Everything You Wanted to Know About Lazy Eye

Amblyopia, also popularly called lazy eye, is a visual disorder where the nerve pathways between the brain and one eye aren’t properly stimulated. This causes the brain to favor the other eye that is more receptive and neglect the eye that is slow to process information presented to it by the brain. 

Lazy eye occurs in early childhood before five years of age. It is the most common cause of poor vision in a single eye worldwide. Amblyopia affects about 1-5% of adults. 

What are the symptoms of Lazy eye

Here are signs and symptoms of a lazy eye:

  • Eyes that look like they don’t go together at the same time
  • Decrease vision in one eye
  • Blurred vision
  • Eye misalignment
  • Wandering eye (the eye that wanders inward or outward)
  • Squinting
  • Head tilting in order to see clearly

Causes of Lazy Eye 

Strabismus (crossed eyes)

Strabismus (crossed eyes) is the misalignment of the eye that is caused by nerve injury or a muscle imbalance, which makes it difficult for both eyes to track objects at the same time. Other causes of strabismus are farsightedness, trauma, problems in the brain, and infections. The risk of strabismus increases in premature birth, someone with a family history of strabismus or cerebral palsy; however, strabismus is the most frequent cause of lazy eye.

Refractive anisometropia

Refractive anisometropia is when the light coming into the eye is not focused correctly as it goes through the lens. This causes the eyes to have different varying refractive powers and lead to uneven focus. 

In refractive anisometropia, one eye has a different size or shape in comparison to the other eye, which manifests as asymmetric shortsightedness or asymmetric farsightedness and chronic blur vision in one eye. 

Occlusion /Stimulus Deprivation Amblyopia 

Occlusion /Stimulus Deprivation Amblyopia is obstruction of the passage of light through the lens to the retina. It can be caused by:

  • A congenital cataract is the clouding of the lens that is seen at birth. This can lead to blurry vision, double vision, photophobia, halos around light, and decreased vision. 
  • Cornea ulcer
  • Ptosis: Drooping of the eyelids. 
  • Blockage of the eye by a hemangioma
  • Eye trauma /injury. 
  • Glaucoma. 

Diagnosis of Amblyopia

An ophthalmologist or optometrist usually diagnosed amblyopia during a routine examination of the child’s eyes. Most children go for their first examination between the ages of 3 and 5years. If the ophthalmologist or optometrist notice any unusual findings, further investigation is carried out to confirmed diagnosis and rule out other eye problems. 

Treatment of Lazy eye (Amblyopia)

Early diagnosis and treatment of amblyopia can result in the full restoration of sight in children below seven years of age. It is more challenging to restore sight in children older than seven years of age. The treatment options involve: 

  • Eye patch: covering the healthy eye with a patch forces the problematic eye to respond to the brain faster. The eye patch is worn for about 4-6 hours a day. An eye patch is encouraged if the child’s eye seems to get better after about six months of using the eyepatch. 
  • Eyeglasses with different lens prescription to balance vision and correct the deficit
  • Topical atropine
  • Cataract surgery can be done to remove the cloud covering the eye.

NOTE: 

  • The light goes through the cornea (which is in front of the eyes) to the lens. The cornea and lens focus the light rays onto the retina. 
  • The retina is an inward thin layer of tissue that is in the back of the eyes. It receives light from the lens, then converts the light into neural signals, and sends these signals to the brain for visual recognition.
  • The retina is located near the optic nerve. 

Anything that interrupts how the brain process the signals that it receives from the retina can cause problems with vision.