What are papilledema and diplopia?

Papilledema and Diplopia: Definition and Clinical Significance

Papilledema is optic disc swelling due to increased intracranial pressure, while diplopia is double vision that can result from various causes including strabismus, retinal disease, or neurological conditions.

Papilledema

Definition and Pathophysiology

• Papilledema specifically refers to optic disc edema caused by elevated intracranial pressure (ICP) 1
• It occurs due to transmission of high ICP to the subarachnoid space surrounding the optic nerve, which impedes axoplasmic transport within ganglion cell axons 1
• The main mechanism of permanent optic nerve damage is axoplasmic flow stasis resulting in intraneuronal ischemia 2, 3

Clinical Presentation

• Visual function is usually preserved in the acute phase, distinguishing papilledema from other causes of optic disc edema 1
• Signs of papilledema include elevation and blurring of the disc margins, venous congestion, retinal hard exudates, and splinter hemorrhages 4
• Patients typically present with symptoms of elevated intracranial pressure: headache, nausea, vomiting, diplopia, ataxia, or altered consciousness 4

Etiology

• Common causes include:
  • Idiopathic intracranial hypertension (IIH) - most common cause in patients under 50 1
  • Intracranial mass lesions/tumors 4, 3
  • Cerebral venous sinus thrombosis 5, 2
  • Meningitis or intracranial inflammation 4, 3
  • Subarachnoid hemorrhage or subdural hematoma 4
  • Hydrocephalus 3
  • Head trauma 3

Diagnosis

• Brain MRI with and without contrast is the preferred initial imaging modality 6
• Lumbar puncture with opening pressure measurement and CSF analysis should follow imaging 1
• Additional testing may be needed to identify secondary causes of increased ICP 1

Management

• Treatment should target the underlying cause 1, 3
• For IIH, weight loss and diuretics (particularly acetazolamide) are first-line treatments 2, 3
• Surgical options (optic nerve sheath fenestration or CSF diversion procedures) are considered for patients who fail, cannot tolerate, or are non-compliant with medical therapy 2, 3

Diplopia

Definition and Types

• Diplopia is double vision that can be binocular (resolves when one eye is closed) or monocular (persists with one eye closed) 5
• Binocular diplopia results from misalignment of the visual axes, preventing images from falling on corresponding retinal points 5

Causes of Diplopia

• Strabismus (misalignment of the eyes) - can be caused by:
  • Orbital trauma 5
  • Thyroid eye disease 5
  • Cranial nerve palsies 5
  • Decompensated heterophoria 5
• Retinal disease causing distortion or displacement of the fovea:
  • Epiretinal membranes 5
  • Subretinal membranes 5
  • Post-retinal detachment 5
• Neurological conditions:
  • Increased intracranial pressure (as in papilledema) 4
  • Cranial nerve palsies (particularly CN VI) 5

Diagnosis

• Detailed history and examination are essential to determine the cause 5
• For strabismus-related diplopia, cover testing helps identify the type and magnitude of misalignment 5
• For retinal disease-related diplopia, tests like Amsler grid, M-Charts, and the lights on/off test can be diagnostic 5
• Neuroimaging may be indicated based on clinical suspicion 6

Management

• Treatment depends on the underlying cause 5
• For strabismus-related diplopia:
  • Prism correction may help in some cases 5
  • Fogging techniques (Bangerter foils, occlusive contact lenses) 5
  • Strabismus surgery when appropriate 5
• For retinal disease-related diplopia:
  • Fogging of one eye is often the most suitable long-term solution 5
  • Surgical peeling of epiretinal membranes may help in some cases but can worsen diplopia in others 5
• For diplopia related to increased ICP:
  • Treatment of the underlying cause of increased ICP 1

Clinical Connection Between Papilledema and Diplopia

• Diplopia can be a presenting symptom of papilledema due to sixth nerve palsy from increased intracranial pressure 5
• The presence of both papilledema and diplopia should prompt urgent neuroimaging and evaluation for conditions causing increased ICP 5, 1
• Patients with papilledema and diplopia require multidisciplinary care involving ophthalmologists and neurologists 7