Types of Glaucoma - Know All About Them

Glaucoma is a disease which is caused due to damaged optic nerve of the eyes. It is one of the leading causes of vision loss/blindness among the elderly (over 60 years old). It generally occurs when the fluid builds up on the cornea (eye’s front part), which increases internal pressure and damages the optic nerves. 

The optic nerves have million-plus tiny nerve fibres, just like an electric cable. When these nerve fibres grow non-functional due to ageing, an individual will develop certain blind spots in the eye, killing vision in those areas. These blind spots are unnoticeable until most of these optic nerve fibres are dead. As this condition progresses and when all these nerve fibres die, an individual will ultimately become blind.

There are several types of glaucoma, each with its own unique set of causes, symptoms, and treatment options. Understanding the different types of glaucoma is essential for early detection, proper management, and preventing irreversible vision loss. Considering the reason, glaucoma is mainly of two types: Primary and Secondary Glaucoma.  

Primary Glaucoma

Primary glaucoma is the condition when the doctor is unable to identify any other condition that causes it. It does not occur because of any other factors. The underlying mechanism is when the peripheral iris occludes the anterior chamber angle, it leads to acute elevation of intraocular pressure.

The primary glaucoma is of the following types:

1. Open-angle glaucoma
2. Angle-closure glaucoma
3. Normal-tension glaucoma
4. Congenital glaucoma

Secondary Glaucoma

Secondary glaucoma exists as a side effect of some other underlying medical issue or can occur due to some acquired conditions. 

The secondary glaucoma is of following types:

1. Neovascular glaucoma
2. Pigmentary glaucoma
3. Exfoliation glaucoma
4. Uveitic glaucoma

While there are many types of glaucoma, some are more common than others. Let us explore the most common types of glaucoma, their causes, symptoms, and treatment options.

Open-Angle Glaucoma

This type of glaucoma is a chronic form of glaucoma, and it is also the most common glaucoma type. This eye disease develops gradually over time. In most cases, the person can't even notice the symptoms of the illness, and even slight vision loss is hardly noticeable. Over a period of time, it can also lead to permanent eye vision damage.

1. Causes: It is not clear yet what leads to open-angle glaucoma. But, blood cells, protein or other debris can block the trabecular meshwork (the main pathway of drainage out of the eye) that might lead to this condition.
2. Risk factor: The risk factors of open-angle glaucoma include intraocular pressure, age, family history, refractive history and central corneal thickness.
3. Symptoms: Initially patchy blind spots in the side vision and then the same for the central vision.

Angle-Closure Glaucoma

It is also called acute angle-closure glaucoma or closed-angle glaucoma. This glaucoma suddenly starts, resulting in extreme pain and rapid vision degeneration. The symptoms of this glaucoma are evidently visible and noticeable, and prompt treatment can help minimise eye damage.

1. Causes: This type of glaucoma is a result of a bulged iris. It partially or completely blocks the angle of drainage. Hence, the eye fluid can’t circulate and the pressure increases.
2. Risk factors: Family history, diabetes, high blood pressure, previous eye injury and age are some of the risk factors.
3. Symptoms: Pain, headache, nausea, blurry or hazy vision and experiencing halos or rainbows around light are some of the main symptoms.

Pigmentary Glaucoma

This is a form of secondary glaucoma begin to develop during an individual's early or middle adulthood. In this type of glaucoma, the iris' pigment cells change and start dispersing through the eye, which can also disturb the flow of fluid drainage from the eye.

This leads to high-pressure build-up in the eye's interior region. Since it's another chronic form of glaucoma, it is also very common. The development is gradual and it can also cause permanent eye-vision damage.

1. Causes: Releasing of pigment granules, temporary rise in intraocular pressure and pathological alterations to the trabecular meshwork are some of the main causes of this disease.
2. Risk factors: Myopia, Concave iris, posterior iris insertion, family history and flat corneas are the risks involved here.
3. Symptoms: Unnoticeable symptoms

Neovascular Glaucoma

A neovascular glaucoma is a severe form of secondary glaucoma characterised by the proliferation of fibrovascular tissue in the anterior chamber angle.  A new blood vessel is formed on the iris with occlusion of the central retinal vein occlusion. 

1. Causes: Neovascular glaucoma could be caused by ocular radiation, ocular tumours, diabetic retinopathy, uveitis, ischemic central retinal vein occlusion and ocular ischemic syndrome.
2. Risk factor: Risk factors for these retinal diseases include hypertension, heart ailments, age and diabetes.
3. Symptoms: Extra blood vessels are produced by the eye to cover the area around it. The vision is abnormal, and the eye is usually red and painful.

There are several rare types of glaucoma, which are much less common than the most common types like open-angle and angle-closure glaucoma. These rare types include:

1. Primary congenital glaucoma (PCG) is a very rare form of the disease (primary glaucoma). It is caused because of genetically-determined abnormalities.
   1. These abnormalities exist in the anterior chamber angle and the trabecular meshwork. It ultimately results in raising the intraocular pressure. It can also cause other systemic developmental or ocular anomalies in the individual suffering from it.
2. Uveitic Glaucoma: Uveitis is inflammation of the uvea, the middle layer of the eye, which can cause elevated eye pressure and optic nerve damage. Uveitic glaucoma can occur as a complication of uveitis, and is more common in people with autoimmune diseases like rheumatoid arthritis and lupus.
3. Traumatic Glaucoma: Traumatic glaucoma can occur after an injury to the eye, which can damage the drainage system and lead to increased eye pressure. It can occur immediately after the injury or many years later.
4. Normal-tension glaucoma (low-tension glaucoma or normal-pressure glaucoma) is one of the rare types of glaucoma in which the optic nerve is damaged, but the eye pressure remains within the normal range (less than 21 mmHg).
   1. The damage to the optic nerve is caused by factors other than intraocular pressure, such as poor blood flow to the optic nerve. It is a chronic condition that usually progresses slowly over time and can lead to permanent vision loss if left untreated

Glaucoma is a serious condition, but it shouldn't scare you as well. The blindness that emanates as a result of glaucoma can often be prevented. So, consult a doctor early and get the treatment immediately. This should reduce your chances of having any impairment in vision or any type of vision loss. 

Diagnostic Test

You need to get tested for glaucoma whenever you feel pain in the eye. Here are some leading types of eye tests for glaucoma:

1. Eye angle exam: In this diagnostic exam, the angle where the iris and cornea meet is determined. It is checked whether the angle is wide and open or closed and narrow.
2. Corneal thickness measurement or Pachymetry: The ophthalmologist numbs the eye with sedative eye drops. The ophthalmologist then touches the eye with a small probe to check the thickness.
3. Dilated eye exam: A special tool is used to shine a bright light into the back of your eye. The retina and the optic nerve are magnified to check the extent of the damage.
4. Eye pressure check or Tonometry: The cornea is flattened with the help of an instrument and then the pressure is checked.
5. Optic nerve imaging: After dilating your pupils, pictures of the retina and the optic nerve are taken with the help of a digital camera.
6. Visual field test: This is a physical test where the ophthalmologist asks you to shut one eye and look at an object. What you will be able to see and what you will be unable to view will help them determine the extent of the damage. 

Treatment

Now that you have got yourself tested, you should immediately seek treatment to avoid such conditions in your eye. Here are some of the methods of treating glaucoma:

1. Laser Therapy: A laser is used for opening up the drainage tubes within the eye, which allows excess fluid to drain out for reducing the internal pressure. 
2. Filtering surgery: The eye surgeon creates a new drainage channel, which results in a filtering area or a bleb and the liquid is drained.
3. Drainage tubes: In this procedure, a glaucoma drainage implant is placed in the eye and the excess fluid is drained out restoring the normal eye pressure.
4. Minimally Invasive Glaucoma Surgery (MIGS):  This is a procedure that is conducted with the aid of microscopic instruments for facilitating a small incision. The excess fluid is drained from this incision.

To prevent the detrimental effects of glaucoma, you can take some measures. Some of the most effective ones are:

1. Eat nutritious food: Eating a healthy diet rich in copper, zinc, selenium and antioxidant vitamins A, C and E is recommended. These nutrients can fight glaucoma.
2. Exercise regularly: It helps to reduce eye pressure. Make sure you are doing the appropriate exercises religiously.
3. Limit caffeine intake: Drinking caffeine in copious amounts may increase the pressure in your eyes. Hence, you should consume it in moderation.
4. Drink fluids moderately: Excessive fluid intake within a short time temporarily increases eye pressure.
5. Take prescribed medication: Take prescribed eye drops or other medication as prescribed by your doctor. Skipping treatment in any form could damage the optic nerves.

Hopefully, now you have a clear idea of the types of glaucoma and how they can affect your eye health. You need to understand the underlying causes of the condition and how to get it diagnosed. This will help you in deciding what kind of treatment you should go for, as per your symptoms.

Having said that, the improvement of modern medical science means there are different ways to treat this condition and stop the prospective vision impairment that you can face in the long term.

So, if you notice any symptoms, then it is advisable to contact an expert or get in touch with us at HexaHealth for assistance on the course of treatment. We can identify the type of glaucoma you are suffering from and then guide you with the procedures you might need to cure the condition.

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