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What is Lazy Eye?

What is Lazy Eye?


Lazy eye, also known as amblyopia, is an eye condition noted by blurry or reduced vision in one eye caused by abnormal visual development. Neuroscience has proven that the brain does not fully recognize images seen by the amblyopic eye, ultimately impairing vision. The “lazy” eye tends to wander inward or outward, potentially causing loss of depth perception, two-eyed 3D vision, and overall vision reduction in both eyes. Amblyopia usually develops among children under the age of seven and causes more visual loss for children than all other injuries and diseases combined. While lazy eye treatment can help people of all ages, early diagnosis and treatment can prevent long-term complications. Lazy eye can typically be corrected with glasses, contact lenses, or eye patches, although surgery may be required. To test for lazy eye, see your doctor as comprehensive vision examinations are needed.


Symptoms of lazy eye can include:

  • One eye wandering inward or outward
  • Both eyes not working simultaneously
  • Lack of depth perception
  • One eye squinting or shutting
  • Abnormal head posture or tilting
  • Unusual vision screening test results


Despite the previous list of amblyopic symptoms, a lot of parents and children may not be aware they have lazy eye. Since lazy eye can exist without a noticeable eye turn and symptoms may bypass outside observers, comprehensive vision exams are highly encouraged for infants and young children. A pediatrician-led eye exam and 20/20 eye chart screening may not be enough to detect lazy eye. Instead, eye doctors are needed to use special visual acuity tests and cycloplegic drops to properly detect and diagnose lazy eye.


Lazy eye is caused by an abnormal visual experience affecting the development of the brain. Since the brain is responsible for all visual processing, changes to the nerve pathways between the eye’s retina and the brain can affect depth perception, movement recognition, acuity, and sharp vision. For instance, as the brain suppresses signals from the amblyopic eye, eyes become less able to function together, leading to poor binocular vision. Ultimately anything that interferes with unobstructed vision during the critical periods of visual and brain development can cause lazy eye.

Common causes can include:

  • Strabismus: Strabismus is the most common cause of lazy eye. Strabismus is a misalignment of the eyes from an imbalance in the muscles responsible for the eyes’ positioning, resulting in eyes constantly turned outward or crossed inward. This can lead to incoordination between the eyes and overall vision impairment.
  • Anisometropia: Anisometropia is the difference in sharpness of vision between the two eyes. This is often caused by farsightedness or astigmatism. Although glasses or contact lenses can usually correct these refractive problems, too significant of a difference between the eyes’ prescriptions can lead to lazy eye.
  • Deprivation: Deprivation can be caused by a number of reasons, including cataracts, physical trauma, blocked tear ducts, and lid drooping. Deprivation amblyopia is often the most severe form of amblyopia.


Other less common causes of lazy eye can be the result of the following factors:

  • Premature birth
  • Congenital disorders
  • Vitamin A deficiency
  • Developmental disabilities


Lazy eye is the most prevalent neurological defect of vision in children and adults. If untreated, lazy eye can cause permanent vision loss and is the cause of permanent vision loss in 2.9 percent of adults. Since lazy eye is a neurological condition, occupational, physical, and visual therapies can alter the brain and recover brain function at any age.

If you or your child notice symptoms of lazy eye, it is imperative to see a pediatric ophthalmologist. It is also recommended for all children, even those that don’t appear to have symptoms, to participate in a comprehensive eye exam between the ages of 3 and 5. Vision exams should also be conducted regularly if there is a family history of crossed eyes, cataracts, or other serious eye conditions.

During a comprehensive eye exam, your ophthalmologist may use eye drops causing temporary blurred vision to dilate the eyes. With your eyes dilated, your ophthalmologist will then check for overall eye health, cataracts, a difference in vision between the eyes, and of course lazy eye.

If diagnosed with lazy eye, it is important to start treatment right away, especially for young children. By fixing the problem while the nerves between the eyes and brain are still forming, children are more likely to achieve the best results.

Treatment options depend on the cause and severity of your lazy eye condition. Some common treatments can include:

  • Corrective eyewear: Glasses and contact lenses are often used to correct conditions such as farsightedness, nearsightedness, and astigmatism. Eye patches may also be worn over the stronger eye to stimulate and strengthen the weaker eye.
  • Bangerter filter: Similar to an eyepatch, the Bangerter filter is used on the eyeglass lens of the stronger eye to blur the stronger eye and stimulate the weaker eye.
  • Atropine drops: Atropine drops are medical eye drops used twice a week to temporarily blur the vision of the stronger this. This will help restore the weaker eye, but can make the stronger eye more sensitive to light.
  • Vision therapy: Your doctor may recommend vision therapy in addition to the previous treatment options. Vision therapies can include activity-based treatments, like drawing, putting together puzzles, playing computer games, and other eye exercises.
  • Surgery: Depending on the severity of your condition, your ophthalmologist may recommend surgery to repair the eye muscles, droopy eyelids, or cataracts. Since lazy eye is a neurological deficit, lazy eye surgery is typically performed on the muscles outside of the eyes.


Proper lazy eye treatment can improve vision as quickly as a couple weeks. However, it is important to monitor for the recurrence of lazy eye, as up to a quarter of children affected by lazy eye experience symptoms again.

Are you experiencing lazy eye? Call Eyesight MD at (714) 289-2389 or contact us here to speak with the world’s most renowned strabismus expert. With over 20,000 patients in the field of pediatric ophthalmology and adult strabismus, Dr. David Sami is an experienced opthamologist who can help answer all your amblyopia questions and get you the help you need!