Treatments for Glaucoma

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There are several different types of glaucoma. Treatment depends on properly identifying precisely which kind is present and determining how the glaucoma may affect the person’s quality of life. The goal of treatment is preservation of health.

Photo by Roger Barone.

 

Medications

eyedrops

If treatment is determined to be necessary, usually the first course of treatment with all types of glaucoma is the use of medications. These medications work to either lower the intraocular pressure by increasing the amount of aqueous humor (fluid) that drains from the eye or to reduce the amount of aqueous humor (fluid) produced by the eye. Glaucoma medications are usually in the form of an eye drop but can also be in the form of pills or liquid. In some rare emergency cases medications can be given intravenously to rapidly bring the eye pressure down from dangerously high levels. When medications are used the goal is to lower the intraocular pressure to prevent damage to the optic nerve. The level of intraocular pressure needed to prevent damage varies from one individual to another. There is no magic number; your target eye pressure (the pressure needed to prevent damage) will be determined by your glaucoma specialist.

Medications that increase the flow of aqueous humor:

  • Adrenergic agonists – Alphagan, Epifrin, Glaucon, Iopidine, Propine
  • Cholinergics – Carboptic, Isopto Carpine, Phospholine Iodide, Pilocar, Pilopine HS, Pilostat
  • Prostaglandin analogs – Xalatan, Lumigan, Travatan

Medications that decrease the amount of aqueous humor produced:

  • Adrenergic agonists – Alphagan, Epifrin, Glaucon, Iopidine, Propine
  • Beta-blockers – Betagan, Betimol, Betoptic, Cosopt, Timoptic, Ocupress, Optipranolol
  • Carbonic anhydrase inhibitors – Diamox, Neptazane, Azopt, Cosopt, Trusopt
  • Hyperosmotics – Ismotic, Osmoglyn, Osmitrol, Ureaphil

Medications that act by both mechanisms:

  • Adrenergic agonists – Alphagan, Epifrin, Glaucon, Iopidine, Propine
 

Lasers

There are many kinds of glaucoma. We classify the type of glaucoma according to the reason for the blockage in the outflow of fluid. Angle-closure and chronic open-angle glaucoma are by far the most common, and the main types of glaucoma treated with laser surgery.

 

Trabeculectomy

trubnik_katz_surgery 3 feb272012

One way to relieve the dangerously high pressure in an eye with glaucoma is to make a new drain in the eye, a bypass for the blocked natural drain. This is called a trabeculectomy and takes the form of a “flap valve” which is surgically created in the white part of the eye hidden under the upper eyelid. The eye pressure is relieved because fluid can now drain through the new valve. A trabeculectomy is usually done under local and/or topical anesthesia. An anesthetist administers intravenous medication to relax the patient and reduce the discomfort of the local anesthetic injections. A shot of local anesthetic numbs the eye completely so that it will not move during surgery nor feel any pain. Alternatively, topical anesthetic drops and jell can numb he eye adequately for surgery. If preferred, the anesthesiologist can administer a general anesthetic, keeping the patient asleep for the whole operation. The surgery itself takes 35 minutes to an hour in most cases.

Photo by Roger Barone.

 

Shunts

Glaucoma is a disease in which the drainage mechanism of the eye has become blocked. Since an eye normally produces a watery fluid called aqueous throughout life, this fluid has nowhere to go and backs up. This causes a build-up of pressure within the eye which injures the optic nerve. The safest and simplest type of surgery to reduce intraocular pressure is a trabeculectomy, a procedure which makes a flap valve on top of the eye. This allows the aqueous to seep out under this flap valve and be absorbed under the conjunctiva, the clear layer overlying the sclera, and into the bloodstream. There is little chance that this procedure will work if there is existing inflammation, excessive scarring from previous surgeries, or unusual healing is expected. In these cases, the next step is an aqueous shunt, a tiny plastic tube from the anterior chamber of the eye to a reservoir that is placed halfway back around the eye. The reservoir is a plate that prevents the top layer of the eye from sealing to the wall of the eye and preventing drainage. Aqueous fluid is drained through the tube to the top of these plates and then is absorbed into the lymph and blood vessels around the eye.

 

Cyclocryotherapy

One way to combat the dangerously high pressure in an eye with one of the more difficult to control glaucomas is to cut down on the amount of fluid produced. This is how cyclocryotherapy works. Remember, the ciliary body produces the aqueous fluid in the eye. Applying a freezing probe to half of the ciliary body destroys half of the fluid-making ability of the eye. Hopefully, with less fluid being made, medications can keep the amount of fluid produced equal to the amount of fluid drained – thus, the pressure remains controlled.

 

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