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Complete Eye Examination
A complete eye examination does more than determine how clearly you see from a distance and which lens prescription, if necessary, will give you the best possible vision. Your ophthalmologist (Eye M.D.) will also run a number of tests to check the health and function of your entire eye.
If you have never had an eye examination or are seeing a new ophthalmologist, your doctor or a technician will begin by asking you questions about your medical history, your family's medical history, and any vision problems you may have. If you wear contact lenses, be sure to bring them with you to your appointment. Your ophthalmologist will check them to make sure that they are the correct prescription, fit, and kind of lens for your eyes.
A complete eye examination will include many or all of these painless tests:
A visual acuity test measures how well you can see from a distance. Covering one eye at a time, you will look at an eye chart and be asked to identify letters that get smaller as you read farther down the chart.
If your visual acuity test indicates that you need corrective lenses, you will be given a refraction test to determine the correct prescription. Your ophthalmologist may use retinoscopy to estimate your prescription by shining a light into your eyes to see the movement of the light reflected by your retina. Your ophthalmologist will finalize your prescription by asking you to look through a device called a phoroptor that has many different lenses in it. You will be asked to compare a series of two lens choices and evaluate which lens combination provides you with your best possible vision correction.
To test the function of your eye muscles, your ophthalmologist will have you follow the movement of an object in many directions, looking for weak muscles or poor control of the muscles that move your eyes.
To test your peripheral vision, which is what you are able to see to the sides of your visual field when you look straight ahead, your ophthalmologist uses a visual field test. You may be asked to cover one eye at a time and, while looking straight ahead, tell your ophthalmologist when you can see his or her hand or other object as it moves inward from outside your visual field. Or a computer program may be used to test your visual field. If so, you will look straight ahead into a special device, often a lighted bowl-shaped instrument, and press a button each time you see a flash of light. Your ophthalmologist can use your responses to see if there are any blind spots in your visual field.
Your ophthalmologist will use a slit-lamp microscope to examine the front part of your eye, including the cornea, iris, and lens. You will sit at the slit lamp, which greatly magnifies your eye and shines a bright line of light into it, allowing your ophthalmologist to examine your eye closely. Before the test, you may be given eyedrops with fluorescein, an orange dye, to make your cornea easier to see. This dye will wash away naturally.
To test for glaucoma, a disease that can cause blindness when too much pressure in your eye damages the optic nerve, your ophthalmologist will use a tonometer to measure your intraocular pressure.
Using one method, noncontact tonometry, you will sit with your chin and forehead resting comfortably on the guides of a device that will blow a puff of air into your eye and thereby measure your eye pressure.
Applanation tonometry is another option. Your ophthalmologist will give you eyedrops containing an anesthetic and fluorescein dye to numb the front surface of your eye and will then use a manual tonometer to gently touch your cornea and measure the force required to flatten it. This procedure is quick and painless, and the anesthetic will wear off in 15 or 20 minutes.
Your ophthalmologist may also use pachymetry to measure the thickness of your cornea, which helps evaluate the accuracy of your intraocular pressure measurement. After applying numbing eyedrops, your ophthalmologist will use ultrasonic waves to measure your corneal thickness. This test is also a critical component of evaluating a patient's candidacy for LASIK surgery.
A retinal examination explores the back of your eye including the retina and optic nerve. First, depending on the type of retinal examination your ophthalmologist chooses, your pupils will be dilated with eyedrops, which may sting briefly. If your ophthalmologist chooses to use direct examination, he or she will shine a light in your eye and use a device called an ophthalmoscope to look at the back of your eye. Alternatively, using a method called indirect examination, your ophthalmologist may use a much brighter light mounted on his or her forehead to examine your eye while holding it open. Finally, to get the best look at the back of the eye, your ophthalmologist may choose to perform a slit-lamp examination, which combines the use of the slit lamp and special lenses. Retinal examinations usually take about five minutes, but the eyedrops will continue to blur your vision for several hours. You may not be able to drive and will be sensitive to bright light, but this is temporary and should resolve in several hours.
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How to Instill Eyedrops
Infections, inflammation, glaucoma, and many other eye disorders often are treated with medicated eyedrops.
It is important to remember that all medicines can have side effects. Surprisingly, even the small amount of medication in an eyedrop can create significant side effects in other parts of the body. There are ways to decrease the absorption rate of the eyedrop into the system and to increase the time the eyedrop is on the eye, making the medicine safer and more effective.
Instilling eyedrops may seem difficult at first but becomes easier with practice. To place an eyedrop in your eye, first tilt back your head. Then create a "pocket" in front of the eye by pulling down on the lower with an index finger or by gently pinching the lower lid outward with the thumb and index finger. Let the drop fall into the pocket without touching the dropper tip to your eye, eyelid, or fingers, so as to prevent contaminating the bottle.
Immediately after instilling the drop, press on the inside corner of the eyelids next to the bridge of your nose for two to three minutes with your thumb and forefinger. This prevents most of the drop from traveling down the tear duct to the back of the throat, where it then is absorbed by the rest of the body. Keep your eyes closed for three to five minutes after instilling eyedrops.
Before opening your eyes, dab unabsorbed drops and tears from the closed lids with a tissue.
If you are taking two different types of eyedrops, wait at least five minutes before instilling the second drop. Because the volume of a single drop exceeds the capacity of the surface of the eye, it serves no purpose to use two drops at the same time.
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Smoking & Eye Disease
Tobacco smoking is directly linked to many adverse health effects, including high blood pressure, heart disease, and cancer. Smoking is also linked to eye disease.
How does smoking affect the eyes?
People who smoke cigarettes are at increased risk for developing cataracts, a clouding of the naturally clear lens of the eye. Cataracts cause a variety of vision problems, including blurry distance vision, sensitivity to glare, a loss of contrast sensitivity, and difficulty seeing colors. When eyeglasses or magnifiers are no longer helpful for someone with cataracts, or when cataracts develop in both eyes, surgery is the only option.
Tobacco smoking is also one of the preventable risk factors for age-related macular degeneration (AMD). Studies have shown that current smokers and ex-smokers are more likely to develop AMD than people who have never smoked. AMD has two forms: dry (called atrophic) AMD and wet (called exudative) AMD. In dry AMD, your retina gradually thins. There is no proven cure for this type of degenerative disease. In wet AMD, new blood vessels grow in the retina, leaking blood or fluid and damaging the macula, the part of the retina responsible for your central vision. Permanent vision loss may occur with both types of AMD, so an attempt at prevention is of utmost importance.
Some studies suggest that in people with high blood sugar levels, smoking may be linked to diabetic retinopathy, or damage to the blood vessels in the retina. The optic nerve is also susceptible to damage from smoking. People with poor diets who smoke heavily and drink excessive amounts of alcohol run the risk of developing optic nerve–related vision loss (called tobacco–alcohol amblyopia). Certain optic nerve problems, like Leber's hereditary optic neuropathy, can run in families. People with this condition who smoke have increased risk of vision loss. Some patients with thyroid disease (called Graves' disease) may also have eye involvement; smoking may cause their eyes to become worse, and vision loss is also possible.
People who do not produce enough tears to keep their eyes comfortably lubricated have a condition called dry eye. For these people, smoking is a significant irritant, worsening the symptoms of scratchiness, stinging or burning of the eyes, and excess tearing from irritation.
How does smoking affect fetal and infant eye health?
Studies have also shown a strong association between smoking during pregnancy and the risk of invasive meningitis during early childhood. The risk of bacterial meningitis is five times higher among children whose mothers smoked during pregnancy. In addition to other severe health problems, childhood meningitis can cause inflammation of the cornea and pink eye. Smoking during pregnancy is also associated with low birth weight and premature birth. Finally, oxygen therapy given to sustain the lives of premature infants can cause retinopathy of prematurity, causing permanent vision loss or blindness in the infant.
There are resources to help you quit smoking.
There are numerous community organizations committed to helping people quit smoking. The American Cancer Society (ACS) offers smoking cessation classes across the United States. Contact ACS at 800.ACS.2345 or online at www.cancer.org to find the chapter near you.
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Tanning beds produce high levels of ultraviolet (UV) light, which can tan the skin but can also burn the cornea, the clear covering of the eye. You do not feel the burn until 6 to 12 hours after exposure, so you can suffer a severe corneal burn without realizing it while tanning or immediately after. UV light can also cause cataracts and can be a factor in the development of macular degeneration.
As they say, an ounce of protection is worth a pound of cure, so always wear special protective eyewear while using a tanning bed. Closing your eyes, wearing regular sunglasses, and placing cotton pads on your eyelids do not protect your corneas from the intense UV radiation produced by tanning devices.
Tanning facilities are required by the U.S. Food and Drug Administration (FDA) to provide safety goggles, but it is best to obtain your own pair so you will always be prepared. Make sure your goggles fit snugly, cover your eyes properly, and are completely opaque . If you use the salon's goggles, be sure that the salon personnel sterilize them after each use to prevent infection and that the goggles are approved for this particular use.
Since the skin does not usually get burned from tanning devices, most people do not realize the potential damage to their eyes. If you experience any eye pain after UV exposure, contact your ophthalmologist (Eye M.D.).
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Eye Care Facts and Myths
Myth: Reading in dim light is harmful to your eyes.
Fact: Although reading in dim light can make your eyes feel tired, it is not harmful.
Myth: It is not harmful to watch a welder or look at the sun if you squint or look through narrowed eyelids.
Fact: Even if you squint, ultraviolet light still reaches your eyes, damaging the cornea, lens, and retina. Never watch welding without wearing the proper eye protection. Never look directly at a solar eclipse.
Myth: Using a computer screen is harmful to the eyes.
Fact: Although using a computer screen is associated with eyestrain or fatigue, it is not harmful to the eyes.
Myth: If you use your eyes too much, you will "wear them out."
Fact: You can use your eyes as much as you want—you will not wear them out.
Myth: Wearing poorly fitting eyeglasses damages your eyes.
Fact: Although a good fit is required for good vision, a poor fit does not damage your eyes.
Myth: Wearing poorly fitting contact lenses does not harm your eyes.
Fact: Poorly fitting contact lenses can be harmful to your cornea, the clear front window of your eye. Make certain your ophthalmologist (Eye M.D.) checks your eyes regularly if you wear contact lenses.
Myth: You do not need to have your eyes checked until you are in your 40s or 50s.
Fact: Several asymptomatic yet treatable eye diseases (most notably glaucoma) can begin prior to your 40s.
Myth: Safety goggles are more trouble than they are worth.
Fact: Safety goggles prevent many potentially blinding injuries every year. Keep your goggles handy and use them!
Myth: It is okay to swim while wearing soft contact lenses.
Fact: Potentially blinding eye infections can result from swimming or using a hot tub while wearing contact lenses.
Myth: Children will outgrow "crossed" eyes.
Fact: Children do not outgrow truly crossed eyes. A child whose eyes are misaligned has strabismus and can develop poor vision in one eye (a condition known as amblyopia), because the brain "turns off" the misaligned or "lazy" eye. The sooner crossed or misaligned eyes are treated, the less likely the child will have permanently impaired vision.
Myth: A cataract must be "ripe" before it can be removed.
Fact: With modern cataract surgery, a cataract does not have to mature before it is removed. When a cataract interferes with your regular daily activities, you can talk with your ophthalmologist about having it removed.
Myth: Cataracts can be removed with lasers.
Fact: Cataracts cannot be removed with a laser. The cloudy lens must be removed through a surgical incision. However, after cataract surgery, a membrane within the eye may become cloudy. This membrane can be opened with laser surgery.
Myth: Eyes can be transplanted.
Fact: The eye cannot be transplanted. It is connected to the brain by the optic nerve, which cannot be reconnected once it has been severed. However, the cornea can be transplanted.
Myth: All eye-care providers are the same.
Fact: An ophthalmologist is a medical doctor (M.D.) or doctor of osteopathy (D.O.), uniquely trained to diagnose and treat all disorders of the eye. An ophthalmologist is qualified to perform surgery, prescribe and adjust eyeglasses and contact lenses, and prescribe medication.
An optometrist (O.D.) is not a medical doctor but is specially trained to diagnose eye abnormalities and prescribe, supply, and adjust eyeglasses and contact lenses. In most states, optometrists can use drugs to treat certain eye disorders.
An optician fits, supplies, and adjusts eyeglasses and contact lenses. An optician cannot examine the eyes or prescribe eyeglasses or medication.
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Children and Vision
Many people are confused about the importance of eyeglasses for children. Some believe that if children wear glasses when they are young, they will not need them later. Others think that wearing glasses as a child makes one dependent on them later. Neither is true. Some children need glasses because they are genetically nearsighted, farsighted, or astigmatic. These conditions generally do not go away nor do they get worse because they are not corrected. For people with refractive errors, eyeglasses or contacts are necessary throughout life for good vision.
Nearsightedness (when distant objects appear blurry) typically begins between the ages of eight and fifteen but can start earlier. Farsightedness is actually normal in young children and not a problem as long as it is mild. If a child is too farsighted, vision is blurry or the eyes cross when looking closely at things. This is usually apparent around the age of two. Almost everyone has some amount of astigmatism (oval instead of round cornea). Eyeglasses are required only if the astigmatism is strong.
Unlike adults, children who need glasses may develop a second problem, called amblyopia or lazy eye. Amblyopia means even with the right prescription, one eye (or sometimes both eyes) does not see normally. Amblyopia is more likely to occur if the prescription needed to correct one eye is stronger than the other or if the prescription in both eyes is very strong. Wearing eyeglasses can prevent amblyopia from developing or may treat amblyopia if already present.
Children (and adults) who do not see well with one eye because of amblyopia, or because of any other medical problem that cannot be corrected, should wear safety glasses to protect the normal eye.
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Childrens Eye Safety
Accidents resulting in serious eye injury can happen to anyone, but are particularly common in children and young adults. More than 90% of all eye injuries can be prevented with appropriate supervision and protective eyewear.
Goggles and face protection can prevent injuries in sports like baseball, basketball, racket sports, and hockey. It is more difficult to protect against injuries in boxing, although thumbless gloves help.
Children with vision loss in one eye should wear polycarbonate safety glasses all the time and should wear safety goggles for sports and other dangerous activities. Choose frames and lenses that meet the American National Standards Institute (ANSI) standard for safety (Z87.1).
Appropriate adult supervision is an essential part of preventing eye injuries. Children should never be allowed to play with fireworks or BB guns. Sharp and fast-moving objects such as darts, arrows, scissors, knives, and even pencils or pens can be dangerous. Special care should be taken when working around lawn mowers, which can throw rocks and debris, and when banging two pieces of metal together, which can dislodge small shards of metal. Chemicals such as toilet cleaners and drain openers are especially hazardous.
A primary care physician or an emergency room physician can treat minor injuries, such as a foreign body or an abrasion (scratch) on the cornea. Any foreign material will be removed from the eye, an antibiotic eyedrop or ointment may be used, and an eye patch may be applied for comfort.
More serious injuries, such as blood inside the eye (hyphema), a laceration (cut) of the eye, or rupture of the eye, require examination by an ophthalmologist (Eye M.D.). Both surgery and hospitalization may be necessary.
Chemicals that burn should be rinsed from the eye immediately. Chemical burns can cause severe damage, so eyes should be flushed immediately. If sterile solutions or eyewashes are readily available, use them to flush the affected eye. If not, flush the eye with liberal amounts of water from the nearest sink, shower, or hose for ten minutes. Be sure water is getting under both the upper and lower eyelids. After they eyes have been flushed for ten minutes, bring the child to the emergency room immediately. The ultimate visual outcome after a chemical burn depends on the severity of the injury, which cannot always be identified in the initial examination.
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Eye Examination for Children
Children are examined for any rare congenital problems at birth and at each well-child examination by the primary care physician, who will check for problems that may not be apparent to the parent or child but that could have serious consequences for the child's vision. When the child is old enough, the primary care physician will perform a more formal vision screening examination. If the parent or the child's doctor has any concerns, or if there is a family history of strabismus, amblyopia, or other eye conditions, the child should be referred to an ophthalmologist (Eye M.D.) for evaluation.
Conditions that the primary care physician will screen for include:
- strabismus (misaligned eyes);
- amblyopia ("lazy eye");
- ptosis (drooping of the upper eyelid); and
- decreased vision.
If the child is referred to an ophthalmologist, he or she will conduct a physical examination of the eyes, using eye chart tests, pictures, or letters to test the child's ability to see form and detail of objects, and to assess for any refractive error (nearsightedness, farsightedness, and astigmatism).
Vision problems in children can be serious, but if caught in time and treated early, the child's good vision can be protected.
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First Aid for Eye Injuries
The most common type of eye injury that needs immediate action is a chemical burn. Alkaline materials (lye, plaster, cement, and ammonia) can cause severe damage and even blindness. Solvents, acids, and detergents also can be very harmful to the eye. Eyes should be flushed liberally with water if exposed to any of these agents.
If sterile solutions or eye washes are readily available, use them to flush the affected eye. If not, go to the nearest sink, shower, or hose and immediately begin washing the eye with large amounts of water. If the eye has come in contact with an alkaline agent, it is important to flush the eye for at least 10 minutes or more before even considering going to the doctor. Make sure water is getting under the upper and lower eyelids. After at least 10 minutes of flushing, transport the patient to the nearest emergency room.
Abrasions or scratches of the eyelids and cornea, the clear covering of the eye, occur frequently and can be quite uncomfortable. If the abrasion is dirty, gently cleanse the area with a stream of clean water.
Do not attempt to treat severe blunt trauma or penetrating injuries to the eye. Tape a paper or Styrofoam cup over the injured eye to protect it until proper care can be obtained. Try to avoid strenuous activity if such an injury has occurred and seek proper medical care immediately.
In the case of a blow to the eye, do not assume the injury is minor. The eye should be examined thoroughly by an ophthalmologist (Eye M.D.) because vision-threatening damage such as an intraocular bleed or a retinal detachment could be hidden.
First aid is only the first step for emergency treatment. If you experience pain, impaired vision, or any possibility of eye damage, call your ophthalmologist or go the emergency room immediately.
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Preventing Eye Injuries
Any activity where something might fly at the eye puts the eye at risk for an injury. Over one million people suffer eye injuries each year in the United States. Almost 50% of these accidents occur at home, and more than 90% of them could have been prevented.
Minor injuries to the cornea, the clear, protective covering over the front of the eye, can be quite painful. A corneal abrasion is a scratch to the cornea. Appropriate treatment may include an antibiotic eyedrop or ointment to prevent infection and an eye patch for comfort. Sand or other particles can stick to the cornea. Such foreign bodies may be removed with a moistened cotton swab, usually by a doctor. Do not rub the eye.
Regular prescription eyeglasses or contact lenses do not protect the eyes from injury. Some glasses and some types of contact lenses shatter if the eye is hit. People who play sports and wear prescription eyeglasses can have special safety glasses or prescription goggles made of high-impact polycarbonate plastic lenses and special unbreakable frames.
Unfortunately, many people do not think they are at risk for an eye injury until the injury occurs. The majority of eye injuries are easily prevented. Use common sense to reduce the risk of injuries, and be sure to follow safety precautions, including the following:
- Wear safety goggles when using powerful chemicals. Goggles should fit properly to prevent chemicals from getting under them yet still allow air to circulate between the eye and the lens.
- Polycarbonate sports goggles are recommended for all participants of high-impact sports or activities where there is a high risk of eye injury.
- Never use fireworks. Attend public fireworks displays instead of having fireworks at home. Amateur backyard displays are dangerous to the person lighting the fireworks, nearby family members, friends, neighbors, and pets.
- Supervise children when they are handling potentially dangerous objects, such as pencils, scissors, and penknives. Be aware that even common household items such as paper clips, elastic cords, wire coat hangers, rubber bands, and fishhooks can cause a serious eye injury.
- Avoid projectile toys such as darts and bows and arrows. Do not allow children to play with air-powered rifles, pellet guns, and BB guns. They are extremely dangerous and have been reclassified as firearms and removed from toy departments.
- Wear eye protection while mowing the lawn or using a "weed eater." Stones and debris thrown from moving blades can cause severe eye injuries.
- Always check to make sure that a spray nozzle is pointed away from your face before using.
- Use grease shields to cover frying pans and protect eyes from splattering liquids.
- Wear snug-fitting, completely opaque eyeglasses or goggles to shield your eyes and block all UV light in tanning booths. Tanning facilities are required by the U.S. Food and Drug Administration (FDA) to provide safety goggles, but it is best to obtain your own pair so you will always be prepared. If you use the salon's goggles, be sure that the salon personnel sterilize them after each use to prevent infection and that the goggles are approved for this particular use.
- Read instructions and safety warnings carefully before using tools, chemicals, ammonia, cleaning supplies, and so on.
- Wear safety goggles and be sure you read the instructions carefully before jump-starting a car. Attach the negative ground of the dead battery last. This cable should be attached to the engine away from the dead battery terminal. Never attach a cable to the negative terminal of the dead battery.
- Never use a match or lighter to look under the hood of a car.
- When an eye injury does occur, have an ophthalmologist (Eye M.D.) or other medical doctor examine the eye as soon as possible. Although the injury may not look or feel serious, it could cause serious damage to your eyes. If you have blurred vision, partial loss of vision, double vision, or sharp pains in your eye after an accident, see an ophthalmologist or go to a hospital emergency room right away.
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Intraocular Foreign Bodies and Sharp Trauma
An intraocular lens (IOL) is a tiny, lightweight, clear plastic or silicone disc placed in the eye during cataract surgery. An IOL replaces the focusing power of the eye's natural lens.
Your eye's natural lens plays an important role in focusing images on the retina. When a cataract develops, the lens loses its clarity. Light rays cannot focus clearly, and the image you see is blurry. Eyeglasses or contact lenses usually can correct slight refractive errors caused by early cataracts, but they cannot sharpen your vision if an advanced cataract is present.
The only treatment for a severe cataract is to remove the eye's natural lens and replace it with an IOL. Intraocular lenses offer many advantages. Unlike contact lenses, which must be removed, cleaned, and reinserted, the IOL remains in the eye after surgery.
An IOL may be implanted either in front of or behind the iris. Behind the iris is the most frequent placement site. IOLs can be made of hard plastic, soft plastic, or soft silicone. Soft, foldable lenses can be inserted through a small incision, which shortens recovery time following surgery.
The rapid evolution of IOL designs, materials, and implant techniques has made them a safe and practical way to restore normal vision after cataract surgery.
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Workplace Eye Safety
Eye injuries at work are common. Every year approximately 70,000 workers injure their eyes. The Occupational Safety and Health Administration (OSHA) reports that nearly three out of every five injured workers were not wearing eye protection at the time of their accident. Luckily, 90% of all workplace eye injuries are preventable with the use of proper safety eyewear.
The Occupational Safety and Health Administration (OSHA) provides regulations that employers and employees must follow. The American National Standards Institute (ANSI) provides the following standards of eye protection for any workplace task:
- Unprotected workers will not knowingly be subjected to environmental hazards.
- Protective eyewear is required whenever there is a reasonable probability eye injury may occur.
- Employers must provide the type of eye protection best suited to the task to be performed.
- Employees are required to use the eye protectors provided.
The Bureau of Labor Statistics reports that eye injuries in the workplace cost over $467 million annually. A written eye safety program should be implemented in the workplace to help prevent workplace eye injuries. Employers should consider these tips in developing their safety plan:
- Determine the potential for eye injury for the tasks performed by their employees.
- Decide how best to protect against the injury (e.g., dark lenses for welding, face-shield for flying objects, tight seal for chemical spills).
- Identify the visual needs of the job (e.g., magnification, dark lenses).
- Post rules regarding when and how eye protection must be used.
- Provide adequate and readily available supplies of eye protection at all times.
- Instruct employees on appropriate treatment if injury should occur.
- Require vision screening for new employees to diagnose any eye disease.