When the two eyes fail to focus on the same image, the brain will ignore the inputs from one eye. It is allowed over a period of time, the eye that the brain ignores will not be able to see well. This is called as amblyopia or lazy eye.

In strabismus the visual axes are not parallel to each other and hence the eyes appear to be looking at different directions.

If both the eyes are turned in it is called esotropia. If both eyes are turns out it is called exotropia. If the both eyes turn up it is called hypertropia. If both eyes turn down it is called hypotropia

Causes of strabismus in children

• Congenital rubella
• Cerebral palsy
• Apert syndrome
• Hemangioma near the eye
• Noonan syndrome
• Retinoblastoma
• Brain trauma
• Prader-Willis syndrome
• Retinopathy of prematurity 

Causes of strabismus in adults

• Botulism\Diabetes
• Guillain-Barre syndrome
• Eye injuries
• Stroke
• Brain injury
• Shell fish poisoning
• Eye disease
• Eye injury 

Signs and symptoms

• Crossed eyes
• Double vision
• Uncoordinated eye movements
• Vision loss
• Eyes do not move together
• Malalignment of the eyes
• Vision in only one eye that is in the dominant eye, vision loss in the othere eye 

Tests and diagnosis

• Physical examination of the eye
• Standard Ophthalmic examaintion
• Retinal examination
• Visual acuity test 

Treatment:

• Atropine eye drops are used in the dominant eye.
• Eye muscle Surgery
• Glasses may be prescribed
• Eye exercises