What causes crossed eyes?

In general, strabismus (eye misalignment) may be caused by differences in eyeball size, developmental factors, ocular trauma, refractive errors, or extraocular muscle paralysis. It can be managed under a doctor's guidance through general treatments, medications, and other methods. Specific analyses are as follows:

1. Differences in Eyeball Size

Differences in the size of the eyeballs can affect the synchronized processing of visual information between the two eyes. To coordinate binocular vision, the brain may adjust the position of one eye, leading to strabismus. Regular eye muscle exercises—such as focusing on moving objects or performing eye movement exercises—can help enhance coordination and control of the eye muscles.

2. Developmental Factors

In early childhood, the muscles and nervous system that control eye movements have not yet fully matured, which may lead to imbalance in coordination among eye muscles and result in strabismus. This condition typically does not require treatment and often improves naturally with age.

3. Ocular Trauma

Ocular injuries can damage the eye muscles, nerves, or the eyeball itself, potentially impairing normal eye movement and causing the eye to deviate. It is important to protect the injured eye; rubbing or applying pressure should be avoided to prevent further damage.

4. Refractive Errors

Refractive errors generally occur when external parallel light rays fail to focus properly on the macula of the retina. This causes the two eyes to exert different levels of accommodation when fixating on the same object. Prolonged imbalanced accommodation may lead to eye deviation. Symptoms may include blurred vision and visual fatigue. Under medical guidance, patients may undergo corneal refractive surgery, which reshapes the cornea by altering its curvature radius through stromal ablation to correct the condition.

5. Extraocular Muscle Paralysis

Muscle or nerve damage affecting the control of eye movements usually causes extraocular muscle paralysis. Such damage may restrict normal eye movement, resulting in strabismus. Symptoms may include diplopia (double vision) and limited eye motility. Treatment should follow medical advice and may involve medications such as metformin hydrochloride tablets, pyridostigmine bromide tablets, or neostigmine methylsulfate injection.

It is recommended to develop good eye-use habits, maintain a balance between work and rest, and avoid excessive eye strain, all of which contribute to overall health.