Home > Eye Disorders > Glaucoma
- About Glaucoma
- Causes and symptoms
- How is it Diagnosed
- How is it Treated
- Medication and Care to be Taken
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What is glaucoma?
Glaucoma is hypertension of the eye with raised eye pressure. Glaucoma is disease of the optic nerve-the part of the eye that carries the images we see to the brain. The optic nerve is made up of many nerve fibers, like an electric cable containing numerous wires. When damage to the optic nerve fibers occurs, blind spots develop. If the entire nerve is destroyed, blindness results.
Early detection and treatment by your ophthalmologist are the key to preventing optic nerve damage and blindness from glaucoma. Glaucoma is a asymptotic in the early stages and might be missed if a patient doesn’t come for frequent eye checkups. Every patient after the age of 40 must have eye pressure measurement.
Glaucoma is a leading cause of blindness especially for older people. But loss of sight from glaucoma can often be prevented with early treatment.
What causes glaucoma?
There is a Clear liquid called aqueous humor circulates inside the front portion of the eye. To maintain a healthy level of pressure within the eye, a small amount of this fluid is produced constantly while an equal amount flows out of the eye through a microscopic drainage system. The perfect inflow and outflow of the fluid maintain the normal pressure of the eye any imbalance leads to Glaucoma.
Because the eye is a closed structure, if the drainage area for the aqueous humor—called the drainage angle—is blocked, the excess fluid cannot flow out of the eye and hence the Fluid pressure causes increased intra ocular tension. Within the eye the pressure increases, pushing against the optic nerve and causing damage by strangulating the nerve fibres causing pressure atrophy.
What are the different types of glaucoma?
Chronic open-angle glaucoma: This is the most common form of glaucoma in the West but in India closed angle Glaucoma is preponderant.
The risk of developing chronic open-angle glaucoma increases with age. The cause of this Glaucoma is unknown. The dranage angle of the eye becomes less efficient over time, like the choking of the drainage sink due to collection of debris and pressure within the eye gradually increases, which can damage the optic nerve. Treatment is necessary to prevent further vision loss.
Typically, open-angle glaucoma has no symptoms in its early stages, and vision remains normal. As the optic nerve becomes more damaged, blank spots begin to appear in your field of vision. You typically won’t notice these blank spots in your day-to-day activities until the optic nerve is significantly damaged and these spots become large. If all the optic nerve fibers die, blindness results.
Closed-angle glaucoma: This is the commonest type of Glaucoma in the India population Some eyes have the iris (the colored part of the eye) too close to the drainage angle. In these eyes, which are often small and farsighted, the iris can be sucked into the drainage angle like the bellowing of the sail causing Iris Bombe and block it completely. Since the fluid cannot exit the eye, pressure inside the eye builds rapidly and causes an acute closed-angle attack.
Symptoms may include:
- Red Eye
- Blurred vision;
- Severe eye pain;
- Rainbow-colored halos around lights;
- Nausea and vomiting.
This is a true eye emergency. The eye pressure might increase upto 50 mm of m Mercury ( Normal Pressure 14 to 21mmhg) If you have any of these symptoms, call your ophthalmologist immediately. Unless this type of glaucoma is treated quickly, blindness can result.
Unfortunately, two-thirds of those with closed-angle glaucoma develop it slowly without any symptoms prior to an attack. This is called as a creeping angle closure.
Narrow angles can be very easily diagnosed on Gonioscopy test.
Who is at risk for glaucoma?
Your ophthalmologist considers many kinds of information to determine your risk for developing the disease.
The most important risk factors include:
- Elevated eye pressure;
- Family history of glaucoma;
- Farsightedness or nearsightedness;
- Past eye injuries;
- Thinner central corneal thickness;
- Systemic health problems, including diabetes, migraine headaches, and poor circulation.
Your ophthalmologist will weigh all of these factors before deciding whether you need treatment for glaucoma, or whether you need treatment for glaucoma, or whether you should be monitored closely as a glaucoma suspect – A person who has a high index of developing Glaucoma in the nearer future and should be closely followed up.
How is glaucoma detected?
Regular eye examinations by your ophthalmologist are the best way to detect glaucoma. A glaucoma screening that checks only the pressure of the eye is not sufficient to determine if you have glaucoma. The only sure way to detect glaucoma is to have a complete eye examination.
During your glaucoma evaluation, your ophthalmologist will:
- Measure your intraocular pressure (tonometry);
- Inspect the drainage angle of your eye (gonioscopy);
- Evaluate whether or not there is any optic nerve damage (ophthalmoscopy);
- Test the peripheral vision of each eye (visual field testing, or perimetry).
These tests may need to be repeated on a regular basis to monitor any changes in your condition and to see for progression of damage.
How is glaucoma treated?
As a rule, damage caused by glaucoma cannot be reversed because optic nerve is part of brain tissue and cannot regenerate. Eyedrops, laser surgery, and surgery in the operating room are used to help prevent further damage. In some cases, oral medications may also be prescribed.
The treatment of narrow angle Glaucoma is surgical – Nd YAG laser Iriditomy while the treatment of open angle Glaucom is the early stages is medically and Trabaculectomy surgery in advance cases.
With any type of glaucoma, periodic examinations are very important to prevent vision loss. Adjustments to your treatment may be necessary from time to time depending on disease progression.
Medication and Care to be Taken
Open angle Glaucoma is usually controlled with eyedrops taken daily. These medications lower eye pressure, either by decreasing the amount of aqueous fluid produced within the eye or by improving the flow through the drainage angle.
Never change or stop taking your medications without consulting your ophthalmologist. Glaucoma medications can preserve your vision, but they may also produce side effects. You should notify your ophthalmologist if you think you may be experiencing side effects.
Some eyedrops may cause:
- A stinging or itching sensation;
- Red eyes or redness of the skin surrounding the eyes;
- Changes in sense of taste;
- Blurred vision;
- Change in eye color.
Various new drugs are very powerful in reducing the eye pressure to safe levels ans hence the need for surgey is now reducing. EG Prostaglandin analogues.
Laser surgery treatments may be recommended for different types of glaucoma. In open-angle glaucoma, the drain itself is treated. The laser is used to modify the drain argon laser trabeculoplasty – ALT, SLT to help control eye pressure. In closed –angle glaucoma, the laser creates a hole in the iris laser iridotomy to improve the flow of aqueous fluid to the drain and relieve the relative papillary block by providing an alternate pathway.
Surgery in the operating room – Trabeculectomy, NPDS
When surgery in the operating room is needed to treat glaucoma, your ophthalmologist uses fine microsurgical instruments to create a new drainage channel for the aqueous fluid to leave the eye. This is like a by pass surgery of the eye. Surgery is recommended if your ophthalmologist feels it is necessary to prevent further damage to the optic nerve.
Treatment for glaucoma requires teamwork between you and your doctor. Only you can make sure that you follow your doctor’s instructions and use your eye drops on time.
Loss of vision can be prevented if Glaucoma is diagnosed and treated early.
Regular medical eye exams can help prevent unnecessary vision loss. Recommended intervals for eye exams are:
- Ages 40 to 64: Every 2 to 4 years.
- Ages 65 or older: Every 1 to 2 years.