Contact Lenses 101 | Magruder Eye Institute

Contact Lenses 101

There are numerous contact lens options out there on the market, but how do you know which one is right for you?

In this article we break down the most common types of contact lenses, and exactly how to pick the best one for you.

A Brief History of Contact Lenses

People have always tried to correct poor eyesight. The first evidence of this dates back to the 5th century B.C.E. in ancient Egypt. Archaeologists found that the Egyptians used lenses.

The technology made its way to Rome. Romans used lenses to magnify an image until it became clear.

But after that, lenses were mostly forgotten until the 1200s. Then, Italian inventors made the first pair of eyeglasses. An Italian friar named Giordano da Pisa revealed the very first pair of eyeglasses in 1286. Only 15 years later, Venice introduced regulations for the first eyeglass manufacturing guild.

Technology progressed until Ben Franklin invented bifocals in 1784.

After that, not much happened to correct eyesight until 1971, when contacts came to the market.

Even still, these early contact lenses were stiff and uncomfortable. They moved when the wearer blinked. They didn’t allow enough oxygen to the cornea. In short, they were itchy, gritty, and uncomfortable – a far cry from the relative ease of eyeglasses.

Since then, manufacturers have made comfort their number one priority. They’ve succeeded.

Now, each new type of contact lenses is easier to use and much more comfortable. Even still, 30 – 50% of contact users find them so uncomfortable they return to their eye doctor for help.

So if your first contacts aren’t comfortable, that’s normal. A good Optometrist will work with you to find a style and comfort that fits.

Eyesight is Getting Worse

As we spend more and more time indoors, we spend less time flexing our long distance vision. This has caused an increase in myopia (nearsightedness).

In the early 1970s, only about 25% of the population suffered from myopia. The number is closer to 42% in the early 2000s.

In part, the extra strain from glowing screens close to our eyes attributes to the increase in myopia. Fortunately, there are ways to take care of your eyes to prevent eyesight loss.

In the U.S., about 41 million people wear contacts. Contacts have global annual sales of over $7.2 billion.

The Different Types of Contact Lenses

Contact lenses are possible thanks to various forms of specialized plastics. The most common contact lens material is a silicone hydrogel mix.

Contact lenses need to be rigid enough to maintain their shape and correct a person’s vision. They have to be permeable enough for your cornea to get oxygen, and liquid enough to be comfortable.

Silicone Hydrogel

Silicone hydrogel lenses are the most popular lenses prescribed in the U.S.

They allow more oxygen to reach the cornea compared to other types of lenses. If your cornea doesn’t get enough oxygen, the eye can develop corneal neovascularization.

This develops in 1-20% of contact lens users. Don’t worry though. If you maintain your contacts, you can avoid this and other contact complications

Silicone hydrogel lenses are made of hydrogels – a type of water-containing plastic. This keeps them moist and gives them the ability to form comfortably to your eye.

Silicone hydrogel lenses are popular because they’re comfortable and disposable. Many even offer UV protection to keep your eyes safe from the sun’s rays.

But they can absorb particles from the air around them. Particles include chemicals, bacteria, mold, smoke, sprays, lotions, and soaps. They’re more fragile than hard lenses and can rip and tear more easily.

Since they can absorb particles, most silicone hydrogel lenses only last a few months. Some types of contacts call for the user to dispose and replace their contacts every night.

Gas Permeable Lenses (GP or RPG)

Gas permeable lenses are rigid contact lenses. But they’re more comfortable than conventional hard lenses since they’re permeable.

This gives them a closer fit to your cornea, which enhances comfort. These are only prescribed 11% of the time, but they are great lenses for those with astigmatism.

The user doesn’t need to discard GP lenses as often as other lenses, provided they’re well cared for. In fact, some GP lenses can last a year or longer.

Many gas permeable hard lenses are designed for extended wear.

Hybrid Contact Lenses

Hybrid contact lenses have a small, rigid lens surrounded by a soft hydrogel skirt. This is the best of both worlds. The rigid lens provides crystalline vision and the hydrogel skirt makes them comfortable.

Despite these benefits, hybrid lenses only make up 2% of prescriptions in the U.S.

The hydrogel skirt makes hybrid lenses harder to put in. And they’re more expensive than either silicone hydrogel lenses or gas permeable lenses.

PMMA Lenses

PMMA stands for polymethyl methacrylate. These were the first types of contacts. They’re rigid lenses that are hard for many people to adapt to. They don’t transmit oxygen well. As a result, PMMA lenses are relatively outdated, and they’re rarely prescribed anymore.

How Long Can You Wear Your Lenses?

Depending on your prescription, you need to replace lenses at different frequencies. Some lenses need replacing anywhere from daily to once a year. Your Optometrist will tell you how often you need to replace your lenses, or you can usually find out on the box.


The wearer disposes day to day contacts at the end of the day, and you get new contacts in the morning. Because of this, these types of contacts are more expensive than other options. But if you know you won’t maintain your contacts, these are a great option.

They’re also best for individuals with severe chronic allergies. By getting a new pair every day, you guarantee to keep allergens from building up in your eyes.

Some conditions cause proteins to build up more quickly in their eyes and on their contacts. Dailies are a great option for these individuals as well.

Extended Wear

The user should still remove and clean extended wear contacts at least once a week.

Even though extended wear contacts are safe to be slept in, many eye professionals don’t encourage this. When you sleep in your lenses, your eyes don’t get as much oxygen.

This makes the user more vulnerable to infections – especially corneal infection. This is common because contacts make it harder for your cornea to get the oxygen it needs. So make sure you give your eyes a chance to breathe.


Disposable contacts are usually replaced every 1 – 3 months. Most soft contacts are disposable since they tend to gather particles in the air or wear out. These can also be a good option for those who suffer from allergies.

Power Diameter Curvature: The Parameters of Your Contact Lens

When your optometrist prescribes your contacts, they look at three things. They look at the diameter and curvature of your eye, and the power your contacts need. These factors provide the information to give you the best vision possible.


The power on your contact lenses refers to how strong your prescription needs to be. A positive number indicates farsightedness, and a negative number indicates nearsightedness. Power is measured by 0.25. A 0 power has no corrective nature, and the further away from 0, the stronger the prescription.

Contact lenses have come a long way. Contacts can help vision all the way up to +/- 30.00!


You can find the diameter on your contact lens box by looking for the number labeled DIA. This tells the optician the lens width that fits your eye the best.


The curvature, or BC (base curvature), is measured in millimeters. Your eye has a natural curve, and it varies from person to person. By knowing the curvature, your optician can choose the contact that best fits your eye. This gives you better vision and provides better comfort.

Questions to Ask Yourself

So contacts are great. They can even correct issues that eyeglasses can’t. But are contact lenses the best option for you or your young child? Improper contact use can lead to discomfort or even permanent eye damage.

The following questions will help you choose the best contacts for you.

How Often Will You Wear Your Contacts?

Will you wear your contacts all day every day? Or for sports or special occasions?

Soft contact lenses work best for users who don’t want to wear their contacts every day. Hard contacts need daily wear to get the best results. They actually change the shape of your cornea over time.

Will You Be Able to Care for Your Contacts?

This is crucial to consider. Poor contact maintenance leads to discomfort, infection, and even permanent eye damage. Will you take out and replace your contacts as often as recommended?

Will you set aside time to rinse and care for them daily?

If you know you won’t be able to maintain your contacts, consider sticking with glasses.

If you have young kids, will they be able to maintain their contacts? A good way to tell is by how well they keep their room clean. When they keep a clean room, it’s a good sign that they’re responsible enough for contacts.

Do You Use Bifocal Glasses?

If you use bifocal glasses, you’re in luck! There are special contact lenses available to help you. Ask your optometrist about multifocal contact lenses.

Do You Have Chronic Allergies?

If you have chronic allergies, consider getting daily disposable contact lenses. These can keep allergens from building up in your lenses.

How to Take Care of Your Contact Lenses

The first contact lenses needed several different chemicals to maintain and clean them. Some contacts needed special enzymes to break down proteins. Others would have to sit in solutions for hours at a time before they were safe to use again.

Now, contact maintenance is pretty easy. Every night, gently rub your lenses with contact solution and store them in the case provided. This knocks off any protein or debris build-up and keeps them wet for optimal comfort the next day.

Common Contact Lens Problems

Poor contact maintenance or the wrong prescription cause most contact lens problems. Most often, this causes only mild discomfort, but occasionally poor maintenance causes infections.


Discomfort is the biggest issue with contact lenses. Fortunately, it’s also relatively easy to fix.

To reduce contact discomfort, use eye drops, or take a short break from your contacts, especially if you have dry eyes. If your pair is old, consider a new pair of replacement contacts to ease the issue.

If you have a new pair of contacts and discomfort persists. Return to your optometrist. They can offer a new prescription or a different type of contact. This can remove the discomfort.


If you have the following symptoms, you may have an eye infection.

  • Red eyes
  • Pain
  • Eye discharge
  • Watery Eyes
  • Dry eyes
  • Light sensitivity
  • Swollen eyes
  • Swelling around the eyes
  • Itching
  • Blurry vision

If you’re worried about your eye health, visit your eye doctor immediately to treat the issue.

A Good Optometrist Will Help You Make the Right Choice

There are hundreds of combinations for the different types of contact lenses. Research is always important and a great place to start, your optometrist will help you find the best fit.

Ready to get the best contact lenses of your life? Request an appointment today.