The oculomotor nerve (CN III) is responsible for controlling the superior rectus, inferior rectus, medial rectus, and inferior oblique muscles of the eye, as well as the levator palpebrae superioris muscle, which controls eyelid elevation.

The trochlear nerve (CN IV) controls the superior oblique muscle of the eye, which helps to rotate the eye downward and outward.

The abducens nerve (CN VI) controls the lateral rectus muscle of the eye, which helps to move the eye outward.

Strabismus is a condition in which the eyes are unable to move in a coordinated manner, resulting in misalignment of the eyes.

Esotropia is a type of strabismus in which the eye turns inward, towards the nose.

Nystagmus is a condition in which the eyes move involuntarily back and forth, horizontally, vertically, or in a circular pattern.

Diplopia is the condition in which a person sees two images of the same object, either side by side, vertically, or diagonally.

Ptosis is a condition in which the eyelid droops, partially or completely covering the eye.

Strabismus can be caused by muscle imbalance, refractive errors (such as nearsightedness or farsightedness), neurological disorders, or a combination of these factors.

Hyperopia (farsightedness) is the most common type of refractive error that can cause strabismus, especially in children.

Nystagmus can be caused by albinism, retinal detachment, multiple sclerosis, and other neurological disorders.

Aging is the most common cause of ptosis, as the muscles that support the eyelid weaken over time.

Strabismus can be treated with eyeglasses or contact lenses to correct refractive errors, surgery to align the eyes, vision therapy to improve eye coordination, or a combination of these treatments.

Nystagmus is typically treated with vision therapy to improve eye coordination and stability.

Ptosis is typically treated with surgery to tighten the muscles that support the eyelid.