Angle-Closure Glaucoma in a Hyperopic Eye with a Cataract
A 72-year-old woman presents with a 2-day history of severe right eye pain, nausea, and blurred vision. She has a history of intermittent eye pain in dim light. Examination: visual acuity 6/60 right eye, 6/9 left eye. Right eye shows a mid-dilated pupil, corneal edema, shallow anterior chamber, and IOP of 48 mmHg. Gonioscopy of the left eye shows a narrow angle with peripheral anterior synechiae. The right eye has a dense nuclear sclerotic cataract. Axial length is 21.5 mm in both eyes. She is on no ocular medications.
1. Explain the pathophysiological mechanism of acute angle-closure glaucoma in this eye and why her hyperopic, short axial length anatomy predisposes her.
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Mechanism:
- In a hyperopic eye with a short axial length (21.5 mm), the anterior segment is crowded: the lens is relatively large, the anterior chamber is shallow, and the ciliary body is anteriorly positioned.
- This crowding leads to pupillary block: the lens apposes the iris, obstructing aqueous flow from the posterior to the anterior chamber.
- Pressure builds behind the iris, bowing it forward (iris bombé) and narrowing the angle until it closes, obstructing trabecular outflow.
- The mid-dilated pupil (from dim light or stress) worsens pupillary block by increasing iris–lens contact.
Predisposing factors: Hyperopia, short axial length, shallow anterior chamber, thick lens, and female sex are classic risk factors. Her history of intermittent pain in dim light suggests prior subacute attacks.
2. Compare immediate medical management with definitive surgical management, and justify the choice of lens extraction versus laser peripheral iridotomy in this patient.
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Immediate medical management:
- Topical beta-blocker, alpha-agonist, and carbonic anhydrase inhibitor to lower IOP.
- Systemic acetazolamide (500 mg IV or oral) to reduce aqueous production.
- Hyperosmotic agents (IV mannitol or oral glycerin) to dehydrate the vitreous and lower IOP.
- Pilocarpine after IOP starts to fall (it is ineffective when the iris is ischemic).
- Analgesics and antiemetics for symptoms.
Definitive management:
- Laser peripheral iridotomy (LPI) relieves pupillary block and is the traditional definitive treatment.
- However, in this patient with a dense cataract and a short eye, lens extraction is increasingly favored: it removes the bulky lens, deepens the anterior chamber, and eliminates the pupillary block while also treating her cataract.
- Justification for lens extraction: The cataract is visually significant, the eye is crowded, and phacoemulsification with IOL implantation has been shown to be at least as effective as LPI in preventing further attacks and improves quality of life. LPI alone would leave the cataract untreated and the angle still narrow.
Plan: Control IOP medically, then perform phacoemulsification with IOL; consider LPI in the fellow eye.