People see with both eyes. The images from both eyes are combined by the brain into a single image. This ability for dual vision develops in the first 6-7 years of life. If this development is disrupted, strabismus may be the result. The causes of squint in children are not always clear, but hereditary and environmental factors probably play a role:
- Hereditary predisposition
- Ophthalmic abnormalities
- Refractive disorders (e.g. high degree hypermetropia), unequal eye strengths
- Medical problems experienced during birth and shortly afterwards
- Cranial nerve disorders, the most common cause of late onset strabismus. A malfunctioning cranial nerve might be the result of other pathology such as heart attack and diabetes, etcetera.
- Premature birth, smoking or drug use during pregnancy