Glaucoma is the clinical condition in which there is adequate
increase in intra-ocular pressure. It is one of the leading causes of
blindness all over the world.
Anatomy of the eye:
To understand the etiology of glaucoma, one should be well familiar with the anatomy of the eye ball. As shown in
fig.1, the eye ball comprises of
three coverings: a) Sclera, b) Choroid, c) Retina.
Cornea is the anterior most past of sclera.
 |
| fig.1 structure of the eye ball |
Iris is the curtain in front of the
lens, ligaments of zonule, with aperture (
pupil) in the center. It allow only adequate rays of light from the object to form the image on the retina. Its radial and circular muscles determine the intensity of light that is required for adequate illumination on the retina. Behind the lens, there is
Vitreous Humor which is transparent lequid medium(shown by oblique blue lines in the fig.1). Another important structure is the
cilliary body, located at corneo-scleral junction, which produce a very important fluid secretion, i.e,
Aqous Humor. This is the brief review of some of the aspects of eye structure that are related to understand the Glaucoma.
Causes of glaucoma:
Now let us proceed to the
etiology and important
treatment regimens of Glaucoma. As mentioned above the glaucoma is associated with raised intra-ocular pressure. This pressure being applied may be by the fluid secretion of the cilliary body, the
aqous humor in the anterior chamber of the eye ball. Physiologically, Aqous humor is constantly produced by the cilliary body. It flows behind the iris and then come out through the pupil on the front of iris, just behind the cornea.
This fluid has to be drained into the
canal of Shelmn. The normal intra-ocular pressure, i.e,
12-20mmHg, is maintained by the
balance between the production of the fluid and its drainage.
causes:
- When there is excess production or
- there may be any obstruction in the drainage of aqous humor, this will lead to the raised I.C pressure that eventually lead to the blindness, if it exists chronically and not treated.
Two types of Glaucoma:
- Open angle
- Closed angle
1. Open angle glaucoma:
It is the chronic condition in which glaucoma persist over the period of time and needs proper treatment to avoid the fatal consequences. This class of glaucoma has got very much interest in modern pharmacology, because of its responsiveness to the appropriate drug therapy with different classes of pharmacological agents.
How to Treat the glaucoma patient:
Basic theme behind the use of pharmacologic agents is "to reduce the aqous humor production or to facilitate the out-flow of aqous humor."
Five groups of drugs are choice of treatment depending upon the condition of the patient.
- Cholinomimetics
- alpha-blockers
- beta-blockers
- prostaglandins F2a
- Diuretics.
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