Much of what we know and love in the world around us comes to us through our sight, yet many of us ignore our eye health and don't get regular eye checkups. What a short-sighted attitude this is, especially when you consider that many eye disorders present no physical symptoms and can only be detected through an eye exam.
October is eye-health month, and Canadian Living has asked two eye-health professionals to enlighten readers about their eye care.
(Newborn to 24 months)
While newborns are able to see, their eyes tend to wander. They need to learn how to focus and how to use both eyes together. At about 10 weeks old, their eyes come into alignment and will fix on items that are within a metre.
Dr. John Lloyd, a staff ophthalmologist at Sunnybrook Health Sciences Centre in Toronto, says family doctors will refer infants to an ophthalmologist if they have any of the following symptoms:
• the pupil looks white instead of black;
• the eye is turned (in any direction); or
• there are signs of other disorders, such as obvious differences between the eyes; black, white or red spots; or various infections.
(Ages two to 12)
The Ontario Association of Optometrists recommends that all children undergo a thorough eye examination before entering preschool, or between the ages of three and four. Children do not have to be able to read an eye chart. The examination is based on what the optometrist or ophthalmologist sees, and is designed to detect and treat a range of problems, the most common of which follow.
• Amblyopia, or lazy eye: the most common disorder in children. It occurs when one eye is weaker than the other and the brain "shuts off" the weaker eye. Amblyopia may be caused by strabismus, or because one eye doesn't focus properly, or because of other, less common reasons. Only an eye exam will detect it, because children can function well using just one eye.
Eyes continue to develop up to the age of about nine; it is important to begin treatment early (ideally before age six), because once the eyes mature, the condition is not reversible. Treatment may involve prescription glasses, a combination of glasses and an eye patch, or just patching the strong eye to force the weaker eye to work harder. Surgery also may be necessary to mechanically realign the eyes.
• Astigmatism: a condition caused by an irregularly shaped cornea (the clear window in front of the eye), which prevents the eye from focusing correctly. If astigmatism exists at birth, that usually signifies a large amount of astigmatism, requiring treatment. Corrective glasses, corrective soft toric lenses or hard contact lenses are the usual treatment options.
• Conjunctivitis, or pink eye: inflammation of the membrane covering the white of the eye. The pink tinge, burning, itching, swelling and occasional discharge of pus indicate that the eye is infected with a virus or, sometimes, a bacteria. This condition spreads easily with close contact, so it’s especially common among children attending day care or school.
Most infections clear up on their own without causing damage. Antibiotics are used to treat bacterial infections, which are indicated by the presence of pus. Try to avoid touching or rubbing the eyes and never share washcloths or towels.
Page 1 of 5 – find out about eye care for teens and adults on page two!
• Strabismus: crossed eyes or eyes that are not straight. One eye may be turned in toward the nose, or turned out or up. The condition may be present at birth, it may develop a few months later, or it may not show up until a child is age two or three. The cause may be genetic; muscle or nerve problems; or a tumour or cataract. Treatment is similar to that used for amblyopia.
(Ages 13 to 19)
Some estimates say that up to 10 per cent of children start school with a vision problem, according to information from the Canadian Association of Optometrists. By the time children reach high school, the percentage of those who have problems more than doubles. Because these are the years when bodies are growing and eyes are changing quickly, William J. Ulakovic, an optometrist and president of the Ontario Association of Optometrists, recommends an annual eye exam for all teens, not just those who wear corrective lenses. This may not be covered by your provincial health plan.
• Hyperopia, or farsightedness: a condition in which people can see objects at a distance clearly, but have difficulty seeing things that are close to them. Hyperopia is actually more common than myopia, but it doesn't require correction. Most children entering school are slightly farsighted, but because the lenses of their eyes are young and strong, they’re able to see clearly objects both near and far. As â€¨the body grows and changes, this farsightedness generally decreases.
• Myopia, or nearsightedness: people with this condition can see only close objects clearly. It affects about 25 per cent of the entire population. Myopia is usually diagnosed or detected by age 12. It does not normally develop in adults. Myopia is treated with corrective lenses; as the teen ages, the prescription usually becomes stronger, until it stabilizes.
Are you worried about your children sitting too close to the computer screen or TV for too long? No need to worry – there is no proof this leads to the need for corrective lenses.
(Ages 20 to 40)
Eye conditions for most people remain stable during these decades. It is the time when some people may consider some form of laser refractive surgery, such as LASIK, to correct their hyperopia, myopia or astigmatism.
Adults only need to see a doctor if they experience the following: changes in vision (such as sudden spots or wavery or blurry vision); changes in the field of vision (such as shadows or blurriness in central or side vision); changes in colour vision; the loss of or a decline in vision; or physical changes to the eye (such as crossed or turned eyes, redness or swelling).
Healthy adults who don't notice anything wrong with their eyes only need to see an optometrist or ophthalmologist once every 10 years.
Page 2 of 5 – on the next page: eye health for older adults
(Ages 40 and over)
At age 40 and beyond eyes start to change, sometimes dramatically, so people are encouraged to have a comprehensive eye exam every year or two. "This is when eye diseases (for instance, glaucoma) become more prevalent again and often without symptoms or warning signs," says Ulakovic.
• Hyperopia: by about age 40, 10 per cent of people are farsighted and experience difficulties seeing and reading fine print. Inexpensive corrective magnifying glasses, found at pharmacies and other stores, may help some; others may require prescription lenses. Laser surgery may be an option.
• Presbyopia: the normal loss in flexibility of the eye's lens as it ages. Presbyopia affects 100 per cent of the population by about age 50. Reading and seeing at close range becomes difficult. Inexpensive corrective magnifying glasses may help some people, but most people need corrective lenses of increasing strength, with bifocal or trifocal lenses.
• Floaters: small clumps of material that float in the clear, gel-like substance (vitreous humour) that fills the inside of the eye. Floaters appear as shadowy spots, lines or circles that drift in front of the eye. Present in half the population by age 50, floaters are usually caused by the normal eye-aging process. There is no proven, safe treatment.
• Open-angle glaucoma: the most common type of glaucoma. There are no physical symptoms. The disease, caused by increased pressure in the eye, damages the optic nerve, affecting the peripheral vision first. If not treated, the disease results in further vision loss and blindness. About one in 100 adults over age 40 are affected. Other risk factors include age; family history; myopia; being of African or Hispanic descent; having diabetes; having had a heart attack or stroke; and increased intraocular pressure (IOP), caused by a blockage that stops the normal flow of fluid from the eye.
This disease can be diagnosed before vision loss occurs, but once IOP is detected, some irreversible damage has already occurred.
The usual treatment for glaucoma is eye drops, or other forms of medication, which lower the IOP and prevent further damage. Treatment may also progress to include laser therapy, which can halt the progess of the disease.
• Closed-angle glaucoma: the less common, more acute type of glaucoma, this is caused by the blockage of fluid inside the eye, leading to a rapid and painful rise in IOP. Symptoms such as severe eye pain, swelling, redness, and decreased and cloudy vision signal a medical emergency. Blindness can occur in just a few days. Having this kind of glaucoma in one eye puts the other eye at risk, but preventive treatment is available. Doctors can lower IOP intravenously; sometimes surgery is required, which can also prevent a future attack. An eye-health professional can tell you if you have â€¨the type of eye structure that may lead to this problem.
Page 3 of 5 – should you get laser eye surgery? Find out on page 4.
• Cataracts: the hardening and clouding of the lens of the eye, occurring most commonly as a result of aging. Other causes are eye injuries, diabetes and some medications.
Cataracts are painless. Early signs are blurring and clouding of vision, double vision in one eye, and sensitivity to light and glare. Another sign may be acquiring glasses of increased prescription strength, but finding they don't help improve your vision. Surgery is the only effective remedy. An ophthalmologist will examine your eye and measure it for an artificial lens that will be implanted during surgery. More than 95 per cent of people say they have better vision after surgery.
The risk of a serious adverse effect after cataract surgery is one in a thousand or better, says Lloyd. The most common complication is swelling of the retina, called cystoid macular edema. This significantly prolongs recovery time, increasing it from a few days to a few weeks. The swelling can be treated with eyedrops.
• Age-related macular degeneration (AMD): the most common cause of severe vision loss. AMD is a disease of the macula, the central part of the retina, that results in blurry central vision and an inability to see fine details and colours. There are two types.
In dry AMD, the macula becomes distorted, coloured or thinned. Vision loss is gradual and almost unnoticeable (which makes it difficult to identify in the beginning) and leads, eventually, to severe vision loss. You can delay the onset of dry AMD by taking a special combination vitamin/mineral supplement, available from pharmacies.
Wet AMD is more severe; abnormal blood vessels develop and leak fluid into the retina. Severe vision loss can be sudden. Wet AMD can sometimes be detected in an exam before symptoms develop, but not always.
Lucentis (ranibizumab), a drug recently approved for use in Canada to treat wet AMD, is injected directly into the eye. It is often given monthly for a time, then the injections may be spaced at longer intervals. "It inhibits the leakage and formation of the abnormal blood vessels that are growing and bleeding. It is a breakthrough," says Lloyd, who notes that this is the first time we have a drug that can both halt the bleeding and improve the vision of some patients. Possible adverse effects include diarrhea, headache, nausea, flu-like symptoms, eye irritation and dry eye.
Laser refractive surgery, such as LASIK, can be performed on adults of all ages who wish to correct hyperopia (farsightedness), myopia (nearsightedness) or astigmatism (a condition that prevents the eye from focusing correctly).
The procedure is fairly painless, can be performed without a hospital stay and is low risk. As with any surgery, however, there can be complications; in this case, painful dry eyes, blurred or double vision, or seeing a permanent glare and halos around objects. About 10 per cent of patients will need a second surgery.
Not everyone is a good candidate for the surgery, says Dr. John Lloyd, a staff ophthalmologist at Sunnybrook Health Sciences Centre in Toronto. A cornea may be too thin or too irregular or may require a strong corrective prescription.
Laser surgery also will not stop or correct the natural aging process of the eye, which can lead to presbyopia or cataracts.
Laser surgery is not recommended for those under age 20, because the condition of the eyes has yet to stabilize.
Page 4 of 5 – eye protection tips on the next page.
Many eye injuries are preventable. Use foresight and follow this advice.
• Keep damaging rays away from the eyes. Infants should wear sun hats when outside, and all other ages should wear sun hats and sunglasses. Since evidence suggests that the amount of UV exposure during youth and young adulthood may be a risk factor in developing age-related macular degeneration, the most common cause of severe vision loss, Dr. John Lloyd, a staff ophthalmologist at Sunnybrook Health Sciences Centre in Toronto, recommends wearing impact-resistant UV-blocking sunglasses during prolonged outdoor activities.
• Wear eye protection. The number of work-related eye injuries is lower today than it used to be, says William J. Ulakovic, president of the Ontario Association of Optometrists, because safety glasses and shields are widely employed where required. Most eye injuries are now the result of leisure activities. Make sure you and your children play smartly by wearing a face mask, eye shield or other appropriate device at the rink, on the field, in the garden or in the workshop.
• Avoid computer eyestrain. Computers are associated with a syndrome called computer eyestrain. "When viewing a monitor, the rate at which you blink your eyes drops by about half," says Lloyd. "Your eyes dry out and the constant prolonged close focusing is tiring. So it's important to give your eyes periodic breaks, look away from the screen, and to consciously think about blinking the eyes to moisten them."
Diabetes and your eyes
People with diabetes have abnormally high blood sugar because their bodies don't produce enough insulin. If not properly treated, diabetes will adversely affect many parts of the body, including the eyes. Blurred vision and difficulties with focusing are common treatable eye conditions of people with diabetes, who are also at risk for cataracts and glaucoma.
Diabetic retinopathy is a significant cause of vision problems. In the early stages, the blood vessels that feed the retina weaken and leak blood or fluid, causing the retina to swell. At a later stage, new abnormal vessels, which are fragile and often bleed and tear, replace dead blood vessels. Scar tissue forms; as it shrinks, it tears the retina and can cause the retina to detach, leading to blindness. Most of those who have had the disease long term (10 years or more) have some degree of retinopathy. Anyone who has diabetes should have a comprehensive annual eye exam by an optometrist or ophthalmologist.
Which eye expert do you need?
Is your knowledge of eye-health professionals a bit blurry? Here's how to clear up any confusion.
Ophthalmologist: a medical doctor who specializes in eye care and the diagnosis and treatment of eye diseases and performs eye surgery.
Optometrist: a university-trained professional who diagnoses diseases and dysfunctions of the eye, assesses vision and prescribes corrective lenses and preventive devices. In some provinces, optometrists are permitted to prescribe therapeutic pharmacological agents for treating eye diseases.
As primary eye-care providers, optometrists work collaboratively with family physicians, who refer patients with diabetes to them for monitoring of eye-health complications related to diabetes.
Optician: a practitioner trained in a community college who fits and dispenses eyeglasses and contact lenses according to prescriptions supplied by an ophthalmologist or optometrist.
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