What are soft contact lenses?

 

If you asked us to come up with a list of the best medical inventions ever, we'd have to include soft contact lenses. These little beauties are made of soft, flexible plastic, so they allow more oxygen to reach your corneas. Thanks to their advanced materials, soft contacts are also extremely comfortable, so you can see clearly without having to rub your eyes or adjust your lenses all day long.

Before John de Carle developed the Permalens in 1974, many people wore rigid gas-permeable contacts. RGP lenses are smaller than soft contacts, so it takes longer to get used to them. It's also easier for RGP contacts to fall out, so soft lenses are a better fit for users who love to play sports.

Soft contacts come in these varieties:

• Daily. Daily contacts are exactly what they sound like — lenses designed to be worn for 1 day.

• Biweekly. Biweekly contacts last for up to 14 days. This doesn't mean you can put them in on Day 1 and leave them in until Day 14, however. You need to remove them every night and clean them thoroughly before you reinsert them.

• Monthly. You can use monthly contacts for up to 30 days before you have to get a new pair. Like biweekly lenses, these contacts aren't meant to be worn continuously. You have to remove them before you go to bed at night (or when you hit the sack in the morning — we don't judge!).

• Extended wear. Extended-wear lenses are designed for continuous wear for up to 7 days. You don't have to remove them every night, making them a convenient alternative to other types of soft contacts.

You can even get toric, multifocal, or spherical lenses to address special vision needs. No matter what type of soft contacts you need, you can count on them having these characteristics:

• Flexible materials that mold to your eye's natural shape

• High level of oxygen permeability (plenty of oxygen reaches your corneas)

• Unmatched levels of comfort

If you're just dying to know what soft contacts are made of, how to read a soft contact lens prescription, or how to remove soft contact lenses, we've got you covered.

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What are soft contact lenses made of?

Many soft contacts are made of silicone hydrogel, an advanced material that packs plenty of moisture into a tiny package. Silicone hydrogel is just a fancy term for an extremely flexible plastic. Some manufacturers also use plain old hydrogels, which have a higher water content than silicone hydrogels.

Both materials have benefits for users, but there's usually a trade-off. With hydrogels, you get more moisture and a lower level of oxygen permeability. Lenses made of silicone hydrogels don't have as much water in them, but they allow more oxygen to reach your eyes. But don't worry — both types of lenses are comfortable and durable, so you can't go wrong with either one.

Soft contact prescription example

So, what exactly goes into a prescription for soft contact lenses? At the top, you'll usually see the name of your eye care professional, their license number, your name and contact information, the prescription number, and the expiration date.

Below that, there are two tables with dispensing information and Rx details. Here's how they look:

 

 

OD stands for oculus dexter. No, it's not one of the spells cast by Harry Potter. It's the Latin phrase for "right eye." OS stands for oculus sinister. It's not as scary as it sounds — it's just the Latin phrase for "left eye."

Now that we have that out of the way, take a look at the dispensing information. The manufacturer is exactly what it sounds like — the company that produced the lenses. In the next column, you'll see the product name: AquaSoft Daily 30-pk.

Keep reading to learn how to interpret the Rx details.

How to read a soft contact lens prescription

At first glance, the Rx table looks like a foreign language — or even worse, the set of math problems that you forgot to finish because you were too busy playing video games. But once you know what all the abbreviations mean, it's easy to decipher. You'll need to know these terms:

• Base curve (BC) measurement

• Spherical power (SPH)

• Cylinder (CYL)

• Axis

• Diameter (DIA)

• Add power (ADD)

• Tint

Base curvature

BC stands for base curvature. As you've probably figured out, your eyes aren't straight; they're curved. For a contact lens to fit properly, it must be curved accordingly. Otherwise, it won't conform to the shape of your eye. BC is measured in millimeters. The lower your BC measurement, the larger the curve or bulge of your cornea.

Spherical power

Spherical power — also known as power — is simply the strength of the lens. Another way to explain it is that lens power corresponds to the amount of vision correction you need. If you see a minus sign in front of this number, you have myopia. Don't panic! This is the medical term for nearsightedness.

If you see a plus sign, you have hyperopia (farsightedness). In the example above, the fictional patient is nearsighted, as indicated by the -1.50 SPH value. Spherical power is expressed in diopters, a unit of measurement developed specifically to represent the optical strength of a lens.

Cylinder

Cylinder is the power of correction needed for astigmatism, a condition caused by abnormal curves in your lenses or corneas. In people with astigmatism, the eyes are shaped like footballs, which makes it difficult for the lens and cornea to focus light on the retina.

Every lens has an oval cylinder that allows you to see clearly. The cylinder value in a contact lens prescription measures the degree at which each lens must account for the abnormal curvature of your eyes. Like spherical power, cylinder is expressed in diopters.

Axis

The axis value also relates to astigmatism, specifically which way the football shape is directed. In some people, the cylinder goes up and down. Other people have cylinders that stretch from side to side. Axis indicates where the cylinder correction should go for the biggest improvement in vision.

Diameter

As you might have guessed, diameter has to do with the size of the lens. It's expressed in millimeters.

Add power

You'll see ADD on your prescription if you need extra help seeing up close. This value always has a plus sign in front of it, as it indicates that you need extra power to read, do crossword puzzles, or work on your stamp collection. It's common to see ADD on your lens prescription if you have presbyopia, a normal part of aging that makes it more difficult to see things up close.

Tint

Not all contacts are clear. In fact, you can get lenses in almost every color of the rainbow, from outrageous orchid to brilliant blue. Some people use colored contacts to express their sense of style, while others wear them on the stage or on the screen.

These colors don't affect your vision, but they make your eyes look awesome. You can get colored lenses to enhance your natural eye color or completely change it, giving you even more flexibility.

Are power and sphere the same for contacts?

Yes, power and sphere are the same. You may see this value written as PWR or SPHR, but both abbreviations refer to the same thing.

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Removing soft contact lenses

Once you find the perfect pair of soft contacts, you need to know how to remove them safely. It takes a little practice, but it's really rather easy. The most important thing to remember is that you need to wash your hands first. Otherwise, you can easily transfer bacteria, dirt, and other substances to your eyes.

After drying your hands, simply look toward the ceiling, hold your eyelid open with your nondominant hand, and use your dominant hand to slide the lens out of your eye. Repeat this process with the other contact.

Whether you need tinted contacts or contacts designed to correct astigmatism, 1-800 Contacts can help. Use our website to find your preferred brand of soft contact lenses.

Did you know you can order contacts online? 

Say goodbye to trips to the eye doctor and hello to convenience! With 1-800 Contacts, you can easily order your contact lenses online and have them delivered straight to your door. Plus, our online vision exam makes it simple to get the prescription you need without leaving home. And the best part? You’ll save money on your first order with 1-800 Contacts. It’s never been easier to get your contacts! 

Original author: Austin Brewer

Original publish date: 1/31/2023

Updated date: 8/4/2025