Diplopia

Definition

Diplopia is the perception of two images of a single object, either side by side (horizontal), above/below (vertical), or diagonal. It may be monocular (present with one eye covered) or binocular (resolves with one eye covered).

Common Causes

• Binocular: Cranial nerve palsies (III, IV, VI), myasthenia gravis, multiple sclerosis, stroke, thyroid eye disease, orbital fracture.
• Monocular: Refractive error, cataract, lens dislocation, corneal irregularity.

Associated Red Flags

Sudden-onset diplopia with headache, weakness, or altered consciousness may indicate stroke, aneurysm, or increased ICP. Emergency evaluation required.

Nursing Interventions

Assess safety risk (falls, driving). Apply an eye patch to one eye (alternate) to eliminate the double image temporarily. Refer to ophthalmology and neurology. Educate patient on the underlying condition's management (e.g., pyridostigmine for MG, disease-modifying therapies for MS).

NCLEX Relevance

Common cue in MS, stroke, and MG case studies, always evaluate for sudden onset.