Glaucoma

Glaucoma

Glaucoma is common eye disease in older patients in which the optic nerve of the eye is damaged, resulting in vision loss. There are two main forms of glaucoma: open angle glaucoma and angle closure glaucoma. Open angle glaucoma is the most common form of glaucoma and it often goes undetected in the early stages. The reason it goes undetected is that it is painless so a person does not realize that they are slowly losing they ability to see until it has become too severe. That is why it is important to have regular eye exams to check for disease such as glaucoma that can slowly become more damaging over time. The other main form of glaucoma is called angle closure glaucoma. This much less common than open angle glaucoma but it can also cause damage to the optic nerve, sometimes much more rapidly and in a painful fashion that is noticeable to the patient.

 

Regardless of the type of glaucoma, the result is the same, characteristic damage to the optic nerve of the eye. As the eye is damaged from glaucoma, optic nerve fibers are destroyed, causing the optic nerve to look increasingly “cupped,” as if a larger and larger ice cream scooper is used to remove a pit from its center. As this loss of tissue progresses, it becomes visible to the doctor examining the eye, helping make the diagnosis of glaucoma. The progressive loss of optic nerve tissue causes loss of vision as well. The peripheral vision is usually affected at first. Then, as the disease progresses, central vision or even total blindness may occur.

Causes Of Glaucoma

Though glaucoma is a very well-known disease and many treatments are available. Doctors don’t fully understand how it occurs or why it occurs in some eyes and not in others. A prevailing belief among the doctors and scientists that study glaucoma is that the disease may be caused by abnormalities in the drainage system of the eye called the trabecular meshwork. In open angle glaucoma, though the trabecular meshwork looks normal when examined by the doctor, many believe there are internal problems not visible that lead to the inability to drain the eye fluid properly. If the trabecular meshwork drain fails to allow the fluid to leave the eye, a mounting pressure can increase which will cause the eye to inflate. In angle closure glaucoma, the trabecular meshwork drain can become blocked by the iris, abnormal blood vessels or scar tissue which can also cause dramatic and sometimes rapid rises in the eye pressure. An increasing pressure on the eye may be one of the ways in which the optic nerve becomes damaged in glaucoma. In fact, many people who suffer from open angle glaucoma have abnormally high eye pressures, suggesting that eye pressure is related to the mechanism of glaucoma damage. However, some patients who have a high pressure in their eyes do not experience glaucoma, whereas some patients who have no pressure in their eyes suffer from glaucoma. Doctors believe that while eye pressure plays a role in glaucoma to an extent, and that lowering the eye pressure can be a helpful form of treatment, other unknown irregularities in the eye or optic nerve are also at play in the disease.

Symptoms

In most forms of open angle glaucoma, there are often no clear symptoms for a patient to look for in the early stages. As time passes and the disease advances into the later stages and increasing loss of vision become apparent, a patient's peripheral vision maybe be lost. In most cases, the central vision remains strong but this, too, will deteriorate over time until a person is left with tunnel vision. Regular eye exams are encouraged so that patients can be screened for glaucoma.

Most forms of angle closure glaucoma have recognizable symptoms. A person may suffer from periods of pain, ranging from a minimal discomfort to extreme aching pain of the eye and head. With each episode of pain, the vision may become very blurred. For this reason, people with angle closure often seek medical help sooner and are diagnosed with the disease before those with open angle glaucoma. Sometimes, angle closure symptoms are very mild and can go undetected by a patient.

Examination For Glaucoma

To determine if you have glaucoma, your eye doctor will normally perform a series of tests. A thorough evaluation will be performed in order to make sure nothing gets missed. Your doctor will measure your visual acuity. Additionally, your refraction, or best vision with glasses, may also be checked. Your eye pressure will also be measured carefully, and the thickness of your corneas may also be checked, as thinner corneas are a risk factor for glaucoma. Your pupils will also be tested, which help the doctor to determine if your optic nerves are working properly. Your peripheral vision will likely be checked by counting fingers with the edge of your vision. You may also have a computer check your peripheral vision during an automated visual field examination. Your doctor will perform a slit lamp examination to examine the eye and the lens. The trabecular drainage system of your eye may be examined with a special contact lens, called a gonioscopy lens. Your eyes may be dilated to help the doctor view the lens and the back part of the eye and examine the optic nerve carefully. A retinal exam may also be performed during the dilated examination. Photographs of your optic nerves or computer scans of the optic nerve shape may also be taken. 

As glaucoma develops into the moderate or advanced stages of the disease, optic nerve fibers are destroyed, causing the optic nerve to look as if has been hollowed out. Your doctor may also be able to see the loss of small sections of retinal nerves around the optic nerve, or small areas of bleeding on the optic nerve. Additionally, if angle closure is present, your doctor may be able to see iris or scar tissue physically blocking the trabecular drain.

Treatment

Early glaucoma treatment normally involves eye drops that help to lower the eye pressure. These medications commonly work by decreasing the amount of fluid produced by the eye, with less fluid being produced there will be less pressure in the eye. Other forms of eye drops work by allowing my fluid to drain out of the eye(s). The use of these medicated eye drops can slow or halt the formation of glaucoma.

In some cases eye drops alone are not strong enough to delay the glaucoma from becoming worse over time. In cases where eye drops are not work, doctors may suggest a form of surgery. The doctor will go over which surgery is suitable for your eyes depending on the type or glaucoma and the severity of the level it is currently at.

Prevention

Once vision is lost with glaucoma, it cannot be restored. The best way to help prevent glaucoma is to visit your doctor for regular eye exams to ensure that your eyes are in a healthy condition. With regular eye exams glaucoma can be caught before vision becomes impaired. For this reason, everyone should have regular eye exams to screen for glaucoma. If you have a family history of eye diseases and glaucoma, you should have eye exams more frequently as you may be at a greater risk for glaucoma.