The standard representation for normal eyesight where the first “20” refers to the distance in feet between the eye being assessed and the eye chart and the second “20” changes according to your visual acuity compared to the normal eye. When the second number is higher than 20, it indicates nearsighted vision. For instance, 20/80 means that the person being tested must stand only 20 feet from the eye chart to see clearly what a person with normal vision can see clearly from 80 feet. When the second number is lower than 20, it indicates vision that is better than 20/20 vision. For instance, 20/16 means that the person being tested can see from 20 feet what a person with normal vision must be only 16 feet away to see clearly.
This is the American Academy of Ophthalmology.
This is the American Board of Eye Surgeons, a professional organization for ophthalmologists affiliated with the American College of Eye Surgeons (ACES).
The American Board of Ophthalmology, the medical specialty board that certifies ophthalmologists. It offers education and examinations and when an ophthalmologist has completed the 18-month program, he or she is “Board Certified”.
This is the eye’s ability to switch focus between near and far objects by the circular ciliary muscle which surrounds the lens controling its curvature. A flatter curvature focuses distant objects and a steeper curvature focuses nearby objects.
Acuity measures the sharpness of central vision. Normal visual acuity is defined as 20/20 on the Snellen acuity chart used to establish your glasses prescription. The chart has rows of letters that start large at the top and get smaller towards the bottom.
ALCON ACRYSOF RESTOR
Our physicians appreciate the long-term clinical results and unmatched stability of this family of lenses that has been used in more than 50 million surgeries worldwide. They draw upon decades of expertise and technology to truly help cataract patients see near, far, and everything in between without the need for reading glasses or bifocals after surgery. At 6 months post-op, 78 percent of patients reported not needing glasses, and 94 percent of patients indicated that they would have the lenses implanted again.
These are drugs that block receptors in arteries and smooth muscle to relax the blood vessels and lead to an increase in blood flow and a lower pressure for the control of hypertension. In the urinary tract they enhance urinary flow for enlarged prostates. Alpha blockers include doxazosin (Cardura), prazosin (Minipress), and terazosin (Hytrin).
This is the use of one eye less than the other. It causes the less-used eye’s visual acuity to deteriorate. If amblyopia is left untreated, the brain will eventually be unable to interpret any images from the less-used eye. This condition is also called “lazy eye”.
AMBULATORY SURGERY CENTER (ASC)
An ASC is a medical facility staffed with health professionals similarly to conventional surgery departments in major hospitals. However, ASCs are focused on procedures that do not require overnight hospitalization. Most patients who are in relatively good health may receive treatment at ambulatory surgery centers which can be part of a general hospital, a specialty hospital, or an independent medical facility with prearranged hospital support. The Woolfson Eye Institute ASC is exclusive to our patients and affords far more comfort and convenience.
ANGLE CLOSURE GLAUCOMA also NARROW ANGLE GLAUCOMA
Closed-angle glaucoma accounts for less than 10% of glaucoma cases in the United States, but as much as half in Asian countries. Patients can present with sudden ocular pain, seeing halos around lights, red eye, very high intraocular pressure, nausea and vomiting, sudden decreased vision, and a fixed, mid-dilated pupil. This is an ocular emergency.
This is impaired vision where the left and right retinal images have different sizes. It may be caused by refractive surgery and may also occur naturally.
This is the anatomical term for the front part of a structure.
This refers to a large group of chemical substances often produced by various microorganisms and fungi that inhibit the growth of or destroy bacteria and other microorganisms. They are used in the treatment of infectious diseases.
This is a condition where one eye is farsighted and the other is nearsighted.
These are nutrients that destroy or neutralize free radicals.
Is the name for the condition of having no lens present in the eye.
APODIZED DIFFRACTIVE TECHNOLOGY
Apodization is the gradual reduction or blending of diffractive step heights. The AcrySof® IQ ReSTOR® IOL features patented apodized diffractive technology that distributes the appropriate amount of light to near and distant focal points, regardless of the lighting situation. The apodized diffractive optics are also designed to improve image quality and minimize visual disturbances—a significant improvement over traditional multifocal technologies.
This is the fluid in the eye’s anterior chamber flowing between the cornea and the lens and providing nourishment and moisture.
ARGON LASER TREATMENT
Argon lasers produce a focused green light that can be aimed to burn malfunctioning tissue and eliminate their ongoing complications. Examples include poor blood flow through the retina causing retinal tissue malfunction. The laser treatment may also be used to adhere the retina to underlying structures of the eye or destroy (ablate) leaking vessels in wet macular degeneration cases.
Artificial tears are lubricant eye drops used to treat the dryness and irritation associated with deficient tear production in keratoconjunctivitis sicca (dry eyes), to moisten contact lenses, and in eye examinations.
This is the American Society of Cataract and Refractive Surgery, which is a professional organization for ophthalmologists who provide cataract and refractive surgeries.
Astigmatism usually occurs when the front surface of the eye, the cornea, has an irregular curvature and so light entering the eye is not focused equally in all directions. The patient’s vision is much like looking into a distorted mirror, because of this inability of the eye to focus light rays to a point.
This is an ultrasonic procedure to locate foreign bodies in the eye and check for abnormalities.
These are any members of a division (Bacteria) of monerans. They are microorganisms which are typically one-celled, have no chlorophyll, multiply by simple division, and can be seen only with a microscope. They occur in three main forms: spherical (cocci), rod-shaped (bacilli), and spiral (spirilla). Some bacteria cause diseases such as pneumonia and anthrax, and others are necessary for fermentation, nitrogen fixation, etc.
This is inflammation of the eyelids. It can have a variety of causes, such as an allergic reaction, bacterial infection, or excess oil from eyelid glands. Anterior blepharitis affects the outside of the eyelid, where the eyelashes are attached. Posterior blepharitis affects the inner eyelid and is caused by problems with the oil glands. Both types of blepharitis can cause a burning sensation, excessive tearing, itching, sensitivity to light (photophobia), red and swollen eyelids, redness of the eye, blurred vision, frothy tears, dry eye, or crusting of the eyelashes on awakening.
These are eyeglasses with two areas in the lens. One is for distance vision and the other is for near vision.
This is vision with both eyes, providing the brain with two slightly different sets of images that are combined to give depth perception.
This is a small gap in the visual field caused by lack of light-sensitive cells on the retina where the optic nerve exits the eye. Each eye has a blind spot.
Blindness is the condition of lacking visual perception due to physiological or neurological factors. Various scales describe the extent of vision loss, but total blindness is the complete lack of form and visual light perception and is clinically recorded as NLP, an abbreviation for "no light perception."
Blurred vision occurs when images seen with the eye are not clear or distinct. It is a not a disease in and of itself, but a symptom that can be caused by a wide variety of eye problems including astigmatism, glaucoma, macular degeneration, cataracts, diabetes, optic neuritis, corneal edema, keratitis and uveitis.
Cardiovascular problems are typically the symptoms of cardiovascular disease (also referred to commonly as heart disease). They are the class of medical problems involving the heart or blood and arteries and veins (blood vessels).
In this surgery, the cloudy lens (from the cataract) is removed from the eye and in most cases the focusing power of the eye is restored by replacement with a permanent intraocular lens implant.
The thickness of the cornea or Central Corneal Thickness (CCT) is measured by an instrument called a Corneal Pachymeter and the test is called Pachymetry. It is done in the office with a device similar to the one that is used to measure the pressure. It requires only a drop to numb the eye. For most people the thickness of the cornea does not change much over time, so most people need it measured only once. Corneal thickness has been shown to be a good predictor of certain diseases, such as those with thicker corneas are less susceptible to glaucoma.
Central vision describes a person's field of vision when looking straight ahead. It is the most commonly used part of human vision, allowing one to read and perform most other daily tasks and routines. The central vision picks out details of objects, providing the brain with feedback and creating a crisp, clear picture in front of the viewer's eyes. It is also responsible for interpreting colors and shapes of the objects being viewed. Central vision depends on the human eye having a properly functioning macula which includes tightly packed cones, the cells responsible for proper viewing of colors and details.
CHALAZION also CHALAZIA (the plural)
A chalazion is a slowly developing lump that forms due to blockage and swelling of an oil gland in the eyelid. It is more common in adults than children and occurs most frequently in persons 30 to 50 years of age. They initially appear as red, tender, swollen areas of the eyelids. However, in a few days they change to a painless, slow growing lump in the eyelid. They often start out very small but may grow to the size of a pea.
The width of the iridocorneal angle is one factor affecting the drainage of aqueous humour from the eye's anterior chamber. A wide angle allows sufficient drainage of humour through the trabecular meshwork (unless obstructed), whereas a narrow angle may impede the drainage system and leave the patient susceptible to acute angle-closure glaucoma. Gonioscopy indicates the angular width of the iridocorneal angle by the number of ocular structures visible above the rim of the iris – the more structures visible, the wider the angle.
Open-angle (also known as chronic) glaucoma is the most common type of glaucoma. Although, the cause is unknown there is an increase in eye pressure occurring slowly over time that pushes on the optic nerve and the retina at the back of the eye. It tends to run in families, and people of African descent are at particularly high risk for the disease
These are a step in medical research conducted to allow safety and efficacy data to be collected for drugs, diagnostics, devices, and therapy protocols. They can take place only after satisfactory information has been gathered on the quality of the non-clinical safety, and Health Authority/Ethics Committee approval is granted.
This refers to collaboration between doctors in the care of a patient. In the case of refractive surgery, an optometrist will often co-manage with an ophthalmologist, providing the initial testing and the post-operative care, while the ophthalmologist performs the surgery itself.
Collagen fibers are naturally occurring proteins found exclusively in animals. They are the main proteins in the connective tissues, and are the most commonly found protein in mammals making up 25 to 35% of the protein.
This is a genetic confusion of red and green, and because this gene is on the X chromosome; it most often occurs in males.
This is a disease or injury that develops during the treatment of the primary disorder being managed. An example is an infection that is contracted during surgical recovery. The complication frequently alters the prognosis.
This is your consultation with your Woolfson doctor where your medical condition and history and current case are reviewed and a comprehensive eye exam and appropriate additional testing is performed to begin to craft a customized treatment plan for you.
COMPREHENSIVE EYE EXAM
This is sometimes referred to as a “medical” eye exam to differentiate it from a less clinical exam such as one simply designed to fit you with glasses or contacts. This exam may take as long as an hour and typically includes tests for visual acuity, field of vision, extraocular movements, pupillary reactions, retinoscopy/refraction, overall eye health, intraocular pressure, and a dilated fundus examination.
These are one of the two types of light-sensitive cells in the retina that cluster around the center part of the retina and give sharp central vision in bright light. They also detect color, with one kind of cone absorbing blue, another kind absorbing red, and another kind absorbing green. Rods are the other types of light-sensitive cells.
This is the thin, clear, and moist membrane that covers the inner surfaces of the eyelids and the outer surface of the eye. The part that coats the inner aspect of the eyelids is called the palpebral conjunctiva while that covering the outer surface of the eye is called the ocular or bulbar conjunctiva.
This is a contagious inflammation of the conjunctiva, the lining of the eyelids. It is itchy and makes the white sclera look pink or red and is often treated with eye drops.
A contact lens, or simply a contact, is a small plastic or glass lens placed directly onto the front of the eye to correct vision. They can also be ordered in various colors to cosmetically mask the iris and make it appear to be a different color.
The cornea is the clear front covering of the eye, in front of the iris and pupil. It is a type of lens and refracts light entering the eye. The light is then further refracted by the crystalline lens, behind the cornea, so that it focuses on the retina. Please see our page Eye Anatomy: The Cornea for more detail.
Corneal curvature is key to correcting refractive problems. Placido disk technology is currently one of the standards for measuring corneal curvature with topography. All corneal topography nomograms and individual maps use thousands of data points to graphically present information. The different types of maps represent different data of the same corneal shape. Axial and tangential maps represent measurements of corneal curvature. Central tangential maps show detailed patterns and reveal a more exact location of a corneal defect.
There are many diseases and disorders that can occur related to the cornea including: allergies, conjunctivitis, corneal infections, dry eye, Fuchs’ Dystrophy, Herpes Zoster or shingles, etc. Regular comprehensive eye exams and a quick response to any symptoms are important to catch and treat corneal diseases early.
Corneal Edema is the swelling of the cornea following ocular surgery, trauma, infection, inflammation, as a secondary result of various ocular diseases, or following over-wear of certain contact lenses. When the cornea swells, it may impair transmission and focusing of light, possibly decreasing vision.
This is another term commonly used for a corneal transplant. See corneal transplant.
A corneal infection is a viral or bacterial attack on the cornea, the clear lens which covers the eye. Infections in the cornea are an ocular emergency and should be treated immediately by your Woolfson medical experts.
This is scarring, similar to a scar anywhere else on your body, which is found on the cornea – normally clear covering – of the eye. These scars produce opacity of the cornea and can definitely obscure vision.
The clear covering of the eyeball is called the cornea. Surgery is performed on the cornea using standard surgical techniques or lasers for two main reasons. One is to remove scarring and clouding that interfere with vision. The other is to change the curve of the cornea to correct vision problems.
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behavior.
The eye's natural lens. Transparent, biconvex intraocular tissue that helps bring rays of light to a focus on the retina.
DEEMED STATUS FROM THE CENTERS FOR MEDICARE AND MEDICAID SERVICES
a status conferred on a hospital or other organization by a professional standards review organization in formal recognition that the organization's review, continued-stay review, and medical care evaluation programs meet certain effectiveness criteria.
This is nearsightedness that begins at birth or in childhood and can lead to blindness. It is thought to be hereditary.
This is the ability for a person to assess the relative distances of objects. The dominant eye looks directly at an object while the other eye looks from a slight angle. The brain processes the two images to estimate the distance.
Disorder in which repeated hemorrhage results in permanent opacity of the vitreous humor; blindness may eventually result; occurs most frequently in individuals with long-standing, poorly controlled diabetes.
Dilation is the widening of the eye’s pupil, in the center of the iris. The iris, which is a muscle, changes the pupil size to allow more or less light into the eye and for some procedures the eyes are dilated with special eye drops.
This is the unit of measurement for a lens. A convex lens (curving outwards) has positive diopter numbers and a concave lens has negative diopter numbers. A lens of +1 diopter will refract (bend) light rays to a focus one meter away from itself.
This is the clinical term for double vision.
This is the eye that looks directly at objects. The other eye sees the objects at a slight angle. Use of two eyes is known as binocular vision and provides depth perception.
Double vision or “ghosting” is a condition where you see a relatively faint second image of each object.
DRY EYE SYNDROME
This is chronically insufficient moisture in the eyes that gives a feeling of burning and increased light-sensitivity. It can be caused by an eye condition such as Ocular Rosacea. Dry eyes are a temporary side effect of LASIK, but Dry Eye Syndrome is long-term.
DRY MACULAR DEGENERATION (ATROPHIC)
Dry macular degeneration is sometimes called atrophic, nonexudative, or drusenoid macular degeneration. With dry macular degeneration, yellow-white deposits called drusen accumulate in the retinal pigment epithelium (RPE) tissue beneath the macula.
DSAEK (DESCEMET’S STRIPPING AUTOMATED ENDOTHELIAL KERATOPLASTY)
This is a procedure developed in 2007 to improve corneal transplants. Descemet’s Membrane is the cornea’s innermost layer. DSAEK transplants just this layer instead of the entire cornea. No stitches are needed and recovery time is one to three months instead of one to two years.
This is the wasting or weakening of body tissue. In the eye there can be Epithelial, Stromal, and Endothelial dystrophies, affecting the cornea’s epithelium, stroma, and endothelium respectively. Fuch’s Dystrophy and Keratoconus are endothelial dystrophies.
Endothelial cells line the entire circulatory system, from the heart to the smallest capillary. These cells reduce turbulence of the flow of blood, allowing the fluid to be pumped farther.
See Fuch’s Dystrophy
The epikeratome is a surgical tool used in Epi-LASIK to make the corneal flap. It has similarities to the microkeratome used for the LASIK flap, but instead of a thin, sharp blade, it has a blunt separator. The flap in Epi-LASIK is thinner than the LASIK flap.
The epithelium is a surface layer of cells that protects the tissue beneath it. The corneal epithelium is where the LASIK flap is created, although it also includes some of the stroma, the middle corneal layer. In IntraLase, epi-LASIK and LASEK, the flaps are made thinner, consisting only of epithelial cells.
This is the condition of crossed eyes. Typically one eye looks directly ahead and the other turns inward. Esotropia can be congenital, infantile, accommodative, or partially accommodative. Misaligned eyes should be corrected as soon as possible.
EXTREME SENSITIVITY TO LIGHT
Photophobia is not a disease, but a symptom of many conditions such as infection or inflammation that can irritate the eyes.
Optometrists and ophthalmologists use a wide variety of tests and procedures to examine your eyes. These tests range from simple ones, like having you read an eye chart, to complex tests, such as using a high-powered lens to visualize the tiny structures inside of your eyes.
Tumors in the eye usually are secondary tumors caused by cancers that have spread from other parts of the body, especially the breast, lung, bowel or prostate. Two types of primary tumors arise within the eye itself and are known as retinoblastoma in children and melanoma in adults.
EYE'S FOCUSING MUSCLES
The eye has both internal and external muscles. The internal muscles control focusing and pupil size. The external muscles direct the eyes to the point of interest and keep the retinal image in constant slight motion.
Crystalens is currently the only FDA-approved accommodating PIOL. An accommodating lens adjusts and changes shape with the natural movement of the muscles in the eye to focus in a manner similar to a healthy human lens.
This is a Fellow of the American College of Surgeons.
This is the popular name for hyperopia.
Is the acronym for the U.S. Food and Drug Administration.
FIND AN AFFILIATE DOCTOR
These are strands or specks floating in the field of vision. They cannot be focused upon because they move when the eyes move, as they are the shadows cast on the retina by clumping cells in the vitreous humor. Typically they are more visible against a blank background such as snow or the sky. In most cases they are harmless unless flashes of light accompany them which could suggest a possible retinal detachment.
This refers to the combined action of the cornea and lens in refracting light to focus on the retina. The cornea does most of the refraction and the lens completes it, changing its curvature to accommodate for relative distances.
FOOD AND DRUG ADMINISTRATION (FDA)
The FDA is the U.S. agency that tests, evaluates, and approves drugs and medical devices. FDA approval is specific to a procedure. Other, non-approved applications are referred to as “Off-Label” use.
This is the central part of the macula, the most sensitive area of the retina with the highest concentration of cones. It occupies less than one percent of the retina but uses more than 50 percent of the brain’s visual cortex to give us our sharpest central vision.
This is an inherited and progressive disease of the cornea’s innermost layer, the endothelium, which regulates fluid levels in the cornea and removes impurities. When these cells are dysfunctional, the eye swells from too much fluid. Fuch’s Dystrophy causes blurry vision, blisters, light sensitivity and decreased depth perception. There is no cure and a corneal transplant will eventually be necessary. This is also called Endothelial Dystrophy.
Glaucoma is an eye disease related to the optic nerve and intraocular pressure (IOP). In most cases IOP is elevated and causes damage to the optic nerve where it exits from the retina. In some cases the IOP is normal, but the damage still occurs to the optic nerve. This damage gradually reduces the visual field, starting around the periphery, and left untreated it will cause blindness. The most common way of managing glaucoma is with eye drops to reduce the IOP.
This is a hereditary eye disease where granules appear in the cornea’s middle layer, the stroma, which is most often diagnosed about the age of 20. By mid-life vision becomes progressively impaired as the granules expand, multiply, and penetrate more deeply into the cornea.
HIGHER ORDER ABERRATIONS
These are microscopic irregularities in the eye’s contour which cause a variety of night vision problems. They are not treatable with Traditional LASIK. However, the Wavefront technology used in Custom LASIK diagnoses them and they are incorporated into the treatment plan. Some have only mathematical representations and some have been given names such as coma, starburst, and halos.
This is the clinical name for farsightedness, one of the three Lower Order Aberrations along with nearsightedness and astigmatism. Intraocular The term intraocular refers to anything “inside the eye”.
IMPLANTABLE CONTACT LENS (ICL) also PHAKIC IOL
Implantable contact lenses, or phakic intraocular lenses, are lenses implanted in the eye to work with the crystalline lens to correct vision. Because an ICL can correct a wider range of myopia than laser refractive procedures, implantable contact lenses are sometimes turned to as an alternative to LASIK surgery. Implantable contact lenses are often referred to as phakic IOLs. The term "phakic" refers to an eye with the natural lens still intact. Therefore, the main difference between an ICL and traditional IOLs is the fact that an ICL works in conjunction with the eye's crystalline lens and an IOL replaces it. Typically, IOLs are used to treat cataracts and in some cases presbyopia. Implantable contact lenses treat myopia, myopia with astigmatism, and hyperopia (farsightedness).
This is the surgical removal of corneal tissue.
This is an inherited corneal disease where the cornea gradually becomes thinner and less able to maintain its shape against the pressure of the fluids inside the eye. Eventually the eye bulges forward, blurring vision and eventually requiring a corneal transplant.
This is the measurement of the cornea’s curvature with a keratometer.
A keratoplasty is a corneal transplant.
This is a progressive eye disease where abnormal protein fibers develop on the stroma and enlarge over time to become more opaque. This blocks light from entering the eye and clouds the vision. In some cases they cluster at the upper part of the stroma where the corneal nerve endings are, which can be very painful.
This is defined as visual acuity of 20/200 or worse (severe myopia) or tunnel vision of 20 degrees diameter in the better eye.
A lens is a curved, transparent structure that refracts light. In the eye, the natural lens is behind the iris and is able to change its curvature depending on how distant an object is under control of the circular ciliary muscle around it.
LOWER ORDER ABERRATIONS
This is a collective name for myopia, hyperopia, and astigmatism. They are refractive problems, meaning that they stem from how the eye is bending light.
Is vision impairment that interferes with daily activities but cannot be corrected by glasses or contact lenses. It is not quite a severe a legal blindness.
This is the swelling of the macula, the central area of the retina causing blurry vision, light sensitivity, and a pinkish color to the vision. It can happen after an eye injury or disease and usually lasts a few months.
This is an inherited but rare eye disease where small cysts develop on the corneal surface that cause irritation and can rupture. The condition is progressive and in some cases a corneal transplant becomes necessary.
This is the more clinical name for nearsightedness, a refractive error and one of the eye’s lower order aberrations. Light is refracted too sharply and focuses in front of the retina causing blurriness of distance vision.
These are parts of the tear system that carry tears out of the eyes and into the nasal passages. They can become obstructed, causing tears to accumulate in the eyes and overflow. Left untreated, this can result in infection.
These are rapid and uncontrollable eye movements. The two basic types are Early Onset Nystagmus and Acquired Nystagmus which is related to neurological conditions appearing in later life.
This is herpes simplex, type 1 causing cold sores that can also infect the eyes. When minor it affects only the corneal surface and heals well. In severe cases it penetrates more deeply to cause corneal scarring and leads to vision loss. Sometimes it occurs on the retina (Herpes Retinitis) or in the eye wall (Herpes Uveitis).
OCULAR MIGRAINE also RETINAL MIGRAINE
This is a migraine occurring around the eye area. Although it may or may not involve a headache it does cause nausea, vomiting and double vision. Typically it affects one eye where vision can become grayed out or even temporarily lost.
This is the use of a medical device or drug for a purpose not specifically FDA-approved. A physician can make a judgment call, and it is legal.
This is simply an adjective indicating a noun is related to the eye.
This is a physician specialized in diagnosing and treating vision and eye diseases. Ophthalmology is one of the specialties acknowledged and overseen by the American Board of Medical Specialties (ABMS), which examines and certifies each ophthalmologist to practice in the U.S.
This is the area of the eye that light passes through. It traces the entire path of light as it enters through the cornea and travels through the aqueous humor, pupil, lens, and vitreous humor and then stops at the retina.
OPTIC DISC (ALSO OPTIC NERVE HEAD)
This is the eye’s blind spot, the area of the retina where the optic nerve fibers exit the eye and where blood vessels enter and exit. There are no light-sensitive cells in the optic disc.
Technicians qualified by the American Board of Opticianry (ABO) to fit eyeglasses. An optician may grind the lenses from raw materials and will also fit them in frames and check their accuracy.
A doctor of optometry (O.D.) Optometry is not a branch of medicine. An optometrist diagnoses eye diseases and vision problems, and prescribes remedies (glasses, contact lenses and drugs). Optometrists do not perform surgery but do provide post-surgical care. The education required is a B.A. followed by four years of optometry school. To practice optometry, the student must pass an exam administered by the National Board of Examiners in Optometry (NBEO).
This is the measuring of cornea thickness with a pachymeter.
PENETRATING KERATOPLASTY (PK)
This is a full-thickness corneal transplant. The central part of the cornea, the button, is replaced with one from a donor. This can restore vision if corneal problems were causing vision impairment or blindness, for example keratoconus.
This refers to the period of time between hospital admission for surgery and discharge.
This is side vision as opposed to the sharp central vision of direct focus. It is provided by the light-sensitive cells on the retina outside the macula in less detail but including night vision. Without peripheral vision, a person would only have tunnel vision and would be legally blind.
This is the procedure of breaking up a lens with cataracts with ultrasound waves before removing it. These waves are delivered with a probe through a tiny incision outside the visual field and lens pieces are removed with suction.
Phakic IOLs are IOLs positioned in front of or behind the natural lens to improve vision. The term Phakic refers to having the natural lens in place.
This instrument tests visual acuity. It has many lenses through which a patient looks at a digital vision chart and is asked to read the smallest line of letters seen clearly. This provides the data used for glasses or contact lens prescriptions.
This is the area between the lens and the retina. It is filled with a clear gel called vitreous humor and is the largest area of the eyeball.
This is the progressive loss of vision which begins in mid-life. Near vision becomes blurry and makes reading glasses necessary. Over time, the blurriness extends to intermediate vision, making computer glasses useful. Bifocals are worn to improve near vision and distance vision if necessary.
This is a method for treating dry eyes where plugs made of silicone, plastic, or collagen are inserted into the eye’s puncta to slow or prevent tear drainage. Absorbable plugs are used for short-term treatment and non-absorbable plugs for long-term treatment.
A punctum is an opening in the eye for tear drainage. They are in the inner corners of the eyes, two in each upper lid and two in each lower lid.
This is the opening in the center of the iris, a circular muscle which contracts and relaxes to change the pupil size according to ambient light. Pupil dilation admits more light and pupil contraction admits less. Pupil dilation is often part of eye examinations.
This reflects the refraction of light that does not focus on the retina and therefore gives blurry vision. A myopic eye refracts some incoming light too sharply, giving blurry distance vision. A hyperopic eye refracts some too little, giving blurry near vision. An astigmatic eye has an oval-shaped cornea with two curvatures, one steeper and one flatter. This type of eye refracts light at two angles, giving blurriness at all distances. Refractive error is expressed in diopters.
REFRACTIVE LENS EXCHANGE (RLE)
This is a surgery that removes the natural lens and replaces it with an artificial lens called an intraocular lens.
REIS-BUCKLER’S DYSTROPHY (ALSO BUCKLER’S DYSTROPHY, BUCKLER’S SYNDROME)
This is an inherited eye condition where multiple opacities form in the cornea, just below the surface. It causes scarring along with impaired vision, increased light sensitivity, and eye irritation. It tends to occur between the ages of about eight and twenty.
This is a separation of the retinal nerve layer from the layer below it that contains the retinal blood supply. Fluid then seeps into the gap and vision is lost in this area. When retinal detachment is diagnosed and treated early, vision can be restored. Retinal detachment is more likely among diabetics who develop Diabetic Retinopathy.
RETINAL VEIN OCCLUSION
This is the blockage of a vein carrying blood away from the retina causing blood to back-up increase pressure within that vein and its branches or capillaries. They may then leak onto the retina. Retinal vein occlusion can cause retinal detachments.
RETINITIS PIGMENTOSA (RP)
This is a hereditary degeneration of the retina that usually leading to legal blindness. Peripheral vision is gradually reduced, causing tunnel vision.
Rods are one of the two types of retinal light-sensitive cells. Rods provide vision in low light conditions and do not detect color. Cones are the other light-sensitive cells.
This is the “white” of the eye that is actually a tough, protective layer of the eyeball wall that joins with the cornea at a junction known as the limbus. It continues around the back of the eye to connect with the sheath over the optic nerve.
SCOTOPIC PUPIL SIZE
This is the size of a person’s pupil in low light conditions.
This is a systemic, chronic autoimmune disease. White blood cells damage glands that produce moisture. Most sufferers are female and typically it occurs in mid-life. In many cases it occurs with other autoimmune diseases such as Rheumatoid Arthritis and Lupus.
This is a well-lit microscope for examining the eye’s interior. It has a selection of magnification settings and can be reduced to a slit to provide detailed views of the eye’s structures and fluids.
This is the standard vision chart used to determine your vision prescription. It has a large letter at the top and rows of increasingly smaller letters beneath. It was named for Herbert Snellen, the Dutch ophthalmologist who first devised it in 1862. Originally it was in the form of a chart on the wall but now is digital inside the phoropter in every eye doctor’s office.
SOFT CONTACT LENSES
This is one of the Higher Order Aberrations. It occurs in night vision where light sources look blurry and have spikes projecting around them. It can occur naturally and can also be a complication of laser vision correction, particularly Traditional LASIK.
STRABISMUS (ALSO CALLED CROSSED EYES OR TURNED EYE)
This refers to misaligned eyes. One eye turns out, down, or up while the other looks straight ahead. Sometimes both eyes turn. Strabismus can be ongoing or intermittent and causes impaired vision, including reduced depth perception.
This is the middle and thickest layer in the eye’s cornea. It is the layer where laser vision correction is done, as it is stable, whereas the surface or epithelium is continually renewing itself.
These are a group of hereditary conditions that impair the middle layer of the cornea, the stroma. The three main ones are Macular Dystrophy, Granular Dystrophy and Lattice Dystrophy.
STULTING RESEARCH CENTER
A sty is an infection of an oil gland in the eyelid. It produces a red, swollen, painful lump on the edge or inside surface of the eyelid. Sties usually occur closer to the surface of the eyelid than do chalazia, and a chalazion is generally not due to an infection. They are formed from a blockage of the oil gland itself. So, a chalazion may occur as an after-effect of a sty.
This is a canal which distributes tears in the eye produced by the lacrimal gland to the corneal surface where they are spread by blinking. Tears drain out into nasal cavities through tiny openings called puncta.
This is a loss of peripheral vision, with only central vision remaining. Tunnel vision can be caused by Glaucoma or Retinitis Pigmentosa (RP) and can make a person legally blind.
This is the center layer of the eyeball wall. It lies between the sclera on the outside and the retina on the inside. The iris is part of the uvea.
This is the separation of vitreous gel from the retina. When the vitreous pulls on the retinal surface layer it sometimes tears it and causes retinal detachment. This tends to occur more with older people and those with diabetes.
This is the transparent gel in the eye’s posterior chamber, between the lens and the retina.