In some ways, using contact lenses is easy. Simply pop them in your eyes and you’re good to go. But understanding contact lens terminology can be trickier — especially if you’ve never worn contacts.

“There can be a certain fear people have of asking questions,” says Jennifer Palombi, O.D. She’s a contact lens specialist and spokesperson for CooperVision, a global leader in contact lenses, including Sofmed, with the widest range of prescription options. “But if you don’t understand a term that gets thrown around, there’s not an eye doctor out there who’s going to be mad if you ask what it means.”

In fact, your eye health may depend in part on your ability to understand the terms. For example, if you don’t know the difference between dailies and extended wear lenses (or even multipurpose solution and rewetting drops), you could run the risk of an eye infection.

Here are some terms your optometrist may use and what they really mean.

Did you know that contact lens prescriptions need to be renewed every year? Find an exam time that fits your schedule.

Bifocal Contact Lenses

Bifocal contact lenses have two prescriptions in each of the lenses — one for seeing up close (such as reading) and the other for seeing distances.

Segmented bifocal contacts can work in much the same way bifocal eyeglasses do. The lower part of the lens would contain your up-close prescription and the top part would be set for distance.

There are also concentric bifocal contact lenses, in which the center has the distance prescription and the surrounding ring has the up-close prescription.

Daily Wear Contact Lenses

Daily wear contact lenses are soft contacts that are worn during the day and disposed of at night. (They’re also called “dailies” or “daily disposables.”)

Dr. Palombi says many optometrists prefer to fit their patients in daily contacts for these reasons:

• You’ll wear a new lens every day
• They don’t have to be cleaned every night
• You don’t have to keep track of when you need to replace them

Extended Wear Lenses

Extended wear lenses can be worn continuously — even while you sleep — for up to six nights and seven days, says Dr. Palombi.

They’re made with a particularly breathable type of material (silicone hydrogel), which lets more oxygen into your eyes. Extended wear contacts may be a particularly good option for people who work longer schedules or do shift work.

Eye Exams

Eye exams, also known as comprehensive eye exams, are performed by an optometrist or ophthalmologist, who can check your eye health and prescribe new contact lenses. People who wear contacts need to see their doctor at least once a year.

MiSight^® Contact Lenses

MiSight lenses are a brand of soft, daily disposable contact lenses for children. 

MiSight lenses don’t just correct a child’s vision. They’re also approved to slow the progression of myopia (nearsightedness) in kids who start wearing them between the ages of 8 and 12.

If your child starts wearing MiSight contact lenses, they’ll likely wear them for years or until their vision stops changing, says Dr. Palombi.

Learn more by reading Ask an Optometrist: Is There Anything I Can Do to Prevent Myopia in My Child?

Monovision Contact Lenses

Monovision contact lenses correct for presbyopia, an eye condition in which you have trouble seeing up-close tasks. One lens has a prescription for distance, and the other has a prescription for near vision.

While it can take some adjusting, this type of “blended vision” correction isn’t as radical as it may sound, says Dr. Palombi. Most people, in fact, have a naturally dominant eye that they prefer to see with. With monovision contacts, this naturally dominant eye is usually corrected for distance, and the other is corrected for near vision.

 

Multipurpose Solution

Multipurpose solution is a liquid that’s used for cleaning and disinfecting contact lenses. After you take out your contacts (remember to wash your hands first), wet them with the multipurpose solution and rub them between your fingers to clean off the debris and bacteria. Then rinse the lenses in the solution and store them in a case that also has solution in it.

Multifocal Contact Lenses

Multifocal contact lenses have a gradual transition between a prescription for distance and a prescription for near vision.

Multifocal contact lenses work similarly to bifocal contact lenses in that you can switch between up-close and faraway tasks. The difference is that multifocals don’t have a sharp transition zone where the prescription dramatically changes.

Learn more about the differences between multifocal and monovision lenses by reading Monovision vs. Multifocal Contact Lenses: What's the Difference, and Which One Is Right for You?.

Planned Replacement

Planned replacement refers to lenses that are replaced on a regular schedule — every two weeks or month, for example.

Redness-Relieving Eyedrops

Redness-relieving eyedrops are typically decongestants that reduce the swelling in the eye’s blood vessels, which causes the redness to disappear. (Your eyes can become red when you’re tired or have allergies, among other reasons.)

You’ll need to take out your contacts before you use these drops because deposits can build up on the lenses and further irritate your eyes.

Rewetting Drops

Rewetting eyedrops help keep your contact lenses lubricated while you’re wearing them. They aren’t disinfectants, however, so don’t store your contacts in these drops or use them to clean your lenses.

Rigid Gas Permeable (RGP)

Rigid gas permeable contact lenses are a type of hard contact lens. They tend to hold their shape well.

That makes them a commonly prescribed option for people with astigmatism (an eye condition in which the cornea is curved). They can also be less comfortable to wear than soft contacts, so they aren’t a particularly popular option these days.

Toric Contact Lenses

Toric contact lenses correct for astigmatism. This is a condition in which the cornea or lens of the eye is curved like a football, rather than a basketball. This curvature causes blurry vision.

An eye with astigmatism has a unique shape, so toric lenses are specifically contoured to fit on your eye. Toric contacts can be soft or hard (rigid gas permeable) and are available as daily disposables or for extended wear.

Learn more by reading Have Astigmatism? You Have Contact Lens Options (More Than You Think!).

Recommended reading: America’s Best Guide to Contact Lenses