Three days after uncomplicated trabeculectomy, a 60-year-old man presents with a high IOP of 38 mmHg and a diffusely shallow anterior chamber. The bleb is flat, there is no bleb leak on Seidel testing, and the pupil is sluggish. The most likely mechanism is:

• A Wound leak causing hypotony
• B Excessive filtration through an overfunctioning bleb
• C Choroidal haemorrhage pushing the lens-iris diaphragm forward
• D Aqueous misdirection with anterior rotation of the ciliary body ✓

Explanation

Malignant glaucoma, or aqueous misdirection, classically follows intraocular surgery with a flat chamber plus raised IOP and no leak. Aqueous is diverted posteriorly into the vitreous cavity, and the ciliary body rotates forward, so cycloplegics such as atropine are first-line treatment to pull the ciliary ring back. An overfunctioning bleb or wound leak gives low IOP, and suprachoroidal haemorrhage typically causes severe pain with a tense eye.

Reference: Parson's Diseases of the Eye / Shields Textbook of Glaucoma, Latest edition ed.

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Written and medically reviewed by the StethoPrep medical team.