Glaucoma is a condition in which the pressure within the eye is elevated. The elevated pressure damages the optic nerve. Because such nerve damage can lead to blindness, the pressure must be lowered by medication, laser therapy or surgery.
In most people, glaucoma can be controlled with medicated eyedrops. While most patients are prescribed one or two different types of eyedrops, there are actually four major classes of eyedrops that can all be used together if needed.
Surgery may be necessary in severe cases of glaucoma that do not respond to medication. In the standard "filtering" procedure, the surgeon creates an "escape" hole that allows excess fluid to drain from the eye, thereby lowering the pressure.
If a person has a visually significant cataract along with glaucoma, a surgeon may recommend combined glaucoma-cataract surgery. This surgery is very effective at both lowering eye pressure and improving vision (by removing the cataract-clouded lens and inserting a new artificial lens).
There are two main forms of glaucoma: open-angle (which is the most common form and affects approximately 95% of individuals) and closed-angle. There are also several other varieties of glaucoma, including normal-tension, congenital, juvenile and secondary.

Open-angle glaucoma, the most common form of the disease, has no symptoms at first. It is a progressive disease characterized by optic nerve damage. High eye pressure is the most significant recognized risk factor for the development and progression of the disease. The pressure in the eye builds up gradually. At some point, side vision (peripheral vision) is lost and without treatment, total blindness will occur.

Closed-angle glaucoma may be acute or chronic. Acute closed-angle glaucoma results when the normal flow of eye fluid (aqueous humor) between the iris and the lens becomes suddenly blocked. Symptoms may include severe pain, nausea, vomiting, blurred vision, and seeing a rainbow halo around lights. Acute closed-angle glaucoma is a medical emergency and must be treated immediately or blindness could result in one or two days. Chronic closed-angle glaucoma progresses more slowly and can produce damage without symptoms, similar to open-angle glaucoma.
 
Normal-tension or low-tension glaucoma occurs in people with normal eye pressure who have optic nerve damage and experience narrowed side vision. Lowering eye pressure at least 30 percent through medicines slows the disease in some people. Glaucoma may worsen in others despite low pressures. A comprehensive medical history is important in identifying other potential risk factors, such as low blood pressure, that contribute to low-tension glaucoma. If no risk factors are identified, the treatment options for low-tension glaucoma are the same as for open-angle glaucoma.

Congenital glaucoma is a condition where babies are born with defects that prevent the normal drainage of fluid from the eye. Juvenile glaucoma has been used to describe open-angle glaucoma in children, adolescents and young adults.

Secondary glaucoma occurs as the result of some other recognizable medical condition in the eye or the body, and can be of the open-angle or closed-angle variety

Neovascular glaucoma results from abnormal blood vessel growth that blocks the fluid drainage channels of the eye, resulting in increased eye pressure. Low blood supply to the eye as a result of diabetes, insufficient flow of blood to the head due to blocked arteries in the neck, or blockage of blood vessels in the back of the eye can cause the abnormal blood vessel growth.

Currently, there is no “cure” for glaucoma; however, early diagnosis and treatment can control glaucoma before vision loss or blindness occurs. Several tests can help your eye doctor detect glaucoma. Individuals at high risk for glaucoma should have a dilated pupil eye examination every year. Tests involved in the diagnosis of glaucoma include:
Visual acuity measures how well you see at various distances. While seated 20 feet away from an eye chart, the patient is asked to read standardized visual charts with each eye. The test will be performed with and without corrective lenses

Ophthalmoscopy allows the eye doctor to examine the interior of the eye by looking through the pupil with a special instrument. It is helpful in detecting damage to the optic nerve that is due to the effects of glaucoma.
           

Gonioscopy allows the doctor to view the front part of the eye (anterior chamber) to determine if the iris is closer to the back of the cornea than usual. This test can help diagnose closed-angle glaucoma.

Tonometry measures the pressure inside the eye. The following are examples of tonometers: One is the air puff, or noncontact tonometer, that emits a puff of air. The eye’s resistance to the air indicates the eye pressure. Another is the applanation tonometer which actually touches the eye’s surface after your doctor has placed drops in both your eyes to numb them. The applanation tonometer measures the amount of pressure necessary to flatten the cornea. The applanation tonometer is the most sensitive. But, the patient must have a clear, regularly-shaped, cornea in order for the applanation tonometer to function properly.

Ocular Rigidity Analyser
. 

HFAIIi

Pachymetry involves using an ultrasonic wave instrument to help determine the thickness of the cornea. This test can help your doctor better evaluate your eye pressure readings.

Optic nerve imaging helps the eye doctor document how the optic nerve changes over time. Scanning laser polarimetry (GDx), confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph or HRT II), and optical coherence tomography (OCT) are all examples of optic nerve imaging techniques. All three imaging techniques are painless and non-invasive.

There are a number of different eye drop medication categories. If you are taking eye drops, you should be aware of what they do and the side effects associated with their use. Your physician can make the best decision for you based on your medical history and current medication regimen.

Laser Options
Laser surgery can help fluid drain from the eye or decrease the amount of fluid produced. In many cases, medication is still needed after this procedure. If you have glaucoma in both eyes, only one eye will be treated at a time. Laser treatments for each eye will be scheduled several days to several weeks apart.

Laser surgery can cause side effects, such as inflammation and soreness, which can often be controlled by medication. You need to make several follow-up visits to have your eye pressure monitored. Studies show that laser surgery is very good at reducing eye pressure in some patients; however, its effects can wear off over time. Your doctor may suggest further treatment.

Cyclophotocoagulation - a laser is directed towards the ciliary body in an effort to decrease the production of aqueous humor. This is a treatment for more aggressive or advanced forms of glaucoma.
Laser peripheral iridotomy - a small opening is made in the iris (the colored ring of tissue behind the cornea that regulates the amount of light entering the eye by adjusting the size of the pupil) so that the fluid in the eye can drain.

Surgical Options
Conventional surgery creates a new opening for the fluid to leave the eye, and is often performed after medicines and laser surgery have failed to control pressure. It is important to discuss all your treatment options, especially in relation to your other health issues, carefully with an ophthalmologist.
Conventional surgery works best if you have not had previous eye surgery, such as a cataract operation.

Early treatment for open-angle glaucoma will usually begin with medications (eye drops, for example) that either help the eye to drain fluid more effectively or cause it to produce less fluid. Several forms of laser surgery can also help fluid drain from the eye. Incisional surgery to create a new opening for fluid to drain is usually performed after the other treatment options have failed.