What is Glaucoma?

Glaucoma is an important cause of blindness. Glaucoma is a GROUP of disorders. What they all have in common is an increase in the pressure inside the eye. When the pressure is too high, damage occurs to the optic nerve. The optic nerve receives light from the retina and transmits impulses to the brain that we perceive as vision. The optic nerve is made up of a bundle of nerve fibers which sends signals to the brain. Damage to the optic nerve can initially cause blind spots at the outer edges of the field of vision called peripheral or side vision. This is the main sign of glaucoma.

How do I know if I have glaucoma?

Unfortunately glaucoma is typically associated with painless and progressive loss of vision that may escape detection by the patient. This once again stresses the importance of a thorough eye history and examination, especially in patients with a family history of glaucoma. Only one type of glaucoma called angle-closure glaucoma is associated with a red, painful eye with blurred vision and even possibly nausea and vomiting. This is due to very high pressures resulting FROM a block in the drainage system of the eye. Most patients at risk for this type of glaucoma have structural differences in their eye which could be identified prior to an attack and preventative treatment could be performed.


Possible Signs of Glaucoma

Majority of Glaucoma’s can occur and progress without obvious symptoms or signs. Open-angle glaucoma is the most common, and symptoms are slow to develop. As this types of glaucoma progresses, you may notice that your side, or peripheral, vision is failing, causing you to miss objects out of the side and corner of your eye.
If you are suddenly experiencing the following symptoms, you may have angle-closure glaucoma and should seek immediate treatment (Angle Closure accounts for only 1/3rd of all glaucoma’s) and that too the patient should not wait for these symptoms to appear, routine check-up can pick angle closure glaucoma much early:

  • Blurred vision
  • Nausea
  • Headaches
  • Halos around bright lights

Causes and Risk Factors?

What causes Glaucoma?

Glaucoma is basically a nerve disorder characterized by progressive loss of cells. Increased/high intraocular pressure is one feature of this disease and this does not necessarily mean that people with low intraocular pressure cannot have glaucoma. Awareness of the different causes and risk factors for glaucoma may help you identify the condition early on, as timely diagnosis of glaucoma is vital to preventing vision loss.

General Risk Factors for Glaucoma:

Certain people are at a heightened risk of developing glaucoma. These include:

  • People over 40 years of age
  • People who have a family history of glaucoma
  • Steroid users
  • People with prior ocular injuries
  • Patients with ocular hypertension
  • People over 60 years of age

There are also several medical conditions that increase a person’s risk of glaucoma, including:

  • Diabetes
  • Hypothyroidism
  • Leukemia
  • Sickle cell anemia
  • Arthritis

What are the different types of glaucoma?

There are many different types of glaucoma. The glaucoma’s usually affect both eyes, but the disease can progress more rapidly in one eye than in the other. Involvement of just one eye occurs only when the glaucoma is brought on by factors such as a prior injury, inflammation, or the use of steroids in that eye. Most, however, can be classified as either open-angle glaucoma’s, which are conditions of long duration (chronic), or closed-angle (angle closure) glaucoma.

  • Open-angle glaucoma
  • Chronic open-angle glaucoma (COAG)
  • Normal tension (pressure) glaucoma
  • Congenital (infantile)
  • Secondary glaucoma
  • Pigmentary glaucoma
  • Exfoliative
  • Closed-angle glaucoma

What is normal tension glaucoma ?

Cases have been seen where intra-ocular pressure(IOP) has been normal or even in lower range and glaucoma damage to optic nerve has occurred, these group come in Normo-tension Glaucoma(NTG). NTG has led to change in concept of glaucoma screening from only IOP recording to a battery of tests – IOP, Pachymetry, OCT, Fields.

The important point is even if one has normal or low eye pressure, he or she can have advanced glaucoma!

How is glaucoma diagnosed?

An eye doctor (ophthalmologist) can usually detect those individuals who are at risk for glaucoma (because of, for example, a narrow filtering angle or increased intraocular pressure) before nerve damage occurs. The doctor also can diagnose patients who already have glaucoma by observing their nerve damage or visual field loss.
The following tests, all of which are painless, may be part of this evaluation:

  • Non Contact Tonometry: Determines the pressure in the eye by measuring the tone or firmness of its surface.
  • Pachymetry: A relatively new test being used for the management of glaucoma. Pachymetry determines the thickness of the cornea. Thicker corneas may give falsely high eye pressure readings and thinner corneas may give falsely low pressure readings.
  • Ophthalmoscopy: This procedure is done to examine the optic nerve (seen as the optic disc) at the back of the eye. Damage to the optic nerve, called cupping of the disc, can be detected in this way. Cupping, which is an indentation of the optic disc, can be caused by increased intraocular pressure.
  • Visual Field testing: It maps the visual fields to detect any early (or late) signs of glaucomatous damage to the optic nerve. This process produces a computerized map of the visual field.
  • Optical Coherence Tomography (OCT): OCT is the latest and most sensitive tool to diagnose and treat glaucoma. It can detect glaucoma at the earliest. OCT can also measure anterior chamber angle, which is important for angle closure glaucoma.

How often should someone be checked (screened) for glaucoma?

• Age 20-29: Individuals with a family history of glaucoma should have an eye examination every three to five years. Others should have an eye exam at least once during this period.
• Age 30-39: Individuals with a family history of glaucoma should have an eye examination every two to four years. Others should have an eye exam at least twice during this period.
• Age 40-64: Individuals should have an eye examination every two to four years.
• Age 65 or older: Individuals should have an eye examination every one to two years.

How Is Glaucoma Treated?

Glaucoma can be treated, and the sooner the better. The damage that has already occurred from glaucoma cannot be repaired-it will either stay the same or get worse. Catching glaucoma at its earliest stages and treating it promptly will increase the odds of keeping one’s vision.

All of the various glaucoma treatments and procedures are aimed at reducing eye pressure. Eye pressure doesn’t necessarily cause glaucoma, but once it develops, eye pressure speeds up the destructive process.

There are a number of different treatments for glaucoma:

  • Eye drops
  • Oral medication
  • Surgery
  • Laser treatment – PI, SLT.

The type of treatment depends upon individual conditions.