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Contact Lens 101: Understanding the Different Types

ContactsIn order to choose the right type of contact lenses for you, you must work closely with your optometrist. At The Eye Institute (TEI) of Salus University’s Cornea and Specialty Contact Lens Service, optometrists prescribe contact lenses for a wide variety of concerns, including: nearsightedness, farsightedness, astigmatism, bifocal or multifocal correction, postsurgical treatment and prosthetic/cosmetic needs.

Joel Silbert, OD, FAAO, director of the Cornea and Contact Lens Service, explains TEI provides comprehensive evaluations for all patients to properly determine the best types of contact lenses for them. In addition to an eye exam, optometrists will take into account the measurements of the patient’s cornea and place trial lenses in their eye.

“New contact lens patients are given complete instruction in lens handling, including insertion and removal techniques, and in lens care prior to taking diagnostic lenses home,” he said. “The patient will be scheduled to return in approximately seven to 10 days as they build their wearing time so the optometrist can assess vision, prescription, comfort, appearance and health while they’re wearing the lenses. If any adjustments are needed, they are made prior to ordering the final lenses for the patient.” 

There are many variations, and much of the decision depends on your particular eye care needs and comfort. We’ve broken down the basics so you can understand what types of lenses are available.

There are two main categories of lenses – gas permeable (GP) and soft. GP lenses  are made  of tough plastics. They hold their shape, but allow for oxygen to flow freely through the lens. They are more durable, making them less likely to tear and are resistant to deposit buildup. GP lenses generally provide crisper vision, but are not initially as comfortable as soft lenses.

The more commonly used variety, soft lenses, are made of flexible plastics or silicone hydrogel, allowing oxygen to pass through the lens. They are typically easier to adjust to, as they tend to be more comfortable.

Disposable-wear (replacement schedule) lenses are removed nightly and replaced on a specific schedule – usually, daily, weekly, bi-weekly or monthly. The majority of soft contact lens wearers use disposable-wear lenses. This type of lens should be cleaned with contact lens solution and stored in a case after removal.

Extended-wear lenses are intended for overnight use or continuous wear for one to six nights; a small number of brands are available for wear up to 30 days. Your optometrist will indicate how long you can wear the lenses, but they should be removed weekly to be cleaned. Most extended-wear lenses are soft, but there are a few approved that are GP lenses.

Colored contact lenses change the color of your iris. These types of lenses should only be purchased through your optometrist. Over-the-counter colored contacts pose serious health risks including: eye infections, eye injuries and vision loss.

Orthokeratology (Ortho-K) is the fitting of a special type of GP contact lens that is designed to change the curve of the cornea with overnight wear. They are intended to be removed in the morning and slept in nightly. The patient typically does not wear lenses throughout the day because the effects of the Ortho-K lenses help them see clearly. These lenses are typically used to correct nearsightedness, but can also be used for astigmatism and farsightedness. Ortho-K is an alternative to LASIK surgery.

The contact lens center at The Eye Institute of Salus University offers a full range of traditional and specialty contact lens services. If you are interested in contact lenses, contact us today for an exam and complete evaluation.