A 26-year-old man reports unilateral headache and redness of the left eye. Examination shows reduced vision, an intraocular pressure of 38 mmHg, markedly dilated tortuous episcleral vessels, mild proptosis, and an audible bruit over the orbit. The most likely cause of his secondary glaucoma is:
- A Pigment dispersion into the trabecular meshwork
- B Carotid-cavernous sinus fistula raising episcleral venous pressure ✓
- C Steroid-induced trabecular dysfunction
- D Angle recession from prior blunt trauma
Correct answer: B. Carotid-cavernous sinus fistula raising episcleral venous pressure
Explanation
B carotid-cavernous fistula shunts arterial blood into the cavernous sinus, raising pressure in the superior ophthalmic and episcleral veins. Outflow resistance rises because aqueous must drain against this elevated episcleral venous pressure, producing corkscrew conjunctival and episcleral vessels, chemosis, pulsatile proptosis, an orbital bruit and raised intraocular pressure. Pigment dispersion and steroid response lack vascular signs, and trauma history is absent here.
Reference: American Academy of Ophthalmology, BCSC Section 10: Glaucoma, 2022-2023 ed.
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Written and medically reviewed by the StethoPrep medical team.