 | |||||||||||||||||||||||||||||||||||||||||||||||||||
 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Home The Doctors Low Vision Services Visit the Optical Shop This Way to CEC Planning For Your Visit Contact Us
Insurance Information Send Us a Comment Eye Care Links |
Office Number 405-751-2020 Fax Number 405-751-3838
Amblyopia What is amblyopia? Amblyopia is the poor vision which develops when a young child's brain learns to ignore an eye. There are 3 main causes: one eye is more out of focus; one eye is not straight; or one eye has a defect, such as a cataract, which was not promptly corrected. Is amblyopia the same thing as "lazy eye"? Yes and no. People use the term "lazy eye" for amblyopia, but also for disorders which are not amblyopia (for example: an eye which requires a stronger glasses correction, but sees well with glasses; an eye which crosses, but still sees well; a droopy eyelid; even a slight difference in the shape of the eyelid openings). Can amblyopia cause permanently decreased vision? Yes. If not treated early enough, the loss of vision is usually permanent. Is amblyopia common? Yes. 2% - 2.5% of children (between 1 out of 40 and 1 out of 50) develop amblyopia. This represents roughly 5 million Americans. More Americans under 40 have lost vision in an eye from amblyopia than from any other cause. What are the causes of amblyopia?
Can amblyopia occur in both eyes? Yes, rarely. If both eyes are extremely hyperopic (farsighted), the brain becomes accustomed to blurry vision from each eye and the visual part of the brain does not develop properly. Glasses, if worn full time and started at an early enough age, will correct this. Amblyopia in both eyes is almost never a problem with myopia (nearsightedness); even if vision is very poor at a distance, vision is good enough up close that the brain sees how things ought to look and develops normally. Can amblyopia be treated? Yes. The better seeing eye is patched, forcing the brain to pay attention to the eye it has ignored. The underlying problem must also be addressed. If one eye is out of focus relative to the other, glasses are prescribed. If the eyes are not straight, glasses and/or surgery are used to straighten the eyes. What type of patch is used? An adhesive patch, like a large oval Band-aid, is usually the first choice. It has the advantages of completely covering the eye and being difficult for the child to remove. What if my child resists patching? This is normal. After all, it is harder to see with the better eye covered. In general, the more a child resists patching, the more you know he needs it. Be understanding, but firm, from the start. Patching will only become more lengthy and difficult if put off. If you are steadfast the first few days, you will usually be rewarded with improving vision and better acceptance of the patch. If a teacher or day care provider supervises your child part of each week, impress on her the seriousness of patching. Permanently reduced vision is likely if patching fails. What if my child absolutely won't patch? A cloth patch or tape on one lens of the glasses is an alternative to the adhesive patch. These measures, and the proverbial "Pirate" patch, are only successful in the cooperative older child who will not peek by removing the glasses or patch. If a child peeks, patching will not be successful. Period. Alternatively, vision in the better seeing eye may be blurred by using the dilating drop Atropine, which blocks the ability to focus up close. The amblyopic eye must be used for reading and close work, and is thereby strengthened. Finally, an overly strong lens correction may be used in front of the better seeing eye. In this case the amblyopic eye must be used for distance vision, and is thereby strengthened. Is it ever too late to patch? Unfortunately, yes. On the other hand, many people give up too soon. The different types of amblyopia differ greatly in severity. Amblyopia due to cataract must be treated promptly. A child born with a cataract in one eye must undergo surgery in the first 2-3 months of life, as well as intensive patching, to have a chance at good vision in that eye. Older children who develop a cataract as a result of trauma should also have prompt surgery to minimize amblyopia. Amblyopia due to crossing, or other misalignment, may be treated up to age 7 or 8, but responds more quickly in younger children, because the visual part of the brain is not as "set in its ways". An important lesson for parents of children with crossing is that surgery or glasses which straighten the eyes will not eliminate amblyopia by themselves. Improvement in vision also requires that the brain stop ignoring the eye. And this means patching. Amblyopia which results from one eye being out of focus relative to the other (anisometropic amblyopia) is a serious problem, but the least severe of the three forms of amblyopia. With proper glasses, and patching, improved vision can be obtained in children age 8 and older. Restoration of vision is still better and quicker, though, the earlier the problem is detected and treated. Back to top Astigmatism What is astigmatism ? Astigmatism is a condition in which the eye is out of focus. Both distance vision and near vision are affected. What causes the eye with astigmatism to be out of focus? In eyes with astigmatism the cornea, the clear dome covering the front of the eye, is not quite perfectly round. The curvature, if measured closely, is a little flatter in one direction (say, horizontally) and a little steeper in the other direction (say, vertically). This difference in curvature causes a difference in focus for lines of different orientations. For example, when looking at the letter "E" on the eye chart, the person with astigmatism may see the vertical line in focus, but the horizontal lines out of focus, or vice versa. In some patients with astigmatism the flattest and steepest corneal curves are oriented at an angle, instead of horizontally and vertically. These people see shadows of blurriness extending at angles from the letters or objects they view. What causes astigmatism? The cause is unknown. Protein in the corneas of people with astigmatism may be more flexible than normal, making the corneas more likely to get out of round. Is astigmatism always a problem? No. Small amounts of astigmatism may not be noticed. What signs might indicate astigmatism? Eye strain. Squinting. Headaches. When are children given glasses for astigmatism? Children usually do not require glasses prior to grade school unless the astigmatism is fairly severe, or much different in one eye than the other. Older children and adults do not tolerate as much blurriness and require glasses for smaller amounts of astigmatism. Can astigmatism cause amblyopia? Yes. If one eye has much more astigmatism than the other, a young child can begin to ignore the eye. Patching of the better eye will be required in addition to glasses to correct the astigmatism. Can a person have astigmatism as well as myopia or hyperopia? Yes. People often have myopia (nearsightedness) or hyperopia (farsightedness) in addition to astigmatism. How is astigmatism indicated on the glasses prescription? On the glasses prescription the correction for myopia (-) or hyperopia (+) is the number in the first column, marked "Sph" (for sphere); the astigmatism correction is the number in the second column, marked "Cyl" (for cylinder). Can astigmatism change over the years? Yes. Infants typically show a decrease in astigmatism during the first year or two of life. After that, changes in astigmatism tend to be unpredictable. Can astigmatism be corrected with contact lenses as well as glasses? Yes. Glasses are preferred for young children, but contact lenses are an option for older children. Smaller amounts of astigmatism can be well corrected with soft contact lenses or gas permeable lenses. Greater amounts of astigmatism may require a type of contact lens known as a toric lens, with a back surface which matches the different curvatures of the cornea, rather than being perfectly round. Is surgery available for astigmatism? Yes. The laser surgery (PRK, LASIK) and radial keratotomy (RK) that one hears so much about can correct astigmatism as well as myopia (nearsightedness). Predictability and patient satisfaction are generally not quite as high for astigmatism surgery as for myopia surgery, but this may change as equipment and techniques improve. Laser surgery for myopia and astigmatism is usually done on adults. Surgery will have to be even safer and more predictable before it is recommended for children. Back to top Blepharitis What is blepharitis? Blepharitis is inflammation of the edge of the eyelid. What are some of the signs and symptoms of blepharitis? Eyes may sting, burn, or itch. Patients typically blink or rub their eyes more often than usual. Allergies may be blamed mistakenly. There may be crusts on the eyelashes. In extreme cases there is redness at the inside edge of the lid. What problems does blepharitis cause? Blepharitis causes chronic irritation of the eyes and lids, which can be very aggravating. Blepharitis also puts patients at increased risk for other forms of eyelid inflammation, such as stye and chalazion. Inflammation may also spread to the conjunctiva (the lining of the eyelid and the covering of the white of the eye) and the cornea (the clear dome at the front of the eye, through which we see). How is blepharitis treated? There are a variety of treatments which may be used, alone or in combination:
Chalazion What is a chalazion? A chalazion (usually pronounced shuh lay' zee un) is a bump on the eyelid, which is initially red and swollen, and later often just a hard nodule under the skin. What causes a chalazion? A chalazion results from inflammation of oil glands, known as meibomian glands, which begin deep within the eyelid and extend to the edge of the lid. A chalazion may arise either away from the lid edge or at the lid edge. Oils secreted by the meibomian glands normally form a microscopic layer on the surface of the watery tears, reducing evaporation and helping the tears cover the surface of the eye more smoothly and evenly. Inflammation results when the opening of a meibomian gland at the edge of the lid is blocked, causing oils within the gland to back up and extrude into the surrounding lid tissue. The extruded oils, not bacteria, cause the redness and swelling. Blockage at the mouth of an oil gland is caused by swelling around the opening or thickening of the oils in the gland. Swelling may be caused by bacteria normally found on the skin. Thickening of the oils may result from a person's own body chemistry, or from changes in the oils produced by the same bacteria infecting the edge of the lid. What is the difference between a stye and a chalazion? Styes occur near the edge of the lid and usually resolve more quickly than chalazia. Antibiotics may be more helpful in clearing styes than chalazia. The area of redness and swelling will usually "point" or "come to a head" as white blood cells gather to fight the infection. What problems does a chalazion cause? Lid appearance worries patients and parents most. Discomfort may be a problem, especially at first. Larger chalazia can press on the cornea enough to distort vision. In young children this can cause amblyopia, the vision loss which results when the brain begins to ignore the eye with blurrier vision. How is a chalazion treated? There are a variety of treatments which may be used, alone or in combination:
Back to top Dyslexia Consider all the steps involved when you read two simple words, "THE CAT". You must:
Others believe dyslexia is a problem involving steps 2 through 7. Back to top Esotropia (Crossed Eyes) What is esotropia? Esotropia literally means a turning in (eso, in + tropia, turning). It is the medical term for eyes that cross. Can esotropia cause permanently decreased vision? Yes. The brain may develop the habit of ignoring an eye that turns in. Vision will not develop as well in that eye. The poor vision will be permanent unless treatment is begun at an early age -- 6 or 7 at the latest, but ideally as soon as crossing is noticed. Is esotropia common? Yes. 1-2% of children will have some misalignment of the eyes. Esotropia (eyes turning in) is 3-4 times as common as eyes turning out. Is all crossing the same? No. This cannot be emphasized too much.
Yes and no. People use the term "lazy eye" for esotropia, but also for other disorders, such as poor vision or a droopy eyelid. When people ask about lazy eye, it should be clarified whether they mean 'lazy'/not sraight, or 'lazy'/not seeing well, or both? Also, it must be emphasized that the child is not lazy: crossing cannot be eliminated by trying harder. Does esotropia run in families? Yes, but not in a predictable way. Families in which crossing occurs should watch more closely for crossing in their children. Is it ever normal for a baby's eyes to cross? During the first 2-3 months of life, a baby's eyes may not always be straight. Coordination of the movement of the two eyes is still developing. By 3-4 months of age, though, the child's eyes should be straight at all times. A pediatric ophthalmologist should check any child 4 months or older whose eyes aren't straight. How is esotropia treated? Treatment may require glasses, surgery, or both. Patching the better seeing eye can improve vision in an eye that turns in, but usually cannot straighten the eye. Is prompt treatment of esotropia important? Yes. Prompt treatment is more successful in eliminating crossing and the problems which accompany it. Prompt treatment is more successful in preventing amblyopia, the poor vision which results from the brain ignoring the eye which turns in. Prompt treatment also leads to better ability to use the eyes together, better depth perception, and more stable alignment of the eyes over time. What are the characteristics of esotropia which begins at birth? Children whose eyes cross in the first few months of life usually require surgery. These children may have difficulty using their eyes together even after the eyes are surgically straightened. Vertical misalignment (an eye that turns up when looking to the side or straight ahead) may develop later in childhood and require further surgery. What are the characteristics of esotropia which develops later in childhood? Children are often found to be more hyperopic (farsighted) than normal. If so, glasses are tried. If the eyes straighten completely with glasses, the child will need to remain in glasses, usually at least through grade school. If the eyes do not straighten completely with glasses, surgery is necessary. These children often do well using the eyes together after surgery. Is it ever too late to straighten an eye that is turned in? No. This a common misunderstanding among patients and other doctors. Surgery can always be done to straighten an eye. If the eye has poor vision due to longstanding crossing, though, there may be nothing that can be done to improve the vision in that eye. There are many people who needlessly suffer the embarrassment of an eye that is not straight because they have been wrongly told it is too late to do anything. Back to top Exotropia (Eyes that Drift Out) What is exotropia? Exotropia literally means a turning out (exo, out + tropia, turning). It is the medical term for eyes that turn out. Can exotropia cause permanently decreased vision? Yes. The brain may develop the habit of ignoring an eye that turns out. Vision may not develop as well in that eye. The ability to use the eyes together may also decline, resulting in poorer depth perception. Poor vision in an eye that turns out is usually permanent unless treatment is begun at an early age. Is exotropia common? Yes, although it is more common for kids' eyes to turn in, rather than out. 1-2% of children will have some misalignment of the eyes. Is all exotropia the same? No. Exotropia may be constant (present all the time). More commonly it is intermittent (present only some of the time). Typically it is worse when the patient is tired. Exotropia is usually just a problem involving the eyes, and the brain's coordination of their movements, but occasionally it can be a sign of serious underlying disease. Is exotropia the same thing as "lazy eye"? Yes and no. People use the term "lazy eye" for exotropia, but also for other disorders, such as poor vision or a droopy eyelid. When people ask about lazy eye, it should be clarified whether they mean 'lazy'/not sraight, or 'lazy'/not seeing well, or both? Also, it must be emphasized that the child is not lazy: crossingcannot be eliminated by trying harder. Although an eye that drifts may straighten if the child concentrates harder, it is neither right nor fair to blame the drifting on poor concentration. Does exotropia run in families? Yes, but not in a predictable way. Families in which eye misalignment occurs should watch more closely for misalignment in their children. Is it ever normal for a baby's eyes to drift out? During the first 2-3 months of life, a baby's eyes may not always be straight. Coordination of the movement of the two eyes is still developing. By 3-4 months of age, though, the child's eyes should be straight at all times. A pediatric ophthalmologist should check any child 4 months or older whose eyes aren't straight. How is exotropia treated? Treatment often requires surgery. Glasses may help children found to be myopic (nearsighted). Patching the better seeing eye can improve vision in an eye that turns out, and may make it turn out less often, but usually cannot straighten the eye permanently. Is prompt treatment of exotropia important? Prompt evaluation is always important, but prompt treatment may not be essential in all cases. If there is decreased vision in the eye that turns out, or decreased ability to use the eyes together, these problems should be addressed. What are the characteristics of intermittent exotropia? Parents may notice one eye turning out, or the child squinting or closing one eye. Over time this behavior becomes more frequent. Ultimately, the eye may turn out permanently. Intermittent exotropia almost never goes away on its own, yet many parents are mistakenly told their child "will grow out of it". What are the characteristics of constant exotropia? An eye that stays turned out all the time may be due to poor vision in that eye. Or, an eye that occasionally drifts may eventually turn out permanently. Some people alternate which eye turns out. Unlike crossing, which commonly develops in infancy, constant exotropia is rarely present from birth unless there are other neurological problems. Is it ever too late to straighten an eye that is turned out? No. This a common misunderstanding among patients and some doctors. Surgery can always be done to straighten an eye. If the eye has poor vision due to longstanding misalignment, though, there may be nothing that can be done to improve the vision in that eye. Back to top Hyperopia What is hyperopia (farsightedness) ? Hyperopia is a condition in which the eye is out of focus. Near vision may be limited. Hence the term "farsighted": one sees far away, but there is a limit on focusing up close. What causes the hyperopic eye to be out of focus? The curvature of the cornea, the clear dome covering the front of the eye, may be relatively flat, limiting the focusing power of the eye. Alternatively, the eye may be relatively short from front to back. What does it mean for the eyes to be out of focus? To understand hyperopia (farsightedness) and myopia (nearsightedness), one needs to become aware of the eyes' ability to adjust focus automatically. Try this experiment. Close one eye and hold your thumb six inches in front of your face. Look past your thumb to focus on an object in the distance. Notice that when the distant object is seen clearly, the thumb is out of focus. Now focus on your thumb. When your thumb is seen clearly, the distant object is out of focus. We do not usually realize that our eyes are focused at a given distance because our eyes look around and adjust so quickly. We look out the window, then at the person across the desk, then at our watch -- all seem in focus. We are fooled into thinking our eyes are in focus at all distances at once. How do the eyes adjust focus? A circular muscle inside the eye, called the ciliary muscle, attaches around the lens inside the eye. When this muscle contracts, the lens thickens, adjusting the eye's focus. Understanding eyes that are out of focus Imagine looking through a small, hand held telescope with a knob around the eyepiece which is turned to adjust the focus. Numbers around the knob go from 0 to 10. When turned one way the knob stops at 0; when turned the other way the knob stops at 10. If the telescope is properly focused, it is in focus at far distances when the focusing knob is set on 0, and in focus at closer distances as the knob is turned toward 10. When the focusing knob is turned to 1, the scope is in focus at 1 meter (about 40 inches); when turned to 2, the scope is in focus at 1/2 meter (20 inches); when turned to 4, the scope is in focus at 1/4 meter (10 inches), etc. The closest distance at which the scope can focus clearly on an object is 1/10 meter, or about 4 inches, with the focusing knob turned all the way to 10. An eye which is neither hyperopic (farsighted), nor myopic (nearsighted), is like the properly focused telescope above. Now imagine a scope which is 2 units out of focus. To see well at far distances the focusing knob must be turned to 2, rather than set on 0. Up close, when the knob is turned all the way to 10, the scope is in focus at 1/8 meter rather than 1/10 meter (5 inches vs. 4 inches). Distance vision is thus good, but requires extra focusing power. Near vision is also good, but the limit of near focus is not quite as close. A hyperopic (farsighted) eye is like the scope in this example. What causes hyperopia? The cause is unknown. Is hyperopia always a problem? No. It is usually not a problem, because hyperopia is typically mild. Most people, in fact, are slightly hyperopic. If a person can only focus on print as close as 6 inches away, for example, instead of 3 inches away, this is usually not bothersome. What signs might indicate hyperopia? Eye strain. Lack of interest in reading. Crossing which is worse up close. When are children given given glasses for hyperopia? There are 2 reasons to give glasses to a child with hyperopia: crossed eyes and extreme hyperopia. How do glasses help the hyperopic child whose eyes cross? The child with hyperopia has to focus harder to see clearly at a given distance. In some children, this greater focusing effort causes the eyes to cross, especially when looking at near objects. Glasses may reduce or eliminate the crossing by reducing the focusing effort required. In this case glasses are given not to improve vision, but to straighten the eyes. How do glasses help the child who is very hyperopic? The child who is extremely hyperopic may not be able to focus clearly on objects any closer than, say, 3 feet away. Because the young child devotes so much attention to objects which can be held and examined closely, this degree of blurry vision up close may interfere with development of the visual part of the brain. In effect, the world appears blurry and the child becomes accustomed to this level of vision. Lack of interest in reading may be seen. Glasses are given in this case to improve vision and make normal visual development possible. Does hyperopia change over the years? Yes. A child typically becomes more hyperopic until age 6 or 7, then gradually becomes less hyperopic. Can hyperopia be corrected with contact lenses as well as glasses? Yes. Glasses are preferred for young children, but contact lenses are an option for older children, even those whose eyes tend to cross. Is surgery available for hyperopia? Laser surgery (PRK, LASIK) for hyperopia in adults is now being done. There is not as much experience with correction of hyperopia as with myopia, though. Back to top Myopia What is myopia (nearsightedness)? Myopia is a condition in which the eye is out of focus. Ability to see far away is limited, hence the term "nearsighted". Objects "that are near" are in focus but blurry at a distance. What causes the myopic eye to be out of focus? The curvature of the cornea, the clear dome covering the front of the eye, may be greater than normal. The eye may be relatively long from front to back. What does it mean for the eyes to be out of focus? To understand myopia (nearsightedness) and hyperopia (farsightedness), one needs to become aware of the eyes' ability to adjust focus automatically. Try this experiment. Close one eye and hold your thumb six inches in front of your face. Look past your thumb to focus on an object in the distance. Notice that when the distant object is seen clearly, the thumb is out of focus. Now focus on your thumb. When your thumb is seen clearly, the distant object is out of focus. We do not usually realize that our eyes are focused at a given distance, because our eyes look around and adjust so quickly. We look out the window, then at the person across the desk, then at our watch -- all seem in focus. We are fooled into thinking our eyes are in focus at all distances at once. How do the eyes adjust focus? A circular muscle inside the eye, called the ciliary muscle, attaches around the lens inside the eye. When this muscle contracts, the lens changes shape, adjusting the focus of the eye. As the muscle contracts, one sees things up closer; as it relaxes one sees farther away. In myopia, even when the ciliary muscles are maximally relaxed, vision is blurry beyond a certain distance. Understanding eyes that are out of focus: Imagine looking through a small, hand held telescope with a knob around the eyepiece which is turned to adjust the focus. Numbers around the knob go from 0 to 10. When turned one way the knob stops at 0; when turned the other way the knob stops at 10. If the telescope is properly focused, it is in focus at far distances when the focusing knob is set on 0, and in focus at closer distances as the knob is turned toward 10. When the knob is turned to 1, the scope is in focus at 1 meter (about 40 inches); when turned to 2, the scope is in focus at 1/2 meter (20 inches); when turned to 4, the scope is in focus at 1/4 meter (10 inches); etc. The closest distance at which the scope can focus clearly on an object is 1/10 meter (about 4 inches), with the focusing knob turned all the way to 10. An eye which is neither myopic (nearsighted) nor hyperopic (farsighted) is like the properly focused telescope above. Now imagine a scope which is 2 units out of focus. When the focusing knob is turned to 0, the scope is in focus at 1/2 meter, but not at distances beyond. Up close, when the knob is turned all the way to 10, the scope is in focus at 1/12 meter rather than 1/10 meter (3 inches vs. 4 inches). Distance vision is thus poor. Near vision is good; in fact near focus is possible even closer than normally. A myopic (nearsighted) eye is like the scope in this example. Is myopia a common problem? Yes. More than 50 million Americans have myopia. What signs might indicate myopia? Blurry distance vision. Squinting. Headaches. Eye strain. At what age are glasses typically needed? Myopia usually first appears in grade school or junior high. It occasionally begins as early as infancy, or as late as the early 20's. Are very young children ever given glasses for myopia? Pre-schoolers are not given glasses unless the myopia is significant. Detailed distance vision, such as for school and driving, is not yet needed. If myopia is severe, though, as in some premature babies, glasses are given even in infancy. Can myopia run in families? Yes. If neither parent is myopic, a child's chance of becoming myopic is about 1 in 10. If one parent is myopic, the chance increases to about 1 in 5. If both parents are myopic, odds are 50-50 or more. Does excessive reading or near work cause myopia? Many people believe this, but it is difficult to prove. We know heredity contributes to myopia (see above). But in any given person, it is hard to say how much myopia is due to heredity and how much to something else, like excessive close work. Even if reading tended to make myopia worse, few parents would want to discourage their child from reading. It is also not clear what it is about reading that might make myopia worse. If it were the effort of focusing up close, bifocals or reading glasses would be expected to help. Some studies do show a small benefit with bifocals. But at least one study suggests it might be the constant back and forth eye movement that is the culprit, in which case bifocals would not be expected to help. Can anything be done to prevent myopia from worsening? Some studies have shown that atropine, a long acting dilating drop, reduces the worsening of myopia over time. Treatment is not easy, though. The drop must be used daily in each eye. Bifocals with Photogrey lenses must be worn. Rigid gas permeable contact lenses have been used to flatten the cornea, thus correcting some myopia. A series of lenses must be used to achieve the change. Frequent checkups are required. We do not practice or endorse this treatment. Is surgery available for myopia? Yes. Laser surgery (PRK, LASIK) can correct myopia (nearsightedness). Surgery is usually done on adults, not children. Waiting until the myopia has stabilized improves the odds of an accurate surgical correction. Back to top Patching schedules All day patching, one eye Patch the ________ eye from first thing in the morning until your child goes to bed at night for ________ days a week. All day patching, alternating eyes Patch the right eye ________ day(s), then the left eye _________ day(s). Continue this pattern until you return. Part time patching, one eye Patch the ________ eye every day from first thing in the morning until ________. Patch the ________ eye every day _______ hours a day. After school and weekend patching Patch the ________ eye as much as possible after school and on weekends. If your child won't patch as directed, don't give up without calling us. General principles of patching: The better seeing eye is patched to break the brain's habit of ignoring the poorer seeing (amblyopic) eye. Patching mainly helps vision, not alignment. Patching may help alignment in some cases by forcing the brain to use the poorer seeing eye in a straight ahead manner instead of an off angle, and somewhat ignored, manner. Adhesive patches worn on the skin generally work best. A child can remove glasses to peek around a patch worn on the glasses. Similarly, a patch on an elastic band (pirate patch) can be lifted and peeked around. The pirate patch or patch on the glasses may be an option in cooperative older children who can be trusted not to peek. Dilating eye drops are an option for some children who will not patch. Generally, patching should be given a good try first, though. A change in one lens of the glasses can some times be used as an alternative to patching, but generally requires a cooperative older child and fairly good vision in the amblyopic eye Back to top Presbyopia What is presbyopia? Presbyopia is the decrease in ability to focus up close that comes with aging. How do the eyes adjust focus? A circular muscle inside the eye, called the ciliary muscle, attaches around the lens inside the eye. When this muscle contracts the lens thickens, adjusting focus so that closer objects may be seen. How is this ability to adjust focus lost? The lens inside the eye may become less elastic: when the ciliary muscle contracts, the lens shape no longer changes as much. Another possible explanation: subtle changes in the shape of the eye over time may push the ciliary muscle closer to the lens, weakening its effective pull. Becoming aware of the eyes' ability to focus If you already have presbyopia, you know the eyes can be in focus at one distance and not at another. If you have not yet experienced presbyopia, you may take your eyes' ability to focus for granted. Try this experiment. Close one eye and hold your thumb six inches in front of your face. Look past your thumb to focus on an object in the distance. Notice that when the distant object is seen clearly, the thumb is out of focus. Now focus on your thumb. When your thumb is seen clearly, the distant object is now out of focus. If you already have presbyopia, you may not be able to focus on your thumb unless you hold it farther away from your eye. Understanding the loss of ability to focus up close: Imagine looking through a small, hand held telescope with a knob around the eyepiece which is turned to adjust the focus. Numbers around the knob go from 0 to 10. When turned one way the knob stops at 0; when turned the other was the knob stops at 10. If the telescope is properly focused, it is in focus at far distances when the focusing knob is set on 0, and in focus at closer distances as the knob is turned toward 10. When the focusing knob is turned to 1, the scope is in focus at 1 meter (about 40 inches); when turned to 2, the scope is in focus at 1/2 meter (20 inches); when turned to 4, the scope is in focus at 1/4 meter (10 inches), etc. The closest distance at which the scope can focus clearly on an object is 1/10 meter, or about 4 inches, with the focusing knob turned all the way to 10. The normal eye of a child or young adult is like the scope described above. Now suppose that over the years the focusing knob gradually cannot be turned as far. The loss of focusing range might not be noticed much at first. If the knob can only be turned as far as 5, for example, one can still focus in as close as 1/5 meter (7 or 8 inches). But when the knob cannot be turned as far as 3, the scope can no longer be focused as close in as 1/3 meter (13 inches), a normal reading distance. One must now either hold reading material farther away, or fit an extra lens over the end of the scope to allow closer focus. The presbyopic eye is like the scope in this example. The reading glass or bifocal is like the extra lens on the end of the scope. At what age does presbyopia become a problem? Most adults develop a need for reading glasses or bifocals in their early 40's. Is presbyopia always a problem? Almost always. Some people who are myopic (nearsighted) adjust by taking their glasses off to read. Other people are myopic in only one eye. They adapt by using the normal eye for distance vision and the myopic eye for near vision. There is some loss of depth perception and contrast, though, when the eyes are not the same. What signs might indicate presbyopia? Holding reading material farther away. Needing better light to read. Eye strain when reading. What types of glasses are available for presbyopia? People who do not require glasses for distance vision may use reading glasses. Typically these are narrow in height, which allows reading through the glasses and distance viewing over the glasses. People who already wear glasses may have a bifocal correction put in their lenses. The bifocal segment of the lens may have a flat top, less commonly a round top, or be invisible. Typically the bifocal is placed in the lower portion of the lens for reading. Are bifocals hard to adjust to at first? Yes! Reading while sitting still is not too bad, but looking around while moving takes some getting used to. Does presbyopia change over the years? Yes. It gradually becomes worse. The power of the bifocals or reading glasses typically must be increased about every three years. Can presbyopia be corrected with contact lenses? Yes, in some cases. Contact lenses may be fit with one eye corrected for distance and the other eye corrected for near. There is some loss of depth perception and contrast, but glasses are avoided. This approach is often called "monovision". Many people are happy with this, but many others do not tolerate it. Bifocal contact lenses are also available. Some people tolerate these, but many do not. Is surgery available for presbyopia? No. Laser surgery (PRK, LASIK) is designed to correct myopia (nearsightedness), not presbyopia. People over 40 undergoing surgery for myopia should realize that presbyopia will still develop. They may not need glasses for distance vision after surgery, but they will still need reading glasses unless one eye is intentionally left slightly myopic. Research to find a way to surgically correct presbyopia is ongoing. None of the approaches tried thus far can be recommended at this time. Back to top Stye What is a stye? Styes may be external or internal, that is, on the outside or inside of the lid. An external stye is a bacterial infection of a shallow oil gland next to an eyelash. These glands produce oil for coating the eyelashes. An internal stye is a bacterial infection of a meibomian gland. Meibomian glands begin deep within the eyelid and extend to the edge of the lid, where they secrete oil which forms a microscopic layer on the surface of the watery tears, reducing evaporation and helping the tears cover the surface of the eye more smoothly and evenly. What is the difference between a stye and a chalazion? Styes occur near the edge of the lid. The area of redness and swelling will usually "point" or "come to a head" as white blood cells gather to fight the infection. Antibiotics are more helpful in clearing styes than chalazia. Chalazia may occur away from the edge of the lid. They are less tender and take longer to resolve. Redness and swelling are due to backup of oil in the gland when the gland opening becomes clogged. A firm lump may remain in the lid even after the redness and swelling have resolved. How is a stye treated? There are a variety of treatments which may be used, alone or in combination:
Periodically cleaning the eyelids and lashes can reduce the bacteria which cause these infections. Use Johnson's Baby shampoo or a mild soap designed specifically for the eyelids, on a clean finger or washcloth, to clean the closed lids and lashes. This eliminates harmful bacteria and removes crusts and debris. Standing under the shower with eyes closed, letting the water rinse and massage the lids, can also be cleansing and soothing. This is more practical for older children and adults than for younger children. Back to top | ||||||||||||||||||||||||||||||||||||||||||||||||||