You may not notice peripheral loss of vision as central vision is maintained till end stage of Glaucoma.
Glaucoma is the second most common cause of blindness. Patients may not get any symptoms like pain in the eye or loss of vision and may lead to permanent loss of vision.
Glaucoma can be detected by checking the eye pressure, examination of the Optic nerve and computerized visual field testing with the latest Humphrey Perimeter from Zeiss.
Glaucoma is an eye disorder in which the major risk factor is increased pressure within the eye. Glaucoma is a disease that damages the optic nerve and causes loss of vision. Unfortunately, there are no discernible symptoms in the early stages of the disease, and glaucoma-induced damage to your eye is irreversible.
Globally, glaucoma is the second most common cause of blindness after cataract. It accounts for 7-8 million bilaterally blind people. In India, it is responsible for 8-12% of blindness. Half of the people with glaucoma are usually unaware of it until serious loss of vision has occurred. The good news is that there are simple diagnostic tests, which, if performed regularly, can detect the disease in its early stages while serious vision loss is still preventable.
Types of Glaucoma
There are many types of Glaucoma. The four most common varieties include:
Chronic Open-Angle Glaucoma
By far the most common type, open-angle glaucoma can steal vision so quietly that you may be unaware of any problem until your optic nerve is badly damaged. Blockages in your eye’s natural drainage system build up over time, often as a result of the natural aging process. The first symptom of open-angle glaucoma may be vision that is blurred at the edges, but by this time the optic nerve is irreparably damaged.
Acute Angle-Closure Glaucoma
This type of glaucoma occurs suddenly when the iris presses against the drainage area and closes it off. Fluid backs up and pressure rises rapidly. Symptoms of angle-closure glaucoma include blurred vision, severe pain, nausea, vomiting and the appearance of rainbow halos around lights. Immediate medical attention is essential as angle-closure glaucoma can lead to blindness within days.
Channels within the eye can become blocked for reasons such as infection, injury, diabetes, certain drugs, hemorrhage or tumors. This condition, called secondary glaucoma, may exhibit symptoms similar to angle-closure glaucoma. Secondary glaucoma requires prompt medical attention to prevent serious vision loss.
In rare cases, the drainage system within the eye is poorly formed at birth. The natural elasticity of the infant eye may allow rising pressure to be accommodated for a while, but eventually a problem develops. The infant may be sensitive to light or may tear excessively; the front of the eye may appear cloudy or “foggy.”
Signs & Symptoms,
What are the Symptoms?
At first, there are no symptoms. Vision stays normal, and there is no pain. However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease worsens, the field of vision narrows and blindness results.
Same scene as viewed by a person with glaucoma
What Causes Glaucoma?
Normally, a clear fluid called the aqueous humour flows through your inner eye, bathing it constantly and nourishing the surrounding tissue. With glaucoma, the fluid drains too slowly and builds up causing pressure inside the eye to rise. The pressure, in turn, affects the optic nerve, which is like an electronic cable carrying messages to your brain - messages that normally result in sharp, clear vision. If the entire nerve is destroyed, blindness is the result.
Are there other risk factors?
Race: Narrow angle glaucoma is more common in Asians. African-Americans and older Hispanics are four or five times more likely than Caucasians to develop open angle glaucoma, and are six times more likely to suffer blindness as a result of glaucoma.
Risk factors in addition to age and race include:
- High blood pressure
- Injury to the eye
- Family history of glaucoma.
- Open angle glaucoma is associated with myopia (shortsightedness), while narrow angle glaucoma is associated with hyperopia (far sightedness)
People with two or more risk factors are urged to have a complete eye examination, including dilation, every year.
Early detection is the key
It is estimated that nearly half of the patients who have glaucoma are unaware of it. That is why regular examinations- even when you have no symptoms- are so important. However, elevated eye pressure is not always a sign of glaucoma. Approximately one-third of those who develop glaucoma do not have elevated eye pressure.
A far better precaution is a professional eye exam which includes pupil dilation and inner eye examination by ophthalmoscope, as performed at DLEI. If you are over 40, we recommend you have your eyes professionally checked for glaucoma every year.
How is glaucoma detected?
Glaucoma is detected through a Comprehensive Eye Exam, which may include:
- Measuring your intraocular pressure (tonometry)
- Inspecting the drainage angle of your eye (gonioscopy)
- Evaluating whether or not there is any optic nerve damage (ophthalmoscopy)
- Testing the peripheral vision of each eye (visual field testing or perimetry)
- Photography of the optic nerve or other computerized imaging may be recommended. Some of these tests will not be necessary for everyone.
Generally, damage caused by glaucoma cannot be reversed. Glaucoma treatments include medicines - oral tablets and eyedrops, LASER treatment, conventional surgery, or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from glaucoma.
Surgical and Non-Surgical Glaucoma Treatments
If you are found to have glaucoma, you will probably be treated with medication in the form of eye drops or pills. The medication works to reduce pressure by decreasing the amount of fluid entering your eye or assisting fluid flow through your eye.
In some cases, your medication may produce side effects such as blurred vision or occasional headaches; the eye drops may redden your eye or sting, and your night vision may be reduced. Most of these simple side effects lessen over time; however if you experience more serious side effects such as drowsiness, tingling of fingers and toes, loss of appetite or changes in pulse, heart rate and breathing, you should notify your doctor.
In cases where medication cannot be tolerated or loses its effectiveness over time, surgery is necessary to prevent further vision loss.
Controlling glaucoma is up to you
As we have said, glaucoma- often called the "sneak thief" of sight- is not normally heralded by obvious symptoms. To safe-guard vision, anyone over 40 should undergo a comprehensive eye examination every year. This also applies if other risk factors are present such as high blood pressure, diabetes or a family history of glaucoma.
If you have been diagnosed with glaucoma, you must follow instructions meticulously with regard to your medication. It must become a central part of your daily routine if it is to be effective! You should never stop taking your medication without talking to your ophthalmologist or optometrist. Also, if you are seeing other physicians for any reason, tell them about your eye medication.
Finally, because the effects of glaucoma may worsen (or improve) without your being aware of the change, follow your eye doctor's recommendations on regular check-ups to monitor your progress.
Glaucoma and high blood pressure
Glaucoma is not generally related to high blood pressure, however, any patient on high blood pressure medication should inform their ophthalmologist and family doctor of all medications they are currently taking. Certain drugs taken for glaucoma can interact with those taken for other conditions.