Glaucoma

Glaucoma is a grouping of eye disorders that typically have little to no preliminary signs or symptoms. However, eventually they will cause damage to the nerve that carries data from the eye and into the brain. The optic nerve is the affected area.

The majority of cases of glaucoma are connected with more than normal pressure inside the eye which is called ocular hypertension. If it's not treated and controlled, glaucoma can cause loss of peripheral vision and blindness is the next eventuality.

While glaucoma is the number one cause of global blindness, cataracts come in at a close second.

Signs and Symptoms

Glaucoma is often referred to as the silent thief of sight. This is because most forms will be symptom and pain free until there is a noticeable loss of vision. Because of this, glaucoma usually goes undetected until there is already irreversible damage to the optic nerve.

However, symptoms that occur from acute angle-closure glaucoma come on suddenly and may include the following:

• Blurred vision
• Intense eye pain
• Nausea
• Vomiting
• Halos surrounding lights

If you notice any of these signs and symptoms you should see your practitioner immediately so vision loss prevention steps can be taken.

Test, Screening, and Diagnosis

During regular eye exams, intraocular pressure (IOP) is tested through use of a tonometer. Typically the eye is first numbed with dilation drops. Next, there is a small probe rested gently against the surface of your eye.

An IOP reading that is abnormally high indicates that there is a problem, fluid in the eye is too high. This is because it is not properly draining or has a high rate of fluid production. The IOP should normally be under 21mmHG (this means millimeters of mercury). This is a unit of measurement that is based upon the amount of force that is exerted in a specifically defined spot. If this number is above 30mmHG then your risk of going blind from glaucoma is 40 times higher than those with a measure of 15mmHG, and this is the reason glaucoma treatments are made to keep the IOP number low.

Additional methods of glaucoma monitoring include using imaging technology like optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy. These tests help to develop base line measurements and images of the optic nerve and other inside structures. Then, at specific times, more measurement and images are taken in order to make sure that no changes have happened which may indicate more progressive damage caused by glaucoma.

A method for determining if you are having vision loss due to glaucoma is visual field testing. This method involves looking straight forward into a machine and pressing a button when you see a blinking light within your peripheral vision. This test can be repeated regularly to ensure that blind spots are not developing due to optic nerve damage or to determine the progression of your vision loss due to glaucoma.

Gonioscopy can also be done to ensure that the aqueous can freely drain from the eyes. This test uses special lenses along with a biomicroscope which enables your eye doctor to see the inner eye structure that controls the flow of the aqueous and therefore affects the intraocular pressure. Another technique used to evaluate drainage angles is ultrasound biomicroscopies.

Glaucoma Types

There are two major kinds of glaucoma; acute angle-closure and open-angle glaucoma (POAG). These can both be primary or chronic types of glaucoma. In both cases angle refers to drainage within the eye that controls the outflow. Additional variations include pigmentary glaucoma, normal tension glaucoma, congenital glaucoma and secondary glaucoma.

Angle Closure Glaucoma: Also known as narrow angle glaucoma comes with sudden signs such as headaches, halos surrounding lights, eye pain, vision loss, nausea, vomiting, red eyes and dilated pupils. These symptoms might last for only a couple of hours, and then come back later. Every attack can cause more vision loss; it is a progressive condition.

Primary Open Angle Glaucoma: This kind of glaucoma slowly reduces your peripheral vision with no other symptoms. By the time it is noticed, permanent damage has already occurred.

If your IOP stays high, the damage caused by POAG can grow until you develop tunnel vision and you will only be able to see things straight ahead.

Normal Tension Glaucoma: As with POAG, normal tension glaucoma is a kind of open angle condition that has the ability to cause loss of visual field which is due to damage to the optic nerve. However, with normal tension glaucoma, the IOP stays within a normal range.

Pain is not likely and the damage to the optic nerve might not be noticed until signs like tunnel vision develop.

Secondary Glaucoma: The symptoms of this type of chronic glaucoma typically come after an injury to the eye, though it can also happen due to an infection of the eye or a tumor.

Congenital Glaucoma: This kind of glaucoma is genetic and is present at the time of birth. 80% of cases are found by the time the child reaches the age of 1 year old. The children who have congenital glaucoma are born with narrowed angles or another drainage system defect. Spotting signs of this condition is difficult since children are not old enough to understand what is going on. If you notice a white, cloudy, hazy or protruding or enlarged eye in the child, consult with an eye doctor. Congenital glaucoma usually presents in boys more than it does girls.

Pigmentary Glaucoma: This kind of glaucoma is rare. It is caused when clogging occurs in the drainage angle of the eye because pigment has broken away from the iris. This reduces the rate of outflow and over a period of time, the drainage system is damaged.

With this kind of glaucoma, you are not likely to notice any signs or symptoms even though there may be some blurred vision or pain after exercise. Pigmentary glaucoma most commonly affects white men between 35 and 45 years old.

Prevention

According to research done recently in Europe, exercising may help reduce the risk of developing glaucoma. Researchers in the United Kingdom found that doing higher amounts of exercise seem to provide benefits that include lowering the incidence of OPP which is a factor important to glaucoma risk. OPP is a math value that is figured out by using the intraocular pressure and blood pressure. The results of this study showed that those who engaged in at least moderate exercise 15 years before the study was done has a 25% reduction of OPP that could lead to glaucoma development. Overall, maintaining a lifestyle that is active seems to be a good way for people to lower the risk of developing glaucoma and other health problems. Plus, not smoking, staying at a healthy weight and having good eating habits can also reduce the risk of glaucoma.

Available Treatments

Treatment for glaucoma can involve surgery, medication, or lasers depending on how severe the case. Eye drops are usually tried first since it is the least invasive course of treatment. Since glaucoma is usually painless, people may not be as careful about using eye drops to help control the pressure and prevent damage to the eye. In fact, not complying with a treatment programs is the biggest reason that people go blind from glaucoma.

If you are using eye drops and find that they are not comfortable or convenient, do not stop taking them until you speak to your doctor about other forms of treatment.