DR. ASHOK EYE HOSPITAL

Glaucoma – “The sneak thief of sight”

This article is intended to increase awareness of Glaucoma, a potentially blinding eye condition, which is mostly symptomless and hence neglected.
The eye is the organ of sight, a nearly spherical hollow globe filled with fluids. The fluids in the eye are divided by the lens into the vitreous humour (behind the lens) and the aqueous humour (in front of the lens).

Enquiry Now
The aqueous humour is being made behind the coloured part of the eye (the iris). It leaves the eye through channels in the front of the eye in an area called the anterior chamber angle, or simply the angle, which acts as a drain for the eye. This forming and draining of the fluid (aqueous) is a continuous process and also is a fine balance maintaining a certain pressure in the eye called intraocular pressure.

What is Glaucoma?

Anything that slows or blocks the flow of this fluid out of the eye will cause pressure to build up in the eye.
The increased pressure causes compression of the optic nerve which can eventually lead to nerve damage. Glaucoma can cause partial vision loss, with blindness as a possible eventual outcome.
Glaucoma refers to the condition of increased intraocular pressure causing nerve damage at the back of the eye which can be detected clinically and/or by a set of specialized investigations called Visual Fields and Retinal Nerve Fibre Analysis. Increased pressure alone does not constitute glaucoma but must raise an alarm, similarly normal pressure may also cause nerve damage.
This nerve loss causing VISION LOSS IS IRREVERSIBLE, hence the need to detect and arrest progression of nerve loss in the early stages.

Types of Glaucoma

Anything that slows or blocks the flow of this fluid out of the eye will cause pressure to build up in the eye.
Open-angle (chronic) glaucoma
Open-angle (chronic) glaucoma is the most common type of glaucoma. The cause is unknown. It is usually seen after the age of 40 years. An increase in eye pressure occurs slowly over time. The pressure pushes on the optic nerve. This type tends to run in families, so the risk is higher if one has a parent, a grandparent or a sibling with open- angle glaucoma.
Angle-closure (acute) glaucoma
Angle-closure (acute) glaucoma occurs when the exit of the aqueous humour fluid is suddenly blocked. This causes a quick, severe, and painful rise in the pressure in the eye. Acute angle-closure glaucoma is an emergency. This is very different from open-angle glaucoma, which painlessly and slowly damages vision. If you have had acute glaucoma in one eye, you are at risk for an attack in the second eye, and your doctor is likely to recommend preventive treatment in the form of laser in the second eye. Often during routine examination the angles are noted to be narrow, in such cases the intraocular pressure may be normal and the patient is otherwise asymptomatic but is still advised to undergo a laser treatment called YAG PI(peripheral iridectomy). This laser forms an alternative route for the aqueous to flow should the angles suddenly close. This is a preventive treatment done in persons having narrow angles (angles are the natural drainage system in the eye). This is an outpatient procedure and both eyes are done in the same sitting. This does not mean they have glaucoma.
Congenital glaucoma
Congenital glaucoma is seen in babies. It often runs in families (is inherited).It is present at birth. It is caused by abnormal eye development.
Secondary glaucoma
Secondary glaucoma is caused by drugs such as corticosteroids, certain eye conditions like uveitis, systemic diseases and trauma.
Normal-tension glaucomaglaucoma
Normal-tension glaucoma – A type of Glaucoma in which eye pressure can be normal, but the nerve may get damaged.

What tests are done to detect Glaucoma?

A comprehensive (complete) eye examination is needed to diagnose glaucoma. The examination will include vision, refraction, tonometry (eye pressure checkup), and evaluation of the nerve and retina after dilatation. Some of the other tests may include using a special lens to look at the angle (drain) of the eye (gonioscopy),visual field testing and scanning of the nerve with the help of specialized equipments(OCT).

Treatment of Glaucoma

The goal of treatment is to reduce eye pressure. Treatment depends on the type of glaucoma that one has. Most people can be treated successfully with eye drops. Most of the eye drops used today have fewer side effects than those used in the past. Tablets may also be given to lower pressure in the eye. Other treatments may involve Laser therapy. Eye surgery for glaucoma is reserved for those whose pressure doesn’t get controlled with drops or laser.

Expectations (prognosis)

Open-angle glaucoma cannot be cured. However, you can manage your symptoms by closely following your doctor's instructions. Regular check-ups are needed to prevent blindness. Angle-closure glaucoma is a medical emergency. You need treatment right away to save your vision. Babies with congenital glaucoma usually do well when surgery is done early. How well a person with secondary glaucoma does depends on the disease causing the condition.

Please Note......


  • Routine eye examination by an ophthalmologist is the key to early detection of glaucoma.
  • Risk factors for developing Glaucoma, Increasing age (>60yrs), Family history of glaucoma, Injury to the eye, Nearsightedness Diabetics, High blood pressure, Long-term steroid treatment, African lineage

Frequently Asked Questions (FAQ)

What is glaucoma and why is it called the “sneak thief of sight”?

Glaucoma is a group of eye diseases that damage the optic nerve, often due to increased pressure inside the eye. It is called the “sneak thief of sight” because it can cause gradual, irreversible vision loss without noticeable symptoms in its early stages.

What are the early symptoms of glaucoma?

In most cases of open-angle glaucoma, there are no early warning signs. As the disease progresses, people may notice gradual loss of peripheral vision. Acute angle-closure glaucoma, however, can cause severe eye pain, blurred vision, halos around lights, headache, nausea, and vomiting.

Who is at a higher risk of developing glaucoma?

People over 40, those with a family history of glaucoma, diabetes, high blood pressure, severe nearsightedness, long-term steroid use, or previous eye injuries have an increased risk. Regular comprehensive eye examinations are recommended for early detection.

Can glaucoma cause permanent blindness?

Yes. Vision loss caused by glaucoma is irreversible because the damaged optic nerve cannot regenerate. However, early diagnosis and timely treatment can slow or prevent further vision loss in many patients.

How is glaucoma diagnosed?

Glaucoma is diagnosed through a comprehensive eye examination that may include measurement of intraocular pressure, optic nerve evaluation, visual field testing, corneal thickness assessment, and imaging studies to detect early damage.

Can glaucoma be cured?

There is currently no cure for glaucoma, but it can often be effectively managed. Treatments such as prescription eye drops, laser procedures, or surgery are designed to lower eye pressure and preserve remaining vision.

What treatments are available for glaucoma?

Treatment depends on the type and severity of glaucoma. Options include medicated eye drops, oral medications, laser therapy, minimally invasive glaucoma surgery (MIGS), and conventional glaucoma surgery to reduce eye pressure and protect the optic nerve.

How often should I get screened for glaucoma?

Adults should have regular comprehensive eye examinations as recommended by their ophthalmologist, especially after age 40 or if they have risk factors such as diabetes, Hypertension or a family history of glaucoma. Early screening is the best way to detect the disease before significant vision loss occurs.

Can glaucoma develop even if my vision seems normal?

Yes. Many people with glaucoma have no symptoms and maintain normal central vision until the disease is advanced. This is why routine eye checkups are essential, even if your eyesight appears to be unaffected.

Is glaucoma related to cataracts?

Glaucoma and cataracts are different eye conditions, although they can occur together, especially in older adults. Cataracts cloud the eye’s natural lens, while glaucoma damages the optic nerve. An ophthalmologist can evaluate and manage both conditions appropriately.

Does insurance cover glaucoma surgery?

Yes, many insurance plans provide coverage for glaucoma surgery if it is considered medically necessary and performed at a network hospital. Coverage limits and eligibility vary as per policy.

Enquire Now