WHAT IS GLAUCOMA ?
Glaucoma is a condition where the optic nerve gets gradually and irreversibly damaged due to various reasons. The optic nerve is like an electric cable with over a million wires which is responsible for carrying images from the eye to the brain. In glaucoma, loss of this nerve tissue results in vision loss. Its popularly known as “the silent thief of sight”, because in most cases, it does not manifest with
symptoms until the later stages of the disease. Initially, glaucoma affects peripheral or side vision, but it can advance to central vision loss. If left untreated, glaucoma can lead to significant vision loss in both eyes, and may even lead to blindness. It is estimated that half of the people affected by glaucoma may not know they have it. It is the second leading cause of blindness in the world.
Glaucoma can not currently be prevented. But if it is diagnosed and treated early, it can usually be controlled. Medication or surgery can slow or prevent further vision loss. However, vision already lost to glaucoma cannot be restored. That is why at Rushabh Eye Hospital and Laser Centre, we recommend a regular dilated eye examination for people at risk for glaucoma. Depending on your specific condition, our glaucoma specialist may recommend more frequent examinations.
WHAT CAUSES GLAUCOMA ?
There are many theories about the causes of glaucoma, but the exact cause is unknown. Most commonly, a build-up of the fluid in the eye causing a rise in eye pressure, also known as intraocular pressure (IOP) is responsible for the progressive nerve damage. The mechanisms leading to an increase in IOP are varied.
Think of the eye as a sink with a tap that is always open. The water flows through if the drainage mechanism is working all right. The trouble arises when the drainage is clogged and the water begins to collect. In the same way, the inside of the eye contains fluid that is constantly flowing and is drained out of the eye. When the drainage channels in the eye don’t function properly, the fluid in the eye gets accumulated and over a period of time it leads to increased IOP.
Although IOP is clearly a risk factor, we now know that other factors must also be involved because even people with “normal” levels of pressure can experience vision loss from glaucoma, possibly due to lack of adequate blood supply to the nerve.
TYPES OF GLAUCOMA
ADULT GLAUCOMA BROADLY FALLS INTO TWO CATEGORIES :
- Primary Open Angle Glaucoma
- Closed Angle Glaucoma
These are marked by increase of intra ocular pressure (IOP), or pressure inside the eye.
PRIMARY OPEN ANGLE GLAUCOMA
This is the most common form of glaucoma. Damage to the optic nerve is slow and painless. Those affected can lose a large portion of vision before they notice any vision problems.
It is believed that the eye’s drainage system becomes inefficient over time due to possible microstructural changes in the drainage channels. This leads to an increased amount of fluid and a gradual build-up of IOP. Other theories also exist.
CLOSED ANGLE GLAUCOMA
This type of glaucoma, also called narrow-angle glaucoma, is a less common form of the disease. It is a medical emergency that can cause vision loss within a day of its onset. This happens when the drainage canals get blocked or covered over, like a sink with something covering the drain. With angle-closure glaucoma, the drainage angle is not as wide and open as it should be. The outer edge of the iris bunches up over the drainage canals when the pupil enlarges too much or too quickly. This can happen when entering a dark room or lying down on your stomach. It can also happen in predisposed individuals who have a narrower drainage angle because of genetic reasons or due to a cataract.
Glaucoma can develop slowly or acutely. Symptoms of acute angle-closure glaucoma include headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision.
This type of glaucoma can result from an eye injury or other eye disease. It may be caused by a variety of medical conditions, medications such as steroids, topiramate, and other eye abnormalities. Infrequently, eye surgery can lead to secondary glaucoma.
NORMAL-TENSION OR LOW-TENSION GLAUCOMA
In this form of glaucoma, eye pressure remains within the “normal” range, but the optic nerve is damaged nevertheless. The exact reasons for this are unknown. Lack of adequate blood supply to an already compromised optic nerve can be one of the reasons. This form of glaucoma is often difficult to diagnose and treat in time.
Glaucoma is not confined only to adults. Congenital Glaucoma occurs in newborns. A child born with Glaucoma is also known as Buphthalmos. The child’s eye may appear large, whitish, and have constant watering and aversion to light. It needs to be treated at the earliest as the child may lose vision completely if not treated surgically.
WHAT ARE THE RISK FACTORS FOR GLAUCOMA?
- Age: Glaucoma is much more common among older people. You are six times more likely to get glaucoma if you are over 40 years old. Everyone is at risk for glaucoma from babies to senior citizens. Yes, older people are at a higher risk for glaucoma but babies can be born with glaucoma (approximately 1 out of every 10,000 babies born in the world). Young adults can get glaucoma, too.
- Positive Family History: The most common type of glaucoma, primary open-angle glaucoma, is hereditary. If members of your immediate family have glaucoma, you are at a much higher risk than the rest of the population. A family history of glaucoma increases the risk of glaucoma four to nine times.
- Indiscriminate use of Steroids: Studies indicate Steroids increase intraocular pressure. These could be in the form of Oral medications, Steroid Inhalers, and Steroid Eye Drops used for long periods.
- Injury to Eye: Injury to the eye may cause secondary open-angle glaucoma. This type of glaucoma can occur immediately after the injury or years later.
- Advanced cataract: Cataracts, if allowed to progress without any surgery can lead to glaucoma.