Glaucoma

Glaucoma is a progressive optic nerve disease normally associated with elevated pressure inside the eye. The resulting damage to the optic nerve makes glaucoma one of the leading causes of blindness in America.

Primary Open-Angle Glaucoma

Primary open-angle glaucoma is the most common form of glaucoma. This type develops slowly and is caused when the drainage area clogs, not allowing fluid to properly drain out of the eye. The excess fluid increases the intraocular pressure, which can cause damage to the optic nerve.

  • Symptoms and Signs – Although there are usually no symptoms or pain to indicate primary open-angle glaucoma, some patients do note decreased vision or seeing halos around lights, usually in late or severe cases. Peripheral vision is usually the first to be affected, but this occurs so slowly most patients are unaware of the changes. The end stage of glaucoma is typically tunnel vision or even blindness.

Angle-Closure Glaucoma

Angle-closure glaucoma develops very quickly and is caused when part of the iris blocks the opening of the drainage canals, which allow the fluid to drain from the eye. The fluid builds-up rapidly, as does the rise in intraocular pressure. This is considered a medical emergency and patients require immediate treatment. Without treatment, angle-closure glaucoma can cause blindness within one or two days.

Symptoms and Signs – The following symptoms and signs of angle-closure glaucoma come on suddenly and may disappear only to come back again.

  • Headaches
  • Severe eye pain
  • Nausea
  • Vomiting
  • Redness of the eye
  • Halos around lights
  • Very blurred or loss of vision

Normal Tension Glaucoma

Normal tension glaucoma is similar to primary open-angle glaucoma, but is not as common. The difference is, with normal tension glaucoma, the damage to the optic nerve occurs when the eye has nearly normal fluid pressure.

  • Symptoms and Signs – There are usually no symptoms or pain to indicate normal tension glaucoma. Peripheral vision is the first to be affected. Some patients may express decreased vision or halos around lights, as the condition progresses over time. Gradually, the straight-ahead vision decreases as well. If left untreated, normal tension glaucoma may cause complete vision loss.

Congenital Glaucoma

When glaucoma is found in infants or children, it is called congenital glaucoma. It is a defect of the eye drainage system and occurs when the fluid drains from the eye at a slower rate than normal. This causes an increase in intraocular pressure, which results in optic nerve damage. This form of glaucoma is often hereditary.

Symptoms and Signs – Some children with congenital glaucoma may exhibit no symptoms, others have signs that may be difficult to recognize as eye-related, and some children have obvious symptoms of glaucoma. It may be difficult for children to express a symptom like vision loss, due to age, the inability to verbalize, or incapacity to understand what is happening to them. Symptoms and signs may include the following:

  • Light sensitivity
  • Cloudy or gray cornea
  • Enlarged eye
  • Excessive tears
  • Vision loss
  • Loss of appetite
  • Vomiting
  • Fussiness
  • Pain

 

Secondary Glaucoma

Secondary glaucoma is diagnosed when increased intraocular pressure, along with the resulting optic nerve damage, is caused by another condition or factor. The risks and contributing factors may include: eye injury, steroids, and other diseases. There are several types of secondary glaucoma.

  • Pigmentary Glaucoma – This type of secondary, open-angle glaucoma occurs when pigment released from the iris clogs the drain inside the eye and prevents the aqueous fluid from draining properly. This is caused when tiny pigment granules (from the iris – the colored part of the eye) are knocked off by the supporting structures of the lens.
  • Pseudoexfoliative Glaucoma – This is a type of secondary open-angle glaucoma. The drainage canals are unable to effectively allow the fluid of the eye to drain properly, due to a flaky material from the lens on the inside of the eye, which has peeled off and caused blockage. The blockage results in an increased intraocular pressure and optic nerve damage.
  • Traumatic Glaucoma –In this type of secondary, open-angle glaucoma, injury to the eye and resulting scarring results in damage to the drainage area of the eye and can result in increased eye pressure and optic nerve damage. Traumatic glaucoma may occur immediately or many years after the initial injury.
  • Neovascular Glaucoma – This type of secondary open-angle glaucoma can be caused by uncontrolled diabetes, high blood pressure, or other irregularities. It occurs when new blood vessels form and block the eye’s drainage canals. The fluid in the eye cannot drain properly, which increases the intraocular pressure and eventually damages the optic nerve.

Symptoms and Signs – Like the causes of glaucoma, the symptoms and signs can vary. Some patients do not notice any symptoms, while others experience severe eye pain. As with all other forms of glaucoma, untreated secondary glaucoma can lead to complete loss of vision. Some of the symptoms and signs may include:

  • Headaches
  • Severe eye pain
  • Nausea
  • Vomiting
  • Redness of the eye
  • Halos around lights
  • Decreased vision – most notably in peripheral vision, causing tunnel vision
  • Very blurred or loss of vision

Risks and Contributing Factors

Everyone is at risk for developing glaucoma; however, some people have a higher risk than others. The following are possible risks and contributing factors:

  • Everyone over 60 years old, especially Hispanics
  • African Americans over age 40
  • Family history of glaucoma
  • Use of steroids – such as high doses of a steroid inhaler to control severe asthma
  • High eye pressure
  • Thin cornea

  • Abnormal optic nerve anatomy
  • History of eye injury
  • High myopia
  • Hypertension
  • Diabetes
  • Cataracts
  • Eye tumors

 

Diagnosis

Early diagnosis and treatment are essential to detect glaucoma and prevent vision loss. Glaucoma can be detected and diagnosised while performing a comprehensive eye exam. Pressure will be evaluated inside the eye using tonometry, peripheral vision with a visual field test, and optic nerve damage with dilation. When signs of glaucoma are found during the comprehensive eye exam, further assessment is performed through optical coherence tomography and specialized photographs of the optic disc. Optical coherence tomography uses the reflection of laser light to create a three dimensional image of the optic nerve, providing a clear representation of the extent of the damage.

Treatment

It is imperative to begin treatment immediately following the diagnosis of glaucoma. This helps prevent any further damage to the optic nerve, including resulting blindness. Depending upon the type and severity of glaucoma, drops may be prescribed to lower the intraocular pressure, laser treatment to increase the outflow of fluid from the eye, conventional surgery to remove blockage, or create new drainage canals for fluid to drain from the eye.

Continuing glaucoma treatment is the only way to prevent further irreversible damage, which ultimately leads to blindness. Patients may not have any symptoms or may experience discomfort with the current course of treatment; however, one should never discontinue treatment without consulting their doctor.