👁️ Optic Disc Drusen (ODD) [Neurosurgery Wiki]

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====== 👁️ Optic Disc Drusen (ODD) ======

Optic disc drusen are calcified deposits located anterior to the lamina cribrosa within the optic nerve head. They can mimic papilledema but do not represent increased intracranial pressure.

🧬 Pathophysiology
Thought to result from axonal degeneration and abnormal axoplasmic flow.

Calcify over time and become more visible with age.

Often bilateral and congenital.

More common in small crowded discs (“disc-at-risk”).

🧒 Epidemiology
Present in up to 2% of the population

Can be familial (autosomal dominant in some cases)

Often asymptomatic but may cause visual field defects

🔬 Clinical Features
Feature	Description
Age of onset	Often detected in teens or young adults
Appearance	Lumpy, irregular disc with no true hyperemia; drusen may autofluoresce
Laterality	Usually bilateral
Symptoms	Often asymptomatic; some have transient visual obscurations or visual field loss
Visual fields	Enlarged blind spot, arcuate defects, nasal steps (similar to glaucoma)
Visual acuity	Usually preserved
🧪 Diagnostic Tools
Tool	Findings
OCT	Elevation of optic nerve head without subretinal fluid; RNFL may show thinning
B-scan ultrasound	High reflectivity (hyperechoic calcifications)
Fundus autofluorescence	Drusen often autofluoresce
CT orbit	Hyperdense calcifications
Fluorescein angiography	No leakage (unlike true papilledema)
⚠️ Differential Diagnosis
True papilledema (e.g., idiopathic intracranial hypertension)

Optic neuritis

Ischemic optic neuropathy

Leber's hereditary optic neuropathy

Tumor or infiltrative optic neuropathy

🩺 Management
No specific treatment needed

Regular monitoring of visual fields

Educate patient about the benign nature

Avoid misdiagnosis as papilledema (to prevent unnecessary work-up)