Glaucoma


What is Glaucoma?

A fluid called aqueous humor is produced by a part of the eye called ciliary body. This fluid nourishes the cornea,iris and lens.It then drains tiny holes that lines the iris called trabecular meshwork and goes back to the blood stream.This drainage is impaired and the aqueous does not drain properly which causes increase in IOP(intraocular pressure) which eventually destroys the nerve fibres that transmit signals to your brain. This leads to gradual loss of vision.

Types of Glaucoma

There are two main forms of glaucoma. Open angle and Narrow angle. Other types of glaucoma include Closed angle and Neovascular  glaucoma.

Open Angle Glaucoma

This type of glaucoma occurs when the drainage system does not work properly.Fluid formed is unable to drain off causing increase in pressure within the eye. This pressure damages the optic nerve.This is the most common form of glaucoma.

In narrow angle glaucoma,the drainage angle between the iris and back of the cornea becomes too narrow.This causes difficulty in draining the fluid from inside the eye.

In Closed angle glaucoma there is rapid rise in intraocular pressure as the angle is so narrow blocking the trabecular meshwork completely .Patients may suffer from headache,pain around the eye,blurred vision/halos,nausea or vomiting.This condition must be treated immediately to prevent vision loss.

 This condition usually affects patients with diabetic retinopathy. With neovascular glaucoma, abnormal blood vessels grow within the drainage angle. These abnormal vessels block the trabecular meshwork, preventing fluid from draining from the eye raising the intraocular pressure.

 Diagnosis of Glaucoma

A combination of factors determine if you have glaucoma.

 Medical History

A complete medical history along with family history is taken as glaucoma is mostly hereditary.  History of other medical conditions like diabetes and hypertension also are taken as it may affect the pressure of the eyes.

Measurement of  Eye Pressure

The intraocular pressure inside your eyes may be determined by a Tonometer.

 Your corneal thickness may also be measured. It has been discovered that patient’s who have thicker than normal corneas may register false high intraocular pressures. This may be an important factor in making a diagnosis.

Examination of the Optic Nerve

 A slit lamp(microscope)is used to examine your optic nerves for signs of glaucoma.Using a device called a slit lamp (a microscope), the doctor can examine your optic nerves for signs of glaucoma.  Sometimes, retinal photographs are taken. . Your doctor can compare your optic nerve to past visits to see if any changes have occurred in your condition. You may have them repeated from time to time. Sometimes, patients may have abnormal looking optic nerves but show no other signs of glaucoma. These people are called Glaucoma Suspects and are followed closely to see if they develop any other signs of glaucoma.

Examination of the Drainage Angle

To examine your drainage angle the doctor performs gonioscopy. To do this, the doctor numbs your eye with a few anesthetic drops, the places a special lens on your eye. This lens has a mirror in it which allows the doctor to examine the drainage angle to see whether it is open or closed.

Visual Field Testing

If your eye shows signs of glaucoma, your doctor may order a special test called a visual field. This test measures your peripheral or side vision. In glaucoma, nerve fibers that carry the impulses to the brain are damaged and/or destroyed.

Treatment of Glaucoma

Medications- Eye drops or oral tablets

Surgery- Trabeculoplasty

                 Iridotomy

                Trabeculectomy

.Routine Eye Exams

 People over the age of 35 should have routine eye exams every two years.  People over the age of 50 should  have them yearly. People who are of African-American heritage are more at risk to developing open angle glaucoma. People of Asian heritage are more at risk to developing closed or narrow angle glaucoma..

 Medication

If you are diagnosed with glaucoma and taking medication for it, it is very important that you follow your doctors advise exactly.  Even after your pressure is under good control, stopping your medications will cause the pressure to rise again damaging your optic nerve further. If you forget your medication, take it as soon as you remember, don’t wait for your next scheduled time. Never stop you medication, unless directed to do so by your doctor. Let your other doctors know you have glaucoma and are taking medication for it. This can help prevent drug interactions.