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CHRONIC OPEN ANGLE GLAUCOMA

GLAUCOMA is a disorder of the optic nerve associated with elevated intraocular pressures, changes in the appearance of the optic nerve head, and characteristic visual field disturbances.

GLAUCOMA is a very common disease which affects about 2% of the population over the age of 65. It also occurs in younger age groups, but with much less frequency.

There is a constant circulation of a nutrient fluid INSIDE the eye. This is not to be confused with the normal circulation of tears on the OUTSIDE of the eye. This inner broth nourishes the lens, cornea and other vital structures inside the eye. When the drainage of this fluid is slowed down, the pressure inside the eye goes up. This elevated pressure is not called GLAUCOMA unless we find evidence that it has harmed the eye in some way.

Most patients have NO SYMPTOMS when first diagnosed, usually at the time of a routine eye examination. Only late in the course of the disease, if left untreated, is central vision effected. Rarely is tearing, photosensitivity or headache an initial symptom.

Only rarely can GLAUCOMA be cured. The goal of therapy is to CONTROL the disease so that vision is STABILIZED. Control is a matter of reducing intraocular pressure down to a level tolerated by the eye. Control is manifest in stable pressures, stable visual field and stable appearance of the optic nerve head. Good GLAUCOMA management consists of the vigilant and frequent monitoring of these three factors. This is why patients with glaucoma should be reexamined every 3 to 6 months for the rest of their lives. Glasses need to be updated in glaucoma patients just as in the normal population.

The TREATMENT of first choice at this time is medicines in the form of eye drops. There are several types of medicines; some reduce the inflow (Timoptic, Epinephrine and Betoptic etc.), while others increase the outflow of fluid from the eye (Pilocarpine, Carbachol, Epinephrine and others). Sometimes pills are used, but because of their long term side effects, they are rarely used any more, except for short periods of time.

When drops cease to be effective, if the pressure rises as a result of the normal progression of the disease, or if allergies or sensitivities develop to the prescribed medicines, other forms of therapy are used. The most useful tool in this setting is Argon LASER trabeculoplasty. In a single sitting the outflow channel is treated with LASER light resulting in greater outflow of fluid from the eye.

If LASER is not successful, Glaucoma surgery should be considered. This can be tricky surgery and is somewhat unpredictable. A permanent tiny hole is created surgically under the upper eyelid. If the fluid drains too slowly, the operation can fail. If the fluid drains too rapidly, the eye can collapse. Fortunately, in most cases, we can get just the right amount of fluid to drain from the eye gaining control of the pressure.

With careful exams and good cooperation the outlook is bright for almost all patients with this disease.

PSEUDOEXFOLIATION SYNDROME

This is an uncommon condition in which a deposition of white "sugar coating" is found on the surface of the lens as well as on other structures inside the eye. The cause is unknown. The material in all likelihood comes from the blood stream and for some strange reason is only deposited in the tissues around and inside the eye. It usually effects both eyes, but may be asymmetrical.

It is seen in all races and nationalities. It usually is not seen before age 55. PSEUDOEXFOLIATION is important to diagnose because it is associated with two important ocular diseases, namely CATARACTS and GLAUCOMA.

75% of patients with Pseudoexfoliation syndrome will eventually develop cataracts. There is nothing unusual about this type of cataract and should be managed as any other cataract. Surgery is not necessary until symptoms begin to bother the patient. There is a slight increased risk with surgery, but most do very well with the operation.

Between 15 and 20% of patients with Pseudoexfoliation will develop glaucoma over a 5 year period. This is compared to 1-2% of the normal population.

This disorder is somewhat more difficult to manage than the average case of glaucoma. Extra effort is needed in keeping a close eye on intraocular pressures, visual fields, and optic nerve changes. Often medicines must be supplemented with LASER treatments. Of all the types of glaucoma, happily Pseudoexfoliation is the most amenable to LASER therapy.

Pseudoexfoliation, by itself, is not a threat to vision. It is a "red flag" which tell us that caution and careful follow up are needed to insure continued good vision.
ARGON LASER TRABECULOPLASTY

 LASER TRABECULOPLASTY (LTP) is a procedure which was developed in the late1970's as an alternative to conventional glaucoma surgery. Dr. Jim Wise of Oklahoma City deserves full credit for perfecting this procedure. Several others before him experimented with LASERS in the same area and contributed to our knowledge of their usefulness in the eye, but no one had hit upon the exact combination of factors necessary to make the treatment work. LTP is now a proven tool in the treatment of glaucoma. At present, medical therapy, in the form of drops, is still the preferred form of initial treatment for glaucoma. If this is successful with an acceptable level of side effects, it is continued indefinitely.Sometimes glaucoma medicines are not well tolerated in the eye or in other body systems because of allergies, sensitivities, or other drug related side effects. At other times intraocular pressure is not well controlled by the medicines being used. In either of these cases LTP should beconsidered as a logical next step in good glaucoma control.It is an almost painless procedure in which LASER light is directed to a delicate structure (the trabecular meshwork) where the normal intraocular fluids exit the eye. The application of multiple LASER bursts changes this tissue in some, as yet mysterious way. The result is that the exit of intraocular fluids is greatly enhanced. This, in turn, reduces high intraocular pressure, the real culprit in glaucoma. A few anesthetic drops are used to numb the eye. The placement of the LASER is done through a contact lens. Exact focusing of the light is necessary to achieve the desired effect. The procedure takes only a few minutes and is done as an outpatient. Vision may be blurry for a few hours but returns to normal by the next day.Results have been very favorable.
  The amount of pressure reduction depends upon many factors including age of the patient, the exact type of glaucoma present, local tissue response to the therapy and skill of the surgeon.The average reduction taking into consideration several studies is about 10to 12 mm. A small minority of patients derive NO benefit at all from theprocedure. In general over 80% of patients get a good response. Medicines may be reduced or completely eliminated in 20-30% of patients.The potential complications are few, but real. Intraocular pressure may be elevated shortly after the application of the LASER. All patients need to be rechecked for this a few hours after treatment. It is possible to damage vision with the LASER; this is distinctly rare, however. Other potential complications; hemorrhage, continued inflammation, and slight refractive changes.

 

© nholland 2002