Nearsightedness

Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry. It occurs when the shape of your eye causes light rays to bend (refract) incorrectly, focusing images in front of your retina instead of on your retina.

Nearsightedness may develop gradually or rapidly, often worsening during childhood and adolescence. Nearsightedness tends to run in families.

A basic eye exam can confirm nearsightedness. You can compensate for the blur with eyeglasses, contact lenses or refractive surgery.

Symptoms

Nearsightedness symptoms may include:

• Blurry vision when looking at distant objects
• The need to squint or partially close the eyelids to see clearly
• Headaches caused by eyestrain
• Difficulty seeing while driving a vehicle, especially at night (night myopia)

Nearsightedness is often first detected during childhood and is commonly diagnosed between the early school years through the teens. A child with nearsightedness may:

• Persistently squint
• Need to sit closer to the television, movie screen or the front of the classroom
• Seem to be unaware of distant objects
• Blink excessively
• Rub his or her eyes frequently

When to see a doctor

If your difficulty clearly seeing things that are far away (distance blur) is pronounced enough that you can't perform a task as well as you wish, or if the quality of your vision detracts from your enjoyment of activities, see an eye doctor. He or she can determine the degree of your nearsightedness and advise you of your options to correct your vision.

Seek emergency medical care if you experience:

• The sudden appearance of many floaters — tiny specks that seem to drift through your field of vision
• Flashes of light in one or both eyes
• A curtain-like shadow over your visual field

These are warnings signs of retinal detachment, which is a rare complication of myopia. Retinal detachment is a medical emergency, and time is critical.

Regular eye exams

Since it may not always be readily apparent that you're having trouble with your vision, the American Academy of Ophthalmology recommends the following intervals for regular eye exams:

Adults

If you're at high risk of certain eye diseases, such as glaucoma, get a dilated eye exam every one to two years, starting at age 40.

If you don't wear glasses or contacts, have no symptoms of eye trouble, and are at a low risk of developing eye diseases, such as glaucoma, get an eye exam at the following intervals:

• Every five to 10 years in your 20s and 30s
• Every two to four years from 40 to 54
• Every one to three years from 55 to 64
• Every one to two years after age 65

If you wear glasses or contacts or you have a health condition that affects your eyes, such as diabetes, you'll likely need to have your eyes checked regularly. Ask your eye doctor how frequently you need to schedule your appointments. But, if you notice any problems with your vision, schedule an appointment with your eye doctor as soon as possible, even if you've recently had an eye exam. Blurred vision, for example, may suggest you need a prescription change, or it could be a sign of another problem.

Children and adolescents

Children need to be screened for eye disease and have their vision tested by a pediatrician, an ophthalmologist, an optometrist or another trained screener at the following ages and intervals.

• Age 6 months
• Age 3 years
• Before first grade and every two years during school years, at well-child visits, or through school or public screenings

Causes

Your eye has two parts that focus images:

• The cornea is the clear, dome-shaped front surface of your eye.
• The lens is a clear structure about the size and shape of an M&M's candy.

In a normally shaped eye, each of these focusing elements has a perfectly smooth curvature, like the surface of a marble. A cornea and lens with such curvature bend (refract) all incoming light to make a sharply focused image directly on the retina, at the back of your eye.

A refractive error

If your cornea or lens isn't evenly and smoothly curved, light rays aren't refracted properly, and you have a refractive error.

Nearsightedness usually occurs when your eyeball is longer than normal or your cornea is curved too steeply. Instead of being focused precisely on your retina, light is focused in front of your retina, resulting in a blurry appearance for distant objects.

Other refractive errors

In addition to nearsightedness, other refractive errors include:

• Farsightedness (hyperopia). This occurs when your eyeball is shorter than normal or your cornea is curved too little. The effect is the opposite of nearsightedness. In adults, both near and distant objects are blurred.
• Astigmatism. This occurs when your cornea or lens is curved more steeply in one direction than in another. Uncorrected astigmatism blurs your vision.

Risk factors

Certain risk factors may increase the likelihood of developing nearsightedness, such as:

• Genetics. Nearsightedness tends to run in families. If one of your parents is nearsighted, your risk of developing the condition is increased. The risk is even higher if both parents are nearsighted.
• Environmental conditions. Some studies support the idea that a lack of time spent outdoors may increase the chances of developing myopia.

Complications

Nearsightedness is associated with a variety of complications from mild to severe, such as:

• Reduced quality of life. Uncorrected nearsightedness can affect your quality of life. You might not be able to perform a task as well as you wish. And your limited vision may detract from your enjoyment of day-to-day activities.
• Eyestrain. Uncorrected nearsightedness may cause you to squint or strain your eyes to maintain focus. This can lead to eyestrain and headaches.
• Impaired safety. Your own safety and that of others may be jeopardized if you have an uncorrected vision problem. This could be especially serious if you are driving a car or operating heavy equipment.
• Financial burden. The cost of corrective lenses, eye exams and medical treatments can add up, especially with a chronic condition such as nearsightedness. Vision reduction and vision loss also can affect income potential in some cases.
• Other eye problems. Severe nearsightedness puts you at an increased risk of retinal detachment, glaucoma, cataracts and myopic maculopathy — damage in the central retinal area. The tissues in long eyeballs are stretched and thinned, causing tears, inflammation, new blood vessels that are weak and bleed easily, and scarring.

Diagnosis

Nearsightedness is diagnosed by a basic eye exam, which includes a refraction assessment and an eye health exam.

A refraction assessment determines if you have vision problems such as nearsightedness or farsightedness, astigmatism, or presbyopia. Your doctor may use various instruments and ask you to look through several lenses to test your distance and close-up vision.

Your eye doctor likely will put drops in your eyes to dilate your pupils for the eye health exam. This may make your eyes more light sensitive for a few hours after the exam. Dilation enables your doctor to see wider views inside of your eyes.

Treatment

The standard goal of treating nearsightedness is to improve vision by helping focus light on your retina through the use of corrective lenses or refractive surgery. Managing nearsightedness also includes regular monitoring for complications of the condition, including glaucoma, cataracts, retinal tears and detachments, and damage to central retinal areas.

Prescription lenses

Wearing corrective lenses treats nearsightedness by counteracting the increased curvature of your cornea or the increased length of your eye. Types of prescription lenses include:

• Eyeglasses. This is a simple, safe way to sharpen vision caused by nearsightedness. The variety of eyeglass lenses is wide and includes single vision, bifocals, trifocals and progressive multifocals.
• Contact lenses. These lenses are worn right on your eyes. They are available in a variety of materials and designs, including soft and rigid, gas permeable in combination with spherical, toric and multifocal designs. Ask your eye doctor about the pros and cons of contact lenses and what might be best for you.

Refractive surgery

Refractive surgery reduces the need for eyeglasses and contact lenses. Your eye surgeon uses a laser beam to reshape the cornea, which results in a decreased nearsighted prescription. Even after surgery, you may need to use eyeglasses some of the time.

• Laser-assisted in situ keratomileusis (LASIK). With this procedure, your eye surgeon makes a thin, hinged flap into your cornea. He or she then uses a laser to remove inner layers of your cornea to flatten its domed shape. Recovery from LASIK surgery is usually more rapid and causes less discomfort than other corneal surgeries.
• Laser-assisted subepithelial keratectomy (LASEK). The surgeon creates an ultra-thin flap only in the cornea's outer protective cover (epithelium). He or she then uses a laser to reshape the cornea's outer layers, flattening its curve, and then replaces the epithelium.
• Photorefractive keratectomy (PRK). This procedure is similar to LASEK, except the surgeon completely removes the epithelium, then uses the laser to reshape the cornea. The epithelium is not replaced, but will grow back naturally, conforming to your cornea's new shape.

Talk with your doctor about the possible side effects, as this procedure is not reversible. Refractive surgery is not recommended until your nearsighted prescription is stable.

Treatments to slow or stop progression of nearsightedness

Researchers and clinical practitioners continue to seek more-effective approaches to stop nearsightedness from getting worse over time. Therapies that show the most promise to date include:

• The topical medication, atropine. Topical atropine drops are commonly used to dilate the pupil of the eye, often as part of eye exams or before and after eye surgery. Atropine eyedrops in various doses may also help slow the progression of nearsightedness. The exact mechanism for this effect is unknown.
• Increased time outside. Spending time outdoors during adolescence and your early adult years may decrease the lifetime risk of nearsightedness. Researchers think exposure to the sun's ultraviolet (UV) rays may change the molecular structure of the sclera and cornea and help maintain a normal shape.
• Dual focus contact lenses. A new type of dual focus contact lens has been shown to slow the progression of nearsightedness in children between 8 and 12 years old.
• Orthokeratology. In this procedure, you wear rigid, gas permeable contact lenses for several hours a day until the curvature of your eye evens out. Then you wear the lenses less frequently to maintain the new shape. If you discontinue this treatment, your eyes return to their former shape. There is evidence that this lens does slow down the elongation of the nearsighted eyeball, which decreases myopia.

Lifestyle and home remedies

You can't prevent nearsightedness at this time. Some studies suggest you may be able to slow its progression though. You can, however, help protect your eyes and your vision by following these tips:

• Have your eyes checked. Do this regularly even if you see well.
• Control chronic health conditions. Certain conditions, such as diabetes and high blood pressure, can affect your vision if you don't receive proper treatment.
• Protect your eyes from the sun. Wear sunglasses that block ultraviolet (UV) radiation.
• Prevent eye injuries. Wear protective eyewear when doing certain things, such as playing sports, mowing the lawn, painting or using other products with toxic fumes.
• Eat healthy foods. Try to eat plenty of leafy greens, other vegetables and fruits. And studies show that your eyes benefit if you also include in your diet fish high in omega-3 fatty acids, such as tuna and salmon.
• Don't smoke. Just as smoking isn't good for the rest of your body, smoking can adversely affect your eye health as well.
• Use the right corrective lenses. The right lenses optimize your vision. Having regular exams will ensure that your prescription is correct. There is evidence that wearing a prescription that is too weak (undercorrecting) can increase the development of nearsightedness.
• Use good lighting. Turn up or add light for better vision.
• Reduce eyestrain. Look away from your computer or near-task work, including reading, every 20 minutes — for 20 seconds — at something 20 feet away.
• See your doctor immediately if you experience any of these symptoms: Sudden loss of vision in one eye with or without pain; sudden hazy or blurred vision; double vision; or you see flashes of light, black spots or halos around lights. This may represent a serious medical or eye condition.

Preparing for an appointment

You may encounter three kinds of specialists as you seek help for various eye conditions:

• Ophthalmologist. An ophthalmologist is an eye specialist with a doctor of medicine (M.D.) or a doctor of osteopathy (D.O.) degree followed by a residency. Ophthalmologists are trained to provide complete eye evaluations, prescribe corrective lenses, diagnose and treat common and complex eye disorders, and perform eye surgery.
• Optometrist. An optometrist has a doctor of optometry (O.D.) degree. Optometrists are trained to provide complete eye evaluations, prescribe corrective lenses, and diagnose and treat common eye disorders.
• Optician. An optician is a specialist who helps fit people for eyeglasses or contact lenses, following prescriptions from ophthalmologists and optometrists. Some states require opticians to be licensed. Opticians are not trained to diagnose or treat eye disease.

No matter which type of eye specialist you choose, here's some information to help you get ready for your appointment.

What you can do

• If you already wear glasses, bring them with you to your appointment. Your doctor has a device that measures your current glasses prescription. If you wear contacts, bring to your appointment an empty contact lens box from each eye.
• List any symptoms you're experiencing, such as trouble reading up close or difficulty with night driving.
• Make a list of all medications, vitamins or supplements that you're taking.
• Create a list of questions to ask your doctor.

Preparing a list of questions can help you make the most of your visit. For nearsightedness, some basic questions to ask include:

• When do I need to use corrective lenses?
• What are benefits and drawbacks to glasses?
• What are benefits and drawbacks to contacts?
• How often do you recommend that I have my eyes examined?
• Are more-permanent treatments, such as eye surgery, an option for me?
• If so, which do you recommend?
• What types of side effects are possible from these treatments?
• Will my insurance company pay for surgical procedures or a contact lens fitting?
• Do you have any brochures or other printed material that I can take home with me? What websites do you recommend?

What to expect from your doctor

Your doctor may ask:

• When did you first begin experiencing symptoms?
• Does your vision improve if you squint or move objects closer (or farther) away?
• Do others in your family use glasses or contacts? Do you know how old they were when they first began having trouble with their vision?
• When did you first begin wearing glasses or contacts?
• Do you have any medical problems, such as diabetes?
• Have you started to take any new medications, supplements or herbal preparations?

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