Glaucoma is the disease of the optic nerve head caused by the increase of the fluid pressure in the eye. The fluid which is secreted into the eye is constantly being drained out of the eye. This maintains a constant intra ocular pressure. When this circulation gets blocked, it results in fluid accumulating in the eye ball. As the fluid builds up it begins to exert pressure inside the eye. Abnormally high levels of IOP can damage the delicate visual structures like the optic nerve head, which can lead to gradual loss of visual field and finally to blindness if left untreated.

Types of Glaucoma

There are basically two types of primary glaucoma

• Open Angle Glaucoma (OAG) or Chronic Simple Glaucoma (CSG) in which there is a gradual painless loss of visual field.
• Angle Closure Glaucoma (ACG) is an acute onset glaucoma with sudden increase in the IOP with pain in the affected eye, headache and vomiting. This needs emergency treatment.

People at Risk

People with certain health conditions or in certain age groups are at greater risk of Glaucoma than others. The following are considered risk factors:

• Family history of Glaucoma.
• Diabetes.
• Myopia (- power or short sightedness) or high hypermetropia ( + power of long sightedness).
• Age factor ( 55 or above)

Symptoms of Glaucoma

Some types of Glaucoma may affect without warning signals. However, the following symptoms may be observed in some cases:

• Frequent change of glasses
• Painless and gradual diminution of vision
• Loss of peripheral field of vision and haloes around light
• Sudden onset of pain, redness, headache, vomiting. (in angle closure glaucoma)

Investigation and Diagnosis

The following diagnostic tests may be performed to confirm the presence of Glaucoma:

• IOP measurement by Applanation tonometer.
• Gonioscopy: It helps determine whether the angle of the eye is open or closed or narrow.
• Ophthalmoscopy : Direct, Indirect, non contact lens study of the optic nerve head.
• Visual field test: Perimetry done by the computerized automatic field analyzer.

Treatment

The treatment options for Glaucoma include:

• Medical Treatment: Open angle glaucoma is treated with medication.
• Laser Therapy: Laser Iridotomy is done as an out patient procedure for asymptomatic narrow angles and angle closure glaucoma. The laser makes a small opening in the iris and widens the angle and prevents glaucoma in patients with narrow angle.
• Surgery: In advanced or moderately advanced cases, not controlled by medication or laser, surgery is performed. This is called trabeculectomy and is a microsurgical procedure, usually with good results.

Follow Up

Once glaucoma is diagnosed, life long care is required. It is important for the patients to use the drops regularly as prescribed by the doctor and have for a regular follow up. Glaucoma if diagnosed early can be controlled to a large extent with proper medication or laser. Therefore it is imperative for the patient to understand the importance of regular follow up and compliance to medication.