Nearsightedness

Definition

Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry.

The degree of your nearsightedness determines your ability to focus on distant objects. People with severe nearsightedness can see clearly only objects just a few inches away, while those with mild nearsightedness may clearly see objects several yards away.

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 easily correct the condition with eyeglasses or contact lenses. Another treatment option for nearsightedness is surgery.

Nearsightedness (myopia)

Nearsightedness (myopia)

With normal vision, an image is sharply focused onto the retina. In nearsightedness (myopia), the point of focus is in front of the retina, making distant objects appear blurry. ...

Symptoms

Being nearsighted may mean:

• Distant objects appear blurry
• You need to squint to see clearly
• You have headaches caused by excessive eyestrain

Nearsightedness is often first detected during childhood and is most common during early school years through the later teens. A child with nearsightedness may:

• Persistently squint
• Need to sit very close to the television, movie screen or blackboard
• Hold books very close while reading
• Seem to be unaware of distant objects
• Blink excessively
• Rub his or her eyes frequently

When to see a doctor
If your degree of nearsightedness 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.

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 an eye exam every two to four years up to age 40, then every one to three years between 40 and 54, and finally every one to two years for those 55 and older.

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, it's recommended that you have an eye exam at the following intervals.

• At least once between puberty and age 40, and then every five to 10 years if you don't have vision problems or risk factors for eye diseases, such as glaucoma
• Between ages 40 and 64 — every two to four years
• Age 65 and older — every one to two years

If you wear glasses or contacts, you'll likely need to have your eyes checked every year. 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 or another trained screener at the following ages and intervals.

• Between birth and 3 months
• Between 6 months and 1 year
• Around 3 years
• Around 5 years

Additionally, it's recommended that school-age children be screened at school or through community programs approximately every two years to check for vision problems.

Causes

Nearsightedness is a type of refractive error. That means you can't see clearly because the light that enters your eye doesn't bend (refract) properly.

Normal vision
To focus the images it sees, your eye relies on two critical parts:

• The cornea, the clear front surface of your eye
• The lens, a clear structure inside your eye that changes shape to help focus objects

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

A refractive error
However, if your cornea or lens isn't evenly and smoothly curved, light rays aren't refracted properly, and you have a refractive error. Nearsightedness is one type of refractive error. Nearsightedness can occur when your cornea is curved too much or when your eye is longer than normal. 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 cornea is curved too little or your eye is shorter from front to back than normal. The effect is the opposite of nearsightedness. Light is focused beyond the back of your eye, making nearby objects blurry. You're usually able to see faraway objects clearly.
• Astigmatism. This occurs when your cornea is curved more steeply in one direction than in another. Uncorrected astigmatism blurs your vision. Typically, the images you see will be blurred more in one direction than another. For example, horizontal images may be more out of focus than are vertical or diagonal images.

Anatomy of the eye

Anatomy of the eye

Your eye is a complex and compact structure measuring about 1 inch (2.5 centimeters) in diameter. It receives millions of pieces of information about the outside world, which are quickly processed by ...

Nearsightedness (myopia)

Nearsightedness (myopia)

With normal vision, an image is sharply focused onto the retina. In nearsightedness (myopia), the point of focus is in front of the retina, making distant objects appear blurry. ...

Risk factors

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

• Family history. Nearsightedness tends to run in families. If one of your parents is nearsighted, your risk of developing nearsightedness is increased. The risk is even higher if both parents are nearsighted.
• Premature birth. Babies born prematurely are more likely to have eye conditions that can affect the shape of the eyes, increasing the risk of nearsightedness.
• Close work. Some studies have shown that there is an increased incidence of nearsightedness among people who do a lot of reading or other close work.

Complications

Nearsightedness may be associated with several complications, 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. Squinting to see in the distance can cause eyestrain and headaches.
• Impaired safety. For your own safety and that of others, don't drive or operate heavy equipment if you have an uncorrected vision problem.
• Glaucoma. Severe nearsightedness increases your risk of developing glaucoma, a potentially serious eye disease.
• Retinal tear and detachment. If you're significantly nearsighted, it's possible that the retina of your eye is thin. The thinner your retina, the higher your risk of developing a retinal tear or retinal detachment. If you experience a sudden onset of flashes, floaters or a dark curtain or shadow across part of your eye, seek medical assistance immediately. Retinal detachment is a medical emergency, and time is critical. Unless the detached retina is promptly surgically reattached, this condition can cause permanent loss of vision in the affected eye.

Preparing for your appointment

Three kinds of eye specialists, each with different training and experience, can provide routine eye care:

• Ophthalmologists. An ophthalmologist is an eye specialist with a doctor of medicine (M.D.) or doctor of osteopathy (D.O.) degree who provides full eye care, including performing complete eye evaluations, prescribing corrective lenses, diagnosing and treating common and complex eye disorders, and performing eye surgery when it's necessary.
• Optometrists. An optometrist has a doctor of optometry (O.D.) degree. Optometrists are trained to evaluate vision, prescribe corrective lenses and diagnose common eye disorders. Complicated eye conditions, including those requiring surgery, must be treated by an ophthalmologist.
• Opticians. An optician is an eye specialist who fills prescriptions for eyeglasses — assembling, fitting and selling them. In some states, opticians are also allowed to sell and fit contact lenses.

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

What you can do

• If you already have glasses, bring them with you to your appointment. Your doctor has a special device that tells what type of prescription you already have. If you wear contacts, bring an empty contact lens box — or a box from each type of contact you use if you wear a different strength contact lens in each eye — to your appointment.
• Write down any symptoms you're experiencing, such as trouble reading up close or difficulty with night driving.
• Make a list of all medications, as well as any vitamins or supplements, that you're taking.
• Write down questions to ask your doctor.

Your time with your doctor is limited, so preparing a list of questions can help you make the most of your visit. List your questions from most important to least important in case time runs out. 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 this treatment?
• Will my insurance company pay for this procedure?
• Are there any alternatives to the primary approach that you're suggesting?
• Are there brochures or other materials that I can take with me? What Web sites do you recommend?

In addition to the questions that you've prepared, don't hesitate to ask questions during your appointment whenever you don't understand something.

What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to spend more time on. Your doctor may ask:

• When did you first begin experiencing symptoms?
• How severe are your symptoms?
• Does your vision improve if you squint or move objects closer (or farther) away?
• Do others in your family use corrective lenses? 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?

Tests and diagnosis

Nearsightedness is diagnosed by a basic eye exam. A complete eye examination involves a series of tests. Your eye doctor may use various instruments, aim bright lights directly at your eyes and request that you look through an array of lenses. Each test allows your doctor to examine a different aspect of your vision.

Treatments and drugs

The goal of treating nearsightedness is to help focus light on your retina through the use of corrective lenses or refractive surgery.

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

• Eyeglasses. Eyeglasses come in a wide variety of styles and are easy to use. Eyeglasses can correct a number of vision problems at once, such as myopia and astigmatism. Eyeglasses may be the easiest and most economical correction solution.
• Contact lenses. A wide variety of contact lenses are available — hard, soft, extended wear, disposable, rigid gas permeable (RGP) and bifocal. Ask your eye doctor about their pros and cons and what might be best for you.

Refractive surgery
This treatment corrects nearsightedness by reshaping the curvature of your cornea. Refractive surgery methods include:

• Laser-assisted in-situ keratomileusis (LASIK). LASIK is a procedure in which an ophthalmologist uses an instrument called a keratome or a special laser called a femtosecond laser to make a thin, circular hinged cut into your cornea. Your eye surgeon then uses a different type of laser, called an excimer laser, to remove layers from the center of your cornea to flatten its domed shape.
• Laser-assisted subepithelial keratomileusis (LASEK). Instead of creating a flap in the cornea, the surgeon creates a flap only in the cornea's thin protective cover (epithelium). Your surgeon will use an excimer laser to reshape the cornea's outer layers and flatten its curvature and then reposition the epithelial flap. To encourage healing, a bandage contact lens is worn for several days after this procedure.
• Photorefractive keratectomy (PRK). This procedure is similar to LASEK, except the surgeon removes the epithelium. It will grow back naturally, conforming to your cornea's new shape. Like LASEK, PRK requires the use of a bandage contact lens following the procedure.
• Anterior chamber intraocular lens (IOL) implant. These lenses are surgically implanted into the eye, in front of the eye's natural lens. They may be an option for people with moderate to severe myopia, although these lenses aren't currently approved by the Food and Drug Administration solely for treating nearsightedness. IOL implants are not currently considered a mainstream treatment option.

All eye surgeries have some degree of risk, and possible complications from these eye procedures include infection, corneal scarring, vision loss and visual aberrations, such as seeing halos around lights at night. Discuss the potential risks with your doctor.

Lifestyle and home remedies

Although you can't prevent nearsightedness, you can help protect your eyes and your vision. Follow these steps:

• Have your eyes checked. Regardless of how well you see, have your eyes checked regularly for problems.
• Control chronic health conditions. Certain conditions, such as diabetes and high blood pressure, can affect your vision if you don't receive proper treatment.
• Recognize symptoms. Sudden loss of vision in one eye, sudden hazy or blurred vision, flashes of light, black spots, or halos or rainbows around lights may signal a serious eye problem, such as a retinal tear or detachment, requiring urgent medical attention. Similar symptoms can be caused by other serious medical problems, such as acute glaucoma or a stroke. Talk to your doctor immediately if you experience any of these symptoms.
• Protect your eyes from the sun. Wear sunglasses that block both ultraviolet A (UVA) and ultraviolet B (UVB) radiation. This is especially important if you spend long hours in the sun or are taking a prescription medication that increases your sensitivity to UV radiation.
• Eat healthy foods. Maintain a healthy diet that includes plenty of fruits and vegetables, which have shown to enhance eye health. Try foods that contain vitamin A and beta carotene, such as carrots. Dark leafy greens and fish also may be especially helpful for good eye health.
• Don't smoke. Just as smoking isn't good for the rest of your body, it can affect your eye health as well.
• Use the right glasses. The right glasses optimize your vision. Having regular exams will ensure that your eyeglass prescription is correct.
• Use good lighting. Use adequate light for optimal vision.

Prevention

Although a number of scientific attempts have been made to halt or slow the progression of nearsightedness, there are no proven ways to prevent the condition from occurring or progressing.