What is the most common cause of compressive optic neuropathy?

What is the most common cause of compressive optic neuropathy?

• A. Thyroid eye disease
• B. Optic neuritis
• C. Ischemic optic neuropathy
• D. Glaucoma

Answer: (A)

Compressive optic neuropathy happens when something presses on the optic nerve from outside, rather than damaging it from within. The most common cause is thyroid eye disease, where autoimmune inflammation enlarges the extraocular muscles (and sometimes orbital fat), crowding the orbital apex and squeezing the optic nerve. This mechanical pressure disrupts axonal transport and diminishes blood flow, leading to progressive vision loss that may show up as a central or cecocentral defect and color vision changes, often with afferent pupillary defect. Clinically you may also see proptosis and restricted eye movements, and imaging often reveals apical crowding from enlarged muscles. The other options reflect different mechanisms: optic neuritis is inflammatory demyelination of the nerve itself; ischemic optic neuropathy is due to compromised blood supply; glaucoma is a nerve injury from elevated intraocular pressure, not external compression.

Compressive optic neuropathy happens when something presses on the optic nerve from outside, rather than damaging it from within. The most common cause is thyroid eye disease, where autoimmune inflammation enlarges the extraocular muscles (and sometimes orbital fat), crowding the orbital apex and squeezing the optic nerve. This mechanical pressure disrupts axonal transport and diminishes blood flow, leading to progressive vision loss that may show up as a central or cecocentral defect and color vision changes, often with afferent pupillary defect. Clinically you may also see proptosis and restricted eye movements, and imaging often reveals apical crowding from enlarged muscles. The other options reflect different mechanisms: optic neuritis is inflammatory demyelination of the nerve itself; ischemic optic neuropathy is due to compromised blood supply; glaucoma is a nerve injury from elevated intraocular pressure, not external compression.