Eye Glossary
Aberrations:
Small refractive imperfections in the eye that cannot be corrected with conventional LASIK techniques but maybe mapped and treated with Zyoptix Custom LASIK.
Accommodation:
The ability of the eye to change its focus from distant to near objects as well as from near to distant; new multifocal implants such as the ReStor and Technis intraocular lens utilize accommodating technology to give patients a broader range of vision.
AK:
The acronym for Astigmatic Keratotomy, a surgical procedure used to correct mild to moderate degrees of astigmatism; often performed at the time of cataract surgery.
Amblyopia (Lazy Eye):
A condition of decreased vision in one or both eyes that occurs without noticeable abnormalities or diseases in the eye. The best-corrected vision is usually less than 20/20.
A-Scan:
A type of ultrasound measurement used to accurately measure the length of the eyeball.
Astigmatic Keratotmy (AK):
A surgical procedure used to correct mild to moderate degrees of astigmatism.
Astigmatism:
A condition that occurs when the cornea or natural lens of the eye is asymmetrically steepened, resulting in refractive light rays being bent out of focus and distorted vision. Astigmatism is very common and can be corrected by glasses, contact lenses, LASIK, an AK procedure, or special implant lenses such as Toric implants.
Bifocals:
Eyeglasses incorporating two different powers in each lens, usually for near and distance vision corrections.
Blepharitis:
Common, persistent and sometimes chronic inflammation of the eyelids usually resulting from bacteria that reside at the base of the eyelashes or in the oil glands near the eyelid, with dandruff-like scales and particles; usually, only a minor irritation which can be relieved by careful cleaning of the eyelids.
Blepharoplasty:
Surgery to improve the appearance and/or function of drooping eyelids; usually, surgery is performed on an outpatient basis.
B-Scan:
Ultrasound procedure which provides a cross-sectional view of eye tissues; the procedure is used to evaluate structures that cannot be directly seen.
Cataract:
A condition in which the eye’s natural lens becomes cloudy, usually a result of aging or excessive exposure to ultraviolet sun rays, causing blurred vision. Most people over 60 years of age have some degree of cataracts. During modern cataract surgery, this (cloudy) natural lens is removed and replaced by an intraocular lens, which can be monofocal, multifocal, or astigamatic in its correction.
Chalazion of the eyelid:
Inflammatory and oily lump in a meibomian gland of the eyelid. This gland, located just inside the eyelid, supplies the outer portion of the tear film, preventing rapid tear evaporation and overflow and providing airtight eyelid closure.
Clear Lens Exchange (CLE)/ Clear Lens Extraction (CLE):
Also know as Refractive Lens Exchange (RLE), these terms refer to a refractive surgical procedure in which the clear lens of the eye is removed and replaced with a multifocal or accommodating intraocular lens, such as the ReStor, Technis or crystalens. Usually used for LASIK patients who are not good candidates for conventional LASIK.
Color blindness:
A condition which occurs when color-sensitive cone cells in the eye fail to properly pick up or send correct signals to the brain. Red-green deficiency, the most common form, results in the inability to distinguish certain shades of red and green. In rare cases, no colors can be detected, only shades of black, white and gray. Color blindness is usually inherited and cannot be cured.
Conjunctivitis (Pink Eye):
Inflammation of the conjunctiva, the thin clear tissue that covers the white of the eye and lines the inner surfaces of the eyelid. Conjunctivitis is characterized by discharge, grittiness, redness, and swelling. May result from a virus, bacteria, allergens, chemical exposure or ultraviolet light exposure and, depending on the cause, can be contagious.
Cornea:
The clear structure that covers the front part of the eye including the iris and pupil. The cornea provides most of the eye’s optical power, while the crystalline inner lens, located behind the iris serves to “fine-tune” the focus of the images. When both have the correct power, a sharp image is focused on the retina and transmitted through the optic nerve to the brain.
Corneal Abrasion:
A tearing, scrape or puncture of the cornea, resulting in a loss of epithelium, the outer tissue layer of the cornea. This exposes underlying nerves, meaning a corneal abrasion can be very painful. The epithelial layer of cornea heals quickly, usually in a day or two.
Corneal Topography:
A procedure that creates detailed maps of the surface of the cornea using an instrument that combines a computer and video camera; these maps are used to evaluate the cornea prior to surgical treatment and are especially valuable in preparing for refractive vision correction.
Crystalens:
An accommodating intraocular lens (IOL) which, like other premium multifocal implants such as ReStor and Technis, can provide a greater range of vision than the traditional monofocal IOL used in cataract or certain refractive surgical procedures.
Custom LASIK:
Advanced laser vision correction procedure which uses wavefront technology to track and then treat the smallest refractive imperfections (aberrations) that could not be corrected with conventional LASIK techniques.
Diabetic Retinopathy:
A potentially serious complication of diabetes that results in the weakening of tiny blood vessels that nourish the retina. These vessels may leak causing a variety of complications including the formation of scar tissue on the retina, a decrease in nourishment to the retina or bleed into the vitreous humor (the fluid that fills the inner cavity of the eye) causing cloudy vision. If the condition is not treated during the early stages, it can result in blindness. For this reason, diabetics should have regular eye examinations.
Dry Eyes:
A condition due to a deficiency in the production and/or composition of tears in the eye. Symptoms are redness, swelling and irritation, often accompanied by excessive watering (tearing due to irritation) of the affected eye. The condition is more common in older patients and may be worsened by a dry climate, exposure to wind such as from air conditioners and ceiling fans, smoke, or smog. Most cases of dry eyes can be controlled by the use of artificial tear drops prescribed by your eye doctor.
Excimer laser:
A high-energy, cold laser that is guided by a computer under the direction of an ophthalmologist; this type of laser is used in the PhotoRefractive Keratectomy (PRK) and Laser In-Situ Keratomileusis (LASIK) procedures to reshape the cornea, correcting nearsightedness, farsightedness or astigmatism.
Epithelium:
The outer tissue layer of the cornea.
Epi-LASIK:
Refractive eye surgery procedure in which the epithelial (top) layer of the cornea is removed and the excimer laser used to reshape the corneal surface to correct refractive errors. Afterward, the epithelial layer is repositioned over the treated area. This procedure differs from LASIK in that no flap is created.
Far-Sightedness (hyperopia):
The inability to see near objects as clearly as distant objects. This condition occurs when the eyeball is shorter (and/or the cornea is flatter) than the normal eye. LASIK and Refractive Lens Exchange (RLE) are two options available to correct farsightedness.
FDA:
The abbreviation for the Food and Drug Administration, the US government agency responsible for the evaluation and approval of medical devices and pharmaceuticals.
Femto Laser-Assisted Cataract Surgery:
Femto Laser-Assisted Cataract Surgery, or FLACS, replaces many of the steps during cataract surgery that requires a blade and softens the cataract, allowing for easier and smoother removal.
Floaters:
Particles that float in the vitreous (the jelly-like substance that fills the center cavity of the eye) and cast shadows on the retina. The particles may appear to be strung together with a web-like thread. Some floaters are formed before birth while others occur normally with aging. The sudden appearance of many floaters may indicate a serious eye disorder and should be checked by an eye doctor.
Fluorescein angiography:
A test used to examine blood vessels in the retina, choroid, and iris of the eye. Fluorescein dye is injected into an arm vein and rapid, sequential photographs are taken of the eye as the dye circulates, describing any flow abnormalities.
Glaucoma:
A condition associated with elevated pressure in the eye; untreated it can result in gradual, painless, irreversible loss of vision and, eventually, blindness. Two types of glaucoma exist open-angle (the most common) and narrow-angle (less common, but more serious). Glaucoma has few if any symptoms, but a simple, painless eye test to check for elevated pressure often detect the problem.
Hyperopia (nearsightedness):
The inability to see near objects as clearly as distant objects. This condition occurs when the eyeball is shorter (and/or the cornea is flatter) than the normal eye. LASIK and Refractive Lens Exchange (RLE) are two options available to correct farsightedness.
Intraocular lens (IOL):
High tech lens surgically implanted to replace the focusing power of the natural crystalline lens; used in the following procedures: traditional cataract extraction, advanced multifocal implants, Phakic lens implants or during Refractive Lens Exchange (RLE).
Intraocular pressure (IOP):
Measurement of eye pressure. All eye exams include a measurement of this eye pressure using a tonometer. Glaucoma, the leading cause of blindness in adults, is associated with a buildup of fluid pressure. This buildup puts pressure on the optic nerve, permanently damaging eyesight or even causes blindness.
IOL:
The acronym for intraocular lens.
Iris:
Ring of pigmented tissue lying behind the cornea that gives color to the eye and controls the amount of light entering the eye by varying the size of the pupil.
Iritis:
Inflammation of the iris causing pain, tearing, blurred vision, small pupil, and a red congested eye.
Keratitis:
Inflammation of the cornea can be caused by a variety of conditions, including infections, dry eyes, foreign objects, contact lenses, intense light or allergies. The usual treatment is with antibiotics, lubrication or anti-viral eye drops and ointments. An eye care professional should provide medical advice.
Keratoconus:
Hereditary, a degenerative corneal disease characterized by generalized thinning and cone-shaped protrusion of the cornea, usually affecting both eyes.
Laser-Assisted In-Situ Keratomileusis (LASIK):
Currently the most widely used refractive eye surgery procedure. During the procedure, first a flap of corneal tissue is lifted to expose underlying corneal tissue, and then the underlying tissue is reshaped by the cool Excimer laser. Afterward, the corneal flap is repositioned. By changing the shape of the cornea, the eye surgeon can correct nearsightedness, farsightedness, and astigmatism.
LASIK:
The acronym for laser-assisted in situ keratomileusis.
Lazy eye (amblyopia):
A condition of decreased vision in one or both eyes that occurs without noticeable abnormalities or diseases in the eye. The best-corrected vision is usually less than 20/20.
Lens:
the part of the eye that provides some focusing power. The lens is able to change shape allowing the eye to focus at different distances
Macula:
The small, centralized area of the retina responsible for acute central vision
Macular Degeneration:
Degeneration of the macula, or central, region of the retina, resulting in loss of central vision.
Microkeratome:
A sophisticated surgical device used to create a very thin corneal flap at a predetermined depth.
Monofocal IOL:
An intraocular lens replaces the eye’s natural lens and which can correct vision in just one particular range, either near or far. New advanced “multifocal” IOLs now provide a wider range of vision.
Monovision:
A technique used to reduce the need for reading glasses or bifocals in which one eye is corrected for near vision and the other corrected for distance vision. The brain figures out which eye to use and when. Monovision can be accomplished with LASIK or contact lens.
Multifocal IOL:
An intraocular lens replaces the eye’s natural lens and which can provide a wide range of vision, both near and far. Examples of such lenses include the ReStor and Technis IOLs.
Myopia (nearsightedness):
The inability to see distant objects as clearly as near objects commonly referred to as “near-sightedness”. This condition occurs when the eye is longer (and/or the cornea is steeper) than the normal eye. LASIK, Phakic implants and Refractive Lens Exchange (RLE) are options to correct nearsightedness.
Nearsightedness (myopia):
The inability to see distant objects as clearly as near objects. This condition occurs when the eye is longer (and/or the cornea is steeper) than the normal eye. LASIK, Phakic implants and Refractive Lens Exchange (RLE) are options to correct nearsightedness.
Non-Phakic:
Phakic derives from the Greek word for the lens; thus a non-phakic intraocular lens (IOL) means the human lens has been removed before the new IOL lens is implanted. In contrast, a “phakic” IOL means the new IOL is implanted in the eye with the natural human lens remaining.
Ocular Hypertension:
Condition in which the intraocular pressure of the eye is elevated above normal without any obvious optic nerve damage or visual field defects. Over time, ocular hypertension may develop into glaucoma.
Open-Angle Glaucoma:
A condition associated with elevated eye pressure, damaging optic nerve fibers. Sometimes called chronic glaucoma, it is the more common type of glaucoma and is caused by a gradual blocking of aqueous outflow from the eye. If untreated, open-angle glaucoma results in a gradual, painless, irreversible loss of vision.
Ophthalmologist:
A medical doctor specializing in the medical diagnosis and surgical treatment of visual disorders and eye disease.
Optic Nerve:
The nerve that connects the eye to the brain; it carries impulses formed by the retina to the brain, which interprets them as images.
Optician:
A technician trained and in some states certified to fill lens prescriptions and contacts and to fit eyeglasses.
Optometrist:
Doctors of Optometry (OD) are primary health care providers who examine, diagnose, treat and manage visual disorders and eye disease. In accordance with state laws, optometrists prescribe, fit and dispense ocular medications, glasses and contact lenses and, while they may not perform surgery, can assist an ophthalmologist with pre and post-operative care.
ORA:
Optiwave Refractive Analysis, which is a measurement system used during cataract surgery, after the cataract is removed, to allow the surgeon to more specifically tailor the procedure to the patient’s eye, potentially allowing the surgeon to adjust the IOL power and improve patient’s visual outcome
Peripheral Vision:
Side vision, as in not in the straight-ahead direction.
Phacoemulsification:
A technique for removing all eye’s natural crystalline lens in cataract surgery or clear lens extraction. The procedure makes use of an ultrasonic instrument called a phaco machine, which produces vibrations at a rate of 40,000 cycles per second, thereby dissolving the lens into small fragments. The surgeon then aspirates (sucks out) the fragments out of the eye via a microincision, thus avoiding an otherwise large wound.
Photorefractive Keratatomy (PRK):
Refractive eye surgery procedure that employs a computer-controlled Excimer laser system on the corneal surface to alter its curve. By changing the shape of the patient’s cornea, the eye surgeon can correct some cases of nearsightedness, farsightedness, and astigmatism. This procedure differs from LASIK in that no flap is created.
Pink Eye (Conjunctivitis):
Also known as conjunctivitis. Inflammation of the conjunctiva, the thin clear tissue that covers the white of the eye and inner surfaces of the eyelid. Characterized by discharge, grittiness, redness, and swelling. May result from a virus, bacteria, allergens, chemical exposure, or ultraviolet light exposure and, depending on the cause, can be contagious.
Phakic:
Phakic derives from the Greek word for the lens; thus a phakic intraocular lens (IOL) means the new IOL is implanted in the eye with the natural human lens remaining. In contrast, a “non-phakic” lens implant means the human lens has been removed before the new lens is implanted.
Plano:
A term used by eye doctors to describe lenses with no focusing power. The term is most often applied to nonprescription sunglasses or contact lenses that are worn for cosmetic purposes only.
Presbyopia:
A gradual loss of flexibility in the eye’s natural crystalline lens, making it harder for the eye to focus on close objects and resulting in blurry near vision. Usually affects people in their 40’s.
PRK:
Acronym for Photorefractive Keratectomy. Refractive eye surgery procedure that employs a computer-controlled Excimer laser system on the corneal surface to alter its curve. By changing the shape of the patient’s cornea, the eye surgeon can correct some cases of nearsightedness, farsightedness, and astigmatism. This procedure differs from LASIK in that no flap is created.
Pseudophakic:
Phakic derives from the Greek word for the lens; thus a pseudophakic (or false/prosthetic ) intraocular lens (IOL) means the human lens has been removed and replaced by a prosthetic lens. In contrast, a “phakic” IOL means the new IOL is implanted in the eye with the natural human lens remaining in place.
Pupil:
Black opening of the iris, behind the cornea, that regulates the amount of light entering the inner eye.
Punctal Plug:
Small, plugs inserted into the tear ducts to slow drainage and loss of tears. Used to provide dry eye relief and/or reduce or eliminate the major cause of contact lens discomfort.
Radial Keratotomy (RK):
A surgical procedure where patterned surgical incisions are made in the peripheral area of the cornea. As these incisions heal, the cornea is flattened to the degree required to make the desired refractive error correction. This early refractive vision correction procedure has been largely replaced by newer, more accurate procedures such as LASIK and Custom LASIK.
Refractive Error:
Optical defect of the eye that causes light rays to focus in front of the retina (nearsighted), behind the retina (farsighted), or in several different places on the retina (astigmatic), resulting in less than perfect vision. These defects can normally be corrected with eyeglasses, contact lenses or refractive eye procedures such as LASIK.
Refractive Lens Exchange (RLE):
Also known as Clear Lens Exchange (CLE) or Clear Lens Extraction (CLE), these terms refer to a refractive surgical procedure in which the clear lens of the eye is removed and replaced with a multifocal or accommodating intraocular lenses, such as the ReStor, Technis or crystalens. Usually used for LASIK patients who are not good candidates for conventional LASIK
Refractive surgery:
Elective eye surgery which corrects optical defects of the eye by either changing the shape of the cornea or by inserting a plastic lens to supplement the eye’s natural focusing ability.
ReStor:
A new generation multifocal IOL that can give patients a wider range of vision than the traditional monofocal IOL used in cataract surgery. It can also be used in Refractive Lens Exchange (RLE) procedures. For most patients, the AcrySof ReStor IOL delivers excellent near and far vision and good intermediate vision without reading glasses or bifocals.
Retina:
The thin inner layer that covers the inside of the back two-thirds of the eye. The retina converts images into electrical impulses that are sent along with the optic never to the brain and converted into images to allow vision.
Retinal Detachment:
A condition that occurs when the retina pulls away from its supporting tissue. Permanent vision loss may occur if detachment is not repaired within 24-72 hours.
Sclera:
The tough outermost layer of the eye that is visible as the white of the eye.
Sjogerns Syndrome:
An inflammatory disease of glands and other tissues of the body that typically combines dry eyes, dry mouth, and another disease of the connective tissues such as rheumatoid arthritis, lupus, scleroderma, or polymyositis. About 90% of Sjogren syndrome patients are female, usually in middle age or older. Sjogren syndrome can be complicated by infections of the eyes, breathing passages and mouth.
Snellen Eye Chart:
Test chart for assessing visual acuity. Rows of letters, numbers, and symbols in standardized graded sizes, with a designated distance at which each row should be legible to a normal eye.
Strabismus (crossed eyes):
A visual defect in which the eyes are misaligned and point in different directions; usually occurs in childhood. Children with crossed eyes usually adapt when the brain learns to ignore the image of the misaligned eye, although they lose depth perception. Adults who develop the problem often have double vision because the brain is already trained to see two images
Sty:
Inflammation of one or more sebaceous, or fluid-producing, glands of an eyelid.
Tears:
Watery, slightly salty secretion of the lacrimal glands that serve to lubricate the front of the eye and wash away particles and foreign bodies. Natural tears are composed of three layers: the outer oily layer, the middle watery layer, and the inner mucus layer.
Toric:
The AcrySof Toric IOL is a premium IOL designed for patients who have significant astigmatism and who in the past would still have needed glasses for near and distance vision after cataract surgery (because of their astigmatism). The Toric lens can reduce or eliminate their astigmatism and significantly improves their uncorrected distance vision.
Twenty-twenty vision (20/20):
Normal visual acuity as gauged by the Snellen Eye Chart. A person with a normal optical system (20/20 vision) can see standardized symbols on the chart at a distance of 20 feet. A person with 20/30 vision can see symbols on the chart from 30 feet that a person with normal vision could see from 20 feet.
Ultrasound A-Scan:
A type of ultrasound measurement used to accurately measure the length of the eyeball.
Ultrasound B-Scan:
Ultrasound procedures which provide a cross-sectional view of eye tissues used to evaluate structures that cannot be seen directly.
Verisyse:
A phakic intraocular (IOL) placed in the eye in front of the iris during refractive surgery. Like the Visian ICL (see below), the natural lens remains in the eye and the Verisyse lens works with it to correct vision.
Vitrectomy:
Removal of the gel from the inside of the eyeball, because of blood and scar tissue in the gel block sight. An eye surgeon replaces the clouded gel with a clear fluid.
Visian ICL:
A phakic intraocular lens (IOL) is implanted during refractive surgery behind the iris and in front of the natural lens of the eye. Because it does not replace the lens but works with it, it acts similarly to a prescription contact lens.
Visual Acuity:
A measure of the eye’s ability to distinguish object details and shape. Assessed by the smallest identifiable object that can be seen at a specified distance, usually 20 feet for distance vision and 16 inches for near vision.
Visual Field:
The extent of space visible to an eye as it looks (fixates) straight ahead. Measured in degrees away from central fixation.
Vitreous:
A clear, jelly-like liquid that fills the middle of the eye. Also called vitreous humor.
Vitreous Detachment:
Separation of vitreous, which is the jelly-like substance that fills the eye behind the lens, from the retinal surface. Frequently occurs with aging, but may occur in diseases such as diabetes and severe myopia. Usually harmless, but can create retinal tears, which may, in turn, lead to retinal detachment.
Yag Laser:
The short-pulsed, high-energy light beam that can be precisely focused by computer to optically cut, perforate, or fragment tissue.
Zyoptix Wavefront Technology:
A type of technology first used to correct imperfections in the Hubble telescope’s mirrors, now used to measure and correct each individual’s unique visual defects during CUSTOM LASIK.
