Glossary of Terms
Accommodation
The ability of the natural crystalline lens to adjust, and with the natural contractions of the muscle in the eye, to focus on objects through a range of near, intermediate, and far distances.
Accommodating lens
As with the natural lens, an accommodating lens moves and flexes, in response to ciliary muscle contractions in the eye. These contractions drive forward movements of the lens so the eye can maintain a clear image as it focuses on near, intermediate and far objects.
Crystalens is the first and only accommodating lens approved by the FDA.
Age-Related Macular Degeneration (pronounced mak-you-lar dee-jen-er-aa-shun) (AMD)
An eye condition in which the center of the retina (the macula) is slowly damaged, affecting central vision.
Amsler Grid
A chart of grid lines and a central dot used to find and check problems with central vision.
Antioxidants
Are the nutrients that neutralize and deactivate free radicals.
Astigmatism
A condition in which the cornea is irregularly shaped, thereby, preventing light rays to be focused so both near and distant objects appear blurred or distorted. Glasses and toric contact lenses (gas permeable and soft lenses) can correct astigmatism.
Cataracts
Are a clouding of the lens inside the eye so that light cannot get through to the retina.
Contact Lens Technician
A specially trained professional, who, in many states, can fit contact lenses after an optometrist or ophthalmologist determines the prescription.
Cornea
The outer, transparent, dome-like structure that covers the eye's iris, pupil, and anterior chamber. Part of the eye's focusing system that transmits and focuses light into the eye.
Daily Wear Contact Lenses
Contact lenses that are worn during waking hours but removed at the end of each day for cleaning and disinfecting.
Disposable Contact Lenses
Contact lenses that are worn and then are discarded and replaced with a new lens.
Extended Wear Contact Lenses
Contact lenses that are worn while sleeping from 1 to 30 days/nights of continuous wear between removals for cleaning and disinfection or disposal.
Free radicals
Are the unstable molecules that disrupt the structure of other molecules, resulting in damage within the eye
Frequent/Planned Replacement Contact Lenses
Contact lenses that are worn on a daily basis with cleaning , rinsing and disinfection each time the lens is removed. The lenses are discarded after the recommended wearing period prescribed by the eye care professional.
Gas Permeable (GP) Contact Lenses
A type of contact lens that is made of a breathable, firm, durable, plastic that is custom fitted to the shape of the cornea.
Hard Contact Lenses
The first widely used type of contact lens, which was made of an inflexible plastic material called PMMA (polymethyl methacrylate). Although they provided excellent optical correction, hard lenses did not allow oxygen through the lens to reach the cornea.
Hyperopia (also Farsightedness)
A condition in which the eye is too short and flat, thereby, preventing light rays from focusing before reaching the retina. This causes an inability to see near objects clearly.
Lens (also crystalline lens)
The transparent, double convex (outward curve on both sides) structure behind the iris. Lenses help to focus light rays into the retina
Macula
Is the part of the eye responsible for detailed central vision.
Myopia (also Nearsightedness)
A condition in which the eye is too long and steep, thereby, causing light rays to focus before reaching the retina. This causes an inability to see distant objects clearly.
Optic Nerve
The nerve at the back of the eye which carries visual impulses from the retina to the brain.
Ophthalmologist
A medical doctor (MD) who specializes in diagnosing and treating eye disorders. They perform eye exams, treat disease, prescribe medication, and perform surgery. They may prescribe glasses and corrective lenses. In some states, ophthalmologists may have opticians and contact lens technicians fit contact lenses.
Optician
Specially trained professional (not a medical doctor or optometrist) who can fill prescriptions for corrective vision by ophthalmologists and optometrists.
Optometrist
A doctor of optometry (OD) who has completed four years of postgraduate education. Optometrists can examine eyes for vision and health problems, and diagnose, treat, and manage many of these diseases and disorders. They can prescribe and fit eyeglasses, contact lenses, and many opthalmic medications.
Orthokeratology
Treatment for corrections, such as myopia, in which the patient wears gas permeable lenses to reshape the cornea in order to be able to see temporarily without vision correction.
Presbyopia
A condition associated with aging in which the normally soft and flexible crystalline lens of the eye hardens and becomes less elastic, making the lens less able to focus incoming light, thereby causing blurred vision at reading distance. Can be corrected with bifocal or multifocal contact lenses or glasses.
Refraction
A test to determine the level of refractive errors and their correction
Retina
The light-sensitive layer of tissue that lines the inside of the back of the eye. The retina translates the optical image into neurologic impulses that are transmitted through the optic nerve to the brain.
