Strabismus (Crossed Eyes): Learn About Causes and Treatment Share Your Story Some people are born with eyes that do not align in the usual way. This is called congenital strabismus. In many children, there is no clear cause of strabismus. In some cases, it is a result of a problem with the nervous system, especially the part that controls the muscles of the eyes. If it is not corrected, strabismus can continue into the adult years. Most adults who have strabismus were born with it. If strabismus does not appear until later in life, it will cause double vision . If the eyes become misaligned in an adult who did not have strabismus as a child, it could be a sign of a serious condition such as a stroke . A sudden, misalignment of the eyes or double vision are important reasons to see a doctor immediately. Someone who is born with strabismus will see without having double vision. There might be other effects on vision, however. Because the two eyes are not working well together, depth perception and peripheral vision (vision off to the side) will not be very good. Eyestrain and headaches can occur frequently.

It might also be necessary to turn the head in unusual ways in order to see in certain directions. How Is Strabismus Treated? Share Your Story A doctor may recommend that patients go through physical therapy to help strengthen their eye muscles. Vision therapy is also used to help a person correct their vision when suffering with strabismus. This therapy helps train a patient's brain to be able to align their eyes and focus and visually process images. Vision therapy uses computerized optical devises, including lenses and filters, to develop the eye muscles. Strabismus - body, causes, Did Abe Lincoln Have Strabismus? Strabismus Strabismus Strabismus is a condition in which the eyes cross or do not work together normally, which may lead to permanent loss of vision in one eye. KEYWORDS for searching the Internet and other reference sources Amblyopia Optometry Vision When people cross their eyes, the world suddenly doubles. Images, like the words on this page, become blurred, and it appears as if there are two of everything. When the eyes function correctly, they work together to focus images and to allow the brain to develop a three-dimensional view of the world.

But when the eyes cannot work together, as when people cross their eyes, the brain sees two of everything. The result is double vision. Fortunately, both eyes work together for most people. But some people have an eye disorder that causes the eyes to fail to line up properly, resulting in blurred or double vision. This condition is called strabismus (stra-BIZ-mus), which comes from a Greek word that means squinting. Often in strabismus, one eye may remain straight and the other eye may turn in, as if the person is crossing one eye. * tumor usually refers to an abnormal growth of body tissue that has no physiologic purpose and is not an inflammation. Tumors may or may not be cancerous. Did Abe Lincoln Have Strabismus? President Abraham Lincoln (1809—1865) is known for many things, from his work as a rail-splitter, to his legendary debates with Stephen A. Douglas, to serving as president of the United States during the Civil War. Lincoln's physical characteristics caused much discussion. He was unusually tall for his time, standing 6 feet 4 inches.

He also was extremely thin for that height and probably weighed about 160 pounds when elected to Congress in 1847. "He was not a pretty man by any means—nor was he an ugly one," wrote William Herndon. "He was a homely looking man." The assessment goes on and sounds extraordinarily harsh, considering that Herndon was Lincoln's friend, law partner, and biographer. Historical researchers have speculated that Lincoln had strabismus. In photographs, his eyes appear slightly off center. His right eye was thought to be abnormal, sometimes described by biographers as "wandering." Researchers also believe that Lincoln may have had Marfan syndrome, a rare disorder that causes exceptional height in combination with especially long legs, hands, and feet. Eye trouble is another characteristic of the syndrome. Some of Abraham Lincoln's descendants are known to have had Marfan syndrome, and it is known to be an inherited disorder. Why Do People Have Strabismus? Strabismus usually develops during infancy or early childhood. In most cases, there is no known cause, although sometimes several members of the same family have the disorder. This may mean that in some cases strabismus is inherited, like eye color.

Other possible causes include: Farsightedness, causing focus difficulties Damage to one eye or to the part of the brain that controls the muscles involved in eye movement Other disorders that affect the brain, including Down syndrome, cerebral palsy, and hydrocephalus Less commonly, vision is blocked by a tumor * or cataract that causes cloudiness in the normally clear lens of the eye Strabismus affects about 3 to 5 percent of children in the United States. It occurs in boys and girls equally. Fortunately, if it is diagnosed and treated early, there is a good chance of saving or improving vision in the affected eye. An uncorrected case of strabismus can create an appearance of "cross eyes." © 1997 Custom Medical Stock Photo. Some adults have strabismus. This may be because they were not treated for it as a child, or because the treatment was not effective. Other adults may develop strabismus when a disorder such as stroke * causes the eyes to cross or not work together normally. How Do Six Muscles in Each Eye Work as One? The eyes and the nerves that connect them to the brain work like the two lenses of binoculars.

They merge the images seen by each eye into one image. Six muscles are attached to each eye, and they control how the eyeball moves left and right or up and down. To make it possible for the brain to develop a single three-dimensional image, the muscles must work together to focus, just as the two lenses of binoculars must be aligned to focus together. People with strabismus have trouble with one or more of the muscles in an eye. Instead of working together, one eye is out of step. Sometimes strabismus seems to come and go, depending on how tired the eyes are, and sometimes the eyes remain out of step. There are different forms of strabismus: When one eye points inward toward the nose, which makes the person look cross-eyed, the condition is called "esotropia" (es-o-TRO-pe-a).

When one eye points away from the nose, as if looking to the outside, the condition is called "exotropia" (ek-so-TRO-pe-a) or "walleye." When the brain turns off the vision in the turned eye in favor of the vision in the straight eye, the condition is called "strabismic amblyopia" (stra-BIZ-mik am-blee-O-pee-a) or "lazy eye." Amblyopia does not mean that the eye is lazy. Instead, the brain turns off the image coming from the optic nerve in that eye so the person sees only one clear image of the world instead of having blurred or double vision. * stroke may occur when a blood vessel bringing oxygen and nutrients to the brain bursts or becomes clogged by a blood clot or other particle. As a result, nerve cells in the affected area and the specific body parts they control do not properly function. * ophthalmologist is a medical doctor who specializes in treating diseases of the eye. A Little Pirate Mrs. Apple noticed that the eyes of her baby Chloe often did not work together. She had read in a book how babies sometimes appear cross-eyed or how it seems one eye is looking off in another direction from the other.

This can be normal for a very young baby. But when Chloe was about four months old, Mrs. Apple became worried. Chloe's left eye seemed to be looking at her nose when Mrs. Apple moved her face close, and the right eye seemed to be looking straight ahead. Mrs. Apple took the baby to an ophthalmologist * for an eye exam and was told that Chloe likely had strabismus. It is usually a parent who first notices the signs of strabismus when children are infants or preschoolers. The children are too young to complain about double or poor vision. If Mrs. Apple had not taken action because of her worries, the strabismus might have developed into ambly-opia, leaving Chloe without vision in the crossed eye. Without treatment, amblyopia may become permanent. The ophthalmologist recommended that Chloe wear an eye patch over her normal eye. The doctor explained that this could force the weaker eye to develop vision more properly. How Do Doctors Diagnose Strabismus and Amblyopia? Diagnosis Doctors use a variety of methods to diagnose strabismus and amblyopia.

Most involve observation of how the child looks at objects, since most children are too young to recognize the letters on a standard eye chart. The doctor will cover one eye and then the other, holding and moving objects, and watching to see if the child squints or tries to cover or close one eye in favor of the other. The doctor also will check the alignment of the eyes by shining a light in both eyes to see if the reflection falls in the same place in the pupils (the black spot in the center of the eye) of both eyes. Many children do not like to have their eyes covered during these exams. Some are frightened of the equipment that may be held close to their faces. New techniques under development use computers to track eye movements from a distance, sometimes while the child is watching a cartoon. Treatment The most common treatment of strabismus involves wearing a patch like Chloe's over the stronger eye. The brain now starts to try to send and receive signals from the weaker eye, and the muscles that control it try to bring the eye back to a normal focus. The same result often is achieved with eye drops that blur the vision in the normal eye to make the other eye work harder.

Doctors also may prescribe special eyeglasses for some children with strabismus. Some of these eyeglasses use prisms that change how the image is sent into the eye. New techniques involve disabling or weakening one or more of the muscles in the eye. This is done to force the other muscles to work harder to bring the affected eye into focus with the normal eye. This can be done surgically by repositioning the eye muscles of one or both eyes. The operations can leave the eyes straight and vision normal, although sometimes the eyes appear straight but people still need eyeglasses to achieve good vision. Sometimes, injections are used to disable one or more eye muscles for a period of time. This may achieve similar results to surgery. Will Crossed Eyes Become Stuck? It seems almost everyone has received this warning from a parent or teacher: "If you keep crossing your eyes like that, they could stay that way forever!" Although the warning may be a way for parents to make children stop silly behavior, it is not medically true. Voluntarily crossing the eyes will not harm them or put them at risk of strabismus. Treatment is most effective when children are young, which is why vision testing and early diagnosis are important.

Strabismus and ambly-opia do not simply go away, as some people believe. With treatment, children like Chloe can have almost normal vision and no restrictions on activities as they grow up. See also Eyes Eyes Los ojos All About Eyes Sight, more than any of our senses, helps us navigate the world around us. In a single glance, lasting a fraction of a second, our eyes work with our brains to tell us the size, shape, color, and texture of an object. They let us know how close it is, whether it's standing still or coming toward us, and how quickly it's moving. The eyes are small compared with most organs, but their structure is incredibly complex. They work together to perceive depth, enabling us to judge distance and the size of objects to help us move around them. They also work with the brain, muscles, and nerves to produce complicated visual images and messages. And they constantly adapt to the changing environment — for example, adjusting so that we can easily move around in a nearly dark room or bright sunlight. To understand how the eyes work, it's important to know about their structure and about conditions and diseases that can interfere with vision.

How Eyes Work Only part of the eye is visible in a person's face. The whole eye — the eyeball — is about the size and shape of a ping-pong ball. All parts of the eye are extremely delicate, so our bodies protect them in several ways. The eyeball sits in the eye socket (also called the orbit) in the skull, where it is surrounded by bone. The visible part of the eye is protected by the eyelids and the eyelashes, which keep dirt, dust, and even harmful bright light out of the eye. Eyes are also protected by tears, which moisten them and clean out dirt, dust, and other irritants that get past the defenses of the eyelashes and eyelids. Tears also help protect against infection. With each blink, our eyelids spread a layer of mucus, oil, and tears over the cornea, which covers the eye. The lacrimal glands in the upper outer corner of each eye socket produce tears, which, after moistening the eyes, flow into canals in the eyelids. These canals drain into the lacrimal sac, a pouch in the lower inner corner of each eye socket. Tears then exit through a passage that leads to the nose.

To see, the eye has to move. Six extraocular muscles surround the eyeball and act like the strings on a puppet, moving the eye in different directions. The muscles of each eye normally move together at the same time, allowing the two eyes to remain aligned. continue How Vision Works The wall of an eyeball is made up of three layers, rather like the layers of an onion: The sclera is the outermost protective layer. This tough, fibrous tissue surrounds the eyeball and attaches to the cornea, which is the clear front surface of the eye. What we see as the white of the eye is the sclera. Over the sclera lies the conjunctiva, a clear skin layer that protects the eye from becoming dry. The choroid is the middle layer that contains blood vessels that deliver oxygen and nutrients to the inside parts of the eye. The retina, the innermost of the three layers, lines the inside of the eyeball. The retina is a soft, light-sensitive layer of nervous system tissue. The optic nerve carries signals from the retina to the brain, which interprets them as visual images. The space in the center of the eyeball is filled with a clear jelly-like material called the vitreous humor.

This material allows light to pass through to the retina. It also helps the eye keep its round shape. Vision is the process by which images captured by the eye are interpreted by the brain, and the visible part of the eye is where the process of sight begins. On the front surface of the eye is the see-through, circle-shaped cornea. You can't see a person's cornea the way you can see the colored part of the eye behind it — the cornea is like a clear window that focuses light into the eye. Behind the cornea is a watery fluid called the aqueous humor. The cornea and aqueous humor form an outer lens that refracts (bends) light on its way into the eye. This is where most of the eye's focusing work is done. The colored circular membrane in the eye just behind the cornea is called the iris. The iris controls the amount of light entering the eye through the pupil, which is the opening in the center of the iris that looks like a tiny black circle.

Like a camera, which controls the amount of light coming in to prevent both overexposure and underexposure, the iris becomes wider and narrower, changing the size of the pupil to control the amount of light entering the eye. The pupil gets bigger when more light is needed to see better and smaller when there's plenty of light. The eye's lens sits just behind the iris. Just like a camera lens, the eye's lens focuses light to form sharp, clear images. Light that has been focused through the cornea and aqueous humor hits the lens, which then focuses it further, sending the light rays through the vitreous humor and onto the retina. To focus on objects clearly at varying distances, the eye's lens needs to change shape. The ciliary body contains the muscular structure in the eye that changes the shape of the eye's lens. In people who have normal vision, the ciliary body flattens the lens enough to bring objects into focus at a distance of 20 feet or more. To see closer objects, this muscle contracts to thicken the lens. Young children can see objects at very close range; many people over 45 have to hold objects farther and farther away to see them clearly.

This is because the lens becomes less elastic with age. The retina (the soft, light-sensitive layer of tissue that lines the back of the eyeball wall) is made up of millions of light receptors called rods and cones. Rods are much more sensitive to light than cones. Each eye has about 125 million rods that help us see in dim light and detect shades of gray, but they cannot distinguish colors. In comparison, the 6 million cones in each eye allow us to see in bright light and they also sense color and detail. The macula is a small, specialized area on the retina that helps the eyes see fine details when we look directly at an object. It contains mainly cones and few rods. When focused light is projected onto the retina, it stimulates the rods and cones. The retina then sends nerve signals are sent through the back of the eye to the optic nerve. The optic nerve carries these signals to the brain, which interprets them as visual images. The portion of the brain that processes visual input and interprets the messages that the eye sends is called the visual cortex. As in a camera, the eye's lens transmits light patterns upside down.

The brain learns that the impulses received from the upper part of the retina are really from the lower part of the object we're seeing and vice versa. Most people use both eyes to see an object. This is called binocular vision, and images are formed on the retina of each eye. These images are slightly different because the object is being viewed from slightly different angles. Nerve signals representing each image are sent to the brain, where they are interpreted as two views of the same object. Some of the nerve fibers from each eye cross, so each side of the brain receives messages from both eyes. Through experience, the brain learns to judge the distance of an object by the degree of difference in the images it receives from the two eyes. This ability to sense distance is called depth perception. previous continue Vision Problems Vision is a fine-tuned process. All the parts of the eye — and the brain — need to work together so a person can see correctly. Because the eye's structure is so complex, though, a lot of things can go wrong. Some of the most common eye problems are refractive errors. These are the problems that eye doctors check for routinely in a vision test. Refraction means bending of light rays to focus the light coming from an image.

Refractive errors are problems with the focusing of the eye, because of the way the eye is shaped, which causes the image you see to be blurred. Refractive errors include: Astigmatism. In astigmatism, there's a problem with the curve of the cornea. This causes part of the eye's image to be blurry. Corrective lenses such as contact lenses or glasses can usually correct vision in people with astigmatism. Myopia. Also called nearsightedness or shortsightedness, myopia happens when the eye focuses the image of an object in front of the retina instead of directly on it. In most cases, people can't see well far away, but can see objects clearly close up. The condition tends to get somewhat worse through childhood and adolescence, but stabilizes in adulthood. People with this condition may need to wear glasses or contacts to correct their vision. Laser eye surgery is now commonly used in adults to correct nearsightedness permanently by changing the shape of the cornea. Laser surgery is not used for teens because the eye may still be growing and the refractive error changing. Hyperopia.

Also called farsightedness or longsightedness, hyperopia happens when the incoming image is not focused on the retina, but behind it. This may make it difficult to see close objects clearly, with far-off objects seen more easily. Many younger children are hyperopic, but because of the ability of the eye to focus itself, may not need glasses to correct this. Glasses or contact lenses can correct this problem in kids and teens when needed. Most adults develop a form of farsightedness called presbyopia as they get older. Other Common Vision Problems Some of the other eye problems that can affect children and teens include: Blindness. This is the loss of useful sight. Blindness can be temporary or permanent and it has many causes. Birth defects or damage to any portion of the eye, the optic nerve, or the area of the brain responsible for vision can lead to blindness. The visual impairment cannot be corrected with surgery or corrective lenses, and the condition can make it difficult to perform everyday activities. Diabetes, problems with the macula, and eye changes because of aging account for most blindness in adults in the United States. In children and teenagers, eye injuries and eye trauma account for most blindness. Cataracts.

Some children are born with cataracts, a cloudiness of the eye's lenses that prevent images from being seen clearly or at all. But cataracts are much more prevalent in the elderly among whom surgery to remove cataracts and correct vision is common. In infants and young children, cataracts must be treated early to prevent permanent problems with development of vision. Color blindness. Color blindness is caused by problems in the pigments of the cones in the retina. Most people who are color-blind can see some colors. In most cases, someone who is color-blind confuses some colors with others, usually red and green. People can be born color-blind or they may develop the condition over time. The most common form of color blindness is an inherited condition that affects boys much more often than girls. Color blindness cannot be corrected. Dacryostenosis. Dacryostenosis is a blockage of the tear drainage system of the eye happening in the lower eyelid. This is a fairly common problem in infants, but often improves with time. Eye injuries . Injuries to the eye are one of the most common preventable causes of blindness.

Eye injuries may be caused by irritants such as sand, dirt, or other foreign bodies on the eye's surface. Chemicals or foreign bodies that become embedded in the eye can also cause pain and loss of vision. Forceful blows to the eye can cause bleeding inside the eye and damage to the cornea, retina, and other important eye structures. Glaucoma. One of the leading causes of blindness in the United States, glaucoma is a disorder that causes fluid pressure to build up inside the eye, potentially causing damage to the optic nerve. Although it can happen in infants and children, it is much more common among older adults. Unless detected early by routine screening tests, it usually goes undiagnosed until some vision is lost. Macular degeneration is an eye disease that mainly affects older people. When someone has macular degeneration, the middle area of the retina becomes scarred. This causes eyesight to deteriorate over many years. The cause of macular degeneration is unknown in most cases, but it tends to run in families, which indicates that genes and heredity are involved. Pinkeye (conjunctivitis) .

Pinkeye is a common contagious infection that causes inflammation (redness, pain, and swelling) of the conjunctiva, the clear membrane that covers the white part of the eye and the inner surface of the eyelids. The eyes become pinkish red and watery, and pus may form. Pinkeye is usually treated with eye drops. Conjunctivitis also can be the result of allergies or from a scratch on the surface of the eye. Retinoblastoma . This is a cancerous tumor in the eye that usually appears in the first 5 years of life. There may be permanent vision loss, and the affected eye(s) may have to be removed. If not properly treated, this cancer can be life-threatening. Retinopathy of prematurity . Premature babies sometimes have damage to the blood vessels in the eye's retina, a condition known as retinopathy of prematurity, which can lead to severe vision loss in some cases. Strabismus . A condition in which the eyes appear misaligned, strabismus is usually caused by a defect in the balance of the pull exerted by the muscles that help the eyes stay straight and move together properly.

Surgery on the eye muscles can help realign the eyes. Permanent vision loss in the less-used eye ( amblyopia ) can happen if the condition is not treated in early childhood. Stye . A stye (or sty, also called a hordeolum) is a red, painful bump on the eyelid caused by a backed-up oil gland. Styes are treated by applying warm compresses to allow them to drain. Sometimes antibiotic drops or ointments are necessary if it gets infected. Occasionally, a doctor may need to make a tiny cut in the eyelid to let out the clogged-up material. Proper care of your child's eyes includes having periodic eye exams at routine office checkups and by an eye specialist according to the schedule recommended by your doctor. Signs that a very young child may be having vision trouble include crossing or drifting of one or both eyes, constant eye rubbing, tearing or redness, and trouble following an object. Older kids may squint or sit too close to the TV or have difficulty seeing the board at school.

The Eyes (Human Anatomy): Diagram, Optic Nerve, Iris, Cornea, Pupil, & More Cornea: a clear dome over the iris Pupil: the black circular opening in the iris that lets light in Sclera: the white of your eye Conjunctiva: a thin layer of tissue that covers the entire front of your eye, except for the cornea Just behind the iris and pupil lies the lens, which helps focus light on the back of your eye . Most of the eye is filled with a clear gel called the vitreous. Light projects through your pupil and lens to the back of the eye. The inside lining of the eye is covered by special light-sensing cells that are collectively called the retina. It converts light into electrical impulses. Behind the eye, your optic nerve carries these impulses to the brain . The macula is a small extra-sensitive area in the retina that gives you central vision. Eye color is created by the amount and type of pigment in your iris. Multiple genes inherited from each parent determine a person’s eye color. Eye Conditions Age-related macular degeneration : Causes loss of central vision as you get older. Amblyopia : Often called lazy eye, this condition starts in childhood.

One eye sees better than the other, so your brain favors that eye. The weaker eye, which may or may not wander, is called the "lazy eye." Astigmatism : A problem with the curve of your cornea. If you have it, your eye can’t focus light onto the retina the way it should. Glasses, contact lenses , or surgery can correct the blurry vision it causes. Black eye: Swelling and discoloration ( bruise ) around your eye caused by an injury to the face. Blepharitis : Inflammation of your eyelids near the eyelashes . It can make your eyes feel itchy or gritty. Cataract: A clouding of your eye’s internal lens. It can cause blurred vision. Chalazion : An oil-making gland gets blocked and swells into a bump. Conjunctivitis : Also known as pinkeye , it’s an infection or inflammation of the conjunctiva, the clear layer that covers the front of your eye. Allergies , viruses, or a bacterial infection can all cause it. Corneal abrasion : A scratch on the clear part of the front of your eye.

Pain , light sensitivity , or a feeling of grit in the eye are the usual symptoms. Diabetic retinopathy : High blood sugar damages blood vessels in the eye. Eventually, they start to leak or overgrow in your retina, threatening your vision . Diplopia (double vision): Seeing double can be caused by many serious conditions. It requires immediate medical attention. Dry eye : Either your eyes don’t produce enough tears, or the tears are of poor quality. Medical problems like lupus , scleroderma , and Sjogren's syndrome are often to blame. Glaucoma : This progressive loss of vision comes from increased pressure inside the eye. Your peripheral vision (side vision) will go first, then your central vision will follow. It can go undetected for years. Hyperopia ( farsightedness ): You can’t see near objects clearly. It can happen when your eye is “too short” for the lens to focus light the way it should. Age can also weaken the muscles you use to focus. Hyphema : Bleeding into the front of the eye, between the cornea and the iris. Hyphema is usually caused by trauma. Keratitis: Inflammation or infection of the cornea.

It typically occurs after germs get into a scratch on your cornea. Myopia (nearsightedness): You can’t see clearly at a distance. Your eye is “too long” for the lens, so light won’t focus properly on your retina. Optic neuritis : The optic nerve becomes inflamed, usually due to an overactive immune system . The result: Pain and vision loss , typically in one eye. Pterygium: A thickened mass usually on the inner part of your eyeball. It can cover a part of the cornea and lead to vision problems. Retinal detachment : The retina comes loose from the back of your eye. Trauma and diabetes are the most common causes of this problem, which often requires urgent surgical repair. Retinitis : An inflammation or infection of the retina. It may be a long-term genetic condition ( retinitis pigmentosa ) or come from an infection. Scotoma: A blind or dark spot in your visual field. Strabismus: When the eyes don’t point in the same direction. Your brain may favor one eye. If it happens to a kid, it can decrease vision in the other eye. This condition is called amblyopia.

Stye : A red, painful lump on the edge of your eyelid. Bacteria cause it. Uveitis ( iritis ): The colored part of your eye gets inflamed or infected. An overactive immune system , bacteria, or viruses can cause it. Continued Eye Tests Tonometry: A test that measures pressure in the eye, called intraocular pressure. Your doctor uses it to check for glaucoma . Slit lamp examination: A physician or optometrist shines a vertical slit of light across your eye while looking through a microscope. It can help find many eye problems . Fundoscopic exam: The doctor gives you special eye drops to widen your pupil (he'll call this dilation). Then he shines a bright light into the back of the eye so he can see your retina. Refraction: If you have a vision problem, the doctor will place a series of lenses in front of each eye, one at a time, to figure out your prescription for corrective lenses. Visual acuity test: You’ll read a series of ever-smaller letters from across the room. This helps the doctor spot distance vision problems. Reading up-close can help him find problems with near vision.

Fluorescein angiography: The doctor injects a fluorescent dye into a vein to take a series of retinal images. Regular adult eye exam : This collection of tests may include the ones mentioned above plus others, like eye movement. Eye Treatments Contact lenses and glasses: They correct common eye problems like nearsightedness, farsightedness, and astigmatism. LASIK (laser-assisted in-situ keratomileusis): A doctor creates a thin flap in your cornea. He then uses a laser to reshape it. This procedure improves nearsightedness, excessive farsightedness, and astigmatism . Radial keratotomy (RK): The doctor makes a series of small incisions in your cornea to reshape it. Once a common treatment for nearsightedness, it’s rarely used today. Photorefractive keratectomy (PRK): The doctor rubs surface cells off your cornea, then uses a laser to improve nearsightedness, farsightedness, or astigmatism. The cells grow back and your eye heals the same way it would if you'd scratched it.

LASEK (laser epithelial keratomileusis): It’s similar to PRK. The doctor peels back the upper layer of cornea cells and uses a later to reshape it. He may replace or remove the flap afterward. Artificial tears : These eye drops are a lot like your natural tears. They can help treat dry or irritated eyes. Cyclosporine eye drops ( Restasis ): This anti-inflammatory eye drop can treat dry eye caused by inflammation. Laser photocoagulation: A doctor uses a laser on parts of the retina with poor circulation or to treat abnormal blood vessels directly. It’s often used for diabetic retinopathy but can also seal a retinal tear. Cataract surgery: The doctor removes the cloudy cataract and replaces your natural lens with a man-made version. WebMD Image Collection Reviewed by Alan Kozarsky, MD on December 08, 2016 Sources Strabismus (Crossed Eyes) Strabismus (Crossed Eyes) How is strabismus treated? Crossed eyes, or strabismus, is a condition in which both eyes do not look at the same place at the same time.

It usually occurs in people who have poor eye muscle control or are very farsighted. Six muscles attach to each eye to control how it moves. The muscles receive signals from the brain that direct their movements. Normally, the eyes work together so they both point at the same place. When problems develop with eye movement control, an eye may turn in, out, up or down. The eye turning may occur all the time or may appear only when the person is tired, ill, or has done a lot of reading or close work. In some cases, the same eye may turn each time. In other cases, the eyes may alternate turning. Proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion. But over time the brain will learn to ignore the image from the turned eye. Untreated eye turning can lead to permanently reduced vision in one eye. This condition is called amblyopia or lazy eye. Some babies' eyes may appear to be misaligned, but they are actually both aiming at the same object.

This is a condition called pseudostrabismus or false strabismus. The appearance of crossed eyes may be due to extra skin that covers the inner corner of the eyes or a wide bridge of the nose. Usually, the appearance of crossed eyes will go away as the baby's face begins to grow. Strabismus usually develops in infants and young children , most often by age 3. But older children and adults can also develop the condition. People often believe that a child with strabismus will outgrow the condition. However, this is not true. In fact, strabismus may get worse without treatment. An optometrist should examine any child older than 4 months whose eyes do not appear to be straight all the time. Strabismus is classified by the direction the eye turns: Inward turning is called esotropia Outward turning is called exotropia Upward turning is called hypertropia Downward turning is called hypotropia. Other classifications of strabismus include: The frequency with which it occurs—either constant or intermittent Whether it always involves the same eye—unilateral If the turning eye is sometimes the right eye and other times the left eye—alternating.

Treatment for strabismus may include eyeglasses, prisms, vision therapy, or eye muscle surgery. If detected and treated early, strabismus can often be corrected with excellent results. [back to top] What causes strabismus? Strabismus can be caused by problems with the eye muscles, the nerves that transmit information to the muscles, or the control center in the brain that directs eye movements. It can also develop due to other general health conditions or eye injuries. Risk factors for developing strabismus include: Family history. People with parents or siblings who have strabismus are more likely to develop it. Refractive error. People who have a significant amount of uncorrected farsightedness (hyperopia) may develop strabismus because of the additional eye focusing they must do to keep objects clear. Medical conditions. People with conditions such as Down syndrome and cerebral palsy or who have suffered a stroke or head injury are at a higher risk for developing strabismus. Many types of strabismus can develop in children or adults, but the two most common forms are: Accommodative esotropia often occurs because of uncorrected farsightedness (hyperopia).

The eye's focusing system is linked to the system that controls where the eyes point. So people who are farsighted are focusing extra hard to keep images clear. This may cause the eyes to turn inward. Symptoms of accommodative esotropia may include seeing double, closing or covering one eye when doing close work, and tilting or turning the head. Intermittent exotropia may develop when a person cannot coordinate both eyes together. The eyes may point beyond the object being viewed. People with intermittent exotropia may experience headaches, difficulty reading and eye strain. They also may close one eye when viewing at distance or in bright sunlight. [back to top] How is strabismus diagnosed? An optometrist can diagnose strabismus through a comprehensive eye exam . Testing for strabismus, with special emphasis on how the eyes focus and move, may include: : Patient history. An optometrist will ask the patient or parent about any current symptoms. In addition, the optometrist will note any general health problems, medications or environmental factors that may be contributing to the symptoms. Visual Acuity . An optometrist will measure visual acuity to assess how much vision is being affected.

For the test, you will be asked to read letters on reading charts that are near and at a distance. Visual acuity is written as a fraction, such as 20/40. The top number is the standard distance at which testing is done (20 feet). The bottom number is the smallest letter size you were able to read at the 20-foot distance. A person with 20/40 visual acuity would have to get within 20 feet of a letter that should be seen clearly at 40 feet. "Normal" distance visual acuity is 20/20. Your eye doctor has other methods of measuring vision in young children or patients who cannot speak or comprehend the visual acuity test. Refraction. An optometrist can conduct a refraction to determine the appropriate lens power you need to compensate for any refractive error (nearsightedness, farsightedness or astigmatism). Using an instrument called a phoropter, the optometrist places a series of lenses in front of your eyes and measures how they focus light using a handheld lighted instrument called a retinoscope.

Or the doctor may use an automated or handheld instrument that evaluates the refractive power of the eye without the patient needing to answer any questions. Alignment and focusing testing. Your optometrist needs to assess how well your eyes focus, move and work together. In order to obtain a clear, single image of what you are viewing, your eyes must effectively change focus, move and work in unison. This testing will look for problems that keep your eyes from focusing effectively or make it difficult to use both eyes together. Examination of eye health. Using various testing procedures, your optometrist will observe the internal and external structures of your eyes to rule out any eye disease that may be contributing to strabismus. This testing will determine how the eyes respond under normal seeing conditions. For patients who can't respond verbally or when some of the eyes focusing power may be hidden, your optometrist may use eye drops. The eye drops temporarily keep the eyes from changing focus during testing. Using the information obtained from these tests, along with results of other tests, your optometrist can determine if you have strabismus. Once testing is complete, your optometrist can discuss treatment options.

People with strabismus have several treatment options to improve eye alignment and coordination. They include: Eyeglasses or contact lenses. This may be the only treatment needed for some patients. Prism lenses. These special lenses have a prescription for prism power in them. The prisms alter the light entering the eye and reduce how much turning the eye must do to view objects. Sometimes the prisms can eliminate the eye turning. Vision therapy. Your optometrist might prescribe a structured program of visual activities to improve eye coordination and eye focusing. Vision therapy trains the eyes and brain to work together more effectively. These eye exercises can help problems with eye movement, eye focusing and eye teaming and reinforce the eye-brain connection. Treatment can occur in your optometrist's office as well as at home. Eye muscle surgery. Surgery can change the length or position of the muscles around the eye so they appear straight. Often, people who have eye muscle surgery will also need vision therapy to improve eye coordination and to keep the eyes from becoming misaligned again. Get Connected ODs: Learn how to leverage local media to promote your practice and profession 1 hour ago Crossed Eyes (Strabismus): Symptoms, Causes, and Diagnosis Your message has been sent.

OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Crossed eyes is also called strabismus, a condition in which your eyes don’t line up. If you have this condition, your eyes look in different directions. And each eye will focus on a different object. The condition is more common in children, but it can... Read more What are crossed eyes? Crossed eyes is also called strabismus, a condition in which your eyes don’t line up. If you have this condition, your eyes look in different directions. And each eye will focus on a different object. The condition is more common in children, but it can also occur later in life. In older children and adults, crossed eyes can be caused by a variety of underlying medical conditions, like cerebral palsy or stroke. Crossed eyes can usually be corrected with corrective lenses, surgery, or a combination of both. Symptoms of crossed eyes If you have crossed eyes, your eyes might point inward or outward or focus in different directions. You might also have: impaired vision Your symptoms may be constant or appear only when you’re tired or not feeling well.

What causes crossed eyes? Crossed eyes occur either due to nerve damage or when the muscles around your eyes don’t work together because some are weaker than others. When your brain receives a different visual message from each eye, it ignores the signals coming from your weaker eye. If your condition isn’t corrected, you may lose vision in your weaker eye. Crossed eyes are common in children. Often the underlying cause is unknown. Infantile esotropia is a type of crossed eyes that appears in babies during their first year of life. It runs in families and usually requires surgery to correct. Acquired esotropia occurs in children between the ages of 2 and 5. Eyeglasses can usually correct it. Crossed eyes can also occur later in life. It’s usually caused by physical disorders, like eye injuries, cerebral palsy, or stroke. You may also develop crossed eyes if you have a lazy eye or are farsighted. How is crossed eyes diagnosed? To prevent vision loss, early diagnosis and treatment for crossed eyes is important. If you develop symptoms of crossed eyes, make an appointment with an eye doctor.

They will perform a series of tests to check the health of your eyes that may include: corneal light reflex test to check for crossed eyes visual acuity test to determine how well you can read from a distance cover/uncover test to measure your eye movement and deviation retina exam to examine the backs of your eyes If you have other physical symptoms along with crossed eyes, your doctor may examine your brain and nervous system for other conditions. For example, they may conduct tests to check for cerebral palsy or Guillain-Barré syndrome. It’s common for newborn babies to have crossed eyes. If your baby has crossed eyes that persist beyond 3 months of age, make an appointment with their doctor. Young children should undergo an eye exam before age 3. Who is at risk of crossed eyes? You’re more likely to develop crossed eyes if you: have family members who have crossed eyes have a brain disorder or brain tumor have suffered a stroke or brain injury have a lazy eye, are farsighted, or have vision loss have a damaged retina are diabetic How are crossed eyes treated? Your recommended treatment plan for crossed eyes will depend on the severity and underlying cause of your condition.

If your crossed eyes have resulted from a lazy eye, your doctor may have you wear a patch over your stronger eye to force the muscles of your weaker eye to work harder. They might also prescribe eye drops to blur the vision in your stronger eye. They can also use Botox injections to weaken the muscles of your stronger eye. Other potential treatments include: corrective lenses, such as eyeglasses or contact lenses surgery on certain eye muscles, particularly if corrective lenses haven’t corrected the condition If your crossed eyes are caused by an underlying medical condition, such as a brain tumor or stroke, your doctor may prescribe medication, surgery, or other treatments. What is the long-term outlook for crossed eyes? Often crossed eyes can be corrected with corrective lenses, eye patches, in rare cases surgery, or by other modalities. It’s important to seek treatment right away to lower your risk of vision loss. After you’ve received treatment, watch your eyes for changes. In some cases, the condition may come back. If your crossed eyes are caused by an underlying medical condition, early diagnosis and treatment may help improve your chances of recovery. Ask your doctor for more information about your specific condition and treatment options.

Written by Chitra Badii Muscular System: Facts, Functions & Diseases Muscular System: Facts, Functions & Diseases By Kim Ann Zimmermann, Live Science Contributor | March 11, 2016 07:35pm ET MORE While most people associate muscles with strength, they do more than assist in lifting heavy objects. The 650 muscles in the body not only support movement — controlling walking, talking, sitting, standing, eating and other daily functions that people consciously perform — but also help to maintain posture and circulate blood and other substances throughout the body, among other functions. Muscles are often associated with activities of the legs, arms and other appendages, but muscles also produce more subtle movements, such as facial expressions, eye movements and respiration, according to the National Institutes of Health (NIH). [ Image Gallery: The BioDigital Human ] Three types of muscles The muscular system can be broken down into three types of muscles: skeletal, smooth and cardiac, according to the NIH. Skeletal muscles are the only voluntary muscle tissue in the human body and control every action that a person consciously performs.

Most skeletal muscles are attached to two bones across a joint, so the muscle serves to move parts of those bones closer to each other, according to The Merck Manual . Visceral, or smooth, muscle is found inside organs such as the stomach and intestines, as well as in blood vessels. It is called a smooth muscle because, unlike skeletal muscle, it does not have the banded appearance of skeletal or cardiac muscle. The weakest of all muscle tissues, visceral muscles contract to move substances through the organ, according to The Merck Manual. Because visceral muscle is controlled by the unconscious part of the brain, it is known as involuntary muscle, as it cannot be controlled by the conscious mind. Found only in the heart, cardiac muscle is an involuntary muscle responsible for pumping blood throughout the body, according to The Merck Manual. The heart's natural pacemaker is made of cardiac muscle that signals other cardiac muscles to contract. Like visceral muscles, cardiac muscle tissue is controlled involuntarily. While hormones and signals from the brain adjust the rate of contraction, cardiac muscle stimulates itself to contract. Muscle shapes Muscles are further classified by their shape, size and direction, according to the NIH. The deltoids, or shoulder muscles, have a triangular shape.

The serratus muscle, which originates on the surface of the second to ninth ribs at the side of the chest, and runs along the entire anterior length of the scapula (shoulder blades), has a distinctive sawlike shape. The rhomboid major, which attaches the scapula to the spinal column, is a diamond shape. Size can be used to differentiate similar muscles in the same region. The gluteal region (the buttocks) contains three muscles differentiated by size: the gluteus maximus (large), gluteus medius (medium) and gluteus minimus (smallest), the NIH noted. The direction in which the muscle fibers run can be used to identify a muscle. In the abdominal region, there are several sets of wide, flat muscles, according to the NIH. The muscles whose fibers run straight up and down are the rectus abdominis, the ones running transversely (left to right) are the transverse abdominis and the ones running at an angle are the obliques. As any exercise enthusiast knows, obliques are among the hardest muscles to develop to achieve "six-pack" abs. Muscles also can be identified by their function.

The flexor group of the forearm flexes the wrist and the fingers. The supinator is a muscle that allows you to roll your wrist over to face palm up. Adductor muscles in the legs adduct, or pull together, the limbs, according to the NIH. Diseases of the muscular system There is no single type of doctor that treats muscular diseases and disorders. Rheumatologists, orthopedists and neurologists may all treat conditions that affect the muscles, according to the American Medical Association . There are a number of common neuromuscular disorders, according to Dr. Robert Schabbing, chief of neurology at Kaiser Permanente in Denver. Common primary muscle disorders include inflammatory myopathies, including polymyositis, which is characterized by inflammation and progressive weakening of the skeletal muscles; dermatomyositis, which is polymyositis accompanied by a skin rash; and inclusion body myositis, which is characterized by progressive muscle weakness and wasting. Other common disorders are muscular dystrophies and metabolic muscle disorders, he said. Muscular dystrophy affects muscle fibers.

Metabolic muscle disorders interfere with chemical reactions involved in drawing energy from food.Neuromuscular junction disorders impair the transmission of nerve signals to muscles, Schabbing noted. The most common neuromuscular junction disorder is myasthenia gravis, which is characterized by varying degrees of weakness of the skeletal muscles. Schabbing said. "There are many types of peripheral neuropathies that can be secondary to other medical conditions, such as diabetes, or due to a variety of other causes, including toxins, inflammation and hereditary causes," he said. Motor neuron disorders affect the nerve cells that supply muscles, Schabbing said. The most recognizable motor neuron disease is amyotrophic lateral sclerosis, or ALS, commonly known as Lou Gehrig's disease. Learn about the muscles that move your body and keep you alive. Credit: by Ross Toro, Infographics Artist Symptoms, diagnosis and treatment The most common symptom or sign of a muscle disorder is weakness, although muscle disorders can cause a number of symptoms, according to Schabbing. In addition to weakness, symptoms include abnormal fatigue with activity, as well as muscle spasms, cramping or twitching.

Neuromuscular disorders affecting the eyes or mouth can cause drooping eyelids or double vision, slurred speech, difficulty swallowing or, sometimes, difficulty breathing. Electromyography — commonly referred to as an EMG — is often used to diagnose muscular disorders. An EMG helps characterize causes of nerve and muscle disorders by stimulating nerves and recording responses, Schabbing noted. Rarely, nerve or muscle biopsies are needed. Steroids and other medications can help to reduce spasms and cramping. Milder forms of chemotherapy can help treat many muscular disorders, according to Dr. Ricardo Roda, an assistant professor of neurology, neuroscience and physiology at NYU Langone Medical Center . Editor’s Note: If you’d like more information on this topic, we recommend the following book: 19 Effects of Diabetes on the Body Cataracts and Glaucoma The Effects of Diabetes on the Body After you eat or drink, your body breaks down the sugars in your blood and turns it into glucose. The glucose travels through your bloodstream and provides your body with energy. To accomplish this, your pancreas needs to produce a hormone called insulin.

In a person with diabetes (diabetes mellitus), the pancreas either produces too little insulin or none at all, or the insulin can’t be used effectively. This allows blood glucose levels to rise while the rest of your cells are deprived of much needed energy. This can lead to a wide variety of problems affecting nearly every part of your body. There are two main types of diabetes. Type 1, also known as juvenile diabetes or insulin-dependent diabetes, is an immune system disorder. In Type 1 diabetes, the patient’s own immune system attacks the insulin-producing cells in the pancreas, destroying the ability to manufacture insulin. People with Type 1 diabetes must take insulin to live. Most people with Type 1 diabetes are diagnosed as children or young adults. The main problem in Type 2 diabetes is the presence of what is called insulin resistance. In this sort of diabetes, the pancreas starts off robust in its production of insulin. However, cells that need energy don’t respond normally to the usual amounts of insulin. The pancreas has to produce much higher levels of the hormone in order to manage blood glucose levels. Over time, the insulin-producing cells in the pancreas can burn themselves out due to this overproduction.

At this point a person with Type 2 diabetes begins to require insulin medication. However, in earlier phases of this more common type of diabetes, the illness can be effectively managed with diet, exercise, and careful monitoring of blood sugars. Some people with Type 2 diabetes may require a variety of oral medications and eventually, as described above, some will eventually need insulin. Gestational diabetes is high blood sugar that develops during pregnancy. Most of the time, gestational diabetes can be controlled through diet and exercise, and it typically resolves after the baby is delivered. Common symptoms of diabetes include excessive thirst, frequent urination, and sluggishness. Blood tests will reveal high sugar levels. Endocrine, Excretory, and Digestive Systems Your pancreas produces and releases insulin to help make energy out of sugars. If your pancreas produces little or no insulin, or if your body can’t use it, alternate hormones are used to turn fat into energy. This can create high levels of toxic chemicals, including acids and ketone bodies, which may lead to a condition called diabetic ketoacidosis. This is a serious complication of the disease. Symptoms include extreme thirst, excessive urination, and fatigue.

Your breath may have a sweet scent that is caused by the elevated levels of ketone bodies in the blood. High blood sugar levels and excess ketones in your urine can confirm diabetic ketoacidosis. Untreated, the condition can lead to loss of consciousness or even death. Diabetes can damage your kidneys, affecting their ability to filter waste products from your blood. Elevated amounts of protein in your urine (microalbuminuria) may be a sign that your kidneys aren’t functioning properly. Kidney disease related to diabetes is called diabetic nephropathy. This condition doesn’t show symptoms until it advances to later stages. People with diabetes should be evaluated for nephropathy in order to avoid irreversible kidney damage and kidney failure. Diabetic hyperglycemic hyperosmolar syndrome (HHS) occurs in Type 2 diabetes. It involves very high blood glucose levels but without ketones. Symptoms also include dehydration and loss of consciousness. It usually happens to people whose diabetes is undiagnosed or who have not been able to control their diabetes. It can also be caused by heart attack, stroke, or infection. High blood glucose levels can make it hard for your stomach to completely empty (gastroparesis).

In turn, the delay causes blood glucose levels to rise. Diabetes is the leading cause of gastroparesis. Symptoms include nausea, vomiting, bloating, and heartburn. Circulatory System High blood glucose levels can contribute to the formation of fatty deposits in blood vessel walls. Over time, that can restrict blood flow and increase the risk of hardening of the blood vessels (atherosclerosis). Lack of blood flow can affect your hands and feet. Poor circulation can cause pain in the calves while you’re walking (intermittent claudication). People with diabetes are particularly prone to foot problems due to narrowed blood vessels in the leg and foot. Your feet may feel cold, and you may be unable to feel heat due to lack of sensation. A condition called diabetic neuropathy causes decreased sensation in the extremities, which may prevent you from noticing an injury or infection. Diabetes increases your risk of developing infections or ulcers of the foot. Poor blood flow and nerve damage increase the likelihood of having a foot or leg amputated. If you have diabetes, it is critical that you take good care of your feet and inspect them often. Diabetes raises your risk of developing high blood pressure, putting strain on the heart.

According to the National Diabetes Information Clearinghouse , people with diabetes have double the risk of heart disease or stroke than people without diabetes. Monitoring and controlling your blood glucose, blood pressure, and cholesterol can lower that risk. So can good eating habits and exercise. Diabetes and smoking are a very bad mix, increasing risk of cardiovascular problems and restricted blood flow. Integumentary System Diabetes can affect your skin. Lack of moisture can cause the skin on your feet to dry and crack. It is important to completely dry your feet after bathing or swimming. You can use petroleum jelly or gentle creams, but be careful: creams or oils left between your toes can become so moist that it can lead to infection. High-pressure spots under your foot can lead to calluses. If you don’t take good care of them, they can become infected or develop ulcers. If you get an ulcer, see your doctor immediately to lower your risk of losing your foot. You may also be more prone to boils, infection of the hair follicles (folliculitis), sties, and infected nails. People with diabetes have a higher incidence of bacterial infections, including staph (Staphylococcus), than the general population.

Moist, warm folds in the skin are susceptible to fungal or yeast infections. You’re most likely to develop this type of infection between fingers and toes, the groin, armpits, or in the corners of your mouth. Symptoms include redness, blistering, and itchiness. A condition called diabetic dermopathy can cause brown patches on the skin. There’s no cause for concern and no treatment is necessary. Eruptive xanthomatosis causes hard yellow bumps with a red ring. Digital sclerosis causes thick skin, most often on the hands or feet. Both of these skin conditions are signs of unmanaged diabetes. They usually clear up when you get your blood sugar under control. Central Nervous System Diabetes causes damage to the nerves (peripheral neuropathy), which can affect your perception of heat, cold, and pain, making you more susceptible to injury. This also makes it more likely that you’ll ignore an injury, especially if it’s in a difficult place to see, such as between your toes, on your heels, or the bottoms of your feet. Swollen, leaky blood vessels in the eye (diabetic retinopathy) can damage your vision and even lead to blindness.

Symptoms include floaters or spots in your field of vision. People with diabetes tend to develop cataracts at an earlier age than other people. They are also more likely to develop glaucoma. Symptoms of eye trouble can be mild at first, so it’s important to see your eye doctor regularly. Reproductive System The hormones of pregnancy can cause gestational diabetes. This also increases the risk of high blood pressure (preeclampsia or ecclampsia). In most cases, gestational diabetes is easily controlled, and glucose levels return to normal after the baby is born. Symptoms are the same as other types of diabetes, but may also include repeated infections affecting the vagina and bladder. Women with gestational diabetes may have babies with higher birth weight, making delivery more complicated. Women who have had gestational diabetes should be monitored, as there’s an increased risk of developing diabetes within ten years. Recommended for You The Not-So-Sweet Facts of Diabetes Get an up-close look at the increasing impact type 2 diabetes has on everything from pregnancy to healthcare costs. Controllable risk factors – diabetes. (n.d.). Retrieved from Diabetes, heart disease, and stroke. (2014, February 19).

Retrieved from Facts about diabetic retinopathy. (2012, June). Retrieved from Foot complications. (2014, May 22). Retrieved from Gastroparesis. (2012, June 15). Retrieved from High blood pressure. (2014, January 4). Retrieved from Kidney disease (Nephropathy). (2013, December 10). Retrieved from Mayo Clinic Staff. (2012, October 23). Diabetic ketoacidosis: Complications. Retrieved from Mayo Clinic Staff. (2012, October 23). Diabetic ketoacidosis: Definition. Retrieved from Mayo Clinic Staff. (2012, October 23). Diabetic ketoacidosis: Symptoms. Retrieved from Skin complications. (2014, March 31). Retrieved from What is diabetes?. (n.d.). Retrieved from

Question: The medical condition Strabismus affects what part of the human body?
Answer: Eyes