Acute Angle-Closure Glaucoma

Aka: Acute Angle-Closure Glaucoma, Narrow Angle Glaucoma, Primary Angle-Closure Glaucoma, PACG

1. See Also
   1. Glaucoma
   2. Open Angle Glaucoma
   3. Acute Red Eye
   4. Eye Pain without Redness
   5. Acute Vision Loss
2. Epidemiology
   1. Relatively rare compared with Open Angle Glaucoma
3. Risk factors
   1. Increasing age
   2. Hyperopia (Far-sightedness)
   3. Family History of Glaucoma
   4. Angle closure Glaucoma in contralateral eye
   5. Pupillary dilation
   6. Anatomic variant with shallow anterior chamber
   7. Female gender (2.4 Relative Risk)
   8. Asian or Inuit race
   9. Older patient with Cataracts
4. Causes: Precipitating Factors (Mydriasis with angle obstruction)
   1. Dim lighting or dark room (results in Mydriasis of the pupil)
   2. Eye Dilating Drops (Mydriatics)
   3. Ophthalmic Anticholinergic Agents
   4. Systemic medications (cause ciliary body edema)
      1. Antidepressants
      2. Sulfa-based medications
      3. Topiramate
5. Pathophysiology
   1. Increased aqueous production
   2. Drainage obstruction of aqueous from anterior chamber (normally drains at margin between Cornea and iris)
      1. Physical blockage of outflow tract by iris (trabecular network)
      2. Narrowing of anterior chamber angle
6. Symptoms
   1. Acute (Usual presentation)
      1. Extreme unilateral Eye Pain
         1. Lack of Eye Pain does not exclude Narrow Angle Glaucoma
      2. Visual changes
         1. Decreased Visual Acuity, Blurred Vision
            1. Severe Vision Loss in hours to days
         2. Colored visual halos or rainbows may occur around streetlights from Corneal edema
      3. Photophobia
      4. Frontal Headache
      5. Nausea and Vomiting
      6. Abdominal discomfort
   2. Sub-acute
      1. Mild Eye Pain
      2. Visual changes
         1. Colored halos or rainbows seen around streetlights (results from Corneal edema)
         2. Visual changes less pronounced with Miosis (well-lit room, on awakening)
         3. Tunnel Vision
      3. Headache
7. Signs
   1. Shallow Anterior Chamber Depth
   2. Decreased Visual Acuity
   3. Pupil mildly dilated (4-6 mm) and sluggishly reactive
   4. Globe feels firm or rock-hard on palpation through upper Eyelid
   5. Increased Intraocular Pressure >30 - 60 mmHg
      1. See Intraocular Pressure
      2. Pressure in acute Narrow Angle Glaucoma is typically >40 mmHg
      3. Discuss suspected Glaucoma with ophthalmology
   6. Eye Redness
   7. Conjunctival edema (Chemosis)
   8. Corneal edema
      1. Cornea cloudy, "steamy", hazy
   9. Ciliary Flush
   10. Fundoscopy
       1. Avoid dilated Eye Exam (risk of worsening Narrow Angle Glaucoma)
       2. See Open Angle Glaucoma
       3. See Fundoscopy
       4. Optic disc cupping
   11. Gonioscopy (Van Herrick Test)
       1. Performed by ophthalmologist
       2. Van Herrick Test
          1. https://www.aao.org/basic-skills/van-herick-technique
          2. Temporal (lateral) edge of Cornea-iris margin is viewed at 60 degree angle with Slit Lamp
          3. Using narrow beam of light from Slit Lamp, width of Cornea is compared with width of anterior chamber
8. Differential Diagnosis
   1. See Acute Red Eye
   2. See Eye Pain without Redness
   3. See Acute Vision Loss
   4. Open Angle Glaucoma
   5. Narrow Angle Glaucoma often misdiagnosed as:
      1. Migraine Headache
      2. Gastroenteritis
9. Management
   1. Immediate ophthalmology referral
      1. Goal is ophthalmologist contact within 1 hour of patient arrival ("time is Optic Nerve")
   2. Analgesics and Antiemetics
   3. Treat both eyes (typically progresses to involve both eyes)
   4. Temporizing measures
      1. Give Carbonic Anhydrase Inhibitor
         1. Dorzolamide eye drops (in combination with drops below)
         2. Acetazolamide 500 mg orally or IV
            1. Indicated if refractory to topical agents or may use in place of Dorzolamide to start
      2. Also administer all 3 ophthalmic medications (repeated every 5 minutes for 3 doses)
         1. Timolol maleate 0.5% (Timoptic) AND
         2. Apraclonidine 1% (Iopidine) or Brimonidine (Alphagan) given 1 minute after Timolol AND
         3. Pilocarpine 2% (Isoptocarpine) given 1 minute after Apraclonidine
            1. Pilocarpine is only effective after lowering eye pressure with Timolol
            2. Timolol decreases the ischemic paralysis of the iris
      3. Recheck Intraocular Pressure 30 minutes after above medications given
         1. If no response to above medications, give Acetazolamide IV if not already given
      4. Monitor Intraocular Pressure hourly until patient is seen by ophthalmology
   5. Surgery (definitive treatment)
      1. Laser peripheral iridotomy
         1. Allows iris to fall back into normal position (and anterior chamber drainage to resume)
      2. Laser iridectomy
      3. Laser peripheral iris genioplasty
10. References
    1. St. Peter and Werner in Swadron (2022) EM:Rap 22(4): 4-6
    2. Gupta (2016) Am Fam Physician 93(8):668-74 [PubMed]
    3. Sharma (2000) Can Fam Physician 46:303-12 [PubMed]
    4. Pokhrel (2007) Am Fam Physician 76:829-36 [PubMed]