Contact Lens & Vision Glossary
Astigmatism
A condition where the eye is irregularly shaped, causing distorted vision. Toric contact lenses are used to correct for astigmatism.
Bifocal contact lenses
A type of contact lens that contains two focal areas or "viewing zones, one for near distances and one for seeing far distances.
Cornea
The clear tissue of the eye that covers the iris and pupil. Contact lenses "float" over the cornea.
Daily-wear contact lenses
The most common form of contacts, daily-wear contact lenses are worn during waking hours and taken out before sleeping.
Disposable contact lenses
Disposable contacts are very popular, and for worn for one day up to two weeks, at which time they must be replaced. Usually come in a box of 12 lenses.
Dry eye syndrome
Dry eye occurs when the eyes don't produce enough tears, which is more common with contact lens wearers.
Extended-wear contact lenses
Extended-wear contacts can be worn 24 hours a day for up to one week.
Hyperopia (Farsightedness)
A condition where one has difficulty focusing at near distances, caused by the eye being too flat and short.
Iris
The colored portion of the eye surrounding the pupil.
Monovision
This is a contact lens fitting technique that is an alternative to bifocal glasses, bifocal contacts or reading glasses. It may be used with either soft or GP contacts. One eye is fit with a contact lens for distance vision, and the other eye is fit for near vision. Although it is an effective technique, it does have disadvantages. For example, many people who use monovision report compromised depth perception.
Multifocal contact lenses
A type of contact lens containing more than one focal area or "viewing zone". Trifocal and bifocal contact lenses are examples of this type.
Myopia (Near-sightedness)
A condition where one has difficulty focusing at far distances, caused by the eye being too long.
Ophthalmologist
Ophthalmologists are medical doctors with an MD degree who specialize in the eyes. They perform eye exams, treat eye disease, and perform eye surgery.
Optometrist
Optometrists are medical doctors with an OD degree that complete four years of post-graduate school. Optometrists perform eye exams, prescribe eyeglasses and fit contact lenses.
Presbyopia
With aging, the eye becomes less able to focus correctly at reading distances. As a result, reading glasses or bifocal contact lenses or eyeglasses are needed.
Progressive contact lenses
Progressive contact lenses offer clear vision at near, intermediate and far distances. The different "viewing zones" on the lens gradually blend together, instead of a sharp delineation such as for trifocal or bifocal contact lenses.
Pupil
The dark portion in the center of the eye that collects light.
Refraction
A measurement of the eyes to determine your degree of vision or visual acuity.
RGP contact lenses
An abbreviation for Rigid Gas Permeable contact lenses, which are made of hard plastic that is custom-fit to the shape of your eye. Also sometimes called GP contact lenses.
Soft contact lenses
Soft contact lenses are made of thin plastic that contains water. Soft contact lenses are very comfortable but are not as sturdy as rigid contact lenses and so must be replaced more often.
Toric contact lenses
A contact lens designed to correct astigmatism.
Trifocal contact lenses
A contact lens that contains three different "viewing zones" for clear vision at near, intermediate and far distances.
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