What Would Happen If You Never Took Your Contacts Out?

​​This is What Would Happen If, a close examination of mundane hypothetical situations. Each week, we look at something that you could do but probably never would, and take it to its logical endpoint. This week: What would happen if you never removed your contact lenses?

If you're wearing contacts right now, ask yourself this: How long have you had them in? Did you happen to fall asleep with them in? Are you proud of how many days you can stretch your daily contacts over? Just how long have those polymer discs been sitting on top of your eyeballs?

Granted, out of all the things we've covered in What Would Happen If, neglecting to take your contacts out seems like the least likely of scenarios. I mean, these are your eyes, after all. Still, just because you'd never leap off a train platform doesn't mean you can't help but wonder what a moving locomotive might do to a human body.

To that end, we spoke with Dr. Jason Jedlicka, a clinical associate professor at Indiana University's School of Optometry, who was more than happy to discuss the long-term effects of leaving a contact lens in.

The first step to understanding what would happen, naturally, is to understand just how the eye works — or, at least, understand what's on top of your eye. If you're shouting "TEARS YOU IDIOT" at your computer right now, yes, correct. 

But to be more specific, your eyes are covered and lubricated by a tear film. You see, there are three layers on top of your eyes: A top layer of oil to keep your eyes from drying out, a watery layer to keep things moisturized and a bottom layer of mucous to keep the tears in place.

Your body naturally refreshes this layer, but since there are contacts in your eyes, things get complicated. "Basically, if you never took your contact lenses out, they would get coated in proteins, oils, mucous, and so on," Dr. Jedlicka writes in an email. "That is in your natural tear layer. These molecules would stick to the lens an cause a film to form over the lens."

Once that film starts to accumulate, well, now we're off to the races in terms of what might happen to your eyes.

The first possibility is just your bog standard human body reaction to anything not normal: swelling. "Your eye might react with an inflammatory event that would make the eyes very light sensitive and painful," writes Dr. Jedlicka. They'd grow red and irritated and someone might mention that, hey do you need some eyedrops?

A second possibility is, you guessed it, infection. "Bacteria might colonize in the film and cause an infection which could range from mild to blinding," writes Dr. Jedlicka. That's right, you could contract a mildly-annoying eye infection, or go blind. It's up to the bacteria.

A third possibility is that the film causes an allergic reaction with the underside of your eyelids. Which will cause redness and itchiness — the eyes only have so many ways to tell you something is wrong, after all.

A fourth, fifth and sixth possibility is that a combination of any of these symptoms might hit you. So your eyes could get swollen and infected, or infected and exhibit an allergic reaction, or all three.

So how long do you have until this kind of fun stuff starts happening? Well, that's the fascinating part according to Dr. Jedlicka. "It is amazing at the range of reactions to leaving a lens in," he writes. "Some individuals can experience these kind of reactions in a matter of just a few days, others can seemingly leave lenses in for weeks and not have these reactions occur."

Alternatively, you could just wear glasses and never worry about any of this.