Open-Angle Glaucoma: What Does it Consist Of?

Open-angle glaucoma can cause blindness if it isn't treated in time. The problem is that it may go unnoticed, as it doesn't always cause symptoms.
Open-Angle Glaucoma: What Does it Consist Of?

Last update: 08 May, 2021

Open-angle glaucoma can cause blindness if it isn’t treated in time. The problem is that it may go unnoticed, as it doesn’t always cause symptoms.

Open-angle glaucoma is an eye disease that can lead to blindness. It causes optic nerve damage that causes a loss of vision in the visual field. In many cases, it causes increased eye pressure, but not always.

Although there’s both open-angle and closed-angle glaucoma, the former is most common. Experts estimate that it accounts for 90% of cases. It is the second or fourth cause of blindness in the world, depending on the region.

Open-angle glaucoma is also called primary or chronic glaucoma. It’s a progressive condition that may not cause symptoms and, thus, often goes unnoticed.

The possible causes of open-angle glaucoma

In most cases, open-angle glaucoma occurs when the eye’s drainage channels become blocked. This leads to increased intraocular pressure and optic nerve damage.

The eye’s drainage system forms an angle from the iris to the cornea. From there, it connects to the outside by conduits. This condition doesn’t allow proper eye drainage because the ducts are either clogged or too narrow.

As the fluid doesn’t drain outwards, the pressure in the eye increases, damaging the optic nerve. Thus, the patient’s ability to see becomes affected.

Some optic nerves are more susceptible to eye pressure. Africans are at a higher risk of developing this disease, as well as those over 60, especially those of Latino origin, with a family history of the condition, or those who suffer from diabetes.

A diabetic measuring their blood sugar levels.

Main symptoms

Open-angle glaucoma develops very slowly and silently. In most cases, people become aware that something is wrong when they suffer vision loss. By then, the optic nerve is badly damaged.

Those affected initially lose their peripheral or lateral vision. The disease only affects sharpness and visual acuity once it’s very advanced. This condition is usually detected in a routine checkup.

Diagnosis of open-angle glaucoma

Open-angle glaucoma should ideally be detected early on, before optic nerve damage has progressed. Regular eye exams are the diagnostic tests of choice. Those who belong to risk groups should get periodic check-ups.

It’s best to increase their frequency according to age, as follows:

  • Before age 40. A checkup every two to four years.
  • Age 40 to 54. Once a year or once every three years.
  • Age 55 to 64. Once a year or once every two years.
  • Over 65 years old. Once every six months or once a year.

Experts can request different tests to determine if a person is suffering from open-angle glaucoma. The most common are the following:

  • Tonometry. This test measures intraocular pressure (IOP) or pressure inside the eye.
  • Ophthalmoscopy. Doctors use it to look into the back of the eye and examine the optic nerve to establish possible damage.
  • Perimetry. A visual field test. It allows doctors to determine if and to what extent open-angle glaucoma affected a patient’s vision.
  • Gonioscopy. It establishes whether the angle between the iris and the cornea is open and wide or narrow and closed.
  • Pachymetry. This test measures the thickness of the eye’s cornea.

Eye doctors may request all these tests or only some of them. Open-angle glaucoma isn’t always easy to diagnose.

Treatment options

A woman getting laser surgery.
Laser surgery is one of the current treatment options for open-angle glaucoma and other vision disorders.

Treatment of open-angle glaucoma is focused on reducing intraocular pressure. There’s no way to repair optic nerve damage. This is why early diagnosis and treatment are so important.

There are three therapeutic strategies:

  • Medication, usually eye drops. They make the eyes produce less fluid or increase fluid drainage.
  • Laser surgery. This type of surgery helps the eyes drain fluid better or decreases fluid production in the eyes. It’s an outpatient surgical procedure that’s usually effective in reducing eye pressure.
  • Conventional surgery. In this case, the surgeons redirect the fluid to avoid the malfunctioning drainage system. Surgeons can also create new drainage routes.

Open-angle glaucoma isn’t always treated in the same way

The treatment of choice depends on the state of the optic nerve and the patient’s overall health. The eye doctor will talk to them about the benefits of each alternative and will recommend the most appropriate one, depending on the patient’s case.

In many cases, patients who get conventional or laser surgery may need to use medications afterwards. The positive effects of the surgery may also wear off after some time.

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