There are two main reasons why your contact lens are blurry, and they both have to do with a piece of plastic touching your eye and moving around on it.
Have you ever felt like even though you see pretty well with glasses, it’s just not as clear with your contacts? If the answer is no, then I apologize for what could be a massive waste of time if you read this article through to the end. But if, like most people, you answered, “Yes! What’s that all about?!” then this is going to be helpful for you. Helpful enough that we shouldn’t feel too terrible about the people who see perfectly with contacts but are still reading this for some reason.
Truthfully, having blurry contacts is way more annoying than hearing about a problem you don’t have. That’s what I try to remind myself of whenever I have to listen to the pre-flight instructions about my seat cushion being a flotation device if the airplane lands in a lake. “This is annoying to hear again,” I’ll think, “but not as annoying as landing in a lake on this flight from Orlando to Cleveland.”
The prevalence of blurry contacts
This issue is far more common than contact lens commercials mention. I’d guess one in every three patients I meet with contacts mentions that they have trouble with blurriness. Granted, there’s a bit of selection bias in the group that I’m talking to since they are visiting me at a place specifically designed to get people out of contacts. But since the problem is common, and since people sometimes want to know why, it seemed like listing out the reasons might help someone who would rather read about it than go to a doctor. Personally, I’m definitely for reading something instead of talking to a doctor.
Two main reasons your contacts are blurry
The first reason your contacts making your vision blurry is the most obvious, and it has to do with the idea of contacts themselves. We hear the word so often, that we don’t think to ask the question, “Why are they named contacts?” If we did, it would be immediately clear that the reason is because they have contact with your eye. They are literally “contact” lenses.
It’s lucky for contacts that they were an immediate big hit, because even though I’m not a marketing guy it seems like naming something for its most naturally revolting feature is probably frowned upon when naming products. It’d be like naming deodorant “armpit smear.” I would have named contacts something like “clearies” or “hocus focuses.” But they are contacts, and because they are in contact with your eye, there is a collection of debris, mucus, and protein stuck to the surface of a foreign object in your eye.
In addition, the fact that contacts are in contact with your cornea means there’s a barrier to the natural diffusion of oxygen to your cornea and evaporative water loss from your cornea, which prevents swelling. The best contacts are the ones with the ability to best mimic not being on the eye. As you can guess, however, the best possible way to emulate nothing being on the eye is to have nothing on the eye. So not wearing contacts wins that contest every time.
The second reason people can find contacts more blurry than glasses or LASIK (if they’ve had it), has to do with the prescription. If someone has no astigmatism, then a contact correcting pure myopia (near-sightedness) or hyperopia (far-sightedness) can usually hit the nail on the head.
But even minor amounts of astigmatism (one diopter or less) are kind of a no man’s land for contacts. Astigmatism correction goes as low as 0.75 diopter, which is pretty low, but people almost universally hate contacts with low astigmatism correction even when they’re prescribed correctly. The reason is those low levels of astigmatism are enough to affect the vision, but not enough to weather the natural rotation of the contact.
When, not if, the contact rotates several degrees depending on the blink, the fluctuations in vision are so annoying that almost everyone in this prescription range chooses to get a prescription that ignores the astigmatism altogether. And there are a ton of people with astigmatism in the range of a diopter or less; it’s about half the population. That’s not even an estimate.
Warren Hill has this famous chart of astigmatism measured in 6000 eyes and it was just over 50% with one diopter or less of astigmatism. (A quick aside, Dr. Hill is so impossibly smart that when I attend his lectures at meetings, I get distracted looking around the room because of how great it is to see 500 eye doctors making the face you’d make if you were trying to multiply 987 times 754 in your head.) So, digression aside, it’s frustrating wearing contacts when you’ve got just enough astigmatism that you have to get contacts that completely ignore it.
LASIK—or eyeglasses—can help
All of the contact lens issues we just discussed can be avoided with LASIK. In full fairness, they can also be avoided by wearing glasses. LASIK can get rid of astigmatism and glasses can usually effectively neutralize it, and both leave the eye free to be bared to the environment in which it was designed to work. It’s the reason most people who wear glasses (or wore them before getting LASIK) have wondered at one point or another why they felt like their contacts were blurry. And to the people who haven’t wondered that, reading all the way to the end of this article through your perfectly functioning contact lenses, you have my respect. I will remember your patience and perspective the next time I listen to the pre-flight instructions.