Glaucoma Causes, Symptoms and Treatments

Glaucoma Causes, Symptoms and Treatments

What is Glaucoma?

Glaucoma is a chronic disease that damages the eye’s optic nerve and causes vision loss and blindness. But if you found out its early stages and do the proper treatment, you can often protect your eyes against serious vision loss.

What is Optic Nerve?

The optic nerve is a collection of more than 1 million nerve fibers. It connects the retina to the brain.  The retina contains light-sensitive tissue, and it’s the inner lining of the eyeball. So having a healthy optic nerve is necessary for good vision. 

How Does the Optic Nerve get Damage?

Many types of research have shown that eye pressure is a major reason for optic nerve damage. In front of the eye, there is a space named the anterior chamber. A clear liquid flows continuously in and out of the chamber. And also it nourishes nearby tissues. The fluid moves from the chamber at the open angle where the cornea and iris meet.  When the fluid gets at the angle, it flows through a spongy meshwork, like a drain, and leaves the eye.

In open-angle glaucoma, although the drainage angle is “open,” the fluid passes too slowly across the meshwork drain. Because of that, the fluid builds up, the pressure inside the eye increase to a level that may damage the optic nerve. When the optic nerve is damaged from increased pressure, open-angle glaucoma and vision loss may be the result. So it is important to control the pressure inside the eye is important. Having high blood pressure is another risk factor for optic nerve damage. Therefore, it is important to maintain your blood pressure is at a proper level for your body.

What if I have increased my eye blood pressure?

Not all the people whose eye pressure increased will develop glaucoma because of some people able to tolerate higher levels of eye pressure better than others. Besides, a certain level of eye pressure may be high for someone but normal for another.

Glaucoma development depends on the level of pressure your optic nerve can tolerate without being damaged. This level is different for each person. It’s better to have a comprehensive dilated eye test. It can help your doctor to determine what level of eye pressure is normal for you.

Can I develop Glaucoma without increasing eye blood pressure?

Yes. Glaucoma can develop without increased eye pressure. This type of glaucoma is known as normal-tension or low-tension glaucoma. It is a type of open-angle glaucoma.

Types of Glaucoma

Primary Open Angle Glaucoma

Unfortunately, there are no symptoms related to POAG.  The pressure in the eye slowly increased, and the cornea adapts without swelling.  When the time cornea becomes to swell, it normally signals something wrong, then symptoms are present.  Most of the time, this disease goes undetected because it is painless, and the patient rarely realizes that he or she is slowly losing vision until the later stages of the disease.  As a result, the vision becomes low, and the damage is irreversible. 

Glaucoma is really about the problems that occur because of increased intraocular pressure (IOP). The average IOP in a normal population is 14-16 mmHg (millimeters of mercury). However, pressures up to 20 mmHg may be within the normal range. But doctors consider a person with 22 mmHg to be suspicious and possibly abnormal. Yet, not all patients with elevated IOP develop glaucoma-related eye damage. 

Therefore, taking medications daily, as prescribed, is very important in preventing vision-threatening damage. And also you need to discuss possible side effects with your doctor. 

Low Tension or Normal-tension glaucoma

Normal-tension glaucoma or low-tension glaucoma identified as progressive optic nerve damage and visual field loss with a statistically normal intraocular pressure. Normal-tension glaucoma is related, to poor blood flow to the optic nerve, which causes the death of the cells that carry impulses from the retina to the brain. Besides, these eyes appear to be susceptible to pressure-related damage even in the high normal range, and therefore a pressure lower than normal is often necessary to prevent further visual loss. Presently research in optic nerve blood flow and its role in glaucoma is a source of much excitement and hopefully will lead to new methods of treating this disorder. Since the best therapy for normal-tension glaucoma is unknown, much attention is being given to a study known as the International Collaborative Low Tension Glaucoma Protocol.

This increased pressure can destroy the optic nerve cells. Once a considerable amount of nerve cells are destroyed, `blind spots’ begin to form in the field of vision. These blind spots usually develop first in the vision field's boundary, the outer sides of the field of vision. By the time the central vision, which we experience as `seeing',´ is affected. Once visual loss happens, it can't stop. Because once the nerve cells are dead, no chance to restore them.

As mentioned earlier POAG is a chronic disease. There is no cure for it at present, but treatment can slow or arrest the disease development. Since there are no symptoms to visible, many patients find it difficult to understand why lifelong treatment with expensive drugs is necessary, especially when these drugs are often bothersome.

Angle Closure Glaucoma

There is a chance for this disease to be inherited, and often several members of a family will be afflicted. It is most common in people who are far-sighted and people of Asian descent. In people with a chance to develop angle-closure glaucoma, the anterior chamber is smaller than average size.

Why Angle Closure Glaucoma?

As mentioned earlier, the trabecular meshwork is situated in the angle formed where the cornea and the iris meet. In most people, this angle is about 45 degrees. When the angle becomes narrow, the closer the iris is to the trabecular meshwork. As we age, the lens routinely grows larger. The ability of aqueous media to pass between the iris and lens on its way to the anterior chamber becomes decreased, causing fluid pressure to increase behind the iris, further narrowing the angle. If the pressure is considerably high, the iris is forced against the trabecular meshwork, blocking drainage, similar to putting a stopper over the drain of a sink. When this space becomes blocked, angle closure glaucoma shows the (acute glaucoma) results.

Acute Glaucoma

Unlike POAG, where the IOP increases slowly, in acute angle-closure, it increases suddenly. This sudden increase in pressure can happen within a matter of hours and become very painful. If the pressure increases too enough, the pain may become so hard that it can cause nausea and vomiting.

The eye becomes red, the cornea swells and clouds, and the patient may see haloes around lights and may experience blurred vision. An acute attack is an emergency condition. So delayed treatment may cause permanent blindness. Scarring of the trabecular meshwork may appear and cause chronic glaucoma, which is much more difficult to control. Cataracts may also develop. Damage to the optic nerve may occur quickly and cause permanent blindness.

Specialty Of Acute Glaucoma

Many of these sudden `attacks´ occur in darkened rooms, such as movie theaters. If you recall, darkened environments cause the pupil to dilate, or increase in size. There is maximum contact between the eye's lens and the iris when the time this happens. This further narrows the angle and may cause damage. And also the pupil dilates when one is excited or anxious. Many acute glaucoma attacks occur during periods of stress. Some drugs can also cause dilation of the pupil and lead to glaucoma. These include anti-depressants, cold medications, antihistamines, and some medications to treat nausea.

Acute glaucoma attacks are not always full-blown. Also, patients may have a series of minor attacks. A slight blurring of vision and haloes (rainbow-colored rings around lights) may be experienced but without pain or redness. These attacks may end when the patient enters a well-lit room or goes to sleep -- two situations which naturally cause the pupil to constrict, thereby allowing the iris to pull away from the drain. Sometimes an acute attack can stop with a combination of drops that constrict the pupil and drugs that help reduce the eye's fluid production. 

Acute Glaucoma Treatment

When the IOP has dropped to a safe level, your ophthalmologist will perform a laser iridotomy.  As a result, this allows the fluid to flow more freely. Drops will be used to anesthetize your eye and there is no pain involved. This treatment is done for the unaffected eye as well. Since it is common for both eyes to suffer from narrowed angles, operating on the unaffected eye is done as a preventive measure. 

Pigmentary glaucoma

Pigmentary glaucoma is an inherited open-angle glaucoma that develops more frequently in men than in women. Most of the time, this begins in the twenties and thirties, which makes it particularly high risk for normal vision in the lifetime. Nearsighted patients are more typically afflicted. The anatomy of the eyes of these patients appears to play a key role in the development of this glaucoma.

Miotic therapy is the treatment for this glaucoma. However, it may cause disabling visual blurring in younger patients.

Trauma-Related Glaucoma

Trauma-Related Glaucoma a blow to the eye, chemical burn, or penetrating injury may all lead to the development of glaucoma, either acute or chronic. Hence, this can occur in a mechanical disruption or physical change within the eye's drainage system. Therefore, this type is crucial for anyone who has suffered eye trauma to have check-ups at regular intervals.

Risk Factors of Glaucoma

  • African-North American People
  • Asian People (for normal-tension and angle-closure glaucoma)
  • Family history of glaucoma in a first-degree relative(s)
  • History of having blunt ocular trauma or steroid use.
  • Longterm diabetes
  • Obstructive sleep apnea (OSA)
  • High blood pressure 
  • People with thyroid disorders 
  • People who have myopia  

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