Glaucoma Treatment

Glaucoma is a disease that causes damage to the optic nerve, which carries images from the retina to the brain so we can see. In glaucoma, eye pressure plays a role in damaging the delicate nerve fibers of the optic nerve. When a significant number of nerve fibers are damaged, blind spots develop in the field of vision. Vision loss becomes permanent once nerve damage occurs. Most people don’t notice these blind areas until much of the optic nerve damage has already occurred. If the entire nerve is destroyed, blindness results. Glaucoma is a leading cause of blindness in the world, especially in adults over 40.

Fortunately, glaucoma can usually be controlled with drug therapy and/or laser or conventional surgery. Glaucoma damage can usually be stopped with early detection and the right treatment.

Selecting the best form of treatment requires careful consideration of the patient’s particular condition and general health, since some eye drops may have side effects. We use ophthalmic lasers for glaucoma treatment and post-cataracts. We strive to always make sure to maximize the potential benefit while minimizing risk, side effects, cost and maintaining your quality of life.

Diagnosing Glaucoma

The best way to control the eye disease is with early detection and treatment, before glaucoma causes major vision loss. So, if you are in a high-risk group, make sure to have your eyes thoroughly examined every two years. Through the use of advanced diagnostic technology and the extensive medical experience and knowledge of Dr. Chen, early detection of Glaucoma is possible.

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The Tonometer

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The tonometer measures the pressure in your eye. For your comfort, a numbing eye drop in placed in your eye. Your head is then positioned on the slit-lamp’s chin rest so that Dr. Chen and his ophthalmic staff can use the microscope to look into your eye. The tonometer is then moved forward until the plastic prism just touches your cornea and measures your intraocular pressure.

The Pachymeter

The pachymeter measures central corneal thickness. Like the tonometer, your eyes will be anesthetized for this quick test. A small probe will be placed perpendicular to the central cornea to take the measurement.

Some people with thin central corneal thickness will have pressures that are actually higher than when measured by tonometry. Using both the tonometer and pachymeter will allow for a more accurate diagnosis of your true intraocular pressure. Studies have shows that there is a strong predictor of developing glaucoma in patients with high intraocular pressure.

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Visual Field Test

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Visual field is an important measure of the extent of damage to your optic nerve from elevated intraocular pressure. In glaucoma, it is the peripheral (side) vision that is most commonly affected first. Testing your visual field lets us know if your peripheral vision is being lost.

In computerized visual field testing you will be asked to place your chin on a stand which appears before a concave computerized screen. Whenever you see a flash of light appear, you press a buzzer. At the end of this test, your doctor will receive a printout of your field of vision.

Ophthalmoscopy

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Using an instrument called an ophthalmoscope, Dr. Chen can look directly through the pupil at the optic nerve. Its color and appearance can indicate whether or not damage from glaucoma is present and how extensive it is. This technique remains the most important in diagnosing and monitoring glaucoma.

An normal optic nerve is made up of more than one million tiny nerve fibers. As glaucoma damages the optic nerve, it causes the death of some of these nerve fibers. As a result, the appearance of the optic nerve changes. This is referred to as cupping. As the cupping increases, blank spots begin to develop in your field of vision.

Imaging Technology

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A number of new and highly sophisticated image analysis systems such as our Zeiss Cirrus OCT are now available to evaluate the optic nerve and retinal nerve fiber layer, the areas of the eye damaged by glaucoma.

These instruments can help Dr. Chen by giving him a quantitative measure of the anatomical structures in the eye. Photographs of the optic nerve can also be useful to follow the progression of damage over time. Large databases have been established to compare an individual’s anatomic structures to those of other patients in the same age group. This software and technology are developing rapidly and show great promise. However, they have not yet evolved to replace ophthalmoscopy, where the doctor looks directly at the optic nerve.

Gonioscopy

Dr. Chen may perform a gonioscopy to closely examine the trabecular meshwork and the angle where fluid drains out of the eye. After dilating and numbing the eye with anesthetic drops, he places a special type of hand-held contact lens, with mirrors inside, on the eye.

The mirrors enable the doctor to view the interior of the eye from different directions. In this procedure, the doctor can determine whether the angle is open or narrow. Open-angle glaucoma is where the drainage angle is not working efficiently enough and closed-angle glaucoma is where the drainage angle is at least partially blocked.

Individuals with narrow angles have an increased risk for a sudden closure of the angle, which can cause an acute glaucoma attack. Gonioscopy can also determine if anything, such as abnormal blood vessels or excessive pigment, might be blocking the drainage of the aqueous humor out of the eye.

Treating Glaucoma

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Medicated eye drops are the most common way to treat glaucoma. These medications lower your eye pressure in one of two ways — either by slowing the production of aqueous humor or by improving the flow through the drainage angle.

These eyedrops must be taken every day. Just like any other medication, it is important to take your eyedrops regularly as prescribed by your ophthalmologist.

Never change or stop taking your medications without talking with your doctor. If you are about to run out of your medication, ask your doctor if you should have it refilled.

In some patients with glaucoma, surgery is recommended when the glaucoma drugs become ineffective or causing adverse effects. Glaucoma surgery improves the flow of fluid out of the eye, resulting in lower eye pressure.

Laser treatment, which uses high energy beams of light, can be used to open up the blocked trabecular meshwork (drainage tubes) within your eye. This is called laser trabeculoplasty which uses short pulses of energy to target the trabecular meshwork band to reduce intraocular pressure that can damage the optic nerve.

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Laser treatments are usually quick and painless, although during the procedure you may feel a brief twinge of pain or heat. You may still need to use eye drops (see above) after having laser treatment.

Even if laser trabeculoplasty is successful, most patients continue taking glaucoma medications after surgery. For many, this surgery is not a permanent solution. Nearly half who receive this surgery develop increased eye pressure again within five years. Many people who have had a successful laser trabeculoplasty have a repeat treatment.

Laser trabeculoplasty can also be used as a first line of treatment for patients who are unwilling or unable to use glaucoma drops.

Other more aggressive treatment options include trabeculectomy in which an opening or implant is placed within eyes natural drainage network to create a new pathway for aqueous fluid to drain from the eye.

Special Types of Glaucoma

Narrow Anatomical Angles and Narrow Angle Glaucoma

Certain patients are at higher risk for a more serious and rapidly progressing form of glaucoma, called angle closure. These patients are often older, farsighted, or have either Chinese or Inuit genetic backgrounds. The angle sits inside the narrow space between where the iris meets the edge of the cornea. As patients age, the lens grows thicker, and the normal forward flow of intraocular fluid becomes blocked at the pupil by the enlarging lens. Fluid that is produced behind the lens, then builds up inside the eye, causing the iris to bow forwards, triggering an angle closure attack. Treatment is ideally prophylactic laser iridotomy, where either a heat laser and/or cold pulse YAG laser is used to create a new hole in the iris to allow fluid to flow freely into the front chamber of the eye. This procedure is called a laser iridotomy. An alternative treatment involves performing cataract surgery, as removing the thick cataractous and lens replacing it with a thin plastic lens implant, widens narrow angles definitively.

Normal Pressure or Low Tension Glaucoma

Certain patients with glaucoma are never found to have high eye pressures. This is the predominant form of glaucoma among Japanese patients both in Japan and in the US. Patients of Japanese descent should be aware that they are of higher risk of developing glaucoma than the general population.

Specializing in Cataracts and Eyelid Surgery