4. Angle Closure Glaucoma

Predisposing factors for angle closure glaucoma

  • Age: Older

  • Sex: Female

  • Race: Asian

  • Refractive error: Hyperopia

  • Family history: Positive (+ family history)

  • Essentially, predisposing factors are those which predispose to a small eye and a small/shallow anterior chamber (AC)

  • Emergency referral during an acute ACG attack

Mechanisms of angle closure

  • 1) Pupillary block: contact between the lens and iris blocks aqueous outflow

  • 2) Peripheral apposition of iris to the trabecular meshwork (TM) or cornea leading to angle closure

  • 3) Primary angle-closure glaucoma (ACG) is generally attributed to pupillary block causing the iris to bow forward (iris bombé)

  • 4) A very small percentage due to anatomical anomaly of plateau iris, causing TM blockage on dilation

Pupil block and iris bombe

  • Pupillary block: root of the iris cuts off aqueous outflow

  • Iris bombe: iris billows anteriorly, blocking off the angle

Plateau iris

  • Double hump sign: iris demonstrates two convexities in the angle, indicating plateau iris configuration

Clinical presentation

  • Subacute (intermittent)

  • Acute

  • Chronic

Subacute/intermittent angle closure

  • can present without symptoms

  • Important to elicit history of previous attacks and symptoms

  • Triggers: semi-mydriasis causing irido-corneal contact due to emotion, dim illumination, stress, or drugs

Symptoms of subacute ACG

  • Pain

  • Redness: conjunctival and ciliary injection

  • Aching pain in the globe, radiating to temples along the ophthalmic division of the trigeminal nerve

  • Haloes, misty, foggy, or steamy vision

  • Nausea and vomiting

  • Photophobia

Signs of subacute ACG

  • Evidence of previous attacks:

    • Iris stromal atrophy

    • Glaucomflecken (glaucoma flecks): mechanical insult to crystalline lens epithelium after elevated IOP

  • May progress to acute ACG or chronic ACG

Acute angle-closure glaucoma (ACG)

  • Presentation includes a painful red eye with ciliary flush and vision loss

  • More intense pain, with nausea and vomiting

  • Marked vision loss due to corneal edema and vascular compromise of the optic nerve (ON): typically from about 6/366/36 to CFCF

  • Exam shows a fixed, sluggish mid-dilated pupil (iris sphincter paralysis with ↑ IOP)

  • Intraocular pressure (IOP) is raised, often very high: 50-60 mmHG

  • History may show evidence of previous attacks: glaucomflecken, iris stromal atrophy

  • The fellow eye commonly has a shallow angle/AC

Case example (acute presentation)

  • 65-year-old female

  • 1/52 painful left eye

  • Vision: VA down

  • IOP: 65 mmHg

  • Shallow AC

  • Fixed, semi-dilated pupil

  • Corneal edema

  • Glaucomflecken

Chronic angle-closure glaucoma (ACG)

  • Develops insidiously and can be asymptomatic

  • Gradual creeping closure of the angle

  • Shares changes with primary open-angle glaucoma (POAG): optic disc cupping and visual field (VF) defects