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28
SEP
2013

Glaucoma

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Glaucoma refers to a number of conditions that all damage the optic nerve. Increased pressure in the eye is one of the ways the optic nerve is damaged. Glaucoma is one of the leading causes of preventable blindness. Often called the “sneak thief” of sight, most forms of glaucoma do not produce symptoms until vision is already severely damaged. But if diagnosed early, the disease can be controlled and permanent vision loss can be prevented.

glaucoma1

What causes glaucoma?

Open-angle glaucoma
The most common form of glaucoma.In this type of glaucoma there is resistance to the outflow of fluid form the eye.

Causes are:

  • Aging
  • Genetic
  • Anatomical abnormalities
  • Metabolic stress of the optic nerve

 

Symptoms

Open-angle glaucoma is the most common form and initially presents with no symptoms. The pressure in the eye builds up gradually. At some point, the optic nerve is damaged and peripheral vision is lost. Without treatment, TOTAL BLINDNESS will occur. Similarly, people with normal tension glaucoma will not experience any symptoms until they begin to lose peripheral vision.

 

Angle closure glaucoma 
This is a rare form of the disease accounting for just 15% of all glaucoma cases

Causes are:

  • Medications that dilate the pupil
  • Anatomical narrow drainage angle
  • Complete closure of the angle can be induced
  • Naturally, when the eye dilates in low light

 

 Clinical signs and symptoms:

Acute closed-angle glaucoma is the result of a sudden blockage in the normal outflow of eye fluid (aqueous humor) from the eye. Symptoms may include sever pain, nausea, vomiting and blurred vision. Chronic closed-angle glaucoma progresses more slowly and the symptoms are much more subtle, much like in angle closure glaucoma.

 

Normal–tension glaucoma

Causes are:

  • Reduced blood flow of the optic nerve
  • Damage to the optic nerve even though the intraocular pressure is normal
  • Genetic
  • Optic nerve cell death
  • Metabolic damage to the optic nerve

 

Congenital glaucoma
this is present at or near the time of birth

  • Anatomical defects in the drainage angle

 

Secondary glaucoma
associated with previous injury, intraocular conditions or certain medications

What are the risk factors of glaucoma?

Although glaucoma is most common in adults over the age of 40, susceptibility is not determined by age alone. There is a genetic component, and those with a family history of the disease, as well as Africans are at increased risk. Those with hypertension, diabetes and other systemic diseases are also at risk. Studies have shown individuals at greater risk for glaucoma may fit one or more of the following criteria:

  • Over the age of 60
  • A family history of the disease, elevated intraocular pressure
  • African over the age of 40
  • Diabetes or hypertension
  • Farsightedness

Since early detection is critical to avoiding permanent loss of vision, individuals who posses any of the non-age-related risk factors should have regular examinations by an ophthalmologist every one or two years.

Individuals in the general population should have a glaucoma evaluation every two or three years after the age of 40, and every one or two years after the age of 60.

How is glaucoma treated?

At the beginning of treatment, the doctor will generally recommend medication or a combination of medications for the specific condition, and it may include:

  • Eye drops (or combination of eye drops and tablets) to reduce intraocular pressure.
  • Medications work by either reducing the rate at which fluid in the eye is produced or increasing the outflow of fluid from the eye or both.
  • Laser treatment to open the drainage angle and reduce intraocular pressure in a few selected cases.
  • Surgery to create a new passage for fluid drainage. Surgery is usually reserved for cases that cannot be controlled by medication.