Strabismus and Diplopia due to Ocular Paralysis

CLINICAL DIAGNOSTIC MANUAL

Strabismus and diplopia due to ocular paralysis are ophthalmologic conditions that occur when one or more of the muscles controlling eye movement are weakened or paralysed. This dysfunction can lead to abnormal eye deviation (strabismus) and the perception of double vision (diplopia), significantly affecting the patient’s quality of life.

Oculomotor paralysis can be caused by various conditions, including neurological disorders, autoimmune diseases, infections, and tumours. A detailed evaluation is essential to identify the underlying cause and provide appropriate treatment.

Condition	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Oculomotor nerve palsy (III CN)	Ptosis, dilated non-reactive pupil, eye deviated outward and downward	Clinical history and physical exam	Brain CT or MRI, EMG
Trochlear nerve palsy (IV CN)	Difficulty looking down and inward, head tilt to compensate	Clinical history and physical exam	Brain CT or MRI, neurological function tests
Abducens nerve palsy (VI CN)	Inability to move the eye outward, horizontal diplopia	Clinical history and physical exam	Brain CT or MRI, nerve conduction studies
Myasthenia gravis	Progressive muscle fatigue, ptosis, diplopia worsening with activity	Clinical history, ice pack test, edrophonium test	Antibody tests (AChR, MuSK), EMG, repetitive nerve stimulation test
Graves’ disease	Ophthalmopathy, exophthalmos, restricted eye movements	Clinical history, physical exam, signs of hyperthyroidism	Thyroid function tests (TSH, free T4), orbital CT or MRI
Orbital cellulitis	Eye pain, periorbital erythema and swelling, fever, limited eye movements	Clinical history, physical exam, signs of infection	Orbital CT or MRI, blood or orbital secretion cultures
Tumour	Proptosis, vision loss, diplopia, eye pain or discomfort	Clinical history, physical exam, focal neurological signs	Brain and orbital CT or MRI, biopsy if needed
Internuclear ophthalmoplegia	Diplopia, dissociated eye movements, nystagmus in abducting eye	Clinical history, physical exam, neurological evaluation	Brain MRI
Intracranial aneurysms	Sudden severe headache, diplopia, ptosis, loss of consciousness	Clinical history, physical exam, neurological signs	Cerebral angiography, brain CT or MRI
Head trauma	Diplopia, eye misalignment, bruising, signs of fracture	Trauma history, physical exam	Cranial CT, ophthalmologist evaluation
Infections (meningitis/encephalitis)	Fever, neck stiffness, altered mental state, meningeal signs, diplopia	Clinical history, physical exam, meningeal signs	Lumbar puncture, cultures, brain CT or MRI
Stroke (CVA)	Sudden neurological deficit, diplopia, ocular muscle paralysis, weakness, speech or gait difficulties	Clinical history, neurological exam	Brain CT or MRI, cerebral angiography
Diabetes mellitus	Diplopia, peripheral neuropathy, vision changes, signs of hyperglycaemia	Clinical history, physical exam, signs of diabetic neuropathy	Blood glucose tests, HbA1c, neurological evaluation