Blurry vision, spots, glare at night, flashing lights, are common eye complaints. Each could be a harmless annoyance or an early sign of disease. It isn’t always easy to tell the difference. That is why people should not just brush these things aside and carry on. Rather, you should promptly visit an eye specialist once you notice any changes in your vision. As it is commonly said, the eye is the window to the world, for it through the eyes that we see the world around us. The vision is so important even Pentecostal Christians talk about the “eye of the inner man.”
Colour blindness test
When you look at the chart on this page and the number you see is ‘3’ then you probably have normal colour vision. If it’s a “5,” you may be colour blind. The centre panel shows a mild lack of colour vision. Complete colour blindness, which is rare, appears at right. No number is visible. That means you need tinted glasses that may help you see better.
When you’re near-sighted, things in the distance look blurry. This vision condition is called myopia. You’re more likely to have it if: one or both of your parents have it or you do lots of close-up reading.
Near-sightedness can make it harder to drive, play sports, or see a blackboard or TV. Symptoms include blurred vision, squinting, and fatigue. To correct it, you can wear glasses, contacts, or get surgery in some cases.
The cause is usually an eyeball that is too long. Or it can result from an oddly-shaped cornea or lens. Light rays focus just in front of the retina, instead of directly on it. This sensitive membrane lines the back of the eye (seen in yellow) and sends signals to the brain through the optic nerve. Near-sightedness often develops in school-age children and teens, so they may need to change glasses or contacts frequently as they grow. Multifocal contact lens or glasses and eye drops such as atropine, pirenzepine gel and cyclopentolate can help slow the progression. The prevalence of myopia has been rising at an alarming rate, much of it being attributed to increased use of handheld devices and computers.
Most people are born with mild farsightedness and outgrow it in childhood. When it persists, you may see distant objects well, but books, knitting, and other close objects are a blur. This problem runs in families. Symptoms include trouble with reading, blurry vision at night, eyestrain, and headaches. To treat it, you may wear glasses or contacts. Some people get surgery for it.
Farsightedness occurs in people whose eyeballs are too short or an oddly-shaped lens or cornea. Light rays focus behind your retina and close objects look blurry. Your distance vision might be fuzzy, too. Severely farsighted children often have crossed eyes (strabismus) or lazy eye (amblyopia) and may have trouble reading. That’s one reason eye doctors recommend vision exams for young children.
Trouble reading fine print is a sign of aging. It’s called presbyopia, which means “old eye” in Greek. Most people start to notice it in their 40s. The eyes’ lenses become less flexible and can’t change shape to focus on objects at reading distance. The solution: Wear reading glasses or bifocals, which correct both near and distance vision. If you wear contacts, ask your eye doctor about contacts made for people with presbyopia.
If you have astigmatism in one or both eyes, your vision may be out of focus at any distance. It happens when the cornea, the clear “window” that covers the front of the eye, isn’t shaped right. Light rays can’t focus on a single point on your retina. Instead they scatter to many places. Glasses or contact lenses correct it. Surgery may be an option. Symptoms include blurred vision, headaches, fatigue, and eye strain.
Refractive eye surgery
Do you dream of seeing clearly without glasses? Surgery to reshape your cornea can correct near-sightedness, farsightedness, or astigmatism with a success rate of better than 90%. Surgery may not be right for you if you have severe dry eye, thin or oddly shaped corneas, or severe vision problems. Side effects include glare or sensitivity to light.
You can’t feel it, but this disease damages your optic nerve. You may not have any symptoms until you lose your central vision. Your side vision will go first. That’s why you need regular eye exams every 1 to 2 years, especially after you turn 40. Doctors can treat glaucoma with medications or surgery.
The eye is filled with fluid. Sometimes too much of the fluid builds up and raises pressure inside the eye. This can damage theoptic nerve, which is a bundle of nerve fibres that carries information to your brain. Without treatment, glaucoma can cause total blindness. The bright yellow circle shows an optic nerve head damaged by glaucoma. The dark central area is the macula, which controls your finely-detailed central vision.
Age-related macular degeneration (AMD) damages and then destroys your central vision, making it hard to read or drive. Symptoms can include a central blurry spot or straight lines that appear wavy. You’re more likely to have it if you are older than 60, smoke, have high blood pressure, are obese, are female, or have a family history of the condition. See your eye doctor regularly to check for AMD. Prompt treatment can help slow vision loss.
AMD affects the central part of the retina, called the macula. There are two types:
• Dry: Doctors often see yellow deposits called drusen in the macula. As it worsens, the macular tissue breaks down. That causes changes or loss of your central vision over time.
• Wet: Abnormal blood vessels grow in the eye. They leak blood and fluid which causes scars and further damages the macula.
Both types leave you with a central blind spot.
The do a macular degeneration test, cover one eye and stare at the centre dot in this Amsler grid from a distance of 12 to 15 inches. (You can wear your reading glasses.) Do you see wavy, broken, or blurry lines? Are any areas warped or just plain gone? Repeat for your other eye. Although no self-test can take the place of an eye exam, this grid is used to help spot early symptoms of AMD.
As seen in the image here, the Amsler grid can look quite distorted to if you have severe macular degeneration. It may include a central dark spot. Straight lines that appear wavy are also cause for concern, as they can be an early symptom of wet AMD, the more serious, fast-moving type. See your eye doctor right away for a thorough exam.
• Culled from webmd.com