Diplopia due to ocular motor cranial neuropathies

Area of Science:

• Neuroscience
• Ophthalmology

Background:

• Diplopia evaluation necessitates identifying the affected cranial nerve(s).
• Cranial nerve palsies can result from various etiologies, particularly in the modern imaging era.

Observation:

• Dysfunction of the oculomotor (CN III), trochlear (CN IV), or abducens (CN VI) nerves causes ocular misalignment.
• Even a 200 μm vertical misalignment can induce diplopia.

Findings:

• Recent studies highlight diverse etiologies of cranial nerve palsies.
• The C-reactive protein test is crucial for diagnosing giant cell arteritis.

Implications:

• Accurate diagnosis of diplopia requires comprehensive knowledge of cranial nerve structure, function, and potential causes.
• Understanding exceptions to diagnostic rules is vital for effective patient management.