Diplopi

Diplopi, commonly known as diplopia or double vision in clinical contexts, is the perception of two images of a single object. It can be categorized as monocular or binocular. Monocular diplopia persists when one eye is closed and usually points to an abnormality within the affected eye, such as refractive error, cataract, corneal irregularity, or dry eye. Binocular diplopia occurs only when both eyes are open and typically resolves when either eye is closed; this form results from misalignment of the eyes or defects in binocular vision, such as strabismus or neuromuscular disorders affecting eye movements.

Causes of diplopi vary by type. Binocular diplopia can arise from cranial nerve palsies (oculomotor III, trochlear IV, abducens VI), thyroid eye disease, myasthenia gravis, diabetic neuropathy, brainstem or cerebellar lesions, stroke, or orbital trauma or inflammation. Monocular diplopia is commonly due to refractive errors (for example, uncorrected astigmatism or anisometropia), cataract, corneal irregularities, or dry eye.

Diagnosis involves a detailed history and a comprehensive eye examination. Key elements include refraction to assess for refractive error, assessment of visual acuity, and a thorough evaluation of ocular motility with cover tests to determine whether diplopia is monocular or binocular. If there are neurologic symptoms, sudden onset, or signs of systemic disease, further investigations such as imaging (MRI or CT) or neurological consultation may be indicated.

Management depends on the underlying cause. Binocular diplopia may be addressed with prism glasses, occlusion, or vision therapy, and in some cases surgery to correct misalignment. Monocular diplopia typically improves with treatment of the eye condition causing it. The prognosis varies with etiology and the onset pattern.