Nearsightedness

Nearsightedness is a common vision condition in which close objects look clear but far objects look blurry. The medical term for nearsightedness is myopia. Myopia happens when the shape of the eye — or the shape of certain parts of the eye — causes light rays to bend or refract. Light rays that should be focused on nerve tissues at the back of the eye, called the retina, are focused in front of the retina instead.

Nearsightedness usually develops during childhood and adolescence. Typically, it becomes more stable between the ages of 20 and 40. It tends to run in families.

A basic eye exam can confirm nearsightedness. You can correct the blurry vision with eyeglasses, contact lenses or refractive surgery.

Nearsightedness symptoms may include:

• Blurry vision when looking at distant objects.
• The need to squint or partially close the eyelids to see clearly.
• Headaches.
• Eyestrain.

School-age children may have difficulty seeing things on whiteboards or screen projections in the classroom. Younger children might not express difficulty seeing, but they may have the following behaviors that suggest difficulty seeing:

• Constant squinting.
• Seeming to not be aware of distant objects.
• Blinking often.
• Rubbing the eyes often.
• Sitting close to the television or moving screens closer to the face.

Adults with nearsightedness may notice difficulty reading street signs or signs in stores. Some people may experience blurry vision in dim light, as with nighttime driving, even if they see clearly in daylight. This condition is called night myopia.

When to see a doctor

Make an appointment with an eye care specialist if your child shows any signs of vision problems or if a teacher reports possible problems.

Make an appointment for yourself if you notice a change in your vision, have difficulty performing tasks such as driving or find that the quality of your vision affects your enjoyment of activities.

Seek emergency medical care if you experience any of the following:

• Sudden appearance of many floaters — tiny specks or lines that seem to drift through your field of vision.
• Flashes of light in one or both eyes.
• A curtain-like gray shadow covering all or part of your field of vision.
• A shadow in your outer or side vision, known as peripheral vision.

These are warnings signs of the retina becoming detached from the back of the eye. This condition is a medical emergency requiring prompt treatment. Significant nearsightedness is associated with an increased risk of retinal detachment.

Regular eye exams

Both children and adults may not be aware of problems with vision or changes that happen gradually. The American Academy of Ophthalmology recommends regular vision screenings to ensure timely diagnosis and treatment.

Children and adolescents

Your child's pediatrician or other healthcare professional does relatively simple exams to check the health of your child's eyes at birth, between 6 and 12 months of age, and between 12 and 36 months of age. If there are any problems, you may be referred to a doctor specializing in eye health and care, called an ophthalmologist.

Vision screenings are tests to check for vision problems. A screening test may be done by a pediatrician, an ophthalmologist, an optometrist or another trained provider. Vision screenings are often offered at schools or community centers.

The recommended times for screening are as follows:

• At least once between ages 3 and 5.
• Before kindergarten, usually age 5 or 6.
• Annually through the end of high school.

If a problem is found in a screening test, you'll likely need to schedule a complete eye exam with an optometrist or ophthalmologist.

Adults

The American Academy of Ophthalmology recommends that healthy adults with no known problems with vision or eye disease should get a complete eye exam on the following schedule:

• At least once between ages 20 and 29.
• At least twice between ages 30 and 39.
• Every 2 to 4 years from ages 40 to 54.
• Every 1 to 3 years from ages 55 to 64.
• Every 1 to 2 years after age 65.

If you have diabetes, a family history of eye disease, high blood pressure, or other risks of heart or vascular disease, you'll likely need more-regular eye exams. Also, you'll likely need more-regular exams if you already have prescription glasses or contacts or if you've had surgery for vision correction. Your healthcare professional or eye care specialist can recommend how often to get an exam.

The eye has two parts that focus images:

• The cornea is the clear, dome-shaped front surface of the eye.
• The lens is a clear structure about the size and shape of a pinto bean.

For you to see, light has to pass through the cornea and lens. These parts of the eye bend — also called refract — the light so that the light is focused directly on the retina at the back of your eye. These tissues translate light into signals sent to the brain, which lets you perceive images.

Refractive errors

Nearsightedness is a refractive error. This problem happens when the shape or condition of the cornea — or the shape of the eye itself — causes an inaccurate focusing of the light passing into the eye.

Nearsightedness usually results when the eye is too long or oval-shaped rather than round. It also may result when the curve of the cornea is too steep. With these changes, light rays come to a point in front of the retina and cross. The messages sent from the retina to the brain are perceived as blurry.

Other refractive errors include:

• Farsightedness, also called hyperopia. In farsightedness, the eyeball is shorter than that in a typical eye or the cornea has too little curve. Some people may see distant objects somewhat clearer, but close objects appear blurry. For some people with farsightedness, objects are blurry at all distances.
• Astigmatism. In astigmatism, the cornea or lens is curved more steeply in one direction than in another. Vision is distorted or blurry at all distances.

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

• 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 higher if both parents are nearsighted.
• Prolonged close-up activities. Reading or doing other close-up activities for a long time is associated with an increased risk of nearsightedness.
• Screen time. Studies have shown that children who use computers or smart devices for long periods have a greater risk of developing nearsightedness.
• Environmental conditions. Some studies support the idea that not spending enough time outdoors may increase the risk of nearsightedness.

Nearsightedness is associated with a variety of complications, such as:

• Poor school experiences. Children with myopia or other vision problems can experience delays in reading or other academic skills, difficulty with social interactions, and poor self-esteem.
• Reduced quality of life. If nearsightedness isn't corrected, it can prevent you from performing daily tasks well or enjoying activities.
• Eyestrain. Not correcting nearsightedness may cause persistent eyestrain and headaches.
• Impaired safety. Your safety and the safety of others may be jeopardized if you have a vision problem. This could be especially serious if you are driving a car or operating heavy equipment.
• Other eye problems. Severe nearsightedness puts you at an increased risk of retinal detachment, glaucoma, cataracts and other serious eye conditions.

Nearsightedness is diagnosed with a basic eye exam. Your eye care specialist will likely ask about your child's or your medical history and ask about any medicines used.

Visual acuity test

A visual acuity test checks how sharp your vision is at a distance. You cover one eye, and the eye care specialist asks you to read an eye chart with letters or symbols of different sizes. Then you do the same for the other eye. Special charts are designed for very young children.

Phoroptor test

In this test, you read an eye chart while looking through a device that has different lenses. This test helps determine an appropriate prescription to correct vision problems.

Other tests of eye health

Your eye care specialist may do other simple tests to check the following:

• The response of the pupils to light.
• Eye movement.
• Side vision, also called peripheral vision.
• Pressure within the eye.
• The condition of the cornea, pupil, lens and eyelids.

Exam of the inner eye

Your eye care specialist may use a special lens with a light to examine the condition of the retina and optic nerve. The specialist will likely put drops in your eyes to dilate them. This provides a better view of the inner eye. Your eyes will probably be sensitive to light for a few hours. Wear the temporary sunglasses provided by the specialist or your own sunglasses.

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

Prescription lenses

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

• Eyeglasses. Wearing glasses is a simple, safe way to sharpen vision caused by nearsightedness. Eyeglass lenses also can be designed to correct a combination of refractive errors, such as nearsightedness, astigmatism and presbyopia.
• Contact lenses. Contact lenses are small, plastic disks placed directly on the cornea. A single contact lens may correct more than one refractive error. There are a variety of materials and care requirements. Your eye care specialist can recommend contact lenses that are most suitable for your prescription and lifestyle.

Refractive surgery

Refractive surgery reduces the need for eyeglasses and contact lenses. Your eye surgeon uses a laser to reshape the cornea, which results in a decreased need for nearsighted prescription lenses. 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 in your cornea. The surgeon then uses a laser to remove corneal tissue to flatten its domed shape. Recovery from LASIK surgery is usually more rapid and causes less discomfort than recovery from other corneal surgeries.
• Laser-assisted subepithelial keratectomy (LASEK). The surgeon creates an ultrathin flap only in the cornea's outer protective cover, called the epithelium. A laser is used to reshape the cornea and flatten its curve. The epithelium is then put back in place.
• Photorefractive keratectomy (PRK). This procedure is similar to LASEK, except the surgeon completely removes the epithelium. Then the surgeon uses the laser to reshape the cornea. A temporary protective contact lens covers the cornea until the epithelium grows back naturally, conforming to your cornea's new shape.
• Small incision lenticule extraction (SMILE). In this procedure, there is no flap or removal of the epithelium. Instead, a laser is used to cut a small disk-shaped piece of the cornea, called a lenticule. The lenticule is then removed through a small corneal incision.

Surgical treatments are not an option for everyone with nearsightedness. Surgery is recommended only when nearsightedness is no longer progressing. Your surgeon explains the benefits and risks of surgical treatment options.

Treatments to slow or stop progression of nearsightedness

Researchers and clinical practitioners continue to seek more-effective approaches to slow the progression of nearsightedness in children and adolescents. Therapies that show the most promise include:

• Atropine. Atropine drops are commonly used to dilate the pupil of the eye, often as part of eye exams or before and after eye surgery. Low doses of atropine eye drops may also help slow the progression of nearsightedness.
• Increased time outside. Spending time outdoors during childhood, adolescence and the early adult years may decrease the risk of developing nearsightedness.
• Dual focus contact lenses. A type of dual focus contact lens has shown some effect in slowing progression of nearsightedness.
• Orthokeratology. A rigid contact lens worn at night temporarily reshapes the cornea. The lens is not worn during the day. Studies have shown that this therapy may slow the progression of nearsightedness.

Steps you can take to promote good eye health and vision include the following:

• Get regular eye exams.
• Protect your eyes from the sun.
• Wear protective eyewear during sports or work that can result in eye injuries.
• Use good lighting when reading and working.
• Wear prescription corrective lenses as directed.
• Care for prescription glasses or contact lenses as directed.
• Rest your eyes from computer or other close-up work every 20 minutes by looking at something 20 feet away for 20 seconds.
• Eat healthy foods.
• Get regular exercise.
• Control health conditions, such as high blood pressure or diabetes, that can affect your vision.
• Don't smoke.

Eye care specialists

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.) degree or a doctor of osteopathy (D.O.) degree followed by an ophthalmology 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.

What you can do

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

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 eye care specialist 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 medicines, supplements or herbal preparations?