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, a thorough examination and fitting is required.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
- Bifocal & Multifocal Contact Lenses for Near Vision Presbyopia
- Specialty Contact Lenses
- Scleral Contact Lenses
- Other custom lenses to fit irregular corneal shapes
- Decorative Non Prescription Contact Lenses
Soft Daily Wear Contact Lenses
Soft Daily Wear Contact Lenses are made of soft flexible plastics called “hydrogels”, that also have water content and 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 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 less likely to tear. However, they are not as comfortable as soft contacts and it may take several weeks of adaptation, 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” contact lenses. Toric lenses are readily available in both soft contacts and rigid gas permeable contact lens prescriptions. Toric contact lenses require more intricate fitting sessions and professional expertise to achieve optimal visual acuity.
Extended Wear Contact Lenses
There are a number of Extended Wear Contact Lenses that are available and FDA approved to be worn overnight, 1 week, or even 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 the highest degree of oxygen permeability is provided by silicone hydrogel materials. 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 eye doctor 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.
Contact Lenses Over 40
There are manycontact lensoptions for patients over 40. One condition common during the aging process that can be successfully addressed with properly fitted contact lenses is presbyopia, thought to be caused by a gradual thickening and loss of flexibility of the lens of the eye as we age. Presbyopia is characterized by the increasing need to hold books, magazines, newspapers, menus, and other reading materials at arm’s length in order to focus properly. When presbyopia sufferers perform near work, such as reading up close or handwriting, they may develop headaches, eye strain or feel fatigued.
Distance Contact Lenses with Readers
One option is to wear contacts that correct only for distance, and use a pair of reading glasses whenever needed. This option provides the sharpest distance and near vision, but you will still need glasses whenever you are doing any close work.
Monovision Contact Lenses
The next option is called monovision, where one contact lens corrects for distance and the other corrects for near. This option is well accepted by many patients, but not by all. It can decrease depth perception slightly, and it does take a short period of adjustment. This option is good for people with astigmatism, and also for people who don’t normally need any distance correction.
Multifocal Contact Lenses
The final option is multifocal contact lenses. Multifocal lenses can be fit in either RGP or soft contacts. They are also available for patients with astigmatism. These contacts focus on near, intermediate, and far objects at the same time. Your brain learns to select what part of the lens you should be using and tunes out the other part. There is a period of adjustment with multifocal contacts, but most patients find them to be a convenient alternative to wearing reading glasses.
Decorative Non Prescription Contact Lenses
There is a type of specialty contact lens that has become popular among people who have solely a cosmetic goal with no need for vision correction. These lenses are specifically designed to change the appearance of your eyes. These are sometimes called “Plano”, “Zero-Powered” or “Non-Corrective” lenses. Wearers of these contact lenses will appear to have a different eye color. For example, one can “change” 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 THEFDA STRICTLY REGULATES THEM.
This is because, even with 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 are 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 and illegal.
Caution When Refilling Contact Lens Prescriptions
Patients need to be cautious if they do not have their contact lens prescriptions filled at Matossian Eye Associates.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. We generally recommend that extended wear be kept to a minimum, due to the increased risk of infection and corneal ulceration. Your doctor at Matossian Eye Associates will discuss your individual health and needs and make an appropriate recommendation about wearing schedules.
