GLAUCOMA
General Description
To understand how glaucoma affects the vision it is necessary to understand how the aqueous humor works. The aqueous humor is the water-like substance inside the eye which keeps its pressure healthy. The normal pressure oscillates between 10 to 20 mmHg.
The aqueous humor is composed of the ciliary body and it is drained through the trabecular meshwork into the Schlemm’s canal. We can compare the eye to a soccer ball with a tube through which the air is released.
If the valve in this tube is obstructed or narrowed, the pressure begins to increase in the interior of the ball and the air tries to escape through the weakest part. For the eye, this would be the optical nerve. If the pressure inside the eye remains high, the optical nerve begins to sustain damage.
Glaucoma is defined as an optical neuropathy or a disease of the optical nerve. It is generally related to an increase of the intraocular pressure. However, some people with glaucoma have intraocular pressures within the normal range. In this case further testing is required.
If left untreated, glaucoma leads to irreversible damage of the optical nerve. This damage results in loss of the field of vision. The danger of this disease lies in the fact that it is often painless, and the loss of vision starts slowly in the periphery field of vision. By the time the person realizes that there is a problem, the nerve damage is irreversible. The importance of yearly ophthalmic examinations can not be overstated.
Glaucoma may be classified in different ways but it is simple to classify it in two conditions based on the angle of the anterior chamber, which is where the aqueous humor is drained and where the trabecular meshwork is located.
When the angle is obstructed slowly (open angle glaucoma) the loss of vision is slow and painless. If a narrowing of the trabecular mesh takes place suddenly, (closed angle glaucoma) the loss of vision is rapid and intense pain is accompanied by blurred vision. This last case represents an ophthalmic emergency, if untreated it may produce short term blindness.
Risk Factors
In most of the cases Glaucoma is caused by an obstruction of the trabecular mesh with the passage of time. It is associated with the aging process, especially after 40 years, as well as with arterial hypertension, diabetes, myopia, hyperopia, African ancestry or genetic factors.
Benefits of the treatment
The main benefit of treatment is to avoid the onset or further loss of the field of vision.
Description of the treatment
Depending on the severity of the disease, the fist line of treatment is to decrease intraocular pressure by means of the application of eye drops.
If the patient’s field of vision continues to diminish, a surgical approach may be necessary.
Several therapeutic surgical options existIn the case of open angle glaucoma, options include the use of laser trabeculoplasty, surgical trabeculectomy, or even placing especially designed valves to allow the exit of aqueous humor.
The purpose of all these techniques is to diminish the intraocular pressure by facilitating the drainage of the aqueous humor.
In the case of closed angle glaucoma a new conduct is made for the drainage of the aqueous humor. Because the eye’s iris is already blocked, small holes are made in it with a YAG laser beam. This procedure is known as an Iridotomy and is virtually pain free and very fast. The advantage of this treatment is that it is unnecessary to surgically open the eye and it does not require anesthesia. The alternative method is to surgically create another conduit. This is a last resort if the cornea been has sustained elevated intraocular pressures for a long period of time.
Hospitalization
In most cases not necessary
Preparation timeAbout 45 minutes
Length of surgeryFrom minutes to 2 hours depending on the necessary treatment.
Recovery timeDepends on the severity of the glaucoma.