts its own Plan B and starts growing new blood vessels to compensate, which then start to traverse the surface of your eye. If it's left unchecked, the condition can cause problems like eye inflammation, lipid deposits in the cornea, and blindness.
The more you wear your contacts and the less you clean them and throw them out, the greater your risk. Thomas L. Steinemann, clinical spokesperson for the American Academy of Ophthalmology and a professor at Case Western Reserve University School of Medicine, says wear and care are key factors in how much blood vessel growth occurs, and how much it affects sight.
"It's probably inevitable that contact lens wearers will have some corneal neovascularization," Steinemann says. How much is up to you—and, well, how gross you are. "If you don't replace your lenses frequently, there's more of a chance of you getting it," says Bruce Goldstick, a Chicago-based ophthalmologist and president of Optimized Eye Care. Goldstick doesn't agree that it's inevitable, but he does say it's common—and likely.
The cornea, about as big as a dime and as thick as a credit card, doesn't normally have any blood vessels in it at all. If they appear, it's a sign that something's wrong. So what's the big deal some new blood vessels show up? Isn't it just oxygen getting where it needs to go?
"The crystal clarity of your cornea is destroyed by blood vessels," Steinemann says. "[The vessels] can leak. You can end up with deposits on the cornea—cholesterol, lipids. The eye can remain inflamed chronically." If you don't give your eyes a rest, Steinemann says, blindness could be the result. "Think about it," Goldstick says "Can you supply more oxygen to your eye with a contact lens, or without?"
That seems like common sense. So why do so many of us flout doctors' recommendations to take our lenses out to sleep? Why do we wear two-week disposables for a month and a half? "It's laziness," Goldstick says, adding that people enjoy having the ability to see the moment they wake up. It can also be thrift: For instance, my prescription costs me $259 for twelve pairs—a year's supply if I dispose of them appropriately. If I wear them until they're good and grimy, though, that $259 can last me two years, and lets me skip the exam—which means I won't even know about the rogue blood vessels.
"I don't think that's a good strategy," Steinemann says. "A contact lens is not costume jewelry. It's a medical device and it has to be monitored. Your eyes are worth it."
Despite what Steinemann calls a strong consumer movement in contact lens purchasing, with online lens vendors getting more and more convenient, contact lenses remain prescription items. Each state dictates how long a prescription lasts, and in most states, they expire after a year, with some stretching it to two. That's for a good reason, Steinemann says. Corneal neovascularization and other signs of eyeball abuse only show up in eye exams—ideally in time to fix them.
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Taking good care of your contacts is a start, but it's not a foolproof way to avoid the problem. In third grade, I got saddled with spectacles, putting my cool-kid dreams on ice until that glorious day four years later when the eye doctor said the magic words: contact lenses. The only way out of four-eyes town was to swear up and down that I'd take excellent care of them, and I did. Back then, you had to disinfect them every week using a complicated process that involved enzyme tablets. I did it steadfastly, and dutifully counted out thirty seconds of scrubbing each side of each lens every night.
For decades, if I was awake, I was wearing contacts. At my last (okay, overdue) eye exam, though, a new doctor asked me if I slept in them or wore them continuously for weeks on end. After wearing contacts 16 hours a day for 25 years, those telltale vessels were appearing.
I've gone from starving my corneas to crushing my poor nose bridge with Coke-bottle glasses due to my very high astigmatism in both eyes. Going a couple days a week in glasses or just taking my contacts out earlier in the evening would probably take care of it, but the thought of those leaking tentacles snaking across my poor eyes has cowed me into a nerdy, smudgy mess.
Thankfully, if you're at all worried, there's a simple prescription—as long as you're patient. "Give your eyes a rest," Steinemann says. "If you [do], some will regress. It may take months, it may take years."
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