Welcome to our Eye Education section. Below are brief descriptions and links to download packets of information related to your eyes. Click on the letters below to jump to the letter alphabetically.
Strabismus (pronounced struh-BIZ-mus) is a condition in which the eyeballs are not aligned properly, and adults with strabismus may experience eyes that point in different directions. When it occurs in adults, it is called adult strabismus. Nearly four in every 100 adults have adult strabismus.
Amblyopia is poor vision in an eye that did not develop normal sight during early childhood. It is sometimes called "lazy eye." When one eye develops good vision while the other does not, the eye with poorer vision is called amblyopic. Usually, only one eye is affected by amblyopia, but it is possible for both eyes to be "lazy."
Anti-VEGF for AMD
Anti-VEGF treatment is a way to slow vision loss in people who have a condition called "wet" age-related macular degeneration.
Bell's palsy is a nerve disorder that causes partial or slight paralysis on one side of the face. This mild facial paralysis may affect a person's smile, making it seem uneven, or may prevent one eyelid from closing properly. Bell's palsy usually occurs in adults. It develops suddenly and involves a problem with a nerve (known as the facial or 7th cranial nerve) that affects the muscles of the face.
The first signs of aging often appear as wrinkles around the eyes, forehead, cheeks, and lips. While wrinkles are normal defining features of the human face, they can sometimes falsely portray a tired or more aged appearance. Botulinum toxin (brand name BOTOX) injections are used to treat facial wrinkles, restoring a more youthful, rested appearance.
BPH Meds and Eye Surgery
Certain medications known as alpha-blockers are commonly used to improve urination in men with a condition called benign prostatic hyperplasia (BPH) or enlarged prostate. These alpha-blocker drugs include tamsulosin (Flomax®), terazosin (Hytrin®), doxazosin (Cardura®), and alfuzosin (uroxatral®). These medications work by relaxing a type of muscle called smooth muscle in the bladder and the prostate, helping to ease urination.
Carotid Artery and the Eye
The carotid (pronounced ka-RAH-tid) arteries are located in your neck and are the main arteries supplying blood to the eyes and brain. There are two carotid arteries: one on the right side of the neck (which supplies blood to the right side of the brain) and one on the left side of the neck (which supplies blood to the left side of the brain).
To determine if your cataract should be removed, your ophthalmologist (eye doctor) will perform a thorough eye examination. Before surgery, your eye will be measured to determine the proper power of the intraocular lens that will be placed in your eye. Ask your ophthalmologist if you should continue taking your usual medications before surgery. You should make arrangements to have someone drive you home after surgery.
A cataract is a clouding of the normally clear lens of the eye. It can be compared to a window that is frosted or yellowed. The amount and pattern of cloudiness within the lens can vary. If the cloudiness is not near the center of the lens, you may not be aware that a cataract is present.
Conjunctivitis is the term used to describe inflammation of the conjunctiva – the thin, filmy membrane that covers the inside of your eyelids and the white part of your eye (sclera). Conjunctivitis is most commonly referred to as "pink eye."
Contacts are thin, clear disks of plastic that float on the tear film that coats the cornea, the curved front surface of the eye. The health of the corneal surface and tear film are very important to your comfort and the clarity of your vision when you are wearing contacts.
Corneal Abrasion and Erosion
A corneal abrasion is an injury (a scratch, scrape, or cut) to the epithelium. Abrasions are commonly caused by fingernail scratches, paper cuts, makeup brushes, scrapes from tree or bush limbs, and rubbing the eye. Some eye conditions, such as dry eye, increase the chance of an abrasion.
Cystoid Macular Edema
Cystoid macular edema, commonly called CME, is a disorder that affects the retina, the layer of light-sensing cells lining the back of your eye. The retina converts light rays into signals, which are sent through the optic nerve to your brain where they are recognized as images. CME is the presence of multiple fluid-filled, cyst-like (cystoid) structures in the macula, the central part of the retina responsible for central (detail) vision. The result is swelling (edema) of the macula.
Detached and Torn Retina
A retinal detachment occurs when the retina is pulled away from its normal position. The retina does not work when it is detached. Vision is blurred, just as a photographic image would be blurry if the film were loose inside the camera.
If you have diabetes mellitus, your body does not use and store sugar properly. High blood sugar levels can damage blood vessels in the retina, the nerve layer at the back of the eye that senses light and helps to send images to the brain. The damage to retinal vessels is referred to as diabetic retinopathy.
Normally, the eye constantly bathes itself in tears. By producing tears at a slow and steady rate, the eye stays moist and comfortable. WHAT IS DRY EYE? Sometimes, people do not produce enough tears or the appropriate quality of tears to keep their eyes healthy and comfortable. This condition is known as dry eye.
The cornea is the normally clear, front window of the eye that covers the colored iris and round, dark pupil. Light is focused while passing through the cornea, allowing us to see. Many people who require corneal transplant surgery have diseases that only affect the cornea's inner lining of endothelial cells. If the remaining corneal layers are clear and healthy, endothelial keratoplasty (EK) may be considered to improve vision.
Eye Care Facts and Myths
We have all been told by someone at some time, "You'll hurt your eyes if you do that!" But do you really know what is or is not good for your eyes? Test yourself with the following true or false statements and see how much you know about your eyes.
Eye Safety for Children
Accidents resulting in eye injuries can happen to anyone. Each year, thousands of children have eye accidents at home, at play, or in the car. These eye injuries can damage a child's sight and even cause blindness. Perhaps the most startling statistic is that 90 percent of all eye injuries could be prevented.
Eyedrops contain medicines that are used to treat many eye diseases and conditions. Some are also helpful for relieving eye discomfort. It is important to remember that all medicines, including eyedrops, can cause side effects. Some side effects caused by eyedrops are local, which means they affect just the eyes. Examples of local side effects include redness of the eye, eye irritation, or blurred vision.
Eyelid Margin Disease, Including Blepharitis
Eyelid margin disease is a common and persistent inflammation of the eyelids. This condition frequently occurs in people who have a tendency toward oily skin, dandruff, or dry eyes. With blepharitis, both the upper and lower eyelids become coated with oily particles and bacteria near the base of the eyelashes.
People who experience eyelid spasms have a condition in which the eyelids twitch or close involuntarily.
Complete eye health includes having healthy eyes and healthy eyelids. Common eyelid problems include excess eyelid skin, droopy eyelids, or eyelids that turn inward or outward. These problems can cause eye discomfort, limit vision, and affect appearance. Fortunately, they can be corrected with surgery.
Floaters and Flashes
You may sometimes see small specks or clouds moving in your field of vision. These are called floaters. You can often see them when looking at a plain background, like a blank wall or blue sky.
Fuchs' dystrophy is a progressive disease affecting the part of the eye called the cornea. The cornea is like the crystal covering a clock face. It is a clear, round dome covering the iris, the colored ring in the center of the eye, and the pupil, the black circle in the middle of the iris. By helping to focus light as it enters the eye, the cornea plays an important role in vision.
Glaucoma is a disease of the optic nerve – the part of the eye that carries the images we see to the brain. The optic nerve is made up of many nerve fibers, like an electric cable containing numerous wires. When damage to the optic nerve fibers occurs, blind spots develop. These blind spots usually go undetected until the optic nerve is significantly damaged. If the entire nerve is destroyed, blindness results.
Headache is one of the most common health complaints. Headaches are usually not serious and are often triggered by factors, such as stress, fatigue, foods, or alcohol. Although many people believe that headaches are often caused by eyestrain due to improperly fitted eyeglasses, this is not true. Eyestrain and vision problems are not major causes of headaches, although most headaches can be made worse by using your eyes for long periods without a rest break.
Herpes simplex is a virus that infects the skin, mucous membranes, and nerves. There are two major types of herpes simplex virus (HSV). Type I is the most common and primarily infects the face, causing the familiar "cold sore" or "fever blister." Type II is the sexually transmitted form of herpes, infecting the genitals. While both can spread to the eye and cause infection, Type I is by far the most frequent type associated with herpes simplex eye disease.
Herpes zoster, commonly known as "shingles," is caused by the same virus responsible for chickenpox. After being infected with chickenpox as a child, the virus remains in your body in an inactive or dormant stage. Later in life, the virus can be reactivated if your body's immune system breaks down. This may happen due to the normal aging process or a number of other factors.
An intraocular lens, commonly called an IOL, is a tiny artificial lens for the eye. An IOL permanently replaces the eye's natural lens when it is removed during cataract surgery.
Ischemic Optic Neuropathy (ION)
Ischemic (pronounced iss-KEE-mik) optic neuropathy (ION) is a relatively sudden loss of central vision, side vision, or both due to decreased or interrupted blood flow to the eye's optic nerve. In order for you to see, the optic nerve carries impulses from the eye to the brain where they are interpreted as images. Without a healthy, functioning optic nerve, vision would not be possible.
Keratoconus (pronounced KEHR-uh-toh-KOH-nus) is an uncommon condition in which the normally round, dome-like cornea (the clear front window of the eye) becomes thin and develops a cone-like bulge. Keratoconus literally means "cone-shaped cornea."
Laser Eye Surgery
The word laser stands for "Light Amplification by Stimulated Emission of Radiation." A laser is a concentrated beam of light, created when an electric current passes through a special material.
Laser iridotomy is a surgical procedure used to treat angle-closure glaucoma. This laser procedure is also performed in patients who are at risk for angle-closure glaucoma. As with many medical conditions, it is preferable to treat patients at risk and thereby avoid vision loss.
There are two types of laser trabeculoplasty: argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). These procedures both use very focused light energy to treat the drainage channel. The laser does not create holes in the eye but instead, causes the drain to work more effectively. Both types are effective in lowering eye pressure and do so more than 75 percent of the time. Lowering eye pressure is the only proven way to treat glaucoma.
Laser in situ keratomileusis, or LASIK, is an outpatient surgical procedure used to treat myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. With LASIK, your ophthalmologist (eye doctor) uses a laser to reshape the cornea (the clear covering of the eye) to improve the way the eye focuses light rays onto the retina.
A learning disability is a disorder in understanding or using spoken or written language. Individuals with learning disabilities have average or even above-average intelligence but experience problems with reading, writing, listening, speaking, concentrating, or even doing mathematical calculations.
Low vision is a loss of eyesight that makes everyday tasks difficult. A person with low vision may find it difficult or impossible to accomplish activities, such as reading, writing, shopping, watching television, driving a car, recognizing faces, and crossing the street. When vision cannot be improved with regular eyeglasses, medicine, or surgery, people with low vision need help to learn how to make the most of their remaining sight and keep their independence.
The macula is the central area of one of the most important parts of your eye – the retina. The retina is a thin layer of light-sensitive tissue that lines the back of the eye. Light rays are focused onto the retina where they are transmitted to the brain and interpreted as the images you see. The macula is the portion of the retina responsible for clear, detailed vision.
Macular degeneration is a disease of the macula, a small area in the retina at the back of the eye. The macula allows you to see fine details clearly and do things, such as read and drive. When the macula does not work properly, your central vision can be blurry and have areas that are dark or distorted. Macular degeneration affects your ability to see near and far and can make some activities, like threading a needle or reading, difficult or impossible.
The macula normally lies flat against the back of the eye, like film lining the back of a camera. When wrinkles, creases, or bulges form on the macula, this is known as macular pucker.
Microvascular Cranial Nerve Palsy
Microvascular cranial nerve palsy (MCNP) is one of the most common causes of acute double vision in the older population. It occurs more often in patients with diabetes and high blood pressure. MCNP is sometimes referred to as a "diabetic" palsy. This condition almost always resolves on its own without leaving any double vision.
Migraine is a common neurological condition occurring in at least 15 – 20 percent of the population and in up to 50 percent of women. Classic migraine starts with visual symptoms (often zigzag lines, colored lights, or flashes of light expanding to one side of your vision over 10 – 30 minutes), followed by a single-sided pounding, severe headache. The headache may be associated with nausea, vomiting, and light sensitivity. Sometimes, visual symptoms and even neurologic dysfunction may occur without the headache. These are called "migraine variants."
Multifocal and Accommodative IOLs
Various forms of refractive surgery, such as LASIK, improve vision by permanently changing the shape of the cornea to redirect how light is focused onto the retina. In some cases, instead of reshaping the cornea, the eye's natural lens is either replaced or enhanced by an implanted intraocular lens (I0L) that helps correct vision.
Optic neuritis is an inflammation of the eye's optic nerve. In order for you to see, the optic nerve carries nerve impulses from the eye to the brain where they are interpreted as images. Damage or infection of the optic nerve can affect vision significantly.
Overflow Tearing and Chronic Eye Infections in Infants
Abnormal or overflow eye tearing is a common condition in infants. In fact, approximately one-third of all newborns have excessive tears and mucus. It occurs when a membrane (a skin-like tissue) in the nose fails to open before birth, blocking part of the tear drainage system. If tears do not drain properly, they can collect inside the tear drainage system and spill over the eyelid onto the cheek.
What is An Ophthalmologist?
An ophthalmologist (eye doctor) is a medical doctor with additional specialized training in all aspects of eye care – medical, surgical, and optical.
Giant papillary conjunctivitis (GPC) is a condition where the inner surface of the eyelid becomes irritated. It is most commonly related to wearing contact lenses. GPC occurs both in patients who use soft and rigid gas-permeable contact lenses, though it occurs much more frequently in soft contact lens wearers. The condition can appear at any time, even after many years of wearing contact lenses with no problems.
Photodynamic Therapy for Age-Related Macular Degeneration
Photodynamic therapy (PDT) is an outpatient procedure involving the use of a special light-activated drug. The inactive form of the drug is usually injected into a vein in the arm where it travels to and accumulates in abnormal blood vessels under the center of the macula. A special low-intensity laser light targeted at the retina activates the drug only in the affected area, damaging the abnormal blood vessels under the retina and leaving normal blood vessels intact. The benefit of PDT is that it reduces abnormal blood vessel leakage associated with wet AMD without damaging the retina.
Photorefractive Keratectomy (PRK)
Photorefractive keratectomy (PRK) is an outpatient surgical procedure used by ophthalmologists (eye doctors) to treat myopia, hyperopia, and astigmatism. With PRK, an excimer laser is used to sculpt the cornea, permanently changing its shape to improve the way the eye focuses light onto the retina.
Posterior capsulotomy is a surgical procedure that is sometimes necessary after cataract surgery.
Presbyopia is a condition in which your eyes gradually lose the ability to see things up close. It is not a disorder or disease but rather a natural aging process of the eye. Presbyopia literally means "old eye" in Greek.
Preventing Eye Injuries
More than one million people suffer eye injuries each year in the United States. Nearly 50 percent of these accidents occur in the home. Most eye injuries can be prevented by following precautions. Prevention is the first and most important step in avoiding eye injuries.
Pseudostrabismus is the false appearance of misaligned eyes. When eyes are truly misaligned, the condition is called strabismus. In strabismus, the eyes can drift inward, outward, upward, or downward.
Pseudotumor Cerebri (PTC)
Pseudotumor cerebri (PTC) is a condition in which high cerebrospinal fluid (CSF) pressure inside your head can cause problems with vision and headache. What is pseudotumor cerebri? The term "pseudotumor" (which means "false tumor") comes from the days before CT and MRI scans when doctors who noted swelling of the optic disc (the visible portion of the optic nerve in the back of the eye) considered the possibility of a brain tumor. Patients with optic disc swelling but no evidence of a tumor were said to have "pseudotumor."
Pterygium and Pinguecula
Pterygium (pronounced tur-IJ-ee-um) and pinguecula (pronounced pin-GWEK-yoo-Ia) are growths on the cornea (the clear, front window of the eye) and the conjunctiva, the thin, filmy membrane that covers the white part of your eye (sclera). Both types of growths are believed to be caused by dry eye and environmental elements, such as wind, dust, and ultraviolet (UV) light.
Ptosis in Children and Adults
Ptosis (pronounced TOH-sis) is a drooping of the upper eyelid. The lid may droop only slightly, or it may cover the pupil entirely. In some cases, ptosis can restrict and even block normal vision. It can be present in children, as well as adults and may be treated with surgery.
Face-Down Recovery After Retinal Surgery
To repair the damaged retina, your ophthalmologist (eye doctor) removes some of your eye's vitreous (the gel-like substance that fills the inside of your eye) and injects a gas bubble into your eye to take its place. This bubble holds the retina in place as it reattaches to the back of your eye.
In order for our eyes to be able to see, light rays must be bent or refracted by the cornea and the lens so they can focus on the retina, the layer of light-sensitive cells lining the back of the eye. The retina receives the picture formed by these light rays and sends the image to the brain through the optic nerve.
Common refractive surgery procedures include laser in situ keratomileusis (LASIK) and epithelial LASIK (epi-LASIK), advanced surface ablation (ASA), including photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK), and phakic intraocular lenses (I0Ls).
To more closely examine the retina (the back of your eye) and choroid (blood vessels under the retina), your ophthalmologist (eye doctor) may use a diagnostic technique called angiography (pronounced an-jeeAHG-ruh-fee). A colored dye is injected into a vein in your arm where it travels throughout the blood vessels in your body. As the dye passes through the blood vessels in the eye, a special camera takes photographs of the retina or choroid blood vessels.
Retinal Vein Occlusion
A retinal vein occlusion occurs when a vein in the eye's retina is blocked. The retina is the layer of light-sensing cells lining the back of your eye. It converts light rays into signals, which are sent through the optic nerve to your brain where they are recognized as images. A blocked vein damages the blood vessels of the retina. Hemorrhages (bleeding) and leakage of fluid occur from the areas of blocked blood vessels.
Retinitis pigmentosa is a group of genetic disorders that affect the retina's ability to respond to light. The retina is the layer of light-sensing cells lining the back of your eye that converts light rays into impulses. The impulses are sent through the optic nerve to your brain where they are recognized as images.
Retinopathy of Prematurity
Retinopathy of prematurity (ROP) is an eye disease that occurs in a small percentage of premature babies. In ROP, abnormal blood vessels grow on the retina, the light-sensitive layer of cells on the back of the eye that allow us to see.
Rosacea (pronounced rose-AY-shah) is a chronic disease that affects both the skin and the eyelids. People with rosacea affecting their skin may flush easily and have redness, acne-like symptoms or both on their nose, cheeks, chin, or forehead.
Seeing Well As You Grow Older
Many eye diseases and disorders become more common as we age. Advances in ophthalmology allow most people to maintain good vision as they grow older. Many eye problems can be prevented or corrected if detected in their early stages. Regular eye examinations by an ophthalmologist (eye doctor) are the best way to detect eye conditions early while they can be treated. An ophthalmologist is a medical doctor (M.D. or D.O.) with special training and skill to diagnose and treat all diseases and disorders of the eye.
Selective Laser Trabeculoplasty for Glaucoma
Selective laser trabeculoplasty (SLT) uses neodymium:YAG laser to focus light energy on the internal drainage channel of the eye. SLT targets the pigmented (melanin-containing) cells in the trabecular meshwork using a very short application of light. Because SLT uses a low amount of energy, the surrounding tissue is not damaged. The treatment allows the drain to work more efficiently, successfully lowering eye pressure more than 80 percent of the time.
Smoking and Eye Disease
Tobacco smoking is directly linked to many adverse health effects, including high blood pressure, heart disease, and cancer. Smoking is also linked to specific eye diseases.
A subconjunctival hemorrhage is similar to an ordinary bruise on the skin – it's like a bruise of the eye. It usually appears as a single, concentrated spot of red or many scattered red splotches on the white of the eye. The redness is blood under the conjunctiva, a clear membrane that covers the white of the eye (called the sclera) and the inner eyelids. The conjunctiva contains numerous blood vessels and capillaries, the tiniest blood vessels in the body. These vessels can break, causing blood to leak between the conjunctiva and the sclera. This minor bleeding under the eye's outer membrane is what causes the bright red spot to appear on the white of the eye.
Surgery for Open-Angle Glaucoma
A clear liquid called aqueous humor circulates inside the front portion of the eye. In open-angle glaucoma, this liquid does not flow efficiently through the eye's sponge-like drainage system (known as the trabecular meshwork). When this liquid fails to drain properly, pressure builds within the eye. The medical term for this pressure is intraocular pressure. Such pressure inside the eye may damage the optic nerve and lead to vision loss. Medications, laser surgery, or other glaucoma surgeries may be used to lower and control the eye pressure.
Tearing in Adults
The lacrimal gland and other small glands located inside the eyelid and on the white part of the eye constantly produce tears to keep the eye moist, lubricated, and healthy.
Thyroid Eye Disorders
The thyroid gland, located in the front of the neck, produces hormones that help regulate your body's metabolism (the process in which the body transforms food into energy). In a small number of people, the thyroid gland malfunctions and produces more hormones than the body needs. This is called hyperthyroidism, or Graves' disease. The overproduction of thyroid hormones in Graves' disease can cause various eye and vision problems.
The eye is shaped much like a tennis ball with three different layers of tissue surrounding the central gel-filled cavity. The innermost layer is the retina, which senses light and helps to send images to your brain. The middle layer between the sclera and retina is called the uvea. The outermost layer is the sclera, which is the strong white wall of the eye. Uveitis (pronounced you-vee-EYE-tis) is inflammation of the uvea.
Living with Vision Loss
From childhood through middle adult life, eye injuries are the leading cause of acquired vision loss. In later adult life, age-related changes, such as glaucoma, diabetes, and macular degeneration, become the leading cause of blindness. Once vision is permanently impaired in one eye, preserving vision in your remaining functioning eye becomes extremely important. You must take steps to protect vision in your functioning eye because loss of vision in that eye will drastically change your lifestyle.
Visual Field Test
Your visual field refers to how much you can see around you, including objects in your peripheral (side) vision. This test produces a map of your field of vision. Visual field tests help your ophthalmologist (eye doctor) monitor any loss of vision and diagnose eye problems and disease.
Vitrectomy is a type of eye surgery that treats disorders of the retina and vitreous. The retina is the light-sensing tissue at the back of the eye. The vitreous is the clear, jelly-like substance that fills the middle of the eye. The vitreous is removed during vitrectomy surgery and usually replaced by a saltwater solution.
Wavefront Guided LASIK
One of the keys to a successful LASIK procedure is the measurement your ophthalmologist takes to determine your refractive error. Now an enhanced version of LASIK, called wavefront-guided custom laser surgery or wavefront-guided LASIK, is available. Wavefront-guided LASIK uses a special device to precisely measure the eye's unique irregularities and variations. If wavefront-guided LASIK is an option for you, you may benefit from this customized approach to refractive surgery, which results in an improved quality of vision compared to the traditional approach.