Eye Pressure (Glaucoma)

What Is Eye Pressure (Glaucoma)?

It is an eye disorder in which the optic nerve located in the eye is damaged. The optic nerve (medical name Nervus Opticus) transmits the image formed by light entering the eye to the brain and enables vision to take place. Damage occurring in this nerve is generally related to pressure in the eye being higher than normal. However, this does not mean that no damage will occur at normal eye pressure. This disease can also occur at normal pressure and generally worsens over time. Children of families with eye pressure are at risk for this disease. It can affect every age group, but it is more common in older adults. It is one of the leading causes of blindness in people over 60.

The disease has many forms and there are almost no warning signs. This means that people with the disease may not experience any symptoms. The reason is that the damage to the optic nerve caused by increased pressure in the eye develops gradually over time. Damage due to pressure change begins to show itself over time and gradually worsens. In some cases it can cause permanent vision loss and even blindness. The effect is so gradual that its progression often goes unnoticed.

Damage to eyesight is an irreversible condition. However, if the disease is diagnosed early, the increased pressure in the eye can be lowered and vision loss can be slowed or stopped. For this reason, it is healthier not to neglect regular eye examinations for diagnosis and treatment before your eye pressure progresses to long-term vision loss.

Having eye pressure means that you will need treatment and regular monitoring for the rest of your life.

How Does Eye Pressure (Glaucoma) Develop?

To understand how this disease develops, it is first necessary to have a general knowledge of the structures of the eye. The cornea is the part of the eye that allows light to enter the eye, so it is very important for vision. The iris is the colored part of the eye. The optic nerve (Nervus Opticus, also known as the optic nerve) provides the connection between the eye and the brain. It transmits the images received through the eye to the brain. Glaucoma develops when the optic nerve is damaged. As this nerve gradually deteriorates, blind spots form in the field of vision. The exact cause of this condition is not yet fully known. However, damage to this nerve has generally been associated with increased pressure in the eye.

The mesh-like structure in the eye is responsible for draining the fluid in the eye. This structure is located at the angle where the iris and the cornea meet. When the production of fluid in the eye is too high to be expelled through this channel, or when the channel cannot perform its drainage function due to blockages, fluid begins to accumulate in the eye. This accumulation does not happen suddenly; it develops over time. As fluid accumulates, the pressure in the eye increases. Eye pressure is therefore a slowly progressing disease. This pressure can damage the optic nerve. Since the damage to the optic nerve also depends on pressure, its symptoms, if any, also appear over time.

Who Is Affected?

The disease can occur in every age group. However, being over 40 or having a family member with the disease are known risk factors. It is also one of the leading causes of blindness in people over 60.

What Are the Symptoms of Eye Pressure?

The disease generally does not cause any symptoms at the beginning. It tends to develop slowly over time and first affects peripheral vision (medical name Peripheral Vision), which is located at the edges of the field of vision. Vision loss begins in the part of the peripheral visual field closest to the nose in particular. However, this vision loss can take years to develop. For this reason, many people are not even aware they have the disease, and it is generally detected during a routine eye examination.

If you notice any symptoms related to eye pressure while going about your daily life, these may include:

• Blurred vision,
• Headache due to blurred vision, or
• Seeing bright lights and rainbow-colored circles around them.

Eye pressure often affects both eyes at the same time. However, in some cases the pressure may be higher in one eye.

Very rarely, it can develop suddenly and in this case may cause the symptoms listed below:

• Severe eye pain,
• Nausea and vomiting,
• Red eye,
• Headache,
• Sensitivity around the eye,
• Seeing halos around lights,
• Blurred vision.

Untreated glaucoma can progress and lead to blindness.

How Is Eye Pressure Diagnosed?

The tests required for diagnosis are painless and brief. These tests are performed by a physician specialized in the field of eye care. Drops are used to dilate the pupils and examine them.

Your specialist physician may examine the optic nerve for signs of the disease and may take photographs to compare the differences between two examinations at the next check-up. They may perform a test called tonometry to check eye pressure. They may also perform a visual field test to see whether there is any loss in peripheral vision. If glaucoma is suspected, they may request imaging tests specific to the optic nerve.

Since eye pressure is a disease that progresses silently, not neglecting your routine eye examinations is very important for early diagnosis.

If glaucoma is diagnosed, it may be one of the types listed below:

• Open-Angle Glaucoma:

It is named this because the drainage angle formed by the iris and the cornea remains open. It is the most common type. Eye pressure increases slowly and gradually.

• Angle-Closure Glaucoma:

When the iris swells, it partially or completely blocks the drainage angle. Therefore fluid cannot circulate in the eye and eye pressure increases. Since it is due to the swelling of the iris, it can occur suddenly or gradually.

• Normal-Tension Glaucoma:

The optic nerve can be damaged even when eye pressure is normal. The exact cause of this is not fully known. Blood flow to the optic nerve may be reduced. Limited blood flow can result from various causes.

• Glaucoma in Children:

Children may be born with the disease, or the disease may appear in the first few years of life. Blocked drainage, injury, or other underlying medical causes that lead to optic nerve damage can cause this disease in children.

• Pigmentary Glaucoma:

It occurs when small pigment granules flake off from the iris. These granules slow down or completely block the drainage of fluid from the eye. Accumulations of granules increase eye pressure and eye pressure develops.

All of these different types tend to occur with a family tendency. You can consult your doctor to learn whether you are at risk.

What Are the Causes of Glaucoma?

Various causes play a role in the development of the disease. In most cases, eye pressure that results when fluid in the eye cannot drain properly is the cause. The fluid inside the eye, called aqueous humor, normally flows out of the eye through a mesh-like channel. This channel is located at the angle where the iris and the cornea meet and is also known as the trabecular meshwork. If there is a blockage in the channel or the eye produces much more fluid than normal, fluid accumulates in the eye. High eye pressure results from the accumulation in the eye of fluid that should be drained. The increase in eye pressure eventually leads to damage of the optic nerve over time.

It is not yet clearly known why this occurs. However, the following risk factors, among others, can be listed:

• Age: As the patient's age increases, the prevalence of the disease also increases.
• Ethnic origin: People of African, Caribbean or Asian origin are at high risk for this disease.
• Family history: Having a parent or sibling with glaucoma is a known risk factor.
• Other medical conditions: Conditions such as myopia (nearsightedness), hyperopia (farsightedness) and diabetes are thought to be able to contribute to the disease.

Apart from these, eye injury from a blunt object or a chemical, severe eye infection, blocked blood vessels in the eye and inflammatory conditions are less common causes. Eye surgery performed for another reason can also cause this condition, but this is very rare. Although the disease generally affects both eyes, one eye may sometimes be damaged more than the other.

What Are the Risk Factors for Eye Pressure?

As with any disease, some people have a higher than normal risk of developing glaucoma. These risk factors can be listed as follows:

• Being over 40 years old,
• A history of glaucoma among family members,
• Being of African, Hispanic or Asian origin,
• Currently having high eye pressure,
• Suffering from myopia or hyperopia,
• Eye injury,
• Long-term steroid use,
• Structurally thin central corneas,
• Weakness of the optic nerve,
• Having systemic health problems that affect the whole body, such as diabetes, migraine, high blood pressure or similar conditions,

If you suspect you are in a risk group for this disease, you may consider applying to the nearest healthcare facility.

How Is Eye Pressure Treated?

There are different options for treating glaucoma, such as medications (usually eye drops), laser treatment and surgery. It is important to start treatment as soon as the diagnosis is made. Treatments (regardless of type) cannot reverse any damage that has occurred to your vision. They can only prevent the damage in the eye from getting worse.

Treatment methods for glaucoma are as follows:

• Medications:

Prescription eye drops are the most commonly used treatment method. By lowering eye pressure, they prevent further damage to the optic nerve.

• Laser treatment:

In order to reduce eye pressure, your specialist physician may use laser treatment to help fluid drain out of the eye.

• Surgery:

It is recommended if medications and laser treatment are not effective. There are several different types of surgery that can help fluid drain out of the eye.

Although glaucoma is a serious disease, it responds well to treatment. A good precaution against glaucoma is not to neglect your routine eye check-ups.