Basic Eye Care Vocabulary

Anti-reflective Coating – By increasing the amount of light that passes through the lens, this coating reduces reflected glare.

Aspheric Lenses -Aspheric lenses are ground flatter than traditional rounded lenses so that the profile is more pleasing. A flatter lens looks better and weighs less.

Astigmatism – A common disorder in which one or more of the eyes refractive surfaces (i.e., cornea, lens) is not symmetrical.

Autorefractor – A computerized screening device designed to detect abnormalities of vision (i.e., nearsightedness, farsightedness, astigmatism).

Bifocals – This lens corrects the wearer’s original vision problem plus the close vision difficulties that arise from presbyopia.

Bridge – The area of the frame-front that rests on the wearer’s nose.

Cataract – A condition characterized by clouding in the natural lens of the eye. Some medical treatments include surgical replacement of the natural lens with an artificial lens.

Cornea – The clear outer covering of the eye.

Eyewire -The section of the frame enclosing each lens.

Frame Width – The size of the frames from left side to right side.

Glass – The most time honored lens has the advantage of excellent scratch resistance and clarity.

Glaucoma – An eye disease characterized by an increase in pressure inside the eye capable of causing damage to the optic nerve. Left untreated, this condition can lead to blindness. Glaucoma is usually treated with eye drops and medications. Severe cases may require surgical correction.

High Index Lenses – These lenses can provide better correction with less mass. Great for anyone who wants thinner, lighter look and feel.

Hyperopia – Farsightedness.

Keratometer – An instrument used to measure the curvature of the cornea. This measurement enables the doctor to accurately fit contact lenses.

Lensometer– An instrument used to measure the power of an individual’s current prescription eyeglasses.

Myopia – Nearsightedness.

Ophthalmologist – A doctor specializing in the eye who is trained to examine, diagnose, treat and manage diseases of the visual system, including all types of surgical procedures. Requires completion of a four-year undergraduate program, four years of medical school and a minimum of three years in ophthalmology training.

Optical Center – The spot on the eyeglass lens where light passes through without bending (refracting). This point is normally placed in front of the pupil.

Optician – A professional trained to fit and adjust eyewear based on the specifications provided by an optometrist or ophthalmologist. Also trained to dispense contact lenses based on the specifications of the ophthalmologists or optometrists.

Optometrist – A primary health care professional who can diagnose, manage and treat routine conditions of the human eye.

Peripheral Vision – The area of vision lying just outside the line of sight to either side of the face.

Polarized Lenses – Polarized lenses allow light to pass through a lens at only one angle, cutting the scattered or diffused light associated with glare.

Polycarbonate – A lightweight material used to make impact resistant lenses. These lenses have built in UV protection.

Presbyopia – A condition given to “older eyes” whereby the crystalline lenses in the eye lose elasticity and do not change shape as easily as they should. Presbyopia causes people to have increased difficulty with near vision and reading, and is corrected with multifocals.

Progressives – These lenses offer the variable correction of bifocals and trifocals without the telltale lines.

Pupil – In the eye, a round hole formed by the iris that regulates what light passes into the eye. Light must pass through the pupil to get to the retina.

Pupillary Distance – The distance, in millimeters, from one pupil center to the other. PD measurement is used to ensure proper lens placement.

Pupilometer – A machine which measures the precise pupillary distance.

Refractions – Eye examinations conducted to determine appropriate eyewear prescriptions.

Retina – Part of the eye that picks up images and transmits them to the brain via the optic nerve.

Scratch Resistant Coating – A coating applied to the outside lens surface, providing hard, durable protection.

Single Vision Lenses – This lens is ground to correct a single vision problem.

Sphere Power – The first number in a prescription for corrective lenses which indicates the type and amount of correction.

Tinting– From sunglass dark to the faintest hint of color, tinting can protect your eyes or make a fashion statement.

Tonometry – Computerized measure of internal eye pressure-glaucoma screening. A tonometer detects glaucoma by measuring the internal pressure of the eye with a puff of air.

Trifocals – This lens has three distinct corrections in a single lens separated by thin lines.

UV Protection – The degree to which a lens or its coating protects the wearer’s eye from the sun’s harmful rays.

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Billings, MT 59102

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111 S Broadway #B
Red Lodge, MT 59068


1150 W. Main St
Lander, WY 82520

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150 E Arapahoe St
Thermopolis, WY 82443

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