Acquired Sixth Cranial Nerve Palsy: This condition is characterized by the sudden onset of esotropia (inward turning of the eye) due to weakness or paralysis of the lateral rectus muscle, which is innervated by the sixth cranial nerve. It can be caused by various factors such as increased intracranial pressure, stroke, or head trauma.

Third Cranial Nerve Palsy: This condition affects the oculomotor nerve, leading to ptosis (drooping eyelid), outward and downward deviation of the eye, and pupillary dilation. However, in some cases, especially if the palsy is partial, the eye might turn inward.
Fourth Cranial Nerve Palsy: Although less common, a palsy of the trochlear nerve can cause vertical diplopia (double vision) and, in some instances, might be perceived as an inward turning of the eye due to the complex interactions of eye movements.
Strabismus: This refers to a misalignment of the eyes that can occur at any age. Acute onset strabismus in adults can present with sudden eye turning, which might be inward.

Stroke or Cerebral Vasculitis: These conditions can cause sudden onset of cranial nerve palsies, including those affecting eye movements. Early diagnosis is crucial for timely intervention.
Increased Intracranial Pressure: Conditions such as brain tumors, idiopathic intracranial hypertension, or other space-occupying lesions can cause sixth nerve palsy due to increased pressure on the nerve.
Multiple Sclerosis: This demyelinating disease can present with a wide range of neurological symptoms, including cranial nerve palsies and vision disturbances.
Orbital or Cavernous Sinus Thrombosis: These are emergencies that can cause sudden onset of eye movement abnormalities, among other symptoms.

Gradenigo’s Syndrome: A rare condition characterized by a combination of sixth nerve palsy, facial pain, and otitis media, usually due to an infection spreading to the petrous apex of the temporal bone.
Tolosa-Hunt Syndrome: A rare disorder characterized by headache, pain around the eye, and ophthalmoplegia (weakness or paralysis of one or more extraocular muscles), typically due to nonspecific inflammation of the cavernous sinus or superior orbital fissure.
Myasthenia Gravis: An autoimmune disease that can cause fluctuating muscle weakness, including the muscles controlling eye movements, leading to diplopia and squint.