How Glaucoma Medication Works

Eye ChartGlaucoma is a build up of fluid pressure in the eye. This pressure builds up to such an abnormal level that treatment must be given to the patient either surgically or by drug treatment to reduce pressure.

If untreated the pressure compresses the blood vessels that supply the nerve connecting the eye to our brain and again as already mentioned it is possible to suffer irreversible damage to the eye/eyes leading to loss of vision.

It is not possible for drugs to restore damage that has already been done, so the taking of drugs could be life long.

One type of glaucoma is known as open-angle (or chronic) glaucoma. Reduction of drainage fluid from the eye pressure is built up very slowly and could take months or even years before a change in the field of vision is noticed.

Closed angle (or acute) glaucoma occurs when the fluid is suddenly blocked by the iris. This in turn would cause blurred vision in the affected eye. The symptoms could possibly be headaches, red and painful eye/eyes or possibly vomiting. The initial warnings may be seeing a halo round lights some months before the main onset of problems. Various drugs can be used to treat both types of glaucoma.

In chronic (or closed-angle) glaucoma drugs will be used to reduce the pressure in the eye/eyes However, drugs can not put right the damage already done, and as mentioned the taking of drugs could be life long.

Treatment is most likely to begin with eye drops which would contain a beta blocker, this would reduce the amount of fluid in the eye/eyes by affecting the production of fluid. Miotics are another form of eye drops that constrict the pupil and improve drainage from the eye/eyes. Latanoprost can also be given to increase the outflow.

In acute glaucoma (or closed angle) drugs would be used initially to bring the pressure within the eye/eyes down. Having down this surgery or laser treatment can be carried out to prevent a total loss of vision, and a recurrence of the problem. With this method it is possible that long term treatment with drugs would not be required.

How The Medications Works

Drugs to treat this complaint act upon the eye/eyes in various ways. However, they all have one thing in common and that is to reduce the pressure of fluid in the eye, by improving drainage of the fluid. In chronic glaucoma miotics work directly on increasing fluid outflow through a channel called the trabecular meshwork.

In acute glaucoma Micotics have a constricting effect on the pupil, reducing the pupil size using the muscle in the iris. This helps to relieve any obstructions which would allow for normal fluid outflow. This is achieved by pulling the iris away from the drainage channel, allowing for the flow of the thick watery substance (aqueous humour) filling the space between the lens and the cornea, to increase.

Other drugs such as postaglandins analoques work by increasing fluid flow from the eye. Carbonic anhydrase inhibitors and beta blockers work by acting directly on the cells that produce the fluid reducing the amount of aqueous humour produced.

Epinephrine, apraclonidine and brimonidine belong to a group of drugs known as Sympathomimetic. These type of drugs are thought to work not only by improving fluid drainage, they also may act in a similar manner as carbonic anhydrase inhibitors and beta blockers by reducing the amount of aqueous humour produced.

Health Risks

If you suffer from chronic glaucoma the benefits of treatment may at first be less apparent this is because the damage before treatment can not be undone, and what would become apparent is any further deterioration of your vision.

If you are suffering acute glaucoma treatment to relieve pain and other symptoms would be felt within a few hours. If you have been prescribed miotic eye drops there is is a likelihood of you having problems seeing very well in the dark, as well as the darkening of your vision. It is also possible for miotics to cause irritation to the eye/eyes.

Acetazolamide which belongs to the group of drugs known as carbonic anhydrase inhibitors can cause an increase in thirst and urination. A more common complaint would be nausea and a general feeling of being unwell.

Beta blockers are a type of medication that are used for heart, lungs and circulation treatment as well as some forms of anxiety. Betaxolol is a cardioselective beta blocker and would be prescribed with caution to those individuals who suffer from complaints such as asthma or certain kinds of circulatory problems.

The drug acetazolamide which belongs to a group of drugs known as carbonic anhydrase inhibitors may not be given to individuals suffering kidney disorders. This is because of its adverse effects which may cause the formation of kidney stones and although very rare it is possible to suffer kidney damage.

As I have already pointed out in the medication database on this website drugs / medication work by interfering with the body’s normal functioning because of this, there will in my opinion be a price to pay for most of us no matter how small.

Below is a list of the most common drugs used.
Miotics Carbonic anhydrase Inhibitor Prostaglandin Analogues
Carbachol, Pilocarpine. Acetaxilamide, Brinzolamide, Dorzolamide. Bimatoprost, Latanoprost., Travoprost.
Highlighted medication Will open in a new page.
Beta Blockers Sympathomimetics
Betaxolol, Carteolol, Levobunolol, Timolol. Apraclonidine, Brimonidine, Dipivefrine, Epinephrine, Guanethidine.