|CORNEA:||Transparent front segment of the eye that covers iris, pupil, and anterior chamber, and provides most of an eye's optical power.|
|PUPIL:||Variable-sized, circular opening in center of iris; it appears as a black circle and it regulates the amount of light that enters the eye.|
|IRIS:||Pigmented tissue lying behind cornea that (1) gives color to the eye, and (2) controls amount of light entering the eye by varying size of black pupillary opening; separates the anterior chamber from the posterior chamber.|
|LENS:||Natural lens of eye; transparent intraocular tissue that helps bring rays of light to focus on the retina.|
|RETINA:||Part of the eye that converts what we see into electrical impulses sent along the optic nerve for transmission back to the brain. Consists ofmany named layers that include rods and cones.|
|MACULA:||Small, specialized central area of the retina responsible for the sharpest central vision.|
|VITREOUS:||Transparent, colorless, gelatinous filling; in the rear two-thirds of the interior of the eyeball, between the lens and the retina.|
|OPTIC NERVE:||Largest sensory nerve of the eye; carries impulses for sight from retina to brain.|
|SCLERA:||The white of the eye; a protective fibrous layer that is the outer covering of the eyeball except for the part that is the cornea.|
|CILIARY BODY:||A muscular ring under the surface of the eyeball; helps the eye focus by changing the lens shape and also produces aqueous humor.|
|CHOROID:||The vascular layer between the sclera and the retina; the blood vessels in the choroid help provide oxygen and nutrients to the eye.|
Amblyopia, commonly called lazy eye, occurs when one eye develops differently than the other eye, causing one eye to be weaker than the other. Sometimes a difference in focusing ability causes one eye to be used more often. Other times, the eyes are misaligned, causing one eye to "shut off" to avoid double vision.
It's hard to spot amblyopia. Sometimes a child will noticeably favor one eye over the other. Another possible symptom is the child frequently bumping into things on one side. The best way to tell if your child has lazy eye is through a complete exam around six months and three years. Early diagnosis can prevent amblyopia from leading to more serious problems such as loss of the ability to see 3D or functional blindness in the amblyopic eye.
Most of the time amblyopia can't be entirely corrected. The amblyopic eye will always be a bit weaker than the other. However, with treatment, vision in the amblyopic eye can be improved to some extent. Treatment involves encouraging the weak eye to develop. This is done using eye patches, vision therapy, glasses, and usually a combination of the three. The strong eye may be patched to encourage the weak eye to develop. Vision therapy can help to correct improper use of the eyes. If a focusing error is at the root of the problem, then glasses may reduce the error. Most of the time the amblyopic eye will always require glasses.
Sometimes the cornea is irregularly shaped, causing the eye to focus an object on two different areas of the retina. This is known as astigmatism. For the cornea to bend light correctly, it should be dome-shaped, like a basketball. Astigmatic corneas are shaped more like a football. This causes a distorted view when looking at objects which are close-up and far away.
The cause of astigmatism is unknown, but we should remember that astigmatism is NOT an eye disease, but an eye condition which is fairly common. Astigmatism is often associated with myopia or hyperopia, and it usually is present from birth. It may be hereditary, or it may be caused by factors such as pressure on the cornea, incorrect posture, or increased use of the eyes for near work.
Mild astigmatism may not need to be corrected. Eyeglasses, contact lenses, or refractive surgery can correct moderate to high degrees of astigmatism.
Computer Vision Syndrome (CVS) affects 75% of computer users. It is a series of symptoms related to extended periods of computer usage. Don't worry, there is no cause for panic, measures can be taken to relieve it.
CVS can appear as a variety of symptoms such as: headaches, eye strain, neck and back aches, sensitivity to light, blurred vision, double vision, and irritated eyes.
Any computer user can develop CVS. Your vision, your computer, and the environment where you use your computer are all factors which can lead to CVS.
When an eye's optical power is perfectly matched to its length, the eye is said to be emmetropic. Emmetropia is the medical term for 20/20 vision needing no corrective lenses, contact lenses, or reading glasses. It occurs because the optical power of the eye can perfectly focus an image to the retina, giving them "perfect" vision. The opposite of emmetropia is ametropia. With ametropia, the focal point of the eye is some distance in front of or behind the retina.
Hyperopia is more commonly known as farsightedness. As the name suggests, people with farsightedness are able to focus on objects that are further away, but have difficulty focusing on objects which are very close. This is because the eyeball is shorter than normal, which prevents the crystalline lens in the eye from focusing correctly on the retina.
About 25% of the population are afflicted with hyperopia. Hyperopia can lead to chronic glaucoma, a more serious condition, later in life.
A family history of hyperopia is a risk factor for developing hyperopia. Often babies are born with hyperopia but they can usually outgrow the condition as the eye develops into the correct shape.
Hyperopia can be corrected with eyeglasses or contact lenses. There are also new surgical procedures that can correct hyperopia.
Myopia is the medical term for what most people call nearsightedness. It is a condition where you can see objects clearly only when they are closer, but when objects are further away you can't focus on them. Myopia usually develops in early childhood, though it sometimes develops in early adulthood. In rare cases, myopia can lead to more serious conditions such as retinal detachment.
Myopia is considered a genetic disorder. If your parents are nearsighted, you are at greater risk of also being nearsighted. Another risk factor is 'near work' - work involving fine detail or focusing on close objects.
Myopia can be accommodated and sometimes corrected with eyeglasses or contact lenses. Sometimes myopia continues to gradually worsen throughout life, a condition known as myopic creep. Myopia can also be corrected by LASIK surgery.
As a people get older, usually when they hit their mid to late 40s, a condition called presbyopia can set in. Presbyopia is the inability to focus on objects near the eye. Mother nature essentially shuts our auto focusing mechanism down. One usually notices that it is harder to read or use the computer. Bifocals or reading glasses are a way to remedy this condition.
Presbyopia is a natural consequence of the aging process. There is no cure, though researchers are constantly looking for one. Even if someone has never had vision problems before, he can still develop presbyopia. It may seem to occur suddenly, but it actually occurs over a long period of time. Symptoms include having to hold things at arms length to see them clearly, eye strain, fatigue, and headaches from near work.
As people reach their mid 40s, a condition called presbyopia can set in. Presbyopia is the inability to focus on objects near the eye. An easy way to think about it is to realize that Mother Nature simply turns down our autofocus mechanism. One usually notices that it is harder to read or use the computer. Wearing bifocals, progressive lenses, or reading glasses is a common way to remedy this condition.
Presbyopia is a natural consequence of the aging process. There is no cure, though researchers are constantly looking for one. Even if a person has never had vision problems before, he or she can still develop presbyopia. While symptoms can present suddenly, presbyopia usually occurs over a long period of time. Symptoms include having to hold things at arms length to see them clearly, eye strain, fatigue and headaches from near work.
To reduce eye strain and fatigue, we carry specialized computer lenses. These lenses are perfect for computer users who spend a majority of their days working on computers. And since three out of four computer users will suffer from Computer Vision Syndrome, computer lenses are a great way to keep your eyesight healthy.
One of the first areas of your life where presbyopia becomes prominent is in your ability to read. There are a variety of styles available, with sleek designs that allow you to carry them anywhere.
For many presbyopes, bifocal lenses are a necessity. But it can be difficult to adjust to the harsh line that is found in bifocal lenses. Fortunately, there are no-line lenses, which are also called progressive lenses. No more lines! Just a gradual change in focusing power which allows you to comfortably focus on any distance. Just as in wearing bifocals, distant objects are viewed through the top portion of the lenses, and near objects are viewed through the bottom portion of the lenses.
If you need bifocals but cannot stand wearing glasses, you may want to try bifocal contact lenses. Now you can have all of the benefits of progressive eyeglasses in the convenience of contact lenses. Talk with your doctor about bifocal contacts today.
For some of our emerging presybopes we offer another option to glasses, monovision. This is a method of fitting your dominant eye for distance vision and your non-dominant eye for near vision. Contacts are available in disposable, extended wear, and even daily disposable lenses to fit your lifestyle. Most patients require 2-4 weeks to make the adjustment from binocular vision to monovision.
There are two types of blepharitis. Seborrheic blepharitis is often part of an overall skin condition called seborrhea, which may also affect the scalp, chest, back and the area behind the ears. The second form of blepharitis - staph blepharitis - is a more common condition, caused by bacteria, that begins in childhood and may continue through adulthood.
Hormones, nutrition, general physical condition, and even stress may contribute to seborrheic blepharitis. Build-ups of naturally occurring bacteria contribute to staph blepharitis.
Blepharitis could be described as dandruff of the eyelids. Seborrheic blepharitis causes redness of the eyelids, flaking and scaling of the eyelashes, and greasy, waxy scales. Staph blepharitis also causes redness of the eyelid margins and flaking of the lashes, and can cause loss of eyelashes, eyelid scarring, and red eye.
Eyelid scrubs with baby shampoo or a specially formulated cleaner can reduce the symptoms of blepharitis. Application of hot packs to the eyes daily can also help. Staph blepharitis may also require antibiotic drops or ointments. The use of artificial tears is often helpful to relieve associated discomfort or dryness.
A cataract is a cloudiness that occurs in the lens inside of the eye.
The lens is made mostly of water and protein arranged to let light through. When the protein clumps, light is blocked and the lens appears cloudy.Cataracts are not a disease; we will all develop cataracts as we get older.
A person with cataracts may notice faded colors, problems with light (such as halos, or headlights that seem too bright), or poor night vision.
Your eye doctor can detect the presence of cataracts during a thorough eye exam, including a microscopic examination of the inside of the eye. When vision is impaired to a point where it interferes with daily activities, surgery may be indicated. Surgery is done on an out-patient basis and involves a very small incision, through which the cloudy substance of the lens is removed and replaced with an intra-ocular lens implant (IOL). With today's technology and surgical techniques most patients find their vision after surgery to be very clear at distance, without the use of glasses.
Conjunctivitis, is a redness of the eye. It is often accompanied by a discharge and itching or a foreign body sensation.
Pink eye is most often a viral infection, but may also be caused by bacteria or an allergic reaction. Viral and bacterial pink eye can be highly contagious.
To avoid spreading conjunctivitis, wash your hands often, don't touch the infected area with your hands, don't share wash cloths or towels, and avoid using makeup which may become contaminated. A child with pink eye should be kept from school for a few days. Sometimes your doctor will need to prescribe antibiotic eye drops or ointments to treat conjunctivitis.
Diabetic retinopathy is a condition associated with diabetes. High levels of blood sugar can damage tiny blood vessels in the eye, causing poor circulation. This can cause small leaks in the vessels, and swelling of the retinal nerve layer. Eventually new vessels, which are very fragile, may form to replace the damaged vessels. The new vessels can burst, creating a hemorrhage, and resulting in blurred vision or even blindness.
Symptoms of diabetic retinopathy include:
It is critical for all diabetic patients to have a thorough eye health examination at least every year. When diabetic retinopathy is diagnosed early, medical management, including laser treatment and other surgeries, can be more effective in preserving vision. In addition to diabetic retinopathy, diabetic patients also have a higher risk of developing cataracts at a younger age, and of having glaucoma. If you have diabetes, make sure you control your blood sugar level. This will reduce your risk of getting diabetic eye disease and other complications involving the heart, kidneys, and other organs.
Dry eye symptoms also increase with activities such as driving, computer work, and playing video games. There are simple things that can be done to reduce the affects of dry eye and can be discussed with your eye doctor. Keep reading to find out some of the signs and symptoms of dry eye syndrome.
If your eyes are constantly itchy or dry, you may have dry eye syndrome, which affects almost 10 million Americans. Dry eye syndrome is caused by a lack of, or poor quality of, tears. Tears lubricate the outer layer of the eye called the cornea. If the tears are not composed of a proper balance of mucous, water, and oil, the eye becomes irritated.
Dry eye syndrome leads to a number of symptoms, including itching, irritation, burning, excessive tearing, redness, blurred vision that improves with blinking, and discomfort after long periods of watching television, driving, using a computer, or reading.
There are many environmental factors that can contribute to dry eye syndrome. These include dry, hot, or windy climates, high altitudes, air-conditioned rooms, and cigarette smoke. Contact lens wearers, people with drier skin, and the elderly are more likely to develop dry eye syndrome. You may also be more at risk if you take certain medications, have a thyroid condition, a vitamin-A deficiency, Parkinson's or Sjorgen's disease, or if you are a woman going through menopause.
When too much fluid is produced or the fluid is prevented from flowing out, the intraocular pressure increases and damages the optic nerve. This causes a gradual loss in peripheral vision.
Open angle glaucoma is often called the "Sneak Thief of Sight" because it has no symptoms until the disease is in advanced stages. With advanced glaucoma patients develop tunnel vision, where their peripheral field of vision decreases. Glaucoma can eventually cause blindness.
Heredity seems to be a risk factor. Also, you may be at greater risk if you are over 45, of African descent, near-sighted, diabetic, or smoke. Finally, if you have used steroids or cortizone for a long period of time, or if you have suffered an eye injury in the past, you may have a greater chance of developing glaucoma.
Macular degeneration is a disease which affects a small area of the retina known as the macula. The macula is the central area of the retina that allows us to see the fine detail of whatever we look at directly. Macular degeneration occurs when the macula is damaged.
Most often, macular degeneration is accompanied by the formation of yellow deposits called "drusen" under the macula, which dry out or thin the macula. This is called "dry" macular degeneration. In less common cases, abnormal blood vessels develop under the macula and leak fluid. This is called "wet" macular degeneration.
A number of uncontrollable factors contribute to macular degeneration, including age, sex, eye color, farsightedness, and race. Risk factors you can control include smoking, high blood pressure, exposure to harmful sunlight, and diet. Every year millions of dollars of research are spent on studying how to best treat and/or prevent macular degeneration. This research is updated almost continuously. Our eye doctors are committed to staying current with these studies so that we may best serve you with the latest information and treatments.
It is difficult for patients to detect dry macular degeneration in its early stages. The most common symptom is blurred vision. Wet macular degeneration progresses much faster when it occurs. Symptoms include blurred vision and distortion or a dark spot in central vision. Both forms of macular degeneration can cause severe visual impairment.
Currently, there is no cure for macular degeneration, but treatment is available to slow the effects and progression of the disease.
The part of the eye which collects light and transmits the images to the optic nerve and brain is the retina. It lines the inner back wall of the eye. When separated from the back wall, it is known as retinal detachment.
A retinal detachment may cause a sudden defect in your vision. It may just cause a blind spot too small to notice, or it may cause a noticeable shadow which obscures your vision. A sudden increase in "floaters," which look like small particles or fine threads, may also be noticed. Finally, flashes of light may be associated with retinal detachment.
Most retinal detachments are not caused by any specific injury or event, but eye injuries, tumors, and cataract surgery can cause the retina to detach. Very near-sighted individuals and the elderly are at greater risk for spontaneous detachment. Also, diabetic retinopathy, a condition associated with diabetes, can cause bleeding which can lead to retinal detachment.
Did you know that 1 out of every 4 children suffers from vision problems that interfere with learning? Children with uncorrected vision conditions or eye health problems face many barriers in life, academically, socially, and athletically. High-quality eye care can break down these barriers and help enable your children to reach their highest potential! As a parent, make sure you are giving your children the eye care they need. Presented are guidelines from the American Optometric Association.
|Infant's Vision||Pre-School Vision|
|School-Age Vision||Protective Eyewear|
Your baby has a whole lifetime to see and learn. But did you know your baby also has to learn to see? As a parent, there are many things that you can do to help your baby's vision develop.
When your baby is about six months, you should take him to your doctor of optometry for his first thorough eye examination. Things that we will test for include excessive or unequal amounts of nearsightedness, farsightedness, astigmatism, lack of eye movement ability, as well as other eye health problems. These problems are not common, but it is important to identify children who have them at this stage. Vision development and eye health problems can be more easily corrected if treatment is begun early.
Your baby should begin to follow moving objects with the eyes and reach for things, first by chance and later more accurately, as hand-eye coordination and depth perception begin to develop. To help, use a nightlight or other dim lamp in your baby's room; change the crib's position frequently and your child's position in it; keep reach-and-touch toys within your baby's focus, about eight to twelve inches; talk to your baby as you walk around the room; alternate right and left sides with each feeding; and hang a mobile above and outside the crib.
Your baby should begin to turn from side to side and use his or her arms and legs. Eye movement and eye/body coordination skills should develop further and both eyes should focus equally. Enable your baby to explore different shapes and textures with his or her fingers; give your baby the freedom to crawl and explore; hang objects across the crib; and play "patty cake" and "peek-a-boo" with your baby.
Your baby should be mobile now, crawling and pulling himself or herself up. He or she will begin to use both eyes together and judge distances and grasp and throw objects with greater precision. To support development don't encourage early walking - crawling is important in developing eye-hand-foot-body coordination; give your baby stacking and take-apart toys; and provide objects your baby can touch, hold and see at the same time.
Your child's eye-hand coordination and depth perception will continue to develop and he or she will begin to understand abstract terms. Things you can do are encourage walking; provide building blocks, simple puzzles and balls; and provide opportunities to climb and explore indoors and out. There are many other affectionate and loving ways in which you can aid your baby's vision development. Use your creativity and imagination. Ask your doctor of optometry to suggest other specific activities.
During infant and toddler years, your child has been developing many vision skills. In the preschool years, this process continues, as your child develops visually guided eye-hand-body coordination, fine motor skills, and the visual motor skills necessary to learn to read.
As a parent, you should watch for signs that may indicate a vision development problem, including:
There are everyday things that you can do at home to help your preschooler's vision develop, as it should. These activities include:
Your child should have a thorough optometric eye examination to make sure your preschooler's vision is developing properly and there is no evidence of eye disease. If needed, your doctor can prescribe treatment including glasses and/or vision therapy to correct a vision development problem.
Here are several tips to make your child's optometric examination a positive experience:
Unless recommended otherwise, your child's next eye examination should be at age five. By comparing test results of the two examinations, your optometrist can tell how well your child's vision is developing for the next major step. . .into the school years.
A good education for your child means good schools, good teachers and good vision. Your child's eyes are constantly in use in the classroom and at play. So when his or her vision is not functioning properly, learning and participation in recreational activities will suffer. The basic vision skills needed for school use are:
If any of these or other vision skills is lacking or does not functions properly, your child will have to work harder. This can lead to headaches, fatigue and other eyestrain problems. As a parent, be alert for symptoms that may indicate your child has a vision or visual processing problem. Be sure to tell your optometrist if you child frequently:
Since vision changes can occur without you or your child noticing them, your child should visit the optometrist at least every two years, or more frequently, if specific problems or risk factors exist. If needed, the doctor can prescribe treatment including eyeglasses, contact lenses or vision therapy. Remember, a school vision or pediatrician's screening is not a substitute for a thorough eye examination.
Please don't overlook the importance of safety eyewear when playing sports. Each year, hundreds of men, women, and children are injured when playing sports. To help prevent sports eye injuries, athletes should use protective athletic eyewear whether or not prescription eyewear is needed. One choice is a sports frame with prescription or non-prescription polycarbonate lenses is another choice. Baseball or softball players who are hit in or near the eye, or suffer a blow to the head, should seek immediate care at a hospital emergency room or from an eye care professional.
The important thing for parents and their children who wear contact lenses to remember is that contacts are prescribed medical devices. Contact lenses are not a cosmetic accessory. While the wearer may be happy about his or her new look, it's extremely important that the lenses be properly cleaned and worn according to the instruction of the optometrist.
There is controversy in the exact relationship of vision to learning. For example there is a negative correlation between distance refractive error and reading ability. Myopic or nearsighted children who cannot see clearly at a distance without glasses are more commonly good readers. Children who spend tremendous amounts of time reading become nearsighted. Before Alaska became a state myopia was rare. After becoming a state, more than 50 percent of the children in Alaska developed nearsightedness. Thus, correlation is such that nearsightedness or poor distance vision is highly correlated with success in reading. Restated another way, poor distance vision is associated with better reading abilities. Farsighted children statistically are poorer readers than myopic children.
Some of the mechanical visual skills which are related to reading include focusing or accommodation, and eye teaming, or convergence. Fatigue of one or both the systems may interfere with reading. There is also a relationship between eye movement skills such as saccades (whereby we change fixation from one target to the next) and smooth following movements known as pursuits and reading. Children who cannot make accurate eye movements are often found to skip lines and words while reading.
The visual system was originally designed so that the peripheral vision was responsive to motion detection (danger from the jungles) with a central portion for fine discrimination (to identify the source of danger; e.g., a lion.) In the school environment the child is expected to ignore the peripheral portion of their visual system and pay attention with the central portion. If the child can not ignore the peripheral portion, he/she becomes distracted. Improvement in eye movement skills often results in less distraction and fewer errors of skipping words while reading.
Reading requires very accurate saccadics, which are fixations from one spot to another. A second type of eye movement which involves tracking is, also, related to attention and reading. Children who have poor eye movements are easily distracted and lose their place. Remember, the eye movement system was designed so that peripheral vision detects motion and danger. Imagine what happens when the system works correctly in the class room. As soon as there is peripheral movement, the eyes move toward the source of movement. This results in the complaint of inattention. Thus, reflexive eye movement skills must be socialized so that they do not respond reflexively to peripheral information. In addition, speed and accuracy must be trained so that one does not lose ones place.
The skills are easily improvable with vision therapy. Once the information is brought into the eyes, it must be sent back to the brain for appropriate processing. The information must be utilized and integrated with the sensory and motor areas of the brain. Defects in the perceptual (interpretation of visual system) and motor (the integration with output, e.g., hand-eye coordination) may interfere with the reading process. Perceptual motor skills are key in the early acquisition of reading skills. A deficit is important to identify very early on i.e., five to seven years of age. Remediation of the skills at a later date, such as age 12, will be less effective on reading. Thus, early identification and treatment is essential. It is evident that there is more to good vision than 20/20.
It has been presumed that children who reverse letters or words see them backwards. This is false. They have directional confusion. In the real world direction has no meaning. For example, a chair is a chair no matter which way it is placed. Changing direction does not change interpretation. In the world of language direction changes meaning. Connect the bottom of a chair and it looks like a "b". Turn it 180 degrees it becomes a "d", flip it upside down and it becomes a "q" and flip it again it becomes a "p". Thus, direction changes meaning. The difference between "was" and "saw" is direction.
As mentioned previously, we should correct all optical errors of the eyes (glasses); eliminate eye muscle problems; and create smooth accurate eye movements. In addition, we should make sure that we properly interpret what we see and use it appropriately. These are known collectively as perceptual skills and include form perception, size and shape recognition, visual memory, and visual motor integration (hand-eye coordination.)