First, See Your Eye Doctor

If you want to wear contact lenses, you must first see an ophthalmologist, optometrist, or in some states, optician. This is the case even if you don't normally wear glasses, and just want contacts to change your eye color.

The reason? Contact lenses are medical devices that need to be properly fitted by an eyecare practitioner. In the United States, contacts can be legally purchased only with a valid written prescription.

The eye doctor will check your eyes to make sure it's okay for you to wear contacts; today, nearly everyone can, but there are a rare few who can't. Then, he or she will determine your prescription.

Your Contact Lens Prescription

Eye doctors all use pretty much the same shorthand to write down contact lens prescriptions. It can look like a secret code to the uninitiated, but it's really quite simple to decipher. Let's take a look at an example:

In addition to the above information, your prescription may note how often your contact lenses must be replaced (once a month, every two weeks, once a week, daily, etc.). Or you may be instructed verbally, during your exam. Often the lens brand includes this information (e.g., Ophtha-Lens One-Week), but the real judge is your eyecare practitioner, who knows which replacement option is best for your eyes and lifestyle.

Which Way Is the Right Way?

The difference can be subtle, but make sure the lens looks more like a taco than a soup bowl.

A question many first-time wearers have is, "How will I know if my contact lens is inside out?" The trick is to place the lens on your finger so it's forming a cup, then hold it up directly in front of your eyes so you're looking at the side of the cup. If it's forming a "U" with the top edges flared out, it's inside out; if it's forming just a "U," it's correct.

Some contact lenses also have a laser marking, such as the brand name, on the edge to help you (if you can read it properly, the lens is not inside out). Don't worry if you place a contact lens in your eye inside out: it will probably feel uncomfortable, but it can't do any damage.

On to the Good Stuff: Choosing Your Contact Lenses

The selection of contact lenses available can best be described as "vast." Don't worry about becoming overwhelmed, though: contact lenses can be broken down into several main categories based on what they're made of, how often you need to replace them and whether you can sleep in them.

Contact lenses are made of many different types of plastic, but they are divided into two main groups: soft or rigid gas permeable (RGP lenses, now called GP lenses). Soft contacts contain from 25% to 79% water, are easy to adapt to and are quite comfortable. Rigid gas permeable contact lenses take longer to adapt to, but are more durable and more resistant to deposit buildup. They tend to be less expensive over the life of the lens (but the upfront cost is higher) and can offer some people crisper vision than they would have with soft contacts.

The replacement schedule of a contact lens refers to how long you can safely wear it before you need to throw it away. With GP lenses, you generally replace them every couple of years, because they are made of a very durable material (though a prescription change would necessitate new lenses). Soft contact lenses come in a wider variety of replacement schedules:

Wear schedule refers to whether you may sleep in your contacts. The kind you can sleep in are called extended wear, and the others are daily wear.

New Wearing Options

The big buzz in the contact lens world is that 30-day continuous wear contact lenses are back. The good news is, they're made of a different type of material than those that were available in the '80s. With these, a lot more oxygen reaches your eyes while you're wearing them, making them a much safer and more comfortable option. Read more about extended wear contact lenses.

Quite a few companies are now making both bifocal and toric lenses in disposable and frequent replacement styles, in addition to the conventional ones (which last one to several years) that have been around for some time.

Contact Lenses with UV Light Blockers

Another feature of many contact lenses, both soft and RGP, is ultraviolet (UV) light blocking. Researchers have linked UV light to the formation of cataracts. Exposure to excessive UV light also may result in a condition called photokeratitis. Up until 1999, the FDA did not recognize the benefit of UV blockers in contact lenses. That year, manufacturers produced enough studies to show the benefit. As a result, companies may now state that contacts with UV blockers "help protect against transmission of harmful UV radiation to the cornea and into the eye."

You can't tell if a contact lens has a UV blocker just by looking at the lens. The blocker is provided in clear form, so as not to disturb vision. The contact lens packaging will specify if the product has a UV blocker, or you can ask your eye doctor.

But keep in mind that these contacts are not meant to replace sunglasses. A contact lens covers only your cornea, not your entire eye. A sunglass with UV protection can cover more of your eye and the parts of your face that surround the eye, depending on the size of the sunglass lens. That's why contacts with UV blockers are designed to complement sunglass use as an added protection.

Contact Lenses That Can Change Your Eyesight

Wish you could see well without your contacts, but don't want surgery? Orthokeratology or CRT (corneal refractive therapy) might be for you. You wear special contacts at night, and they reshape your eye so that your vision is improved even when you don't have them in.