With chronic glaucoma, there is a restriction rather than a complete blockage of the flow of aqueous humor. The aqueous
humor drains into Schlem's canal, which is located in the area of the eye called the anterior chamber angle. This angle can
be examined only with a special lens utilizing a technique called gonioscopy. When examined, the eye generally appears
normal; however, the pressure slowly rises in spite of the normal appearance of the drainage area. This usually develops
slowly and without symptoms until the condition is very advanced. There is usually no pain associated with this. Initially
the vision is not affected appreciably, but in time the peripheral vision deteriorates, even to the point of "legal
blindness". This type of glaucoma is thought to be inherited and it is detected on routine examination. The high pressure
alone does not complete the diagnosis. A visual field examination and thorough examination of the optic nerve is necessary.
Some people may have high intraocular pressures with no other signs. This condition is called ocular hypertension and
requires treatment. If ocular hypertension is not treated, statistically there will be optic nerve damage within three to
five years. Treatment for chronic glaucoma is either medical or surgical. When the pressure cannot be controlled, the
patient cannot tolerate the medication, or if the visual field or optic nerve shows progressive deterioration, then surgery
is needed. This may be performed utilizing a laser but it is also necessary in some cases to perform regular surgery for
more definitive and lasting results. In extreme cases, drainage devices are surgically implanted.
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