Contact Lenses

Medical Contact Lens vs. Elective (Cosmetic) Contacts
Contact lenses are considered medically necessary if a patient can see well only with contact lenses, and not with glasses. This is best described as eyes that require contact lenses to achieve their best potential vision. Usually, this is due to an irregular front surface of the eye (cornea) that causes the incoming light to be scattered rather than focused on the back inside of the eye (retina). There are many diseases for which this is true. Generally, if you have one of these conditions, you will already have been diagnosed by an eye doctor. Some of the more common causes of this are corneal trauma, post surgical corneal irregularity, and keratoconus. Keratoconus is a condition that causes a progressive steepening and deformation of the corneal surface. The cornea becomes thin and "cone shaped" and in some cases requires surgical intervention if contact lens wear is not successful.

In all of these cases, the contact lens creates a smooth optical surface on the front of the eye that will then allow incoming light to be focused on the retina. Usually rigid gas permeable lenses are prescribed to correct corneal surface irregularities, but in some situations where these lenses are not tolerated, customized soft lenses or a combination of soft and rigid lenses are used.

If you suspect that you might have such a condition, you need an eye exam to diagnose which condition you have. You may arrange an eye exam at Casey Ophthalmic Associates, or with your regular eye doctor. If you see fine with glasses but would like to wear contact lenses for any reason (better side vision, no raindrops on your glasses, better for sports), it is called an elective or cosmetic contact lens fit. We do both types of contact lens fittings here at the Casey Eye Institute.

Some insurance companies will provide benefits under your medical coverage for medical contact lens fittings. Coverage varies dramatically from one carrier to another and we encourage you to check your coverage with your insurance company prior to contact lens fitting.


Daily Wear vs. Extended Wear
Many people want the convenience of putting their lenses in and leaving them in for a week at a time, sleeping with the lenses on. This is called extended wear, and is very convenient. However, it is less healthy for the eyes. "Daily wear" lenses are removed each evening for cleaning and disinfecting, and are more healthful for most patients. Wearing contact lenses for prolonged periods of time, and sleeping in them, reduces the amount of tears and oxygen that reach the cornea (the very front of the eye), and this can lead to various complications, such as eye infections, new blood vessel growth in the cornea, or edema (swelling). Eye infections can be serious, and if an ulcer forms in the 'line of sight", the part of the eye you look through, your vision could be permanently reduced. New blood vessels may grow into the cornea to help bring oxygen to the cornea, but these vessels are abnormal, and if they grow long enough, into the "line of sight", may reduce your clarity of vision. Also, if the vessels become very long, no doctor will prescribe contacts for you, in order to protect your vision. Finally, edema is swelling, and if the cornea in the front of the eye is swollen, you can't see through it very well.


RGP's vs. Soft
There are two main types of contact lenses, soft lenses (hydrogel or hydrophilic) and rigid gas permeable (RGP) lenses. The soft lenses are very flexible, and are larger in diameter than RGPs. The soft lenses are generally very comfortable right from the start, but in some prescriptions may not provide vision as crisp as RGPs. Soft lenses are preferably disposable (see section on disposables vs. conventionals). RGPs are stiffer (they are the improved 'hard' lenses), and smaller. They are comfortable after you become accustomed to them, and may give crisper vision for certain prescriptions. A pair of RGPs generally are used for at least a year. Both soft and rigid contact lenses are good. Your prescription will determine which type of lens will give you the best combination of comfort and clarity.


Disposable, Planned Replacement, and Conventionals
These terms are used for soft lenses. We use the word "conventional" when referring to a lens that is used for an entire year. "Disposables" are lenses that are tossed out after one use, or used for just two weeks before being discarded. Planned replacement lenses are tossed on a schedule, ranging from monthly to every six months, depending on the lens and the condition of the eyes. The advantage of replacing the lens more often is that it's better for your eye health to have a fresh clean lens periodically. The more often the lens is replaced, the better. You toss the lens before the "gunk" (proteins) have a chance to build up, and before the lens has time to deteriorate. The one-day lenses are the best, as you don't need to clean them at all, and you have a fresh, sterile lens each day. The one-day lenses also eliminate reactions to cleaning solutions, since you don't have to use or buy solutions. However, not all prescriptions come in the one-day lenses.

There has been a great reduction in complications associated with contact lens wear since the disposable and planned replacement lenses were developed.

RGPs (rigid gas permeable lenses) are worn for at least a year, but we consider them separately from the soft lenses and don't call them "conventionals." The material they are made from does not deteriorate in the way soft contact lens materials can, so RGPs can be healthful to wear for longer than a year.


Special Uses of Contact Lenses
Contact lenses have many special uses in addition to simply replacing glasses. If your glasses are very thick, or if you have a very complicated prescription, contact lenses may be used in conjunction with thinner glasses to give you better vision than you might have with either glasses or contact lenses alone. The glasses can be a bifocal if needed, and will be thinner and lighter weight than they would be without the contact lenses.

If one eye has a prescription much different than the other eye (anisometropia) so that the glasses lens is much thicker over one eye, a contact lens can be used in only one eye, and then both glasses lenses can more equal and thinner. Also, many people with this type of prescription wear contacts only, without glasses over the contacts.


Bifocal Contact Lenses
Presbyopia is a condition in which the eyes won't focus up close the way they used to. It is a normal, but annoying, aspect of aging, and usually starts sometime after age forty. There are several contact lens options to help with presbyopic eyes.

Both contact lenses can be prescribed for optimum distance vision, with reading glasses used in addition as needed. This works best for people who must have the best distance and/or near vision possible, or for those who don't mind reaching for reading glasses.

The other options for helping near vision in presbyopes with contact lenses compromise the clarity of vision somewhat, so you must be motivated to want to get away from glasses enough to accept slightly blurred vision at distance and at near. Both of the next two options can be done in either soft or rigid contact lenses.

Bifocal contact lenses are available. They offer less clarity of vision than bifocal glasses, but they do allow both of the eyes to see distance and up close, which is an advantage for those who do more near work or computer work.

Monovision is where we set one eye for distance vision and the other eye for near vision. It takes the brain a few weeks to adjust but, as with bifocal contact lens wear, works quite well after you adapt. Driving at night can be more difficult with monovision, at least until you are used to it.


Astigmatism
It used to be that people with astigmatism couldn't wear contacts, or could only wear rigid gas permeable (RGP) contacts. New technology has allowed the development of soft "toric" lenses (that's what we call lenses for astigmatism) for almost any prescription. These lenses are custom fit over several visits. The vision is generally very good with toric lenses, but might not be as crisp as with glasses, especially for people with a high amount of astigmatism. Depending on your prescription, eye health, and vision needs, we may recommend either soft or RGP lenses for you.


Colored Contact Lenses
There are several brands of colored contact lenses now available. The one-day and two-week disposables are favorites with most patients. There are colored lenses that add just a little extra color to blue and green eyes, and there are lenses that completely change the eye color for eyes of any color. There are also fancy, scary lenses for Halloween.


Brands of Contact Lenses
There are many different brands and types of contact lenses. Each has its own use. The lens best for you depends on your visual and eye health needs. After we've analyzed the data from your eye exam, we can tell you which lenses would work best for you. If there are several options, we will involve you in the decision making process. Our goal is to get you into the type of lenses which will be the most comfortable and healthy for your eyes, and give you the clearest vision, at the least expense for you.


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