What is Glaucoma Types of Glaucoma Symptoms of Glaucoma Treatment for Glaucoma Remember FAQ about Glaucoma
Do not let Glaucoma rob you of your vision...

1. What is Glaucoma?

Glaucoma is a group of diseases usually associated with increased pressure within the eye. (Some types of glaucoma are primary open-angle, angle-closure, secondary, congenital, juvenile and low-tension.) This pressure can cause damage to the cells that form the optic nerve, the structure responsible for transmitting visual information from the eye to the brain. The damage is progressive with loss of peripheral vision first, followed by reductions in central vision and, potentially, blindness.



       2. What are the different types of Glaucoma?

       The different types are as under:

  • Simple glaucoma

    It is the most common type wherein the loss of vision is gradual and painless except for frequent change of reading glasses which could be an early sign of glaucoma. Considerable vision could be permanently lost in this form of glaucoma before an affected individual seeks medical attention. The field of vision (peripheral vision) gradually diminishes owing to the damage to the visual neurons subserving vision.

  • Acute glaucoma

    In acute glaucoma, which is more common in the Asian population,there is a sudden and drastic increase of pressure in the eye. There is a sudden blurring of vision accompanied by pain, red eye, headache, nausea and vomitting. The eye pressures could be increased to more than 50 mmHg in the eye (normal pressures within the eye is 20 mmHg) and such sudden rise in the eye pressures could permanently damage the optic nerves within a short period, if not immediately attended to.

  • Secondary glaucoma

    Several diseases and abnormalities within the eye could increase the pressures within the eye. The conditions which could raise the pressures within the eye include trauma, inflammations, tumours, retinal detachments and retinal vessel occlusions and neglected cataracts. Indiscriminate use of drugs like corticosteroids could also induce glaucoma. Early recognition of these eye diseases with appropriate treatment reverses glaucoma. Prolonged increase in eye pressures, however may cause irreversible loss of vision even if the underlying eye problem is corrected.

  • Congenital glaucoma

    Congenital glaucoma refers to the onset of increased eye pressures at birth or within the first few weeks or months of life. Glaucomas at birth are usually due to a hereditary defect leading to inadequate development in the portion of the eye that normally drains the fluid from within the eye. This results in obstruction to the flow of the fluid and elevation in eye pressures. Apart from optic nerve damage, congenital glaucoma causes decrease in vision due to enlargement and opacification of the cornea. Poor vision during infancy can also lead to inadequate development of the visual system with further decrease in the child's vision (amblyopia).

3. What are the symptoms of Glaucoma?

Most types of glaucomas show no symptoms and cause an insidious loss of vision that is irretrievable. In most patients with chronic type of glaucomas, considerable portion of the visual field is lost beyond redemption when first diagnosed. In many individuals glaucoma is incidentally diagnosed by the eye speacialist when the affected person seeks advice for an unrelated eye problem, such as for a refractive error. In acute glaucoma, there is a sudden and dramatic rise in eye pressures with obvious disturbances like pain in and around the eyes, red eyes, headache , nausea and vomiting with sudden decrease in vision. Some individuals with glaucoma could experience the symptoms listed below due to elevated eye pressures and damage to their optic nerves. Individuals with these symptoms should promptly be examined by an eye care professional to exclude glaucoma.

  • loss of side vision;
  • difficulty focusing on close work;
  • frequent need to change eyeglass prescriptions.
  • Dull pain around the eye after being in the dark, like after being in a cinema theatre
  • Seeing colored rings around artifical light especially in the early morning or at night
  • Frequent change of glasses for reading and near work
  • Poor night vision
  • Sensation of a blind area
  • Blurred or foggy vision



4. How is Glaucoma treated?

Visual loss from glaucoma is irreversible.This is due to damage to the neurons comprising the optic nerve, which are damaged due to excessively high levels of intraocular pressure. The visual neurones,once damaged, are not replenished, accounting for permanent loss of visual function in glaucoma. Preservation of vision remains the prime goal of therapy in individuals diagnosed with glaucoma.

Since raised eye pressure is the predominant cause for visual loss in glaucoma, the aim of treatment is to reduce the pressures to a level at which further damage to the optic nerve does not occur. The eye pressures can be reduced by: a) medication b) lasers c) surgery.

Medication (eye drops) is the first line of therapy employed in reduction of eye pressure. Several class of drugs are available which act either by reducing the formation of aqueous humor (the intraocular fluid which bathes the tissues) or improving the outflow of the fluid from the eye.

When the glaucoma cannot be controlled with medication or when the patients are unable to tolerate the side effects of the drugs, the following methods are resorted to -

  • Laser Treatment:

    Laser produces a high energy beam of light used to make pathway for the excess fluid to filter out, thus lowering the pressure. In some eyes, laser treatment is done to prevent glaucoma itself.

  • Surgery:

    New surgical procedures for glaucoma have been found to be effective in arresting deterioration of sight .

Remember

  • Use drops and pills regularly as prescribed by the ophthalmologist - the right number of times and at the right time of the day

  • Glaucoma reguires continuous monitoring and so visit the hospital once every 3 months

  • Never use any eye medication without your doctor's approval

  • Glaucoma is hereditary. Encourage all adults in the family to have regular eye check-ups

  • The best defence against glaucoma is a regular eye check-up especially after the age of 35





Progression of Glaucoma









       Symptoms
when nerve fibers are healthy, the optic cup is small and vision is normal

If nerve fibers are damaged, the optic cup enlarges."Side-vision" is reduced but central vision is normal

As more nerve fibres are damaged, the optic cup enlarges more."Tunnel vision" and then blindness can occur

Frequently Asked Questions about Glaucoma


5. How many people have glaucoma?
Prevalence studies the world over have revealed that 66.8 million people have glaucoma and about seven million people are blind due to glaucoma. Nearly three fourths of this population reside in China, India and other developing nations of South east Asia. Recent studies in South India reveal that nearly 2.5% individuals aged over forty years have one form of glaucoma or the other. This would approximately translate to about 7.5 million persons in India with glaucoma. Glaucoma is the most common cause of irreversible blindness in India and ranks next to cataract and uncorrected refractive errors as a significant cause of visual impairment.

6. How many people have glaucoma and don't know it?
Studies in the western population reveal that at least half of those with glaucoma were not aware of the potentially blinding disease. The number of people unaware of glaucoma tends to be much higher in the developing world. Population surveys in Madurai and Hyderabad had highlighted that more than 90% individuals diagnosed with glaucoma were not aware of the problem.

7. How many people are blind due to glaucoma?
It is a leading cause of blindness, accounting for between nine and 12 percent of all cases of blindness. The rate of blindness from glaucoma is between 93 and 126 per 100,000 population over 40. Nearly seven million people are blind due to glaucoma the world over. From the statistics available from various population studies in India, about a million are blind from glaucoma.

8. Who is at highest risk of developing glaucoma?
The primary Risk factors for glaucoma include:

Age: Increasing age is one of the principal risk factors in glaucoma. Although children and new born are likely to get glaucoma, it is common in individuals over the age of forty. With every decade of life, the risk of glaucoma exponentially increases.

Family History: Most primary glaucomas appear to be hereditary and genetically determined. Individuals with a family history of glaucoma are at significantly more risk of developing the disease than the general population.

Race: Ethnicity and racial backround appears to influence glaucoma. Persons of African ancestry have about four to five times the risk of developing open angle glaucoma than the white population. Asians, especially the Chinese, have enhanced risk of angle closure glaucoma, while the Japanese are at increased risk of normal pressure glaucoma.

Refractory Errors: Near sighted individuals (Myopia) are at increased risk of open angle glaucoma, while the far sighted (hyperopic) individuals are likely to have increased chance of angle closure glaucoma.

Intraocular Pressure: The level of the intraocualr pressure is the single most important risk factor in pathogenesis of glaucomatous visual loss. Although individuals with normal intraocular pressures (12-20 mmHg) are known to develop optic disc damage (Normal Pressure glaucoma), eyes with pressures exceeding 21 mmHg are at increased risk of glaucoma. In general, higher the eye pressures, greater is the likelihood of optic nerve damage from glaucoma.

Diabetes: The role of diabetes as a risk factor in glaucoma is not certain. But diabetes can lead to secondary glaucoma from retinal damage; hence a strict glycaemic control and periodical eye evaluation is mandatory.

9. How is glaucoma detected?
Most glaucomas are asymptomatic and are diagnosed when an individual consults an eye doctor for an unrelated problem. Early detection is crucial since treatment is ineffective when visual loss from glaucoma is advanced. All ophthalmologists are trained to diagnose glaucoma with simple clinical examination, which includes measurement of the intraocular pressure, evaluation of the optic nerve and examination of the visual fields. These procedures are simple and can be carried out in the outpatient Rooms with topical anaesthesia.

10. Can glaucoma be cured?
Glaucoma is a condition in which the visual neurons in the retina and the optic nerve are damaged permanently beyond repair. Visual loss and blindness form glaucoma cannot be cured or reversed. Early recognition of glaucoma and appropriate and regular treatment and periodical follow up by an ophthalmologist can preserve vision and delay vision impairment.

11. Can glaucoma be prevented?
Glaucomas that are hereditary cannot be prevented but early detection and appropriate treatment, strict compliance with the suggested treatment and regular follow up examination by an eye care professional can considerably reduce the possibility of blindness due to glaucoma. Secondary glaucomas due to trauma, inflammation or mature cataracts could be managed by the treatment of the primary condition.

12. What is the best defense against glaucoma?
The most effective way to prevent visual loss from glaucoma is a periodical evaluation by an eye specialist. The eye examination need to performed at least once in two years in individuals who are over forty years. In persons with risk factors, such as those with a relative with glaucoma, the eye examination should be on a more frequent basis, and also should commence earlier in life, preferably when they are about 20-30 years of age. Since glaucoma in the young is not uncommon, all children old enough to cooperate for an eye examination should also be periodically evaluated by an eye specialist.