Glaucoma

Glaucoma the silent stealer of sight

In a normal eye, a clear transparent fluid called aqueous humor is secreted and continuously drained out via microscopic channels inside & then into the blood circulation. If because of any reasons the channels are blocked, the fluid starts accumulating within the eye and pressure starts building up which if not controlled causes damage to the optic nerve of the eye

What is glaucoma?
Glaucoma is a condition where the intra ocular pressure of the eye is sufficiently high to cause damage to the optic nerve. (Which transmits the light rays to the brain). It is one of the leading causes of blindness. It is fairly common in adults over the age of 40. If diagnosed at an early stage, blindness from glaucoma can be prevented.

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How does glaucoma affect normal lifestyle:
Whenever we look at an object, the image of that object falls on the retina (neurosensory layer of the eye). From there it is carried to the brain via the optic nerve. Optic nerve is like an electric cable with millions of nerve fibers with increase of pressure within the eye these nerve fibers die, resulting in damage to the optic nerve. This is usually not noticed by the patients until the damage becomes quite advanced. However it can be diagnosed by eye specialist and by some special tests like the following.

  • Tonometry – eye pressure check up
  • Slit-lamp examination microscopic examination of the eye.
  • Retinal examination (optic nerve examination) to check for the damage.
  • Perimetry /visual field testing

 

Types of glaucoma:
Glaucoma can be of many types depending on cause and mechanism of the disease. Broadly it can be divided into the following categories:

1. Chronic simple glaucoma or open angle glaucoma :

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It is the most common type where the loss of vision is gradual and painless. Usually it is detected when patients come to the eye doctor for routine eye check up. Following are a few symptoms of this type of glaucoma:

  • Gradual diminution of vision with blurred or foggy vision
  • Frequent change of eyeglass with no significant improvement in vision.
  • Mild chronic headache, scotomas in peripheral visual field.
  • Coloured halos around lights

 

Because of this, it is advisable to check the eyes with an eye doctor after 40 years of age and also if there is family history of glaucoma

2. Acute / closed angle glaucoma :

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In certain individuals, the angle from where fluid drains from the eye is genetically narrows. It can be blocked suddenly due to many reasons resulting in sudden increase in eye pressure . It usually occurs in one eye at a time causing some of the following symptoms for which it requires immediate medical attention:

  • Severe pain in the eye with headache and facial pain
  • Sudden blurring of vision
  • Cloudy vision with halos around the lights
  • Redness in the eye with nausea and vomiting

 

3. Secondary glaucoma :
The intra-ocular pressure in the eye can increase secondary to

  • Systemic diseases, eg. Diabetes
  • Eye diseases, eg. Tumors, iridocyclitis
  • Injuries, eg. blunt like a fist injury
  • Overuse of certain drugs, eg. corticosteroids

 

4. Congenital glaucoma:
it is hereditary and present at birth or develops within first few years of life. In this types, the drainage channels in the eye are defective from birth itself. Following are the symptoms:

  • The child has excessive watering of the eyes
  • Abnormal sensitivity to normal light
  • The cornea may become white and cloudy or enlarge in size resulting in loss of vision

One may think of surgery as a treatment.

Glaucoma treatment:
The aim is to reduce the eye pressure to a level at which it will not cause damage to the optic nerve. This prevents further loss of vision but what has already occurred cannot be reversed. The modalities of treatment are:

  • Eye drops should be instilled regularly as prescribed by the eye doctor to reduce and control intra-ocular fluid pressure.
  • Tablets usually given for short span of time to time to decrease the pressure during acute attacks or to help in bringing down the pressure when eye drops alone are not sufficient
  • Laser treatment - 2 types
  1. laser iridotmy- done for acute or narrow angle glaucoma with laser. A “hole” or opening is made in the iris to relieve the blockage of the drainage channels.
  2. Laser trabeculoplasty- useful in open angle glaucoma cases. Here the laser is used to open the blocked passages in the eye hereby facilitating the aqueous fluid from within to reach the outside of the eye.
  • Surgery for glaucoma or trabeculectomy : It is an operation where an additional channel is created surgically to drain the excess fluid bypassing the abnormally blocked channels. It is useful for most types of glaucoma.

 width= width=Once diagnosed, glaucoma patient needs periodic eye check up

  • Best defense against glaucoma is a regular eye check up especially after the age of 40. Timely diagnosis can prevent glaucoma blindness.
  • The risk factor for glaucoma is age over 40. Family history of glaucoma, diabetes for sightedness etc. So encourage all adults in the family to have regular eye check up and especially more when there is a strong family history of the same.
  • Never use any medication without an eye doctor’s approval. Continuous use of different types of drops can cause glaucoma, e.g. steroid eye drops.
  • Once diagnosed, glaucoma patient needs periodic eye check up
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