Case Study of the Week: Acute Angle-Closure Glaucoma

Nothing scares me more than treating eye-related complaints.  Yes, usually the patient is dealing with a simple conjunctivitis or corneal abrasion but I am always concerned about complications.  I am less familiar with opthalmology than other areas of medicine and could use a refresher on opthalmologic conditions.  You may not know that January is Glaucoma Awareness Month.  So, in an effort to raise knowledge and awareness I have selected Acute Angle-Closure Glaucoma (AACG) as this week's case study.

It is incredibly important that you as a a nurse practitioner are able to recognize and diagnose acute angle-closure glaucoma.  If not promptly diagnosed and treated, AACG can lead to significant, permanent vision loss. AACG results from an increase in intraocular pressure (IOP) when the iris is pushed or pulled against the trabecular meshwork at the angle of the anterior chamber of the eye.  This impedes normal flow of the aqueous humor (fluid within the eye) thereby increasing intraocular pressure.  Although only 10% of glaucoma cases are acute in nature, complications can be serious.

Case Presentation

A seventy year old Asian woman presents to your emergency department with sudden onset of right eye pain, blurry vision, right sided headache and one episode of vomiting.  She describes seeing 'halos' around objects.  The patient's vital signs are within normal limits.  She has a history of hyperopia (farsighted).  

When testing the patient's visual acuity, you note she is unable to identify letters at a distance.  She is only able to detect hand movements with the affected eye.  The patient's cornea is injected and her cornea is cloudy and edematous.  You test IOP using a tonometer.  Pressure in the unaffected eye is normal at 15 mmHg (normal range 10-20).  IOP in the affected eye is elevated at 60mm Hg.  You suspect acute angle-closure glaucoma and immediately consult the opthalmologist on-call as well as take measures to reduce IOP including placing the patient in the supine position and administering medications as directed by the opthamologist. 

Management and Outcome

Upon diagnosis of acute angle-closure glaucoma, medications such as Diamox and beta-blockers to decrease aqueous humor production and open the angle as well as topical steroids for reducing inflammation are administered.  Then, the patient is reassessed.  Further pharmacological management such as pilocarpine administration may be prescribed to help open the angle.  

Laser iridotomy 24-48 hours after intraocular pressure is controlled with medications is the ultimate treatment for AACG.  In this procedure, a laser is used to create an opening in the iris through which the aqueous humor trapped in the posterior chamber can pass into the anterior chamber .  As the aqueous humor flows through this created opening, IOP decreases allowing the iris to return to it's proper position opening the angle and correcting the blockage.

Discussion

Asians, Eskimos, women and elderly are at highest risk for developing AACG.  Complications of AACG include permanent decrease in visual acuity, repeat episode and retinal or artery or venous occlusion resulting in complete vision loss.  Due to the serious complications of AACG, if you suspect it based on a patient's symptoms, exam and tonometry readings an opthalmologist must be immediately consulted followed by prompt medication management.