Causes of Glaucoma

DEFINITION
Glaucoma is a disease where the pressure inside the eye increases, causing damage to the optic nerve and cause vision impairment.

There are four types of glaucoma:
* Open Angle Glaucoma
* Closed Angle Glaucoma
* Glaucoma Kongenitalis
* Secondary Glaucoma.

The fourth type of glaucoma is characterized by increased pressure inside the eyeball, and therefore it can lead to progressive optic nerve damage.

CAUSE
Anterior chamber and posterior eye chamber filled with fluid called aqueous humor aqueus. Under normal circumstances, this fluid is produced in the posterior chamber, through the pupil into the anterior chamber of the eye and then flows through a duct.

If the fluid flow is interrupted (usually because of a blockage that prevents discharge from the anterior chamber), there will be increasing pressure.

Increased intraocular pressure will push the boundary between the optic nerve and retina at the back of the eye. As a result the blood supply to the optic nerve is reduced so that the nerve cells die.

Because the optic nerve in decline, it will form a blind spot in the field of view of the eye. The first hit is the edge of the visual field, followed by the central visual field. If left untreated, glaucoma can eventually lead to blindness.

SYMPTOMS
Open-angle glaucoma
In the open-angle glaucoma, the channels where the flow of humor aqueus open, but the anterior chamber fluid from flowing too slowly. Pressure will gradually increase (almost always in both eyes) and optic nerve damage and a progressive decline in visual function.

Loss of visual function starts at the edge of the field of vision and if left untreated will eventually spread to all parts of the visual field, causing blindness.

Open-angle glaucoma often occurs after the age of 35 years, but sometimes occurs in children. These diseases tend to be inherited and is most often found in people with diabetes or myopia. Open-angle glaucoma is more common and usually are more severe disease if suffered by blacks.

At first, the increase in pressure inside the eye causes no symptoms.
Long symptoms include:
- Narrowing of visual field edge
- Mild headache
- Impaired vision are not clear (eg see the circle around the light bulbs or difficult to adapt to darkness).

Will eventually narrowing the field of vision that causes people with difficulty seeing objects that are located on the other side when the patient is looking straight ahead (so-called tunnel vision).

The new open-angle glaucoma may cause symptoms after the damage is irreparable.

Angle closure glaucoma
Closed-angle glaucoma occurs when the channel where the flow is blocked by the iris aqueus humor.

Any thing that causes dilation of the pupil (eg light, eye drops are used to pelebar pupil eye examination or certain medications) can cause a blockage of fluid flow due to blocked by the iris. Iris could move forward and suddenly shut aqueus humor channel resulting in increased pressure inside the eye of a sudden.

Attacks can be triggered by the use of eye drops that dilate the pupil, or can also occur without any triggers. Acute glaucoma is more common at night because it will naturally dilated pupil under dim light.

Acute episode of angle closure glaucoma causes:
- Mild vision impairment
- Formation of a colored circle around the light
- Pain in the eyes and head.
The symptoms are berrlangsung just a few hours before the occurrence of further attacks.

Continued attacks cause sudden loss of vision function and eye pain throbbing. Patients also experience nausea and vomiting.Swollen eyelids, watery eyes and red. Dilated pupils and do not shrink if given bright light.

Most of the symptoms will disappear after treatment, but the attack could be repeated. Each subsequent attack would further reduce the field of view of the patient.


Secondary glaucoma
Secondary glaucoma occurs when the eyes were damaged by:
* Infection
* Inflammation
* Tumor
* Cataracts are widespread
* Eye disease that affects aqueus humor drainage from the anterior chamber.

The most common cause of the uveitis. Other causes of venous obstruction ophthalmicus, eye injury, eye surgery and bleeding into the eye. Some drugs (eg corticosteroids) also can cause increased intraocular pressure.

Glaucoma KONGENITALIS
Glaucoma kongenitalis been there since birth and developmental disorders due to the channel aqueus humor. Kongenitalis often inherited glaucoma.

Diagnosis
Regular eye examinations are carried out are:

* Examination of the ophthalmoscope may reveal changes in the optic nerve caused by glaucoma
* Measurement of intraocular pressure by tonometry.
Pressure in the anterior chamber is called intraocular pressure and can be measured by tonometry.
Usually if the intraocular pressure greater than 20-22 mm, is said to have an increase in pressure.
Sometimes glaucoma occurs at normal pressure.
* Measurement of visual field
* The sharpness of vision
* Tests refraction
* Response pupillary reflex
* Slit lamp examination
* Examination gonioskopi (special lenses to observe channel aqueus humor.

TREATMENT
Open-angle glaucoma Eye drops can usually control the open-angle glaucoma. The first drug was given beta blockers (eg timolol, betaxolol, carteolol, or levobunolol metipranolol), which is likely to reduce the formation of fluid inside the eye.

Also given pilocarpine to reduce pupil and improve the drainage of fluid from the anterior chamber. Other drugs are also given epinephrine, and carbacol dipivephrine (to improve the drainage of fluid or reduce the formation of liquid).

If glaucoma can not be controlled with medication or side effects can not be tolerated by the patient, the surgery is to improve the drainage of fluid from the anterior chamber. Used laser beams to create a hole in the iris or do surgery to cut some slices (iridotomi).

Angle-closure glaucoma
Drinking a solution of glycerin and water can reduce the pressure and stop the attack of glaucoma. Can also carbonic anhydrase inhibitors given (eg acetazolamide).

Pilocarpine eye drops cause the pupil to shrink so that the slices are interested in and open up clogged channels. To control the intraocular pressure can be given beta blocker eye drops.

After an attack, giving pilocarpine and beta-blockers and carbonic anhydrase inhibitors are usually continued. In severe cases, to reduce the pressure of mannitol is usually given intravenously (through a vein).

Laser therapy to make a hole in the iris will help prevent future attacks and can often cure the disease permanently. If glaucoma can not be treated with laser therapy, surgery to make a hole in the iris.

If both eyes have a narrow channel, then both eyes were treated even if the attacks occur only in one eye.

Secondary glaucoma
Treatment of secondary glaucoma depends on the cause. If the cause adala inflammation, corticosteroids and drugs administered to dilate the pupil. Sometimes surgery.

Glaucoma kongenitalis
To address the need kongenitalis glaucoma surgery.

PREVENTION
No action can prevent the occurrence of open-angle glaucoma. If the disease is caught early, the loss of function of vision and blindness can be prevented with treatment.

People who have a lifetime risk for developing angle-closure glaucoma should undergo a routine eye examination and if a high risk should undergo iridotomi to prevent acute attacks