Glaucoma Treatment

What is Glaucoma?

Glaucoma is an ophthalmologic condition that may lead to elevated pressures inside the eye, resulting in blindness.  The condition is typically categorized into angle-closure glaucoma and open-angle glaucoma.  Angle-closure glaucoma occurs due to narrowing of the anterior chamber of the eye, resulting in increased intraocular pressure and optic nerve injury – this is an ocular emergency.  Open-angle glaucoma is an optic nerve disease that results in progressive visual loss – it is also frequently associated with elevated pressures inside the eye.

Glaucoma is one of the leading causes of blindness in the United States and Worldwide.  Acute-angle closure glaucoma may be symptomatic but open-angle glaucoma frequently goes unrecognized by the patient.  Due to the importance of this condition, it is critical that patients understand its causes, symptoms, and treatment.  By the end of this article, you will have the answers to these crucial questions

What causes Glaucoma?

Angle-closure glaucoma is caused by closure of the anterior chamber of the eye, which results impaired drainage of aqueous humor.  This leads to increased intraocular pressure and optic nerve injury.  The optic nerve is critical for normal vision – consequently, patients with this condition often lose vision.  Angle-closure glaucoma is an eye emergency as it can quickly lead to blindness.

Some individuals develop a form of long-term (chronic) angle-closure glaucoma, which may not result in elevated intraocular pressure.  This form of glaucoma may be diagnosed in its late stages, leading to even more visual loss compared to acute angle-closure.

Open-angle glaucoma is an optic nerve disease (neuropathy) characterized by progressive visual loss – the disease is often associated with elevated intraocular pressure.  The condition may be related to elevated aqueous humor synthesis and reduced outflow.

Risk factors for open-angle glaucoma include:

  • Advanced age
  • African American race
  • Family history
  • Increased intraocular pressure

How common is Glaucoma?

Glaucoma is exceedingly common in the United States and typically requires referral to an ophthalmology specialist.

It is a leading cause of blindness in the United States and Worldwide.  In 2010, there was an estimated 3 million Americans with open-angle glaucoma.  In 2015, approximately 58 million people around the world carried the diagnosis.  Open-angle glaucoma most often affects individuals of European or African descent, while angle-closure glaucoma more frequently occurs in people of Asian descent.

What are the symptoms and signs of Glaucoma?

Symptoms of acute angle-closure glaucoma usually include:

  • Loss of vision,
  • Headache
  • Eye pain
  • Nausea & vomiting

On physical examination of the eye, your doctor may notice eye redness, cloudiness of the cornea, and a poorly reactive mid-dilated pupil.  This is an emergency; therefore, you need to see an ophthalmologist emergently.

Open-angle glaucoma generally does not produce symptoms.  Visual field loss is often subtle and many patients unnoticeably advance to developing tunnel vision.  Your doctor may find the disease incidentally during a comprehensive eye examination.

How is Glaucoma diagnosed?

Virtually any person age >40 should be screened for glaucoma by an ophthalmologist or optometrist.

Angle-closure glaucoma is highly suggested based on symptoms and physical examination, but a definitive diagnosis requires gonioscopy.  Gonioscopy is an ophthalmologic examination of the anterior (front) chamber of the eye.  Both eyes are typically checked.

Open-angle glaucoma is diagnosed by performing a funduscopic examination and visual field testing.  Patients typically have characteristic findings of optic nerve damage with both of these studies.  They may also have elevated intraocular pressure.

How is Glaucoma treated?

Acute angle-closure glaucoma is an eye emergency that requires treatment by an ophthalmology specialist.

Patients are typically treated with topical ophthalmic agents to lower intraocular pressure:

  • Timoptic (timolol) - beta-blocker
  • Iopidine (apraclonidine) - alpha agonist
  • Isopto (pilocarpine) – produces pupil narrowing (miosis)

Patients also typically receive one of the following medications to reduce eye pressure:

  • Diamox (acetazolamide)
  • Osmitrol (intravenous mannitol)
  • Oral glycerol
  • Isosorbide

Definitive therapy usually involves laser peripheral iridotomy – this procedure allows aqueous humor to drain out of a small hole in the iris.  Individuals that undergo this procedure should typically avoid medications such as decongestants or anticholinergics as these may cause an attack of angle-closure.

Open-angle glaucoma can be treated with medications, laser therapy, or surgery.  The first-line medical treatment is a topical prostaglandin such as:

Sometimes eye drops from different classes are combined – this may result in a larger decrease in eye pressure than use of one agent alone.  Combinations may include a beta-blocker plus prostaglandin or beta blocker plus carbonic anhydrase inhibitor.

Glaucoma Patient Summary:

  • Glaucoma is an ophthalmologic condition that may lead to elevated pressures inside the eye, causing blindness.
  • Angle-closure glaucoma occurs due to narrowing of the anterior chamber of the eye, resulting in increased intraocular pressure and optic nerve injury.
  • Open-angle glaucoma is an optic nerve disease that results in progressive visual loss – it is also frequently associated with elevated pressures inside the eye.
  • Risk factors for open-angle glaucoma include advanced age, African American race, family history, and increased intraocular pressure.
  • Symptoms of acute angle-closure glaucoma usually include loss of vision, headache, eye pain, and nausea/vomiting.
  • Your doctor may notice eye redness, cloudiness of the cornea, and poorly reactive mid-dilated pupil.
  • Open-angle glaucoma generally does not produce symptoms. Your doctor may find it incidentally during a comprehensive eye examination.  
  • Angle-closure glaucoma is diagnosed with gonioscopy. Open-angle glaucoma is diagnosed with funduscopy and visual field testing showing optic nerve damage. 
  • Acute angle-closure glaucoma is an eye emergency that requires treatment by an ophthalmology specialist.
  • Patients are typically treated with topical ophthalmic agents to lower intraocular pressure: Timoptic (timolol), Iopidine (apraclonidine), and Isopto (pilocarpine).
  • Patients also typically receive one of the following medications to reduce eye pressure: Diamox (acetazolamide), Osmitrol (intravenous mannitol), oral glycerol, and isosorbide.
  • Definitive therapy typically involves laser peripheral iridotomy – a procedure that drains aqueous humor out the iris.

Open-angle glaucoma can be treated with a topical prostaglandin such as Lumigan (bimatoprost), Xalatan (latanoprost), or Zioptan (tafluprost).  Sometimes eye drops from different classes are combined.  Some patients may benefit from laser surgery.

References:

  1. Prum BE Jr, Rosenberg LF, Gedde SJ, et al. Primary Open-Angle Glaucoma Preferred Practice Pattern(®) Guidelines. Ophthalmology 2016; 123:P41.
  2. Weinreb RN, Khaw PT. Primary open-angle glaucoma. Lancet 2004; 363:1711.

Pokhrel PK, Loftus SA. Ocular emergencies. Am Fam Physician 2007; 76:829.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.