Lake Eye Associates

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Eye Care Specialists • Routine Eye Exam • How To Insert Eyedrops
Cataract • Glaucoma • Dry-Eye • Tearing
Diabetic Retinopathy • Eyelid Problems • AMD
Retinal Detachment • Low Vision • Red Eye • Refractive Errors • Amblyopia

Eye Care Glossary

Eye Care Specialists (Watch Video)
An ophthalmologist is a physician who specializes in the medical and surgical care of the eyes and visual system and in the prevention of eye disease and injury.

Routine Eye Exam (Watch Video)
Learn how often you and your family members should get eye exams, depending on your ages and risk factors.

How To Insert Eyedrops (Watch Video)
We can provide you with the proper, and easier, way to insert eyedrops.

Cataract (Watch Video)
Learn about the causes of cataracts and about cataract surgery, which replaces your eye’s natural lens with an artificial one.

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Glaucoma (Watch Video)
Early detection and treatment by your ophthalmologist to are the keys to preventing optic nerve damage and blindness from glaucoma.

Dry-Eye (Watch Video)
Find out what makes eyes get dry.

Tearing (Watch Video)
Excess tearing can result from many different causes.

Diabetic Retinopathy (Watch Video)
Hear about how diabetic retinopathy can cause vision loss.

Eyelid Problems (Watch Video)
Find out about eyelid problems and what treatment is available.

Age-Related Macular Degeneration (AMD) (Watch Video)
Get the facts about this disease that destroys your sharp, central vision.

Retinal Detachment (Watch Video)
The new onset of flashes of light and floaters are classic warning signs of a detached retina and should be evaluated by your ophthalmologist as soon as possible.

Low Vision (Watch Video)
Most people develop low vision because of eye diseases and health conditions like macular degeneration, cataracts, glaucoma, and diabetes.

Red Eye (Watch Video)
It is important to find out the cause of red eyes.

Refractive Errors (Watch Video)
Distorted vision is usually correctable with eyeglasses, contacts, or surgery.

Amblyopia (Watch Video)
Amblyopia, also sometimes called “lazy eye,” develops in young children and can mean permanent vision problems if not treated early.

Eye Care Glossary

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| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |

Nearly all modern cataract/lens implant surgery at Lake Eye Associates is performed under topical anesthesia (no needles). the patient is awake during surgery but may be slightly sedated. there might be some instances, especially when patient cooperation is inadequate, that an "eye block" may be necessary. In this instance, the local anesthetic given "blocks" the pain fibers near the optic nerve and immobilizes the eye temporarily.
APHAKIA: The absence of the eye's natural crystalline lens, usually after cataract removal.
APHAKIC SPECTACLES: Thick, plus-powered eyeglasses that were once the standard correction for optical power following extraction of cataract. The glasses were cumbersome and greatly distorted peripheral vision. Today, an intraocular lens (IOL) is implanted in the eye after the cataract is removed.
ASTIGMATISM: Astigmatism is blurry vision produced by football-shaped corneas which are too steep in one place and too flat in another. Astigmatic corneas focus light in two different places in the eye, making both near and distance vision a problem.
ASTIGMATIC KERATOTOMY (AK): Astigmatic Keratotomy (AK) is similar to Radial Keratotomy (RK) in that it is incisional surgery, but the calculated surgical incisions are made traverse to the cornea. AK may be performed in conjunction to RK.
AUTOMATED LAMELLAR KERATOPLASTY (ALK): ALK was a refractive surgery technique for low to moderate myopia. In the procedure, the ophthalmologist places an instrument called an automated microkeratome on the eye which removes, in a shaving motion, a thin layer of cornea only microns thick. An even thinner layer of cornea underneath this top cap is removed, and the top cap is replaced. The procedure does not require sutures. ALK helped lead to the development of Lasik, the current and most popular technique for refractive surgery.
CATARACT: An opacity or clouding of the crystalline lens that may prevent a clear image from forming on the retina. The cataractous lens may require surgical removal if visual loss becomes significant, with lost optical power replaced with an intraocular lens.
CORNEA: The transparent front segment of the eye that covers the iris, pupil and anterior chamber, providing most of the eye's optical power.
CRYSTALLINE LENS: The natural lens of the eye, located behind the pupil, which helps bring rays of light to focus on the retina. The original state of the lens is transparent, but the lens becomes cloudy with age.
DIOPTER (dy-ahp-tur): A measurement of the degree to which light converges or diverges; also of lens refractive power. Equal to the reciprocal of the focal length of a lens (in meters), e.g., a 2-diopter lens brings parallel rays of light to a focus at half a meter.
EMMETROPIA (em-uh-TROP-pee-uh): Refractive condition in which no refractive error is present and distant images are focused sharply on the retina with no need for corrective lenses.
EXCIMER LASER: The excimer laser produces an ultraviolet beam of light which is emitted in pulses. Each pulse removes 1/4000 millimeter of tissue from the surface of the cornea. It would take about 200 pulses from an excimer laser just to cut a human hair in half. The excimer laser has been used in industry since 1971 and has been used in ophthalmic surgery since 1983.
EXTRACAPSULAR CATARACT EXTRACTION: A cataract surgical procedure which removes the cataractous lens but leaves the rear lens capsule intact. Extracapsular surgery which requires larger incisions is rare now that phacoemulsification has become modern standard technique.

FUNCTIONAL VISUAL DISABILITY: The degree to which a visual error interferes with a person's ability to perform normal daily activities, such as reading, driving at night, or performing hobbies.
HYPEROPIA: Also known as farsightedness, hyperopia is a refractive error caused by an eyeball that is too short to focus light on the retina. Light strikes the retina before it can come to a sharp focus.
INTACS: Intacs are tiny plastic ring segments that are implanted in the cornea. Even though they are very small, their mass is enough to change the shape of the front surface of the eye and correct refractive error.
INTRAOCULAR LENS (IOL): A plastic lens that may be surgically implanted to replace the natural lens of the eye. There are numerous styles of IOLs, including foldable IOLs and multifocal IOLs.
IRIS: Pigmented tissue that lies behind the cornea that gives color to the eye (e.g., blue eyes) and controls the amount of light entering the eye by varying the size of the black papillary opening.
LASER ASSISTED IN-SITU KERATOMILEUSIS (LASIK): Laser Assisted In Situ Keratomileusis, or LASIK, combines PRK with elements of ALK. LASIK is considered effective for all levels of myopia, including high myopia up to -20 diopters. The ophthalmologist uses the automated microkeratome to shave off a thin, hinged layer of the cornea. The surgeon then uses the excimer laser to vaporize a thin layer of the underlying cornea, and the top flap is restored to its place. LASIK is the newest refractive procedure and therefore there is little hard data on its outcomes. However, many refractive surgeons believe LASIK holds the most promise for patients with moderate to high myopia. Many patients with nearsightedness, farsightedness, and astigmatism have, through the Lasik procedure, become completely independent or less dependent on their glasses or contact lenses.
MICRON (MY-kron): A unit of length equal to one-millionth of a meter.
MYOPIA: Also known as nearsightedness, myopia is a refractive error caused by an eyeball that is too long to focus light on the retina or a cornea which is too steeply curved. In these cases light focuses instead in front of the retina
OPHTHALMOLOGIST: A physician specializing in the medical and surgical comprehensive treatment of all eye disorders.
OPHTHALOMOLOGY: The medical science of diagnosis and treatment medically and surgically of all eye disorders. The ophthalmologist is a doctor of medicine (M.D.) or doctor of osteopathy (D.O.), who has had premedical college training, medical school, internship, and then an eye residency training program in the specialty of ophthalmology. This training is intensive and includes everything from measuring for eyeglasses to performing the most delicate eye surgery.
OPTICIAN: An optician prepares and fits the glasses or contact lenses that the ophthalmologist or optometrist has prescribed.

OPTOMETRIST: Health care provider trained to prescribe eyeglasses or contact lenses, examine eyes, and detect eye disease.
PERK STUDY: The Prospective Evaluation of Refractive Keratotomy Study, a multicenter study of radial keratotomy outcomes funded by the National Eye Institute. Ten-year results of radial keratotomy patients who had the surgery in 1983 were published in Archives of Ophthalmology in October 1994.; The study found that seven out of ten patients who had the operation on both eyes no longer wore or required corrective lenses ten years after surgery, and 85% of patients saw 20/40 or better without glasses. It concluded that RK is a "reasonably safe operation" that can "effectively reduce but not eliminate myopia."; The study also found that 43% of patients experienced a hyperopic shift following surgery over the ten-year period. These patients typically experienced an improvement in their vision as their refractive error moved closer to 20/20. It is for this reason that ophthalmic surgeons will often intentionally under correct their patients, then monitor the rate of healing before performing a follow-up enhancement procedure if necessary. However, patients whose vision had achieved full correction or near full correction through surgery and who experience a hyperopic shift could become farsighted and need to wear glasses. In most instances, RK has been replaced by LASIK and other related refractive procedures.
PHACOEMULSIFICATION (fay-koh-ee-mul-sih-fih-KAY-shun): A cataract surgical procedure which uses an ultrasonic vibration to shatter and break up a cataract, making it easier to remove. The vibration is delivered by an irrigation-aspiration instrument. In a survey of ASCRS members in 1994, 86% preferred the phacoemulsification cataract removal technique over the extracapsular cataract extraction technique. The technique was invented by Charles D. Kelman, M.D., and was first published in 1967.
POSTERIOR CAPSULAR OPACIFICATION (PCO): Opacification of the posterior lens capsule, sometimes called "secondary cataract," is often a consequence of modern cataract surgery. It occurs when a thin membrane of tissue grows over the remaining capsule following cataract surgery, and can develop in as many as half of all cases between several months and several years after surgery. PCO is treated using the YAG laser on an outpatient basis.
PHOTOREFRACTIVE KERATECTOMY (PRK): A surgical technique employing an excimer laser to reshape the surface of the cornea and thereby reducing nearsightedness. The laser is controlled by a computer which determines for each patient treated the location, number of pulses, and surface area to be impacted by the laser light beam, based on that individual patient's vision and correction needs.
PRESBYOPIA: Also called "old age vision," presbyopia occurs as the lens of the eye ages and becomes less elastic and able to accommodate. Usually becomes significant after age 45 and is often signaled by the need for bifocals.
PUPIL: The variable-sized, black circular opening in the center of the iris that controls the amount of light that enters the eye.
RADIAL KERATOTOMY (RK): A surgical technique employing radial incisions made in the periphery of the cornea to allow the central cornea to flatten, reducing its optical power and thereby nearsightedness. RK has been largely replaced by LASIK and other related procedures.
RETINA: The thin lining at the back of the eye that converts images from the eye's optical system into electronical impulses sent along the optic nerve for transmission to the brain.
SCLERAL INCISION: The external white of the eye through which an incision is made during a cataract operation that uses a scleral incision.
YAG LASER: The YAG laser is a surgical instrument that emits a short pulsed, high energy light beam that can be precisely focused by computer to cut, vaporize, or fragment tissue. The YAG laser is used to treat posterior capsular opacification, a clouding of the remaining capsular tissue that develops postoperatively in as many as half of cataract removal operations. The tissue is vaporized with carefully controlled pulses of the YAG laser, and the surgery is performed on an outpatient basis.

Used With Permission ~ Copyright © 2000 by ASCRS