What is Glaucoma?
Glaucoma is a group of diseases that can lead to damage to the eye’s optic nerve and result in blindness. It is causes by intraocular pressure (IOP) resulting either from an over production of fluid called aqueous in the eye or reduction in drainage of this fluid.
Glaucoma is frequently referred to as the “SNEAK THIEF OF SIGHT” because it progress without any obvious symptoms.
What is The Optic Nerve?
A bundle of more than 1 million nerve fibers. It connects the retina, the light sensitive layer of tissue at the back of the eye with the brain by carrying visual signals from the eye to the brain.
How Does Glaucoma Damage The Optic Nerve?
Glaucoma can cause damage when the aqueous humor (a fluid that inflates the front of the eye and circulated in a chamber called the anterior chamber) enters the eye but cannot drain properly from the eye. Elevated pressure inside the eye, in turn, can cause damage to the optic nerve or the blood vessels in the eye nourish the optic nerve. This is not the only mechanism of damage.
Who is At Risk?
Although anyone can get glaucoma, some people are at higher risk than others.
- individual over age of 40
- people with a family history of glaucoma
- individuals with other eye diseases which may secondarily result in glaucoma or elevated pressure
- there is a strong prevalence in people with diabetes and hypertension
- people on long use of steroids
- people of African or Scandinavian descend.
Common Types of Glaucoma:
- open angle glaucoma (chronic)
- closed angle glaucoma (acute)
- low-tension or normal-tension glaucoma
- congenital glaucoma (seen in infants)
- secondary glaucoma (results of injury or trauma)
Signs & Symptoms
Glaucoma is an insidious disease because it rarely causes symptoms.
Open Angle Glaucoma
Open angle glaucoma accounts for the majority of glaucoma cases. It occurs slowly as people age. The drainage area in the eye becomes clogged. Not enough fluid drains from the eye, so pressure slowly builds up. This causes loss of peripheral vision. But the loss is so gradual you may not even notice it.
Closed angle glaucoma
Closed angle glaucoma is more prevalent among the Chinese compared with the Caucasians. It usually happens quickly. The drainage area in the eye suddenly becomes completely blocked. Eye pressure builds rapidly. You may notice blurred vision and rainbow halos around lights. You may also have headaches, nausea, vomiting, and severe pain. If not treated right away, blindness can occur quickly. Middle-aged and elderly Chinese women are usually affected.
What Must You Know…..
Angle Closure (Emergency)
- Sudden decrease of vision
- Extreme eye pain & redness
- Nausea & vomiting
- Glare & light sensitivity
- Light sensitivity
- Enlargement of the cornea
- Loss of peripheral vision
A person with glaucoma my notice that although he sees things clearly in front of the, the miss objects to the side and out of the corner of their eye.
How is Glaucoma Detected?
Glaucoma is detected and diagnosed by an Ophthalmologist.
Tests that are usually carried out:-
- Visual acuity test
- Visual field charting
- Pupil dilation and funduscopy
- Tonometry and gonioscopy
- Optical Coherence Tomography (OCT)
A wide variety of treatments are available for reducing the intraocular pressure, the only known effective treatment for glaucoma.
- Medicine: Medicines are the most common early treatment for glaucoma. They come in the form of eyedrops and pills. Some medicines reduce the amount of fluid your eyes make. Others increase drainage in the eyes.
- Laser surgery (also known as trabeculoplasty): A special lens is held to your eye. A high energy beam of light is aimed at the lens and reflected onto the meshwork inside your eye. The laser makes 50-100 evenly spaced burns. These burns stretch the drainage holes in the meshworks. This helps to open the holes and lets fluid drain better through them.
- Laser iridotomy : this procedure creates an alternative path for the aqueous to follow inside the eye. This reduces the risk of sudden increase in eye pressure called acute glaucoma
- Conventional surgery: A new channel for aqueous humor (fluid) to drain into the blood circulation is created. This will enable the intraocular pressure to be maintained at normal tension. This surgery is called Trabeculectomy.
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