Is there any detriment to having a piece of glass or a piece of plastic on the front of your eye all the time? And the reason I ask is not because I think we should live necessarily exactly like our ancestors, but it's a pretty bizarre adaptation to put a lens directly onto the front of the eye.

You have to imagine that the cells and tissues there are accustomed to getting a certain amount of oxygen. They're accustomed to getting a certain amount of interaction with the environment, and you also are now adding another surface. The way that the tears are going to interact with the cornea of the eye are probably changed, and who knows?

Maybe it doesn't make any negative difference at all, but putting a contact lens on the front of the eye is about as close to putting a device on your brain as I can think of, except for maybe the cochlear implant. That's a great question. Now, first of all, I want to distinguish.

There are a few really medical uses for different kinds of contact lenses, like scleral contact lenses. For people who have certain diseases, there are other kinds, but I think what we really want to talk about right now is just kind of the run of the mill. I want to get my prescription taken care of, but instead of wearing glasses, I'm going to wear contacts.

Contacts, even the newest generation contacts, yes, they sort of change the tear dynamics on the surface of your eye. They decrease the oxygen diffusion that's just sort of out in the air onto the surface of our eye, onto the cells that are on the surface of our eye. But most of us, especially as we're younger, have enough tear film reserve, enough oxygen reserve that we can easily tolerate these polymer gel soft contact lenses and wear them happily.

The advantage of contact lenses over glasses, purely from the perspective of correcting your vision, is that there's different elements of the shape of your eye that need to be corrected if you need corrective lenses. And so for example, if the basketball shape of your eye is a little too steep or a little too shallow, that's what the standard glasses correct.

You may have been told that you have something called astigmatism. That's where instead of having a basketball-shaped eye, you have a slightly football-shaped eye. It's not round in the same dimensions on both axes. And again, glasses can correct that. But then there's higher order aberrations in our corneas, in the clear window in the front of our eyes, or to some degree in the lens inside the eye that are focusing the light, that the glasses prescription can't correct.

But if you have a nice, smooth contact lens on the front, it can correct. So a lot of people who wear glasses and contacts will report that they have a much higher quality of vision with their contact lens correction than with their glasses correction. And again, in service of enjoying the best vision that you can enjoy in your daily life, that's an upside to seeing if contacts could work for you.

Now there's another element, though, and that's like, gosh, is there a risk of contact lenses? And especially as we age, we have less tear film reserve, so contacts may become less tolerable as we age. And the other thing is being really good about the cleaning, because the contacts can trap bacteria or fungus.

And if you get a corneal infection from a contact lens, it actually can be quite devastating to your cornea. Even if you successfully treat the infection, you can be left with some corneal scarring. Thankfully, this happens very rarely. But when it does happen, it can be quite difficult on the person thereafter to sort of suffer through having maybe a scar from that infection on the surface of their cornea that leads to some blurring vision, for example.

So we always recommend that if you're going to wear contacts, that you be really attentive to whether you're tolerating them well, and then also to be really attentive to the recommended use and cleaning of the contact lenses. I actually recommend that even though they're a little more expensive to afford, that people should almost always be just using the daily contact lenses that they don't have to clean or use for two weeks or four-week period.

So these are disposable contact lenses? Daily disposable. And I hate to think of, I don't know, filling our oceans or what have you with more polymer or plastic. But at least the contact lenses are small. And it's much safer for your eye to use a daily disposable than to use a two-week or a four-week and be responsible for the cleaning.

The other thing to be really responsible about is sleeping in them overnight. Because overnight when your eyelids are closed, of course, now you're getting even less oxygen to the surface of your eye. And actually, most bacteria, especially many of the infectious bacteria to our bodies and to the surface of our eye, are actually bacteria that don't really like oxygen.

And so we've got a low risk of getting bacterial infections on the surface of our eye. But if we use contacts too much, don't clean them, or sleep in them overnight when our eyelids are closed. And now there's even less oxygen kind of helping keep the surface more clean, if you will.

That increases the risk a lot. So being really good with the recommended use and cleaning of the contacts is critical considering daily use contacts. You don't have to. And look, most contacts are going to be the two-week or four-week kind where you put them in the cleaning solution overnight each time, give them a good rinse, and put them back in the next day.

And again, most people, 99.99-some percent of people, are going to do just fine with that, follow the instructions, and never get into trouble. As we age, they're going to become less tolerable. People are going to say, I used to wear my contacts for 12 hours. Now my eyes feel really dry after 6 or 8 or 10 hours.

Maybe some years after that, they say, gosh, I could barely use it for four hours. I only use them when I go out on a Saturday night. And that's OK. You can back off as you need to back off. But in the meantime, if it helps you, especially in the younger decades, if it helps you really enjoy your best vision, great.

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