Glaucoma

Glaucoma is known as “SILENT THIEF OF SIGHT”

Structure of the Eye

The human eye is structured very much like a camera. Light rays are focused via the cornea and lens on the retina. (The retina is like the photosensitive film of the camera).
The retina transmits the image via the nerve of sight (optic nerve) to the brain. This nerve is like an electric cable. It contains about a million wires, each carrying a message to the brain. The brain co-ordinates and interprets these messages to provide distant vision (including side vision) as well as sharp reading vision.


How common is Glaucoma?

Glaucoma is a chronic, irreversible progressive disease of the optic nerve that affects approximately 70 million people around the world. It is the second most common cause of blindness and there are an estimated 7.5 million blind from the glaucoma, worldwide. It is most common cause for irreversible (permanent) blindness in the world including our India. In India, there are at least 12 million people affected with the glaucoma, 1.5 million are blind from the disease. The disease is more common in old age. The occurrence of glaucoma increases as age increases, approximately 2-3 persons per hundred persons are affected above the age 40 years. It is surprising to see that more than 90% of people are unaware of the glaucoma when first diagnosed even in urban area of metro cities.


What is Glaucoma?


There is a circulation of clear nourishing fluid within the eyeball.
When the drainage of this fluid is defective, pressure begins to build up within the eyeball. (Usually the pressure in normal individuals remains in the range of 10-21 mm Hg.)
Glaucoma is a general term used to describe damage to the optic nerve usually caused by high pressure.
The optic nerve is like a cable. It has more than a million fibers that send messages about what we see from the eye to the brain. Glaucoma damages the optic nerve fibers (the “wires” in the cable) causing blind spots to develop in areas of vision. People seldom notice these blind areas in the side vision until considerable optic nerve damage has occurred. If the entire nerve is destroyed, blindness results.
This rarely occurs if glaucoma is diagnosed and treated before major damage has taken place. Unfortunately if diagnosis has been delayed, permanent and irreversible optic nerve damage takes place which leads to loss of vision.


Relationship of Intraoccular Pressure to Glaucomatous Damage

There are various factors that play a role in causing optic nerve damage in glaucoma. A high intraocular pressure is the single most important modifiable risk factor. The pressure above which glaucomatous damage occurs is different for each eye. In rare cases there may be glaucomatous damage even when the intraocular pressure remains in the so-called 'normal' range, (Normal Tension Glaucoma).


Types of Glaucoma

There are two main types of glaucoma: Primary glaucoma and Secondary glaucoma. Primary glaucoma has two subtypes: Open angle glaucoma and angle closure glaucoma.

Primary Open Angle Glaucoma


In "Open Angle" glaucoma increased resistance to outflow in the canal causes a rise in the pressure inside the eye. It is a long-standing slowly progressive disease process and can cause visual loss so quietly that the patient is unaware of the trouble till the advanced stage of the disease.
The optic nerve cannot withstand the prolonged periods of high pressure resulting in damage, i.e. loss of sight. The angles are open and the obstruction in fluid circulation is usually in the drainage channels. If not checked in time this form of glaucoma is reported to cause painless, progressive and total blindness.

When the disease process happens at normal eye pressure, it is called "normal tension glaucoma."


Primary Angle Closure Glaucoma

There is a relative block to the flow of fluid through the pupil; this causes the iris to bow forwards, obstruct the canal and cause a raised pressure. There are two subtypes: chronic angle closure and acute angle closure glaucoma.
In chronic angle closure, there is no symptom in early phase and behaves very similar to open angle glaucoma. The treatment is different and it is very important to diagnose the disease in earlier stage only. For this only a through gonioscopy can differentiate between open & closed angle glaucoma.


Acute angle closure

As the name suggests its onset is quite sudden. The patient develops sudden blurring of vision with severe pain around the eye. The same patient may have had repeated episodes of a similar nature of lesser intensity which may have passed unnoticed. Every attack, mild or severe leaves behind some residual damage. At times the attack may be so severe that if not relieved promptly blindness can result in a matter of days.

As the treatment of open angle and angle closure glaucoma is different, it is important to identify which mechanism is involved. ('Gonioscopy' is very crucial in diagnosis and management of the disease.

In India, Primary Angle Closure Glaucoma is much more common than Caucasians and Africans which nearly counts for 40% of overall glaucoma population. That’s means in patients with glaucoma, chances of having closed angle is nearly 1:1 and the test we describe, as Gonioscopy is very crucial for diagnosis of the disease and it's further management.

Congenital Glaucoma

Children born with defective drainage channels within the eye are at high risk of developing Glaucoma.
The child's eye appears cloudy and becomes abnormally large in size.
If not diagnosed and treated, it leads to irreversible blindness at an early age.
Some forms of congenital glaucoma may be hereditary and run in families.

Secondary Glaucoma

This type of glaucoma occurs secondary to some other disease process in the eye e.g. bleeding, inflammation, tumour, hypermature cataract, etc. or due to some medicine like steroids. The treatment is primarily aimed at controlling the main disease process.
Very often once the primary condition is treated the glaucoma also gets controlled.
In some cases however there may be residual damage to the drainage channels causing glaucoma even after the primary process is controlled.


How do I know I have Glaucoma?

Symptoms and Sign

Different types of glaucoma have different symptoms:

Open Angle Glaucoma

Very often there are no symptoms in early stage of disease and hence this form is also known as the silent glaucoma. Patients may rarely have headaches or discomfort around the eyes. The decrease in vision starts in form of blurring of side (peripheral) vision, which usually goes unnoticed. As disease progresses, patient eventually is left with only small central "tunnel" vision.

Angle closure Glaucoma

Chronic angle closure glaucoma behaves very similar to open angle glaucoma and does not have any symptoms. In acute angle closure glaucoma, during an attack of acute glaucoma, patient develops sudden blurring of vision with severe pain around the eye and throbbing headache. He may see rainbow haloes around the light. Sometimes nausea and vomiting may be present. If not treated quickly and adequately, blindness may ensue.

Congenital Glaucoma's

The child is sensitive to light and tears excessively. Eyes appear cloudy and become abnormally large in size. Vision is usually very poor. It may be associated with other congenital abnormalities in the eye or in the other organs.


Diagnosis of Glaucoma

To definitely say that a person has glaucoma requires several tests, and many times these need to be repeated over time before confirming the diagnosis.

Intraocular Pressure

This is the pressure within the eyeball, which is usually 10-21 mm Hg. Sometimes a single recording cannot confirm or rule out diagnosis of glaucoma, in which case it needs to be repeated. In all individuals the pressure within the eye is not constant throughout the day; hence sometimes it may be necessary to record the intraocular pressure at different times of the day.

Gonioscopy

This is a test by which the drainage area is examined by a special lens. This area is known as the 'angle'. In case some abnormality is found in the angle, steps can be taken to correct the defect and restore normal fluid circulation in the globe.


Pachymetry

This is a test to evaluate the central corneal thickness. This may influence the recording of pressure within the eyeball.


Perimetry

This is a test to evaluate the field of vision. It is conducted on a computerized machine, which is able to pick-up even subtle defects. The tests have to be repeated periodically, before a clear interpretation can be drawn. Repeat tests are also necessary to pick up any deterioration, so that timely treatment may be given.


Photography of the Optic Nerve

The optic nerve can be photographed with a Fundus Camera. This serves as a permanent record and would help pick-up changes early. In subsequent visits repeat photographs are taken which can be compared with the earlier ones.


HRT III (Heidelberg Retinal Tomogram)

It is an imaging tool that calculates the three-dimensional surface topography of the optic disc region. This calculation is based on a series of images obtained using a laser. Software in the HRT III provides the user with a number of quantitative parameters of the optic nerve head and also several inbuilt diagnostic indices to help the doctor in the diagnosis and progression of glaucoma.


Optical Coherence Tomography (OCT)

It is a recent diagnostic imaging technique that can perform very high resolution (in micro millimeters) cross-sectional imaging of in biological tissues. It is a non-invasive, non contact imaging technology similar to ultrasound but has considerably greater resolution. It allows detailed examination of the retinal nerve fiber layer (RNFL), macular area in the retina and optic nerve head.


Scanning Laser Polarimetry (GDx VCC)

It is a recently developed non-invasive imaging technique for measuring the RNFL thickness. The laser beam is passed through the retinal nerve fiber layer twice and the software in the machine provides numerical values, which can help to predict the likelihood of the patient having glaucoma & also detect early progression in a known glaucoma patient by serial comparisons.


Anterior Segment OCT (Visante OCT)

It is a latest addition in glaucoma management. It is a new optical coherence tomography anterior segment scanner, which uses infrared light to visualize a "slice" through the anterior chamber. It is useful for the assessment of narrow angles and measuring anterior chamber width. The Visante OCT is non-contact.


Each of the above mentioned technology has unique applications. These devices currently cannot replace visual field testing but serve as to complement it in the comprehensive monitoring of patients with glaucoma. Some of this technology is better in regard to early diagnosis and another technology better in providing superior detection of worsening of the disease. Hence a compendium of these diagnostic tools along with visual field testing is the better way to go in the management and follow-up of glaucoma.

We are happy and proud to announce that BCEIRC is the only institute in western India to have all above facility to manage every kind of glaucoma including congenital glaucoma.


How is Glaucoma Diagnosed?

The diagnosis (or exclusion) of glaucoma requires a detailed, comprehensive examination of the eye. Your doctor will do the following examinations:

  • A routine vision test that requires reading letters from a chart
  • Slit lamp (microscope) examination
  • Measurement of the pressure in the eye usually using the applanation tonometer attached to the slit-lamp microscope. A hand held version of same instrument is acceptable. It may be necessary to obtain multiple reading of the pressure during the course of the day and night.
  • Examination of the angle of the eye using a gonioscope. Steps 3 and 4 require the use of a drop to eliminate the sensation in the eye. The drop may burn a little bit
    Drops in the eye to dilate the pupil to facilite:
  • Examination of the optic disc and the back of the eye (retina). Obtaining a stereo scopic view on the microscope using a held lens is the best method.
  • Newer computerized methods of examining the optic disc as shown above may be ordered. This is literally a computerized scan of the optic disc.
  • If glaucoma is suspected, then to confirm the diagnosis, the doctor will obtain an automated field test (perimetry test). Some patient may have difficulty doing this test for the first time. It may also be necessary to obtain several such tests as a baseline for future comparison Considering the importance of the test ANY automated perimeter is NOT acceptable. The field teat (perimetry) is a subjective test and it is important to have a calibrated machine with an appropriate normal database against which to compare your results.
    In some cases a diagnosis may not be possible on one visit. In very early cases it may be necessary to repeat the entire examination after a period of observation.

Effect of Glaucoma


Normal optic nerve

Damaged optic nerve

Normal visual field

Abnormal visual field

Risk Factors

Glaucoma is quite common in the Indian population. Blindness due to glaucoma in India is quoted from 0.5% to 4%. Nearly 12% of glaucoma patients are blind in India. It is more common in patients suffering from diabetes, hypertension and other vascular diseases. The risk of developing glaucoma increases after 40 years of age.
Refractive error also predisposes to glaucoma. Myopic patients have a higher risk to develop primary open angle glaucoma and hypermetropic patients may develop angle closure glaucoma.
Family history is the single most important risk factor. The type of glaucoma, prognosis and response to treatment may be similar amongst relatives.


Who is a 'Glaucoma Suspect'?

An individual in whom early glaucomatous changes are suspected for one or more of the following reasons:

  • Family history
  • Intraocular pressure recorder to be higher than the statistically determined average on few occasions. e.g. more than 21-22 mm of Hg.
  • Optic disc changes suggestive of glaucoma.
  • Suspicious field defects on perimetry.

These individuals are not termed as glaucoma patients till definitive proof suggest progressive changes. Hence this group of patients needs to be on regular follow up in order to diagnose and treat the glaucoma early.


How is Glaucoma Treated?

Once the diagnosis of glaucoma is confirmed, the chief aim of treatment is:

  • To keep the intraocular pressure at a level such that no further damage is caused to the optic nerve.
  • To periodically monitor the optic nerve and visual fields to ensure the effectiveness of the treatment.

Target Pressure:

The intraocular pressure at which no further damage is likely is called the target pressure. This is not fixed and may be different for different cases.


Treatment Modalities Available

Medical Treatment

This consists of eye drops, which have to be put into the eyes on a daily basis. Glaucoma medications are required for long periods, usually life-long. The drops reduce the intraocular pressure and putting drops irregularly will have wide intraocular pressure variation, which may hasten the optic nerve damage. Hence patients on antiglaucoma medication require to follow a strict regime under medical supervision.

Lasers

There are many types of laser procedures available for the treatment of glaucoma.

Laser Iridotomy

This procedure is helpful in certain cases of narrow angle glaucoma. A small opening is made in the iris using the Nd: YAG Laser. This enables easier circulation of aqueous humor within the eye. As the procedure is simple and doesn't have significant side effects, it may also be done as a preventive measure in patients having narrow angles but have not developed glaucoma.

Laser Iridoplasty

In some cases of narrow angle glaucoma, the iris is bunched up to cause narrow angles. The Argon Laser can be used to reduce this bunching and cause angle re-opening.

Selective Laser Trabeculoplasty

This procedure is useful in patients with primary open angle glaucoma. This laser selectively modifies trabecular meshwork (drainage area) to increase drainage of eye fluid and decrease intra ocular pressure. The treatment however has a tendency to lose its beneficial effect over time.

Surgical Treatment



An alternative drainage channel is created micro surgically to allow the aqueous fluid to drain outside the eye. This thereby reduces the intraocular pressure. The effectively of this surgery is usually good (approx. 90%). In some cases there may be a loss of beneficial effect with time. Hence the patient must have regular checkup even after successful surgery.

Sometime after surgery the patient may require to continue with anti-glaucoma eye drops.





Myths and Truths about Glaucoma

Glaucoma is a disease that only happens to older people.

Everyone is at risk for glaucoma from babies to senior citizens. Yes, older people are at a higher risk for glaucoma but babies get glaucoma (approximately 1 out of every 10,000 babies born in this country is born with glaucoma), young adults can get glaucoma.

Glaucoma is curable.

Glaucoma is not curable, however, it is manageable. But first it must be diagnosed. Often glaucoma can be managed with medication and / or surgery. This means that further loss of vision may be halted. However, glaucoma is a chronic disease that must be treated for life.

There are symptoms that will warn you of glaucoma.

With open angle glaucoma, the more common form, there are virtually no symptoms. There is usually no pain involved with the rise in eye pressure. Loss of vision begins with peripheral or side vision. This type of vision loss can be easily compensated for (by turning the head to the side) and may not be noticed until significant vision is lost. The best way to protect your sight from glaucoma is to be tested so that if you have glaucoma, treatment can begin immediately.

Glaucoma does not cause blindness.

Glaucoma can in fact cause blindness if it is left untreated; in fact it is second most common cause of blindness in India. Fortunately approximately in 90% of people with glaucoma who receive proper treatment will able to save further loss of vision.


Who needs an examination to rule out Glaucoma?

“Screening” the general population for glaucoma is neither cost effective nor logistically feasible. It is more effective to target those at high risk for the disease.

The following are advised to seek the described complete examination from their ophthalmologist:

  • All patients over the age of 35 years. The risk for glaucoma increases with age.
  • People with a family history of the glaucoma
  • Those who are using steroid drops, tablets or ointment for any disease
  • Diabetic patients
  • Those wearing minus glasses for short sightedness
  • Anyone with complaints of pain, redness and watering from the eyes.
  • Anyone with Complaints of seeing colored rings around lights.

To rule out glaucoma, your ophthalmologist will do the comprehensive eye examination described above.

In fact, all patients seen by an ophthalmologist for whatever reason should have the comprehensive examination. This detailed examination also helps to detect other “curable” eye diseases such cataract, disease of the retina, retinal detachment, etc.

Purpose of Glaucoma Clinic Membership

To reduce the total expenses without compromising on the best treatment care of your glaucoma, BCEIRC has started the glaucoma clinic membership.

Let’s look at the cost scenario without the membership.
Management Option Cost
Once a year visual field test is mandatory Rs. 1,000
Optic disc imaging (HRT lll,GDx VCC, OCT 3) is mandatory (twice a year) Rs. 2,000
Anterior Segment OCT(Visante) to measure and document angle of the eye Rs. 1,000
IOP measurements at least 5 times a year (more if glaucoma specialist feels necessary) Rs. 1,200
Total Rs. 5,200
We have decided to charge only Rs 3,000 for annual membership. (More than 42% reduction)

Additional Benefits

  • We will cover 5 visits for IOP measurement and if the glaucoma specialist feels that you will require more visits for your disease control, you will not require to pay extra for those extra visits
  • Visual field testing (Perimetry) also will be done at least once a year. Any extra testing considered necessary from glaucoma management point of view will not be charged.
  • If any surgical treatment for glaucoma is required like SLT, YAG laser or glaucoma surgery, then it will be charged 10% less.
  • We will also provide you the updated information about the disease and the newer treatment option including research for knowledge.

If you desire to become Glaucoma Clinic Member, please contact reception person they will help you out in becoming a member.

Contact Person:

Ms. Sadhana
Phone: +91-22 98195 11165 / 022-23671011
Email: Contact@eyecareforall.in

Frequently Asked Questions About Glaucoma

What is glaucoma?

Glaucoma is a general term used to describe damage to the optic nerve usually caused by high pressure.

Who are affected by glaucoma?

People of any age can be affected by glaucoma, but it is more often seen in people over the age of 40

Is there only one type of glaucoma?

No. There are many types of glaucoma. The commonest type is called open angle glaucoma.

How will I know if I have glaucoma?

Glaucoma is usually painless and most people with the condition are unaware that it is developing until it is diagnosed by a doctor.

How is glaucoma usually treated?

Glaucoma is usually treated with eye drops. Patients usually use drops once or twice a day in the affected eye. Some patients can also be helped with laser treatments and operations.

Can glaucoma cause blindness?

Yes. Glaucoma is a major cause of visual loss in developed countries. Fortunately if it is diagnosed and treated blindness is rare.

Do most people with glaucoma realize they have the condition?

Unfortunately a large proportion of patients with glaucoma are unaware that they are suffering from glaucoma.

Does glaucoma run in families?

It is now known that some families have a genetic tendency towards developing glaucoma. Individuals who have family members suffering from glaucoma have 5-7 times higher risk of developing glaucoma, hence they should have their eyes tested regularly.

How often should I have my eyes checked for glaucoma?

After the age of 40 the eyes should be checked for glaucoma every year.

How does glaucoma damage the eyes?

The nerve fibers that run within the optic nerve gradually breakdown. The side vision is initially damaged, and eventually only a small area of central vision may remain. In extreme cases this too can disappear.

Can the damage be reversed?

Unfortunately the damage caused by glaucoma is permanent. Hence, early detection and treatment is vital.