Blepharitis Chalazion Conjunctivitis Corneal Erosions Cataracts Diabetic Retinopathy Eyelid Spasms Flashers and Floaters Glaucoma Glossary How to apply eyedrops The Human Eye Keratoconus LASIK Macular Degeneration Pterygium and Pinguecula Radial Keratotomy Refractive Surgeries Strabismus Visual Field Test	Glossary accommodation the process by which the lens of the eye automatically adjusts to focus objects of different sizes and distances. This process is automatic and unconscious. In far-sighted children and infants, this could lead to strabismus. acuity This is commonly measured with fractional numbers, i.e. 20/20, 20/30, etc., and is a measure of your ability to focus. amblyopia a result of untreated strabismus, also called lazy eye. When the two eyes do not work in parallel, one eye sometimes sends blurry images to the brain. The brain rejects the image, and the eye eventually stops sending any images, causing the eye to stop seeing at all. This can lead to permanent blindness in the wandering eye, though early detection and treatment in a baby or child can reverse the situation somewhat. Amsler grid reveals distortion in vision through a self-evaluation procedure utilizing a grid, centered around a black dot. anesthesiologist medical doctor specializing in the application and control of anesthetics. anesthetic a substance that induces numbness or sleepiness; medically, it is used to block the normal pain of surgery. angiogram photograph of the inside of the eye taken with a florescein angiograph. anterior chamber part of the eye located in front of the iris. This is where a IOL is placed if done after the initial cataract surgery or if a posterior chamber implant cannot be performed. aqueous humor clear fluid generated by the ciliary body. The fluid bathes the area of the eye forward of the lens, and drains into the trabecular meshwork. A-scan an ultrasound test to determine the strength of the new IOL. astigmatism distorted vision due to an ovoid shape of the eye, rather than a round, spherical shape. automated microkeratome an instrument which can make thin, precise cuts. It is used in some refractive surgeries, and separates the corneal flap from the middle layers of corneal tissue below. capsule tissue in the eye supporting the lens, located behind the iris. cataracts clouding of the eyes' lenses, which are normally clear; a normal part of aging, cataracts can also be present at birth, or caused by injury or disease. choroid located beneath the macula, this deepest layer contains blood vessels that carry nourishment to the eye, and waste materials away from it. ciliary body a gland located below and behind the iris, this is the part of the eye which generates the aqueous humor. clear cornea cataract surgery normally, the optic nerve is anesthetized with injections around the eye. Clear cornea cataract surgery uses eye drops to numb only the front of the eye. A very small incision is made for the removal of clouded lenses and the insertion of folded IOLs. Recovery is faster and discomfort is reduced. closed-angle glaucoma the iris is pushed forward of the eye, due to slow or non-flow of fluids through the pupil, and blocks the draining holes in the eye between the iris and the cornea. Rise in pressure is acute, can be painful or cause vision blurring, and must be lowered immediately to prevent loss of vision. This is an acute condition that normally affects one eye at a time. cones located inside the retina, these are light- and color-sensing cells in the macula which shed their outer tips during the day. These are responsible for central vision. cornea membrane covering over the eye. corneal flap upper layers of the cornea are folded back to allow access to the middle section of the cornea. This flap covers the eye after the procedure is complete. corneal topography shows the precise shape of the cornea. This is normally done with computer analyses of your eye as you look into a lighted cone. cotton wool spots white spots on an angiogram of your retina, caused by the re-sealing of weak blood vessels in the retina. The damaged vessels can't carry as much blood and oxygen to the area, causing the spots to appear. Poor circulation will cause spots which resemble cotton batting or wool. crossed eyes a symptom of strabismus, the eyes will move toward each other, especially when trying to focus on a near-by object. double vision sometimes, when eyes do not work in parallel, the brain cannot achieve fusion of images, and the two images -- one send by each eye -- are experienced by the brain as two distinct, and sometimes overlapping, images. drainage angle fluids within the eye drain through a network of holes between the iris and the cornea. For fluids to drain properly, this angle should be relatively open. Blocking of the drainage results in symptoms of glaucoma. drüsen the accumulated debris from cones in the macula. This debris is normally processed by the pigment epithelium; when this is not done efficiently, the drüsen is formed, causing the pigment epithelium to swell, then stop functioning. It is normally found between the pigment epithelium and the choroid layers. epicanthal fold a flap of skin which lies across the bridge of an infant's or child's nose. This skin will eventually lie on the sides of the nose when the child grows. The epicanthal fold sometimes makes the child appear to have crossed eyes. This can lead to a mistaken diagnosis, called false strabismus. epicanthus also called false strabismus, where loose skin on an infant, which will eventually form the nose, lies over the insides of the eyes, making them appear crossed. Unlike true strabismus, this condition will disappear as the child grows. excimer laser a computer-controlled laser used in photorefractive keratectomy (PRK). A precise beam of pulsing ultraviolet light and flattens the cornea. As it gives off almost no heat, the surrounding tissue is rarely affected. extracapsular extraction lens is removed from the eye in one piece eye chart the most familiar of eye tests, an eye chart can be letters, shapes or words. Reading this chart tests your acuity, or ability to see clearly. eye shield protective cover for the eye, allowing it to heal after surgery. The eye shield should be worn while sleeping, and can be used instead of glasses as protection during the day. false strabismus an illusion, also called epicanthus. In some infants, the nose is not fully formed, and the skin that will lie on the sides of the nose instead lie over a portion of the eyes, making the eyes appear to be crossed. Of course, with growth, this epicanthal fold will disappear, making it appear as though the child has outgrown strabismus. far-sightedness the eye tends to be oblong, with the retina closer to the front of the eye than normal. Light entering the cornea focuses the images behind the retina. flashes bright points of light, starts or streaks seen from time to time, though no such object is actually there. These are caused by the vitreous gel in the eye pulling on the retina. These tend to occur in one eye at a time. floaters dark specks, clouds, threads or webs appear to move or float through your vision. These are generally pieces of the vitreous gel material or other debris floating within the eye, and are normally considered harmless. fluorescein angiogram photograph of the retina, showing blood vessels, macula, optic nerve, etc. florescein angiography a yellow dye is injected into a vein in your arm, which travels to the eyes to emphasize veins and features. A photograph is taken and used to discern slight changes in the retina toward diagnoses of retinopathy. focal treatment laser is used to seal tiny bulges near the fovea, to treat macular edemas caused by focal leakage. The laser seals the bulges near the fovea resulting from the leaks. fovea area in the center of the macula, located within the retina at the back of the eye. fundus photograph a picture of the optic disc, taken through a dilated pupil. Successive photographs could show changes as the result of diseases such as glaucoma. fusion the process by which the brain puts together the two parallel images each eye sends to the brain for processing. This enables humans and other animals to experience 3-dimensional vision. glaucoma vision loss due to optic nerve damage caused by high intraocular pressure. gonioscope a small instrument made up of a lens and mirror, and held up to the eye to measure the drainage angle between the iris and cornea. Knowing this angle will diagnose the type of glaucoma the patient is suffering. grid treatment leakage of blood vessels around the fovea can be focused or diffuse; when the leaking is diffuse, a laser can be used to reduce the swelling when the light beam is used in a circular, grid-like pattern around the fovea. hyperopia farsightedness caused when the distance between the retina and cornea is too short. incision in surgery, a controlled cut. These may be closed with stitches or with a non-stitch procedure. infusion line a small tube used in a variety of procedures to insert or inject a substance, such as injecting gas or saline during a vitrectomy. intraocular pressure pressure within the eye. IOL (intraocular lens) or lens placed within the eye, rather than outside of the eye (normal eyeglasses and sunglasses are extraocular). iridotomy a treatment for closed- or narrow-angle glaucoma, where a laser is used to make an opening through the iris to allow eye fluids to drain properly. iris colored part of eye, which controls the amount of light entering the eye by varying the size of the pupil. IV intravenous, or "within the vein." keratometer instrument which measures the central curve of the cornea. laser a focused beam of energy that is often used in the place of a scalpel in delicate surgeries, being smaller and more accurate a cutting or drilling device. laser treatment an outpatient procedure in which a laser is used to seal leaks, adjust shape of the eye, etc. lazy eye also called amblyopia, this is a condition where an eye stops working, due to its inability to focus or send coordinated images to the brain. If untreated, the eye can become permanently blind. lens located behind the pupil, to focus light in the eye to the retina. macula this is the retina's "bull's eye" spot, where the vision is centered and sharpest, and from where vision is processed for images and color. It is close to the optic nerve, and is made of up layers of different cells, including the cones, pigment epithelium, and the choroid. macular degeneration loss of vision due to wear and tear or damage to the macula. There are two types: dry-type and wet-type, so called as the latter is caused by fluid flooding. Occasionally, dry-type degeneration can lead to wet-type. macular edema leakage of blood vessels near the fovea or macula. May cause swelling near the fovea and leave fluid deposits. myopia nearsightedness, caused by too long a distance between the cornea and the retina. narrow-angle glaucoma the iris is pushed forward of the eye and partially blocks the trabecular meshwork, resulting in increased pressure within the eye. It is a non-acute condition that usually occurs in both eyes. near-sightedness the eye tends to be oblong, with the retina farther from the front of the eye than normal. Light entering the cornea focuses the images in front of the retina, rather than on it. nonproliferative retinopathy a form of diabetic retinopathy where weak blood vessels in the retina leak and then close. Both nonproliferative and proliferative conditions may occur at the same time. open-angle glaucoma drainage holes between the iris and the cornea are clogged without change in their normal relative position. it is unknown why this occurs, yet this is the most common type of glaucoma, and usually occurs in both eyes. ophthalmologist medical or osteopathic doctor specializing in total eye care. ophthalmoscope instrument used to examine the interior of the eye. optic cup an area within the optic disc, which defines the severity of vision loss as affected by glaucoma. optic disc spot on the retina where nerve strands bundle together to form the optic nerve. optic nerve nerve connecting the eye directly to the brain, through which images focused on the retina are transmitted. orthoptics eye exercises to strengthen muscles, reverse amblyopia and achieve fusion. orthoptist an eyecare specialist with expertise in eye muscle disorders and their treatments. outpatient procedure surgery which can be done in an office or surgical facility, and does not require an overnight stay. pachymeter instrument which uses sound waves to measure cornea thickness. panretinal treatment laser is used around the macula, discouraging new blood vessel growth. This technique can be used to treat proliferative retinopathy. parallel to work together, without crossing over one another's paths. For eyes, this describes how a pair of eyes works to receive images and sends them through the optic nerve to the brain to be processed as images. When eyes do not work in parallel, this can result in strabismus. pediatrics medical care specializing in children's ailments and surgeries. perimetry a test which measures the loss of peripheral vision. A patient's response to a flash of light traveling in a grid pattern is mapped to show the reduction of vision in different areas of the eye. peripheral vision commonly called "side vision," this vision is processed in the area of the retina outside the macula, where light through the front of the eye is not focused and is less intense. phacoemulsification in cataract surgery, this procedure uses high-frequency sound vibrations to break up clouded lens, the pieces of which are suctioned out. photoroptor instrument that determines how well images focus in the eye. pigment epithelium cells located immediately beneath light-sensitive cones in the eye. It supports and nourishes the cones, and removes the tips of the cones that are shed in the course of the day. posterior chamber located behind the iris. This IOL implant procedure is normally performed immediately after the cataract is removed. posterior lens capsule in the eye, support structure for the lens. proliferative retinopathy a form of diabetic retinopathy. This is more common in those who have a long history of diabetes. Weak vessels growing on the retina can close, allowing for growth of new vessels, or can burst and bleed into the vitreous, or can cause traction, where the vitreous sack pulls away from the retina. pupil the opening into the eye; size is controlled by contractions of the iris. radial keratotomy refractive surgery effected by cutting slits in specific configurations and locations to change the shape of the cornea, affecting how light focuses on the retina. recession moving a muscle further back along the eyeball to weaken it. resection removing a section of muscle fiber and splicing the two cut ends to shorten and strengthen it. refraction how much a beam of light is bent and focused within your eye. refractive surgery operations which alter the shape of the cornea to improve vision. Changing the eye shape alters the way images focus in your eye. These procedures include: LASIK (laser in-situ keratomileusis) RK (radial keratotomy) AK (astigmatic keratotomy) ALK (automated lamellar keratoplasty) PRK (photorefractive keratectomy) retina back of the eye, onto which light coming through the pupil is focused. retinopathy also called diabetic retinopathy, this is an ocular disease caused by high sugar content in the blood. Blood vessels in the retina are weakened and can break, causing leakage and re-sealing of the vessels. The sealed vessels are weaker than the originals. Sometimes, new vessels will grow, but these will also be weak, and can leak. Vision loss is common for untreated retinopathy. saline a mineral salt and water solution that mimics some aspects of fluids found naturally in our bodies, and can be used to treat conditions or replace these fluids temporarily or permanently. sclera the outer white coating of the eye. slit lamps a microscope used to view the front of your eye and your retina. strabismus any condition that results in the two eyes not working together. This is normally caused by weakened eye muscles, but can also be caused by disease, injury, or some other cause. The condition could be present at all times, or can accompany illness, fatigue, or concentration. suppression the process by which the brain ignores a fuzzy image sent by a wandering eye. All images are interpreted via a single eye, causing the wandering eye to stop seeing images, due to lack of use. tension pulling and relaxing of muscles to control movement. Relaxing muscles releases tension, allowing the eyes to move opposite the relaxed muscles. If muscles are unbalanced, the eyes will not work in parallel. tonometer an instrument which measures the pressure within the eye, either via a plastic prism held onto the surface of an anesthetized eye, or via a puff of air directed at the cornea. trabecular meshwork a network of holes in front of the iris in the anterior chamber, through which the aqueous humor drains. Clogging of this series of holes results in glaucoma. trabeculectomy a new drain is carved in the sclera by a laser beam, so that fluids may bypass blocked trabecular meshwork and flow through the new drain. trabeculoplasty a laser treatment in which the clogged trabecular meshwork is opened to allow drainage of fluids produced by the eye. traction scar tissue forming on the retina grows into vitreous humor, causing the eyeball and the retina to pull away from each other. tunnel vision a common term describing the condition which occurs when peripheral vision is lost. vitrectomy surgical removal and replacement of the vitreous. This procedure is normally done after other treatments have been attempted. vitrectomy instrument a surgical, tube-like microprobe used in a vitrectomy which is placed in the eyeball to remove the gel-like vitreous and any scar tissue from the collapse of the eye sac away from the back of the eyeball. vitreous the gel-like liquid in the eye that gives the eye its "body" and shape. wandering eye a symptom of strabismus, one eye will move "independently" or "off center" relative to the other eye. Go to Top