Glaucoma-: An Overview


 

 

Pressure inside eye increases and slowly damages optic nerve

Glaucomatous optic nerve damage causes loss in field of vision leading to tunnel vision

Perimetry-visual Field report showing defects

Gonioscopy-Pigmented Schwalbe's line

Fundus-Glaucomatous Cupping-optic nerve head

OCT-Disc and Nerve Fibre LayerMeasurment

.Nd Yag Laser

Trabeculectomy-filtering surgery

Ahmed Glaucoma Valve in advanced uncontrolled glaucoma

Diode Laser Cyclophotocoagulation for advanced Glaucoma

Neovascular glaucoma-rubeosis

What is Glaucoma?
Glaucoma is a multifactorial condition in which the main culprit is high pressure of the eyes. This slowly damages the retinal nerve fibres and optic nerve resulting in decrease of vision . If not detected and treated in time it can lead to irreversible vision loss.

 

What are the symptoms of glaucoma?
It is also called a silent disease as most of the times it has no symptoms. The optic nerve fibres start getting affected and cause a decrease in the peripheral field of vision which the patient is not aware of. Patients perceive problem only when the central vision gets affected. Sometimes if the pressures inside eye become too high (normal pressure is 10 to 21mmHg) he might feel heaviness in eyes, headches or see colored halos around a light bulb. In few types of glaucoma, there may be sudden redness and pain with blurring of vision.

 

How do I know if I have Glaucoma?
Many a times this condition is detected only upon routine eye examination. Hence all patients at our hospital/ clinic are screened for the same. The symptoms of this disease may vary from no symptoms to eye ache, headache, red painful eye and blurred vision. Sometimes early glaucoma can cause frequent change in spectacles power.

How much is high pressure?
The average normal intraocular pressure is 10 to 21 mHg. Pressure above 21 mHg may slowly damage the optic nerve. This is because of chronic pressure effect on the one million nerve fibres at the back of eye which form the main optic nerve carrying visual impulse to brain.

 

Why do the eye pressures become high?
To understand this, compare your eye to a balloon filled with water. If the water is more, balloon will become tense. Similary, in the eye if the pressures become high, it effects the back of eye where the optic nerve fibres are. Throughout life there is a delicate balance which has to maintained between an area forming the fluid in eye and the area draining out the same. Due to certain microstructural changes in these areas the fluid is either produced more or drained less resulting in high pressures.

 

Can I have Glaucoma with normal pressure?
Yes, some people have susceptibility to damage even with normal pressure (Low Tension or Normal Tension Glaucoma). There are various theories for this kind of glaucoma, mainly a change in vascularity-blood supply of optic nerve.



What tests are done to diagnose Glaucoma?
Routine eye examination includes-

  • Applanation Tonometry-to measure intraocular pressure
  • Fundus- documents the changes of optic nerve head(disc) while looking at your fundus through pupil
  • Gonioscopy- The type of Glaucoma is detected by assessing the angle of an interior chamber of eye by gonioscopy.

 

Depending on the level of suspicion , we ask for following confirmatory test:

  • Perimetry - computerized visual field test to detect areas of fading vision.
  • Central corneal thickness-to refine the results of our eye pressure measurements
  • Optical Coherence Tomography (OCT)-anatomical documentation of the optic nerve head and nerve fibre layer

How is Glaucoma treated?
It could be in the form of medicines,laser and or surgery. Treatment often begins with eye drops to lower intraocular pressure which helps to prevent further damage. Newer medications are now available which are very effective and few side effects. Medicines used for each individual has to be chosen with great care according to his eye condition, systemic illness and lifestyle pattern.

 

What is the role of Laser?
Certain type of Glaucoma eg. Pigmentary Glaucoma are treated by Argon Laser Trabeculoplasty (ALT). Peripheral Iredectomy (P.I.) has a role in narrow angle Glaucoma.

 

Is there surgery for Glaucoma?
With the newer medications, surgical intervention is less required. However in patients who have failed laser treatment or not controlled by medication or advanced progressive glaucoma, filtering surgery trabeculectomy is done. An alternative microtrack is created for the fluid to flow out from, thus controlling the eye pressure. The success rate of this surgery varies according to the type and stage of glaucoma. Various modifications can be done to ensure that filtering passage works throughout life.

 

Will glaucoma surgery lead to an improvement in my vision?
No, the glaucoma surgery is done to control the eye pressures to maintain your vision. Any vision loss due to prior optic nerve damage cannot be treated.  


 
What are the complications of glaucoma surgery?
Glaucoma surgeries require precision of surgeon and patience of patient. The microtrack created by surgery can over or underfiltrate. Like any other surgery ,there might be few complications like bleeding, infection, low or high pressures etc. Some trabeculectomies may fail to function after months or years.

 

I have been diagnosed with glaucoma, what should I do to ensure that my vision remains normal?
Do not worry, you will enjoy healthy sight if you put the antiglaucoma eye drops regularly and keep your eye pressures under control. It is very crucial that you keep in touch with your treating eye specialist and report for follow-ups as he asks to. Normally, we call the patient every 4 months for eye pressure check and repeat the visual field examination every year.  
 


Are there any lifestyle do’s and don’ts for a glaucoma patient?
Not really. There is nothing external influencing the course of glaucoma. There is no diet restriction. Carry on with our routine lifestyle and just be regular with your medicines. If you have hypertension , diabetes or thyroid disease, it needs to be well controlled. Avoid having excess of tea and coffee as caffeine has been shown to increase eye pressures in some individuals.

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