Module 8.4 - Glaucocma

Question 1

What is glaucoma?

Answer 1

• It is a progressive vision loss disorder; typically, peripheral vision decreases first, then central vision, can result in blindness
• It is caused by an elevated intraocular pressure, causing vascular resistance, causing decreased vascular perfusion of the optic nerve leading to ischemia that can lead to partial or complete blindness.

Question 2

What are the two types of glaucoma?

Answer 2

1. Chronic open-angle (wide) (most common) – In the anterior chamber the drainage angle formed by the cornea and iris remains open, but the trabecular meshwork is partially blocked. This causes the intraocular pressure to gradually increase. This pressure damages the optic nerve.
2. Acute or chronic closed angle (narrow) – Occurs when the iris bulges forward to narrow, or block, the drainage angle formed by the cornea and iris. As a result, fluid can’t circulate through the eye and pressure increases.

Angle-closure glaucoma may occur suddenly (acute closed angle glaucoma) or gradually (chronic closed angle glaucoma). Acute angle glaucoma is a medical emergency. It can be triggered by sudden dilation of the pupils.

Question 3

What are some predisposing factors for glaucoma?

Answer 3

A. Advancing Age

B. Heredity- Note:* Asians are more likely to have normal intraocular pressure in open angle glaucoma

C. Myopia

D. African-American ethnicity - Note *Open-angle glaucoma more common in African Americans than Caucasians

E. Ophthalmic corticosteroid therapy

F. Trauma

G. Family History

Question 4

What are the subjective/physical exam findings seen in open-angle glaucoma?

Answer 4

• Visual changes occur slowly, with decreasing peripheral vision noted over time.
• Photophobia and visual blurring may occur
• A headache and halos around lights are atypical.

Question 5

What are the subjective/physical exam findings seen in closed-angle glaucoma?

Answer 5

• Symptoms develop rapidly
• The patient complains of intense eye pain and visual disturbances- halos around lights with nausea and vomiting
• Note* - Although pain is common with closed-angle glaucoma, painless variants may be distinguished only by a fixed pupil.

Question 6

What physical exam findings should you examine for when examining a patient with glaucoma?

Answer 6

• Inspect for external signs such as redness, tearing, lid deformities, foreign body, proptosis, or ptosis, and for corneal clouding.
• Observe for changes in pupillary response, reactivity, symmetry, and accommodation.
• Visual acuity may remain normal
• Examine for increased intraocular pressure (IOP) by measuring IOP with a Schiotz tonometer or Goldmann applanation tonometer.
  
  • Never apply the tonometer to an infected or possibly infected eye.
  • Increased IOP is defined as pressure greater than 23mmHg.
  • In acute closed angle glaucoma, IOP may be 40-80 mm Hg.
  • With specialized equipment, corneal thickness, retinal photography and automatic visual field testing.
  • Observe for decreased peripheral vision with confrontation test.

Question 7

What are some fundoscopic exam changes seen with glaucoma?

Answer 7

1. Optic disc may appear irregular with notching of the physiologic cup or “cupping”.
2. Observe for increased cup to disc ratio.

Question 8

How do you manage acute open-angle glaucoma?

Answer 8

It requires immediate initiation of medication and referral to an ophthalmologist for surgical treatment

Question 9

Describe the medical management of chronic glaucoma

Answer 9

When initiating medical management of glaucoma it will require consult/referral to an ophthalmologist for examination and monitoring of the condition

Medical Management:

1. Prostaglandin analogs (first-line therapy)

• Bimatoprost (Lumigan), latanoprost (Xalatan), Tafluprost (Zioptan), Travoprost (Travatan), Unoprostone (Rescula)

2. Beta-blocking agents (first line therapy)

• Betaxolol (Betoptic), Levobunolol (Betagan), Carteolol (Ocupress), Metipranolol (OptiPranolol), Timolol (Betimol, Timoptic)
• Note* Use with caution in pulmonary disease, bradycardia, heart failure and heart block.

3. Alpha 2 adrenergic agonists (second-line therapy, adjunct therapy)

• Apraclonidine (Lopidine), Brimonidine (Alphagan)

4. Carbonic anhydrase inhibitor (second-line therapy, adjunct therapy

• Brinzolamide Azopt), Dorzolamide (Trusopt), Acetazolamide (Diamox), Methazolamide (Neptazane)
• Oral agents: Note* Indicated only when failing to respond to or tolerate maximum topical therapy due to adverse effect profile.

5. Para sympathomimetic agents (limited role in therapy)

• Carbachol (Miostat), Echothiophate iodide (Phospholine Iodide), Pilocarpine (Isopto Carpine)
• Note * Use decreased significantly because of local ocular adverse effects and/or frequency of dosing
• Reserved primarily for patients who are either not responding to or are intolerant of other therapy due to serious ocular and systemic toxic effects.

6. Sympathomimetic agents (limited role in therapy)

• Dipivefrin HCl (Propine)
• Note *Clinical use has decreased dramatically since the advent of better tolerated and more efficacious agents.

Follow up 3-4 weeks after beginning medication

Question 10

How do you manage closed-angle glaucoma?

Answer 10

• It is an ophthalmologic emergency
• Consult an ophthalmologist as soon as the diagnosis is suspected.
• Followed every 3 months by an ophthalmologist