Stroke: The presence of left side spastic hemiplegia suggests a lesion in the right hemisphere of the brain, which could be due to a stroke. The repetitive left eye movements could be a sign of a seizure or a post-stroke complication, making stroke the most likely diagnosis given the combination of symptoms.

Seizure Disorder: Repetitive eye movements can be a manifestation of seizure activity, particularly if the patient has a history of seizures or epilepsy. The spastic hemiplegia could be a result of a previous seizure or an underlying condition that predisposes to seizures.
Multiple Sclerosis (MS): MS can cause a wide range of neurological symptoms, including spasticity and eye movement abnormalities. The disease often presents with relapsing-remitting episodes, which could explain the development of new symptoms.
Cerebral Palsy: Although cerebral palsy is typically diagnosed in childhood, some forms may not be apparent until later in life, especially if there are minimal symptoms. The spastic hemiplegia could be a manifestation of cerebral palsy, with the eye movements being a secondary feature.

Brain Tumor: A tumor in the right hemisphere of the brain could cause both spastic hemiplegia and abnormal eye movements. It's crucial to consider this diagnosis due to its potential for severe consequences if left untreated.
Intracranial Hemorrhage: Similar to a stroke, an intracranial hemorrhage could cause sudden onset of symptoms, including spastic hemiplegia and eye movement abnormalities. Prompt diagnosis is essential for effective management.
Infections (e.g., Encephalitis, Meningitis): Central nervous system infections can present with a wide range of symptoms, including focal neurological deficits like spastic hemiplegia and abnormal eye movements. These conditions require immediate medical attention.

Whipple's Disease: This rare systemic infectious disease can cause neurological symptoms, including eye movement abnormalities and weakness. Although rare, it's an important consideration in patients with unexplained neurological symptoms.
Progressive Supranuclear Palsy (PSP): PSP is a rare neurodegenerative disorder that affects movement, control of walking, and balance. It can also cause eye movement abnormalities, although the presence of spastic hemiplegia would be unusual.
Rasmussen's Encephalitis: This rare inflammatory neurological disease can cause seizures, hemiplegia, and other neurological symptoms. It typically affects one hemisphere of the brain and can lead to significant disability if not treated promptly.