Jennifer Orenic - SFACTL



Jennifer Orenic

SPE 516- LA 2

7/12/07

What is Glaucoma?

• Glaucoma results from high intra-ocular pressure, causing progressive damage to the optic nerve and causing vision loss.

• 1 out of every 25 cases of glaucoma results in blindness (3 million Americans affected) - second leading cause of blindness in the U.S.

3 basic types:

1. Primary Glaucoma- most common

a. Open angle glaucoma- (most common in the U.S.- also called chronic glaucoma) occurs when the Canals of

Schlemm become clogged and do not allow enough aqueous fluid to drain from the anterior chamber, resulting in

too much intra-ocular pressure. It usually goes undiagnosed until the person notices a loss of peripheral vision,

and by then, permanent damage has already occurred.

b. Closed angle glaucoma- (also called acute glaucoma, narrow angle glaucoma, or angle closure glaucoma) similar

to open angle glaucoma, except that the iris blocks the Canals of Schlemm because the angle between the iris and

the cornea is too narrow. Occurs spontaneously and suddenly, usually when the iris contracts too much or too

quickly. This creates severe eye pain, loss of visual acuity, headaches, haloes around lights, dilated pupils, red

eyes, nausea, and vomiting. Closed angle glaucoma is a medical emergency, and patients experiencing these

symptoms should see a doctor immediately or report to a hospital emergency room.

2. Secondary Glaucoma- This type of glaucoma is a secondary result of other physical problems, such as injury, inflammation, vascular disease, and diabetes.

-A similar type of glaucoma is known as pigmentary glaucoma. This is caused by pigmentary granules in the back of the retina that break-off and clog the Canals of Schlemm, preventing proper drainage.

3. Congenital Glaucoma- This type of glaucoma occurs during embryonic development, when the eye doesn’t develop to allow proper drainage of aqueous fluid. Parents should look for cloudy, white, hazy color to the eye or signs of an enlarged or protruding eye. If noticed, parents should consult an eye doctor.

Signs and Symptoms of Glaucoma

• Beginning stages of glaucoma- loss of contrast (subtle), such as inability to notice the difference between the sidewalk and curb, or inability to see every step on a staircase.

• Difficulty with driving at night

• Gradual loss of peripheral vision- perhaps similar to this:

• Eventual loss of central vision, in advanced stage cases

Risk Factors

• Family history of glaucoma

• Age

• Ancestry (more common in African-Americans and Hispanic-Americans)

• Diabetes

• Presence of myopia (due to likelihood of abnormally thin cornea, which may cause eye pressure readings to appear inaccurate)

Detection of Glaucoma

• Routine eye exams recommended yearly after age 45 to establish baseline. Since there are no early symptoms, early detection is essential to preserve vision.

• Intra-ocular pressure readings are taken, and examination of optic nerve and its functioning are conducted

• Contrast tests- to identify subtle changes in ability to perceive contrast- may indicate loss of retinal cells

• Pachymetry- ultrasound technique that measures the thickness of the cornea to determine whether “normal” pressure readings are accurate or whether a myopic (thin) cornea is causing a faulty reading.

• In 2005 a new procedure, called Heidelberg Retina Tomograph (HRT), a laser imaging technique that measures changes in patients’ optic disks and optic nerve head has been shown to predict glaucoma by determining if they are functioning properly

Medications and Treatments

-MEDICATIONS:

• Pilocarpine- This medication has been used with glaucoma patients for over 100 years. It encourages drainage of aqueous fluid by constricting the pupil and opening the trabecular meshwork. One unpleasant side effect is that the constriction of the pupil causes darkened vision.

• Propine- This works by decreasing aqueous fluid production and increasing fluid drainage, lowering intra-ocular pressure. It may cause red, teary eyes.

• Timolol- This medication is most commonly used with survivors of heart attack but can also be used to treat glaucoma. It is a beta-blocker and interferes with body chemicals that shrink blood vessels. It can be used to decrease intra-ocular pressure in glaucoma patients. It can, however reduce pulse rate and trigger bronchial asthma.

• Xalatan (Latanaprost)- This drug also increases drainage of aqueous fluid from the eye, reducing pressure. It is taken at night as drops. This is the newest and most promising drug for the treatment of glaucoma.

• Other medications (drops and pills) can also be prescribed by an ophthalmologist to treat glaucoma, such as Lumigan, Travatan, and Cosopt.

-OTHER TREATMENTS:

• Laser Surgery- This surgery is effective for reducing eye pressure for a year or more and may be used on conjunction with other medications.

• Filtering Operation- Used only when medications and laser surgery have proven ineffective at controlling glaucoma. This procedure creates an artificial filter through which aqueous fluid can drain, decreasing intra-ocular pressure.

• Cryoprobe (freezing) or Laser Energy- These techniques apply a probe directly to the eyeball over the ciliary bodies (where the aqueous fluid is produced) in order to temporarily halt production of aqueous fluid.

References

Eye Disorders: Glaucoma. (2007). Retrieved July 3, 2007, from Lighthouse International website:



Lee, J., and Bailey, G. (Oct. 2005). Glaucoma: The Second Leading Cause of Blindness in the U.S. Retrieved July 3, 2007, from All About Vision website:

Retina Tomography Shown to Predict Glaucoma. (Sept. 20, 2005). Retrieved July 3, 2007, from Medical Technology Business: Europe website:

Types of Glaucoma. (n.d.) Retrieved July 3, 2007, from from Glaucoma SLT Therapy website:

White, G. (n.d.). Eye Problems: Symptoms From A to Z. Retrieved July 3, 2007, from All About Vision website:

[pic][pic][pic][pic][pic]

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download