Diplopia is commonly associated with which disease?

• A. Multiple Sclerosis
• B. ALS
• C. Parkinson's disease
• D. Guillain-Barré syndrome

Answer: (A)

Diplopia arises when the brain’s eye-movement pathways are disrupted. In multiple sclerosis, demyelinating plaques frequently involve the brainstem and optic pathways, leading to ocular motor abnormalities and optic neuritis. A common manifestation is diplopia, and lesions in the medial longitudinal fasciculus can cause internuclear ophthalmoplegia, a classic cause of double vision in MS.

Other conditions listed can affect the eyes, but diplopia is not as characteristic. ALS mainly affects motor neurons and eye movements are often preserved early. Parkinson’s disease produces bradykinesia, rigidity, and tremor rather than prominent double vision. Guillain-Barré syndrome can involve cranial nerves and occasionally cause ophthalmoplegia, but diplopia is not as commonly associated as it is with MS.