Glaucoma

Silent thief of sight

Glaucoma is the most serious eyesight threatening condition of the eye. It usually manifests as a painless gradual loss of vision. The lost vision can never be recovered. However, medical or surgical treatment can prevent or retard further loss of vision.

Many a times it can be confused with a cataract which also manifests as a painless gradual loss of vision. The difference is that in the case of cataract, the loss of vision is fully recoverable by means of a simple surgery called Phaco. Our eyes contain a clear fluid called aqueous humour, which is continuously produced in the eye to bath and nourish the structures inside it. The fluid normally drains out of the eye through drainage canals in a fine mesh work located around the edge of the iris (the colored part of the eye that surrounds the pupil). In people with glaucoma the fluid fails to drain due to some defect and thus increases the pressure inside the eyes called raised Intraocular Pressure (IOP) (or Tension).

In most cases of glaucoma, the patient is not aware of the gradual loss of sight until vision is significantly impaired.However, if glaucoma progresses without adequate treatment, the following symptoms may occur in some individuals:

  • Pain around the eyes when coming out from darkness (e.g., as soon as the person comes out of a cinema hall)
  • Colored halo rings seen around light bulbs especially in the mornings and nights
  • Frequent change of reading glasses, headaches, pain and redness of the eyes
  • Reduced vision in dim illumination and during nights
  • Gradual decrease of side vision with progression of glaucoma

Types Of Glaucoma

1. Open Angle Glaucoma

It happens when the eye’s drainage canals become clogged over time. The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid can’t drain out of the eye. With open angle glaucoma, the entrances to the drainage canals are clear and open. The clogging problem occurs further inside the drainage canals, similar to a clogged pipe below the drain in a sink. Most people have no symptoms and no early warning signs. If open angle glaucoma is not diagnosed and treated, it can cause a gradual loss of vision. This type of glaucoma develops slowly and sometimes without noticeable sight loss for many years. It usually responds well to medication, especially if caught early and treated. This form of glaucoma is more common in Caucasians.

2. Angle Closure Glaucoma

This type of glaucoma is also known as acute glaucoma or narrow angle glaucoma. It is more common in Asian and is very different from open angle glaucoma in that the eye pressure usually rises very quickly.This happens when the entrance to the drainage canals are very norrow or covered over, like a sink with something covering the drain. Symptoms of angle closure glaucoma may include headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision.

Few other rarer forms of Glaucoma

Low-tension or normal-tension glaucoma:

In this type of glaucoma, the optic nerve is damaged even though intraocular pressure (IOP) is not very high. Lowering eye pressure at least 30 percent through medicines slows the disease in some people. A comprehensive medical history is important in identifying other potential risk factors, such as low blood pressure, that contribute to low-tension glaucoma. If no risk factors are identified, the treatment options for low-tension glaucoma are the same as for open-angle glaucoma.

Congenital glaucoma:

Children are born with a defect in the angle of the eye that slows the normal drainage of fluid. These children usually have obvious symptoms, such as cloudy eyes, sensitivity to light, and excessive tearing. Conventional surgery typically is the suggested treatment, because medicines may have unknown effects in infants and be difficult to administer. Surgery is safe and effective. If surgery is done promptly, these children usually have an excellent chance of having good vision.

Secondary glaucomas:

These can develop as complications of other medical conditions. These types of glaucomas are sometimes associated with eye surgery or advanced cataracts, eye injuries, certain eye tumors, or uveitis (eye inflammation). Pigmentary glaucoma occurs when pigment from the iris flakes off and blocks the meshwork, slowing fluid drainage. A severe form, called neovascular glaucoma, is linked to diabetes. Corticosteroid drugs used to treat eye inflammations and other diseases can trigger glaucoma in some people. Treatment includes medicines, laser surgery, or conventional surgery.

Do I have Glaucoma

Does increased eye pressure mean that I have glaucoma?

Not necessarily. Increased eye pressure means you are at risk for glaucoma, but does not mean you have the disease. A person has glaucoma only if the optic nerve is damaged. If you have increased eye pressure but no damage to the optic nerve, you do not have glaucoma. However, you are at risk. Follow the advice of your eye care professional.

Can I develop glaucoma if I have increased eye pressure?

Not necessarily. Not every person with increased eye pressure will develop glaucoma. Some people can tolerate higher eye pressure better than others. Also, a certain level of eye pressure may be high for one person but normal for another. Whether you develop glaucoma depends on the level of pressure your optic nerve can tolerate without being damaged. This level is different for each person. That’s why a comprehensive dilated eye exam is very important. It can help your eye care professional determine what level of eye pressure is normal for you.

Can I develop glaucoma without an increase in my eye pressure?

Yes. Glaucoma can develop without increased eye pressure. This form of glaucoma is called low-tension or normal-tension glaucoma. It is not as common as open-angle glaucoma.

Who is at risk for glaucoma?

  • Anyone can develop glaucoma. Some people are at higher risk than others. They include:
  • Everyone over the age of 40 yrs.
  • People with family history of glaucoma.
  • Diabetics
  • People with near sightedness (Myopia) for open angle type and far sightedness (hyperopia) for close angle type
  • Hypertention
  • Migraine

When should I get my eyes tested for glaucoma?

  • If you have a family history of glaucoma
  • If you experience blurring of vision
  • If you see haloes around light
  • If you suffer from frequent headaches
  • Frequent change of glasses due to decreasing eyesight

Standard Investigation For Glaucoma

Early detection, through regular and complete eye exams, is the key to protecting your vision from damage caused by glaucoma.

Ophthalmoscopy

Ophthalmoscopy is used to examine the inside of the eye, especially the optic nerve. In a darkened room, the doctor will magnify your eye by using an ophthalmoscope (an instrument with a small light on the end). This helps the doctor look at the shape and color of the optic nerve.

Perimetry

Perimetry is a procedure where the patient wears a patch over one eye and looks straight ahead at a bowl-shaped white area. At the same time, the computer presents lights in fixed locations around the bowl. The patient indicates each time he or she sees a light, which is why perimetry is able to provide a map of the visual fields. The type of vision loss associated with glaucoma is relatively specific, and perimetry can detect the typical visual-field defects of glaucoma disorder.The perimetry test is also called a visual field test.

Gonioscopy

Gonioscopy is used to detect which type of glaucoma you have. Once the surface of the eye has been numbed with eye drops, your eye specialist will place a special contact lens on your eye. This special lens will allow your eye specialist to look at the eye’s drainage system and check if the angle where the iris meets the cornea is open or closed.

Newer Diagnostics In Glaucoma

Retinal Nerve Fibre Analysis/OCT

Retinal Nerve Fibre Analysis/OCT Nerve fibre analysis is a newer method of glaucoma testing in which the thickness of the nerve fibre layer is measured. Thinner areas may indicate damage caused by glaucoma. This test is especially good for patients who may be considered to be a glaucoma suspect and also to indicate if a person’s glaucoma is progressively becoming worse. The OCT instrument utilizes a technique called optical coherence tomography which creates images by use of special beams of light. The OCT machine can create a contour map of the optic nerve, optic cup and measure the retinal nerve fiber thickness. Over time this machine can detect loss of optic nerve fibers.

Pachymetry

Retinal Nerve Fibre Analysis/OCT Nerve fibre analysis is a newer method of glaucoma testing in which the thickness of the nerve fibre layer is measured. Thinner areas may indicate damage caused by glaucoma. This test is especially good for patients who may be considered to be a glaucoma suspect and also to indicate if a person’s glaucoma is progressively becoming worse. The OCT instrument utilizes a technique called optical coherence tomography which creates images by use of special beams of light. The OCT machine can create a contour map of the optic nerve, optic cup and measure the retinal nerve fiber thickness. Over time this machine can detect loss of optic nerve fibers.

Glaucoma Treatment

Glaucoma is a chronic (long lasting) progressive condition. Any vision loss that has occurred, before glaucoma was diagnosed, cannot be reversed. Glaucoma treatments include medicines, laser trabeculoplasty, conventional surgery, or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from glaucoma.

  • Medicines. Medicines, in the form of eyedrops or pills, are the most common early treatment for glaucoma. Some medicines cause the eye to make less fluid. Others lower pressure by helping fluid drain from the eye.
  • Glaucoma medicines may be taken several times a day .Since glaucoma often has no symptoms, people may be tempted to stop taking, or may forget to take, their medicine. You need to use the drops or pills as long as they help control your eye pressure. Regular use is very important.
  • Laser trabeculoplasty. Laser trabeculoplasty helps fluid drain out of the eye. Your doctor may suggest this step at any time. In many cases, you need to keep taking glaucoma drugs after this procedure. Laser trabeculoplasty is performed in your doctor’s office or eye clinic. Before the surgery, numbing drops will be applied to your eye. As you sit facing the laser machine, your doctor will hold a special lens to your eye. A high-intensity beam of light is aimed at the lens and reflected onto the meshwork inside your eye. You may see flashes of bright green or red light. The laser makes several evenly spaced burns that stretch the drainage holes in the meshwork. This allows the fluid to drain better.
  • Glaucoma Filtering surgery. Conventional surgery makes a new opening for the fluid to leave the eye. Your doctor may suggest this treatment at any time. Conventional surgery often is done after medicines and laser surgery have failed to control pressure. Before the surgery, you will be given medicine to help you relax. Your doctor will make small injections around the eye to numb it. A small piece of tissue is removed to create a new channel for the fluid to drain from the eye.

As with laser surgery, conventional surgery is performed on one eye at a time. Usually the operations are four to six weeks apart. Conventional surgery is about 60 to 80 percent effective at lowering eye pressure.

How should I use my glaucoma eyedrops?

If eyedrops have been prescribed for treating your glaucoma, you need to use them properly and as instructed by your eye care professional. Proper use of your glaucoma medication can improve the medicine’s effectiveness and reduce your risk of side effects. To properly apply your eyedrops, follow these steps:

  • First, wash your hands.
  • Hold the bottle upside down.
  • Tilt your head back.
  • Hold the bottle in one hand and place it as close as possible to the eye.
  • With the other hand, pull down your lower eyelid. This forms a pocket.
  • Place the prescribed number of drops into the lower eyelid pocket. If you are using more than one eyedrop, be sure to wait at least five minutes before applying the second eyedrop.
  • Close your eye OR press the lower lid lightly with your finger for at least one minute. Either of these steps keeps the drops in the eye and helps prevent the drops from draining into the tear duct, which can increase your risk of side effects.

Laser Iridotomy

Patients with narrow, occludable angles or who have an attack of acute angle closure glaucoma are treated with laser peripheral iridotomy (LPI).

Laser peripheral iridotomy involves creating a tiny opening in the peripheral iris, allowing aqueous fluid to flow from behind the iris directly to the anterior chamber of the eye This typically results in resolution of the forwardly bowed iris and, thereby, an opening up of the angle of the eye. The narrow or closed angle thus becomes an open angle! Prior to the advent of laser, a surgery was necessary to create this bypass (surgical iridectomy).

The laser peripheral iridotomy procedure is completed in the office. Prior to the procedure, the pupil is often constricted with an eye drop medication known as Pilocarpine. Usually, a lens is placed on the eye (after topical anesthetic drops are applied) in order to better control the laser beam. The entire procedure takes only a few minutes. The lens is then removed from the eye, and vision will quickly return to normal. After the procedure, we may recommend anti-inflammatory eye drops for the next few days and a post-operative visit will be scheduled.

Does laser peripheral iridotomy reverse glaucoma?

Often, patients having a laser PI do not have glaucoma; this procedure is being done prophylactically to prevent the development of angle closure glaucoma. In the cases where there is pre-existing chronic open angle glaucoma, or attacks of acute angle closure glaucoma, the treatment should prevent further damage to the nerve.

Is the procedure painful?

The surface of the eye is numbed by topical anesthetics for this procedure, but the iris is not; therefore, when the laser beam hits the iris to create the peripheral iridotomy, mild discomfort may occur. In general, only a few brief episodes of slight discomfort are associated with this procedure. Also, there is absolutely no discomfort postoperatively in the great majority of cases.

What are the potential complications?

A laser peripheral iridotomy is an extraordinarily safe procedure. Complications, fortunately,are very rare. Potential complications include bleeding in the eye, inflammation in the eye, and transient pressure elevations. Therefore, we recommend treatment with an anti-inflammatory drop following the procedure.

Glaucoma Faqs

What is glaucoma?

Glaucoma is a disease characterised by usually high pressure inside the eye that damages the optic nerve and may lead to permanent loss of vision. Not all 3 criteria (that is, high pressure inside the eye, optic nerve damage, and vision loss) are required to diagnose glaucoma; however, a diagnosis of glaucoma is certain when all 3 criteria are present.

Are there different types of glaucoma?

The 2 main types of glaucoma are open-angle glaucoma and angle-closure glaucoma. In angle-closure glaucoma, the normal drainage canals within the eye are blocked, and this block can be acute (sudden) or chronic (long-lasting). In open-angle glaucoma, the drainage system remains open, but is dysfunctional. Other types include congenital glaucoma, normal tension glaucoma, and secondary glaucoma.

What does glaucoma suspect mean?

A glaucoma suspect is a person in whom, in the doctors opinion, there is a hgh chance of developing glaucoma. This maybe due to the elevated eye pressure or the appearance of the optic nerves. Some people may have pressures that are higher than normal, but is not associated with optic nerve damage and vision loss. but they do not develop glaucoma, and are called oclar hypertensives. Other people have optic nerves that might appear to be abnormal, but, in fact, are actually normal for them.

How is glaucoma treated?

The only known method of treating glaucoma is to decrease the eye pressure. For this, your doctor will prescribe eyedrops, and in rare conditions, oral medications. If eyedrops alone do not lower the pressure enough, laser procedures or surgery may be required. Patients of angle closure glaucoma need a laser treatment called peripheral iridectomy, which is an attempt to create a bypass channel to restore the drainage in the eye.

What are the risk factors for glaucoma?

If you are over age 60, diabetic or have a family member with glaucoma, you are at higher risk for glaucoma than others. Risk factors for glaucoma, rest will reach you one by one

Glaucoma

Glaucoma is the most serious eyesight threatening condition of the eye. It usually manifests as a painless gradual loss of vision. The lost vision can never be recovered. However, medical or surgical treatment can prevent or retard further loss of vision.

Doctors

Dr. Preeti Matah

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Dr. Preeti Matah works as a Glaucoma specialist at Eye7 Janakpuri.

    Dr. Rajat Maheshwari

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        Dr. Alka Pandey

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          Dr. Pawan Gupta

          Cataract - Glaucoma - Retina - Computer Vision - Neurophthalmology

          Dr Pawan Gupta is a senior vitreo-retina specialist at Eye7 Lajpat Nagar.


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