GLAUCOMA

Glaucoma is a term that encompasses a variety of eye diseases, which cause a build up of pressure within the eye. This fluid pressure builds until it eventually pushes the optic nerve back into a concave shape. If the pressure remains too high for too long permanent damage will occur to the optic nerve. Although glaucoma may start in one eye, it usually progresses affecting both eyes equally.
In many cases, the disease advances without causing any discomfort or pain. Visual changes are subtle and limited to the peripheral field as opposed to the central field of vision. If left untreated glaucoma can result in a total loss of vision.
What is the Anterior Chamber?
The Anterior Chamber is simply a space behind the Cornea and in front of the iris that contains a clear, nutrient fluid (aqueous humor). The so called "drainage angle" (trabecular meshwork) is also located here. The trabecular meshwork, or TM, is a circle of specialized tissue where aqueous humor drains out of the eye. It is located at the intersection of the cornea, the sclera (the white part), and the iris, and when it is damaged, glaucoma is often the result. About 95% of patients with glaucoma have the "open angle" type; anatomically the angle is open and fluid flows up to the TM, but microscopically the TM is clogged. Unfortunately, fluid inside the eye is continuously produced by the cilliary body, and when the TM is clogged, the pressure in the eye rises, just like over inflating a ball. High pressure literally crushes the optic nerve, which becomes progressively damaged, and vision is slowly lost. In the vast majority of cases, glaucoma is completely painless and vision loss occurs so slowly (over many, many years) that people don't recognize that they have a problem until they are nearly blind in both eyes, or completely blind in one eye.
A small group of people with glaucoma have "narrow angle" or "angle closure" glaucoma. In these people, the iris mechanically blocks the trabecular meshwork, and their eye pressure can rise suddenly, with abrupt onset of pain and vision loss. Most people with glaucoma have a very slow and completely painless vision loss.

Pupil
The Pupil is literally a hole in the paper thin Iris. The Iris is one part of a layer which wraps itself around the inside of the eye called the Uvea. The parts of the Uvea include the Iris, Cilliary body (a tire like structure just behind the root of the Iris), and Choroid (a thin layer located in between the sclera and retina). The Iris contains a circular muscle that constricts the pupil in bright light, and radial muscles (like spokes on a wheel) that dilate the pupil in low light. Inflammation of the Iris is called Iritis, a painful condition characterized by sensitivity to light.

What is the Optic Nerve?
If you think of the eye as a ball, the inside layer is coated with retina. Each cell in the retina is connected to a nerve fiber (imagine a very, very thin thread) and all the nerve fibers come together in a bundle called the Optic Nerve. The eye can be thought of like a ball, and the retina and nerve fibers are on the inside, so, they need get out of the eye so they can carry information to the brain, and so there has to be a hole in the back of the eye. This hole (anatomically it's really more like a window with a screen over it) in the sclera is our natural blind spot (one per eye) and it's "filled" with the head of the optic nerve, which is just like a bundle of threads (1.5 mm in diameter). When the pressure inside the eye rises (glaucoma), this spot also happens to be the weakest spot in the eye, so the optic nerve literally is crushed, and it dies. For some reason the nerve fibers that go to our peripheral vision die first, so glaucoma in characterized by peripheral visual loss.
Even though glaucoma is due to an abnormality in the trabecular meshwork, visual loss from glaucoma occurs due to damage to the optic nerve. There are many other diseases of the optic nerve, but fortunately they are quite uncommon.
Your Optometrist may wish additional testing, which include a series of diagnostic tests for glaucoma. If glaucoma is suspected, we use the state-of-the-art laser scanning system known as the GDx or OCT Nerve Fiber Layer Scanner to thoroughly evaluate the Nerve Fiber Layer of a patient's optic nerve. The nerve fiber layer analyser is capable of detecting minor changes in the optic nerve over time thus enabling the doctor to diagnose glaucoma years before a patient actually exhibits symptoms. The earlier glaucoma is detected the less likely there will be any permanent loss of vision.
Although glaucoma is most common in individuals over 60, it can occur at any age. Certain factors such as extreme nearsightedness or diabetes have been associated with the disease. It is recommended that all individuals be tested for glaucoma at the age of 35 and then again at age 40 with regular checkups every two years thereafter. Although there is no cure for glaucoma, the disease can be controlled with a series of treatments including eye drops, oral medications, laser surgery, and microsurgery.
AT OMNI, we offer a progressive new laser treatment for glaucoma called Selective Laser Trabeculoplasty or SLT. This laser treatment reduces intraocular pressure in the eye. SLT is performed on an out-patient basis using anesthetic drops to numb your eye. The procedure takes only a few minutes. The laser targets specific cells in the eye leaving surrounding tissue unaffected. The process stimulates the body’s own healing response to lower the pressure in the eye.  Other modes of treatment include 5 different classes of medications that can be used individually or in addition to SLT treatment.

 

Glaucoma Risk-Factor Analysis
TO USE THIS ANALYSIS:  Add the weighted scores assigned to each of the variables below in Table 1 (age, race, family history, and date of last exam) then determine your level of Glaucoma Risk from Table 2.
Other historical variables (high myopia or high hyperopia, systemic hypertension, steroid use, and diabetes) are also risk factors for glaucoma, although they are not strong enough to receive a weight.
Anyone with moderate to high glaucoma risk should be examined by an Eye Care Specialist.
Any person over 75 years of age is at moderate to high risk for developing glaucoma!
All African-Americans over 50 years of age are at moderate to high risk for developing glaucoma!
Table 1

Table 2

Please note: This analysis only refers to "primary open angle glaucoma" the most common type of glaucoma in the United States. There are many, many different types of glaucoma; some can even affect newborns! In other words, you can still have glaucoma even if you score a zero on this risk-factor analysis.
This analysis was created as part of Glaucoma2001; a public service project of the AAO designed to significantly reduce the prevalence of Glaucoma by the year 2001.

Glaucoma is sometimes referred to as the “silent thief of sight” because it can cause blindness with little or no warning. Glaucoma is a group of diseases usually associated with elevated intraocular pressure leading to optic nerve damage and characteristic loss of vision. Glaucoma affects the side vision early in the disease, while the central vision is not affected to late in the disease process. It is possible to lose half of the optic nerve fibers before a change in vision is noted which is why early detection is so important.
People at risk for glaucoma include:

• Anyone over the age of 60
• African-Americans over age 40
• Family history of glaucoma
• Nearsighted individuals
• History of diabetes
• History of high blood pressure
• History of elevated intraocular pressure.

Glaucoma Screenings

We encourage you to visit your Optometrist today for a comprehensive eye exam. If they detect any signs of glaucoma, they can discuss your various treatment options. OMNI EYE CENTERS is available for your Optometrist if additional testing is necessary. A glaucoma screening consists of a complete eye exam including measurement of intraocular pressure and examination of the optic nerve. Those at high risk for glaucoma should also have measurement of corneal thickness, visual field testing, and optic nerve imaging.

 

Treatments

Treatment of glaucoma usually consists of eye drops or laser surgery, but can require major eye surgery in difficult cases. Early detection is key in the successful management of glaucoma. We have at our disposal the most modern tools for glaucoma management including:

• SLT laser treatments
• GDx nerve fiber analysis
• OCT retinal imaging
• Pachymetry
• Glaucoma drug trials