Types of contact lenses

What are the different types of contact lenses?

There are a few ways to talk about the different types of contact lenses. They can be grouped by their intended uses, by kinds of contact lens material, and even by wear or replacement schedules. The best type of contacts for each person will be a specific combination of all these factors.

The most common reason to use contacts is to correct a refractive error. These are the conventional contact lenses most people are familiar with. They are a popular alternative to glasses for those who have blurry vision due to myopia, hyperopia or astigmatism. Other kinds of contact lenses have therapeutic or medical uses, and some are purely cosmetic.

Most conventional contacts are available in different kinds of materials. They can be soft or rigid, depending on the materials they're made from. One of the most important factors in these materials is gas permeability. The cornea requires oxygen, so contact lenses have to allow oxygen to pass through.

Older types of "hard" contacts were made from materials that did not transmit oxygen. But soft and newer rigid gas permeable (RGP) contacts both let plenty of oxygen reach the eye. Many people choose soft contacts as the most comfortable and convenient option. However, rigid lenses have other benefits that can outweigh the extra comfort for some people.

Soft contact lenses (SCLs)

Conventional soft contacts can correct all but the more severe or irregular refractive errors. They are usually made with silicone-hydrogel, which is a thin, soft, pliable plastic. It allows SCLs to drape very closely over the shape of the cornea.

This makes them easier to get used to and more comfortable to wear than other types of contacts. It also helps to keep them from being dislodged or accidentally coming out. 

SCLs need to stay hydrated to keep their corrective shape and to be so soft and comfortable. Therefore, they're designed to absorb a lot of moisture. Even so, they can still become too dry throughout the day, which can lead to blurry vision and dry, irritated eyes.

Being so absorptive also has other drawbacks. It makes soft contacts more vulnerable to bacteria and more prone to buildup than other types of contacts. They are also fragile and may tear easily, especially if they are worn too long or become too dry.

However, SCLs are very safe and comfortable as long as they are worn and cared for correctly. They're also available in disposable, daily and extended-wear options. This allows people to choose the type of contacts that is most convenient for their needs.

Rigid gas permeable (RGP) lenses

Most conventional RGP lenses are a special type of plastic made with silicone and fluoropolymers. The fluoropolymers keep them rigid, while the silicone allows oxygen to pass through. These lenses are sometimes called "semi-soft" contacts.

Vision correction with RGP lenses is generally better than with soft lenses. One reason is that RGP lens fittings and design can be more precise. And, since they are rigid, they can hold their precise, corrective shape with no distortion. This also means they can correct certain refractive errors that conventional SCLs can't. 

For example, RGP lenses are sometimes the best type of contacts for people with:

• Higher amounts of myopia, hyperopia or astigmatism

• Irregular astigmatism

• Keratoconus

• Hard-to-fit eyes

In addition, the materials in RGP lenses allow more oxygen to reach the eye than soft lenses. And because they don't fit as closely, they don't need to absorb as much moisture. This reduces buildup as well as vulnerability to bacteria. It can also make them more comfortable for people with dry eyes.

RGP lenses are much more comfortable than older types of hard contacts, which were made with PMMA. However, they still aren't quite as comfortable or convenient as SCLs. But since they are more durable, they last a lot longer and can cost less in the long run.

LEARN MORE about types of contact lens materials

Specialty contact lenses

Conventional contact lenses can correct most refractive errors. However, sometimes people need more specialized contacts. 

Some kinds of specialty contact lenses correct more difficult or complex refractive errors. Others can work well when standard contacts aren't an option due to corneal conditions. There are even special types of contacts that can help treat or manage certain eye diseases.

Many specialty contacts are RGP lenses, but some are soft, and some are even hybrid. There are different types of contacts available for nearly any need. However, they tend to cost more than standard contacts. Many types of specialty lenses require more detailed, complex fittings.

Toric lenses

Toric lenses are soft or RGP contacts designed to correct astigmatism. Most astigmatism is caused by the curvature of the cornea. Instead of being curved like the side of a baseball, the cornea is curved more like the side of a football. 

Toric contacts have a special shape that can correct for these curves. Some toric lenses also have built-in stabilizers that keep them from rotating too much. This helps the customized shape stay aligned correctly on the cornea.

Soft toric contacts can correct most regular astigmatism (when the cornea's curves are symmetric). For irregular astigmatism (when the curves are asymmetric), RGP lenses or other kinds of specialty contacts tend to work better.

Hybrid contact lenses

Hybrid contacts are a combination of soft and RGP lenses. They have a rigid center surrounded by a soft skirt, so they are more comfortable than typical RGP lenses. This type of contact can work well for people who have severe astigmatism or irregular corneas but can't tolerate RGP lenses.

Custom soft lenses

Custom soft contacts are often prescribed for those who have unique vision or fit needs. They can be made with a much wider range of specifications than conventional SCLs.

Specialty SCLs may be a good option for certain people whose eyes are harder to fit due to:

• Unique corneal diameter

• Surface irregularities or growths (like pterygia)

• Mild or moderate corneal thinning

• Irregular astigmatism

• Previous LASIK or PRK surgery

• Previous corneal transplant

Specialty SCLs can also correct higher and more complex refractive errors than standard soft lenses.

Multifocal lenses

This type of contact lens corrects presbyopia in addition to other refractive errors. Presbyopia is the normal loss of near vision that begins around age 40. For people who already wear corrective lenses, multifocal contacts are an alternative to bifocal- or progressive-lens glasses. 

Multifocal contacts can correct presbyopia in combination with:

• Myopia (nearsightedness)

• Astigmatism

• Myopia and astigmatism

• Hyperopia

Multifocals can be soft or RGP contact lenses. Other types of custom contacts, such as hybrid, scleral and toric, can also have a multifocal design.

Scleral lenses

Scleral lenses are larger versions of RGP contacts. They cover the whole cornea without touching it, and their edges rest on the white of the eye (the sclera).

Since they span the whole cornea, scleral lenses are ideal for refractive errors caused by an irregular corneal surface. They can also help to treat or manage certain eye conditions. The space between the eye and the lens can hold saline or medication, and the extra coverage can protect the whole cornea.

Scleral lenses are often the best type of contacts for people who have:

• Advanced keratoconus

• Corneal scarring or injuries

• Severe dry eye syndrome

• Certain other types of eye surface disease

Orthokeratology lenses

Also known as ortho-k, orthokeratology is a type of vision therapy. It involves wearing special RGP contacts overnight to temporarily change the shape of the cornea.

Ortho-k is most commonly prescribed to correct myopia. In people who have myopia (nearsightedness), the cornea is a little too curved. These lenses flatten the cornea during sleep, so vision is clearer when they are removed in the morning. The clear vision then lasts throughout the day for most people. 

The effects of orthokeratology aren't permanent. The lenses have to be worn consistently, or the shape of the cornea will return to normal.

Colored contact lenses

Some types of colored contacts provide vision correction just like standard lenses. Other types are cosmetic or decorative only. They can enhance or alter the color or appearance of the eyes for a fun change. However, non-corrective lenses do still require a prescription. 

There are also more specialized purposes for adding color to contact lenses. For example, certain tints can improve color perception. This can be helpful for those who have color vision deficiency or who want to boost athletic performance. Custom tinted contacts can also help filter light for people who have photophobia.

In other cases, color can be added to create prosthetic lenses. These lenses may be hand-painted, or the color can be computer generated to look more like real irises. Prosthetic colored contacts can mask corneal and iris defects and help manage some of their symptoms.

Disposable, daily and extended-wear contacts

Contact lenses come in a variety of wear and replacement schedules. Wear schedule refers to how long the lenses can be worn per use. Replacement schedule refers to how many times lenses can be reused before they must be replaced.

Conventional SCLs have the widest range of options, both for wear and replacement. The most common options include:

Daily wear – Worn during the day only; must be removed each night but can be reused

Extended wear – Can be worn overnight for one, six or up to 30 nights, depending on the lenses and wearer

Daily disposable – Worn for one day only; must be removed and thrown away each night 

Planned replacement – Can be reused for up to four weeks, depending on the lenses and wearer

RGP contacts have fewer options, but that's because they last so much longer. Most rigid gas permeable lenses are daily wear only but can be reused for one to three years. Specialty SCLs and hybrid contacts are also a little different. Most custom SCLs are designed for monthly or quarterly replacement. Hybrid lenses typically have semi-yearly replacement schedules.

How to choose the right contact lenses

Different kinds of contact lenses work best for different people. The right kind of contacts for each person depends on a balance of vision correction, comfort and the ability to take proper care of them. 

The first step in choosing the right contacts is always to make an appointment with an eye doctor. Before prescribing contact lenses, eye doctors weigh many different factors, including:

Page published on Wednesday, February 27, 2019

Page updated on Tuesday, December 17, 2024

Medically reviewed on Sunday, December 8, 2024