10 Years Later
3 years ago
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About Gabe
Gabe is 6 yrs old and living each day with congenital glaucoma-although you would never know it! Gabe came home to his forever family in Sept. 09 from Suzhou, China.
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10 Years Later3 years ago
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Gabe
About Glaucoma
Glaucoma is a condition in which elevated pressure inside the eye contributes to damage of the optic nerve, which may eventually lead to complete vision loss. There are usually no symptoms early in the disease, but in later stages it can cause loss of peripheral vision, tunnel vision and eventually complete blindness. (Gabe's type of glaucoma-congenital is not like other late (senior) onset glaucoma and is not at this time expected to cause complete blindness).
www.nei.nih.gov/health/glaucoma/glaucoma_facts.asp
To understand the basic mechanism let me give you an analogy. Imagine a sink with a water tap. The tap is on and water flows at a constant rate into the sink ; while the drainage hole of the sink is unblocked the sink will not overflow. Consider the eye: fluid (aqueous) is produced at a constant rate by the ciliary processes (see figure 1) which flows around the lens into the anterior chamber and drains into the angle between the cornea (window of the eye) and the iris (colored part of the eye) . This drainage angle is like the drainage hole of the sink; if it becomes blocked then fluid builds up and because the eye is a closed chamber, instead of overflowing the pressure rises within the eye. There are three main consequences of raised intraocular pressure:-
- the infant's eye is very elastic and the rise in pressure results in an abnormal increase in the size of the eyeball.
- the cornea is normally clear because there is a special layer of cells (endothelium) lining it on the inside which pumps water out of the cornea continuously; raised intraocular pressure affects this pumping action adversely and causes water logging in the cornea which makes the cornea hazy and, in severe cases, opaque.
- the main danger of raised pressure within the eye (intraocular pressure) is that it eventually damages the optic nerve irreversibly. The optic nerve is the cable that takes the images the eye receives to the ‘seeing centre' (visual cortex) of the brain; damaged cable means bad or no images, depending on the degree of damage.
In congenital glaucoma there is abnormal development of the drainage angle such that it is blocked by abnormal tissue referred to as Barkans membrane after the man who first suggested its presence in such eyes. In our analogy imagine that someone has placed a film of cellophane over the drainage hole of the sink; now the sink will overflow. Similarly the pressure in the eye will go up.
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