Types of Contact Lenses

There are two major categories of contact lenses: Soft Contact Lenses and Rigid Gas Permeable (RGP) Contact Lenses. Regardless of the type of contacts that you are interested in, they require a thorough examination and fitting-and a valid prescription. Within these two major categories are a number of types of lenses for solving different vision problems. These include:

• Soft Daily Wear Contact Lenses
• Rigid Gas Permeable (RGP) Contact Lenses
• Contact Lenses for Astigmatism
• Extended Wear Contact Lenses
• Disposable or Planned Replacement Contact Lenses
• Specialty Contact Lenses
  • Orthokeratology (Ortho-K)
  • Decorative Cosmetic Contact Lenses

Soft Daily Wear Contact Lenses

Soft Daily Wear Contact Lenses are made of soft water containing, flexible plastics, called “hydrogels”, that allow oxygen to pass to the cornea to maintain its health and clarity. Because they are soft, thin and flexible, Soft Contact Lenses are easier to adapt to and more comfortable than Rigid Gas Permeable (RGP) Contact Lenses. A newer type of Soft Contact Lens is made of a “silicone hydrogel” material that allows an even greater amount of oxygen to reach the cornea than any previous soft contact lens, adding additional safety. Soft Daily Wear Contact Lenses require careful cleaning and disinfection, as they tend to attract deposits of protein from your tear film.

Rigid Gas Permeable (RGP) Contact Lenses

Rigid Gas Permeable Contact Lenses (RGPs) are more durable and resistant to deposit buildup, and generally give a clearer, crisper vision. They tend to be less expensive over the life of the lens since they last longer than soft contact lenses. They are easier to handle and do not tear, they can however, break. There is an adjustment period where it may take several weeks of adaptation in order to get used to wearing RGPs as compared to only a few days for soft contacts.

Contact Lenses for Astigmatism

People who have astigmatism, usually have an unequal curvature of their cornea so that it is shaped more like a football than a basketball. Contact Lenses that correct astigmatism are called “toric” lenses. Toric lenses are readily available in both soft contacts and rigid gas permeable contact lens prescriptions. Toric contact lenses require a greater degree of fitting expertise in order to obtain the most precise vision.

Extended Wear Contact Lenses

There are a number of Extended Wear Contact Lenses that are available and FDA approved to be worn overnight or in some cases as long as one to six nights or up to 30 days. Most Extended Wear Contact Lenses are Soft Contact Lenses although there are several Rigid Gas Permeable Contact lens materials that are FDA approved for extended wear.  Soft Extended Wear Lenses are made of highly oxygen permeable hydrogel or “water containing” plastics that allow a great deal of oxygen to pass through to the cornea. Currently, silicone hydrogel materials provide the highest degree of oxygen permeability. The Rigid Gas Permeable Lenses that are designed and approved for overnight wear are typically made of “fluorosilicone” acrylic materials, which do not contain water, but due to the nature of the plastic, are quite permeable to oxygen. How long you are able to wear your contact lenses will depend on the lens type and the specific recommendations of your Optometrist at The Eye Center, based on your contact lens examination, contact lens fitting and the evaluation of your tolerance for overnight wear. In general, it is important for your eyes to have a rest without lenses for at least one night following each scheduled removal. Thus, you must have a pair of backup eyeglasses even if you wear extended wear contact lenses or contact lenses of any type.

Disposable or Planned Replacement Contact Lenses

Today, most daily wear and extended wear soft contact lenses are prescribed with a very specific “planned replacement schedule”. That is, the prescribing eye doctor will give you instructions on how frequently to replace your lenses based on your tear film, how often you may be removing the lenses and how quickly you soil the lenses, even after cleaning and disinfection. True “Disposable” Contact Lenses are worn only once and then discarded. In order to have a “daily wear disposable schedule”, a brand new pair of lenses is used each day.

Patients need to be cautious if they do not have their contact lens prescriptions filled at The Eye Center. Contact lens sellers refer to some soft contact lenses as “disposable”, but actually, they are for frequent/planned replacement. With Extended Wear lenses, the lenses may be worn continuously for the prescribed wearing period (for example, 7 days to 30 days) and then thrown away. If you are wearing your lenses on a planned replacement basis or even an extended wear basis, when you remove your lenses, ALWAYS make sure to clean and disinfect them properly before reinserting them. This is necessary in order to protect the health of your eyes and allow you to continue to wear your contacts comfortably and safely

Specialty Contact lenses

At The Eye Center, the vast majority of contact lenses prescribed fall into the categories as described so far. There are some other types of contact lenses for some special purposes that you may wish to know about.

Orthokeratology (Ortho-K)

Orthokeratology, or Ortho-K, is a contact lens fitting procedure that uses specially designed Rigid Gas Permeable (RGP) Contact Lenses to change the curvature of the cornea in order to temporarily improve the eye’s ability to focus on objects. Orthokeratology is mainly used for the correction of myopia or nearsightedness. Most often, Overnight Wear Ortho-K Lenses are prescribed so that they only need to be worn during sleep. Overnight Ortho-K lenses are commonly prescribed to be worn while sleeping for at least eight hours each night. They are removed upon awakening and not worn during the day. Some people can go all day without their glasses or contact lenses and see clearly enough to carry out most daily activities. Others will find that their vision correction will wear off during the day.

THE VISION CORRECTION EFFECT OF
ORTHOKERATOLOGY IS TEMPORARY!

If Ortho-K is discontinued, your cornea will return to its original curvature and shape, and your prescription will return to its original degree of nearsightedness. Ortho-K lenses must continue to be worn every night or on some other prescribed maintenance schedule in order to maintain the effectiveness of the treatment. Your individual maintenance schedule is determined by the Optometrist who fits you and is based on the fitting characteristics of the lenses, the lens material, the degree of nearsightedness and your overall tolerance to these lenses. If you wish to learn more about Orthokeratology or Ortho-K, please feel free to ask any of our Optometrists questions that you may have, or you can obtain information directly from the FDA (http://www.fda.gov/fdac/features/1998/298_lens.html).

Decorative, Cosmetic Contact Lenses

Another type of specialty lens contact lens that has become popular among people who don’t even have a need for vision correction are contacts that have the sole purpose of changing the appearance of your eyes. These are sometimes called “Plano”, “Zero-Powered” or “Non-Corrective” lenses. Wearers of these contact lenses can temporarily change a brown eyes to blue and can even create different themes such as Halloween or Dracula by modifying the eye’s appearance.

EVEN THOUGH THESE DECORATIVE LENSES DO NOT CORRECT VISION, THEY ARE A MEDICAL DEVICE AND THE FDA STRICTLY REGULATES THEM (http://www.fda.gov/bbs/topics/NEWS/2006/NEW01499.html).

This is because, even without correction, they pose the identical risks to patients that “regular’ contact lenses pose. These include:

• Conjunctivitis or Pink Eye
• Corneal Abrasions
• Corneal Ulcers
• Vision Impairment

Many patients un simply unaware of the need for proper fitting and prescription of these lenses and have purchased decorative contact lenses from beauty salons, record stores, video stores, flea markets, convenience stores, beach shops and the Internet. Buying contact lenses without a prescription is dangerous!

The Eye Center is pleased to offer thorough eye exams, contact lens evaluations and fittings as well as the supply of all types of contacts including soft daily wear contacts, rigid gas permeable contacts, contacts for astigmatism, bifocal contacts, extended wear contacts, planned replacement contacts and disposable contact lenses.

The Eye Center is conveniently located for patients interested in contact lenses from Denver, Aurora, Arvada, Wheat Ridge, Westminster, Highlands Ranch, Conifer, Parker, Pine, Bailey, Centennial, Englewood, Littleton, Sheridan, Cherry Hills Village, Northglenn, Broomfield and Greenwood Village. If you, a family member or friend, would like to schedule a contact lens exam or fitting, please call The Eye Center in Denver, Colorado at 303.777.5455