– Ed

It is called the “thief in the night” because it will come and steal your vision without you being aware of it. From the lay-person’s point of view, the most important thing to know is, that Chronic Open Angle Glaucoma is asymptomatic. There is no sign or symptom until it is too late. The next important thing to know is; once damage has been caused, it cannot be reversed. But here is the good news; although Glaucoma cannot be cured, it can be treated successfully to prevent blindness, provided it is diagnosed early enough. This speaks to the importance of regular eye examinations, particularly in the over-forty age group, when the disease is most likely to strike.

What is Glaucoma?

Chronic Open Angle Glaucoma

This is the most common type of Glaucoma and affects both eyes. The eye is filled with fluid; Aqueous Humour in the anterior chamber just behind the cornea and Vitreous Humour (more gel-like) fills the eye from behind the lens. Fluid is produced into the anterior chamber by the ciliary body and circulates through, to drain out through Schlemm’s Canal.

If the fluid is coming in faster than it is draining, it results in a build-up of pressure in the eye. This pressure then impacts on the optic nerve at the back of the eye and slowly kills off the nerve fibers. The result of this is, that your visual field starts to shrink from the outside in. In an extreme undiagnosed case, you will end up with tunnel vision and ultimately with total blindness.

Acute Closed or Narrow Angle Glaucoma

This type is rare and presents with classic signs and symptoms. With acute (angle closure) glaucoma, there is a sudden increase in the pressure within one eye, resulting in a red and very painful eye. Often, there are mistiness of vision and episodes of seeing halos around lights. The pupil will be dilated. Sometimes, other diseases of the eye cause a rise in the pressure within the eye – this group of conditions is called secondary glaucoma.

Fundus picture showing the optic nerve head (optic disc): In most types of glaucoma, elevated intraocular pressure (IOP) is associated with damage to the optic nerve in the back of the eye.

How is it diagnosed?

Your Eye Care Professional can diagnose the early onset of Open Angle Glaucoma. It is a simple procedure to measure the intra ocular pressure (IOP).The anterior chamber peripheral angle can be measured – this is where the fluid drains out of the eye. Visual fields will be assessed to check for optic nerve damage. Using an ophthalmoscope, they can look at the optic nerve (optic disc). If it is more excavated than it should be, it could be indicative of Glaucoma. Photographs of the back of the eye can assists with diagnosis, as well as monitoring the condition over time (as illustrated in the photos). Acute Angle Closure presents with classic signs and symptoms.

Incidence and risk

Glaucoma is the second-leading cause of blindness in the U.S. (behind macular degeneration), and the second-leading cause of blindness worldwide (behind cataracts). Family history of Glaucoma is significant, especially among siblings. People with very high myopia are more at risk. The incidence of Glaucoma increases with age. There is also a higher incidence of Glaucoma among Africans and Hispanics.


People with Glaucoma rarely go blind provided they receive treatment. Treatment options include drops, tablets and various forms of surgery. Regular check-ups as recommended by the ophthalmologist should be adhered to strictly. Visual field records and retinal photographs are used to monitor the disease.


If you are over forty, and you have never had an eye examination, because you buy ready readers over the counter, this article should convince you to have a comprehensive eye exam, to rule out Glaucoma and several other potentially serious ocular diseases and systemic disorders.

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