What is glaucoma and what are its main types?

Glaucoma is a group of eye conditions that can damage the optic nerve, which is the nerve that connects the eye to the brain. This damage can lead to vision loss and may develop very slowly, such that the affected person may not notice symptoms at first. In most cases, the damage occurs as a result of high pressure inside the eye, but some individuals may develop glaucoma even with normal eye pressure [1].

Common Types of Glaucoma

There are several types of glaucoma, but the most common is open-angle glaucoma. Other types include angle-closure glaucoma and congenital glaucoma [1].

• Open-angle glaucoma: This is the most prevalent type. Early symptoms often do not appear, and the affected person may not notice vision loss until the disease progresses. Experts believe that this type may result from a buildup of pressure inside the eye when fluid is not drained sufficiently. Over time, this pressure leads to optic nerve damage, which affects vision and can eventually lead to blindness [3].
• Normal-tension glaucoma: This is a type of open-angle glaucoma that occurs in people who have normal eye pressure. The exact cause is still unknown, but research indicates that treatments that lower eye pressure can help slow the progression of the disease and prevent vision loss [3].
• Angle-closure (closed-angle) glaucoma: This condition is a medical emergency and requires immediate attention. It occurs when the outer part of the iris (the colored part of the eye) prevents fluid from draining from the front of the eye, leading to a rapid and sudden increase in eye pressure. If not treated immediately, it can cause blindness within a few days [3].
• Congenital glaucoma: Children with this type are born with an eye problem that prevents normal fluid drainage. It is a rare condition, and signs are usually evident at birth, such as cloudy eyes, light sensitivity, excessive tearing, or eyes that are larger than normal [3].

Glaucoma Symptoms and When to Seek Help

Often, there are no early symptoms of glaucoma, or symptoms may begin so slowly that the affected person does not notice them [1]. In the absence of treatment, there is a gradual loss of side (peripheral) vision, and it may feel like you are looking through a tunnel. Over time, direct front vision may decrease until no vision remains [1].

Red flags requiring emergency care: If you experience sudden symptoms such as severe eye pain, blurred vision, eye redness, or nausea, you must immediately go to an ophthalmologist or the emergency room. These symptoms may be an indicator of angle-closure glaucoma, a less common type that causes fluid to build up rapidly inside the eye [1][2].

Diagnosing Glaucoma

The only way to know if you have glaucoma is to undergo a comprehensive eye exam. This exam typically includes [2]:

• Dilated eye exam: Drops are used to dilate the pupil, allowing the ophthalmologist to examine the important tissues at the back of the eye [1].
• Visual field test: This test measures your ability to see objects in your peripheral vision without moving your eyes [1].
• Tonometry: This test measures the pressure inside the eye [1].

If you are at higher risk for glaucoma, you should undergo comprehensive eye exams every one to two years [1]. You can learn more about silent vision loss due to glaucoma by visiting Glaucoma: The Silent Thief of Sight (Arabic).

Glaucoma Treatment

There is no cure for glaucoma, but it can usually be controlled. Early treatment aims to protect the eyes from vision loss and prevent the condition from worsening [2]. Treatments include [1]:

• Prescription eye drops: These are the most common treatment to lower pressure in the eye and prevent optic nerve damage [1].
• Oral medications: May be used in some cases [1].
• Laser therapy: The laser can help improve fluid drainage from the eye to lower pressure [1].
• Surgery: May be necessary if medications and laser therapy are not effective in lowering eye pressure [1].

It is important to continue with the prescribed treatment and see an ophthalmologist regularly to prevent vision deterioration [2].

Medical references

• Glaucoma
• Glaucoma
• Types of Glaucoma