Glaucoma

Glaucoma

In the early stages, glaucoma is not accompanied by any symptoms, so a significant part of glaucoma patients may not even know about their illness. If you regularly see an ophthalmologist once a year, you can reveal glaucoma before vision impairments.

What is glaucoma?

Glaucoma is a disease which damages the optic nerve. It usually happens if fluid builds up in the front of the eye, and an excessive amount of fluid leads to an increased pressure in the eye, damaging the optic nerve.

Glaucoma can cause blindness, but in many cases, early treatment can slow this process down and keep your vision longer.

Terms

Optic nerve is the nerve which connects the bottom of the eye to the brain. The optic nerve sends signals to the brain, so you can see.

Aqueous humour is a clear liquid inside the front of the eye. Aqueous humour has a different chemical composition than tears, it nourishes the eye and keep its shape.

Drainage angle is the area of the eye where aqueous humour drains from the front of the eye.

Iris is the coloured part of the eye with a hole in the centre, the pupil, through which light enters the eye.

What causes glaucoma?

The eye constantly produces the so-called aqueous humour. As the aqueous humour flows into the eye, the same amount of fluid should drain out through the so-called drainage angle. Thus, this process keeps the pressure in the eye (intraocular pressure) stable. If the drainage angle does not fulfill its function, fluid accumulates in the eye, the pressure rises, damaging the optic nerve.

The optic nerve is like an electrical cable with over a million tiny nerve fibres. If these fibres die, blind spots appear in the field of vision. Sometimes patients may not notice blind spots until most of the nerve fibres have died. If all the fibres die, the patient will become blind.

Types of glaucoma

There are two main types of glaucoma:

Primary open-angle glaucoma.. This type of glaucoma develops gradually, when fluid does not drain out of the eye properly (like a clogged drain). As a result, pressure rises in the eye, damaging the optic nerve. This type of glaucoma is painless and does not affect vision in the initial stages.

Some people have optic nerves which are sensitive to normal intraocular pressure. The risk of glaucoma is higher in this case. You need to regularly visit an ophthalmologist in order to timely identify damage to the optic nerve.

Angle-closure glaucoma. This type of glaucoma is caused by the iris being too close to the drainage angle. As a result, the iris blocks the drainage corner, like a piece of paper over a sink drain. If the drainage angle gets completely blocked, eye pressure rises very quickly. It is called acute attack of glaucoma. This situation is a true eye emergency.

Symptoms of an acute attack of angle-closure glaucoma:

– your vision is suddenly blurry;

– severe pain in the eyes;

– headache;

– nausea;

– a light halo or rainbow-coloured rings around lights.

In many cases, glaucoma develops slowly, and it is called chronic. At first, the patient has no complaints, so he or she does not know about this illness until the first attack or severe damage to the optic nerve.

Angle-closure glaucoma can lead to blindness, if not treated immediately.

How is glaucoma diagnosed?

The only reliable way to diagnose glaucoma is with a full examination by an ophthalmologist. One measurement of intraocular pressure is not enough to find glaucoma.

During the glaucoma examination, your ophthalmologist will:

– measure intraocular pressure;

– examine the drainage corner of the eye;

– examine the optic nerve for damage;

– test your peripheral (lateral) vision;

– take a picture or a CT scan of the optic nerve.

– measure the thickness of the cornea.

Your objective in glaucoma treatment

Your doctor needs your help to successfully treat glaucoma. You should follow the advice of your ophthalmologist and take the eye drops prescribed. If you are being treated for glaucoma, you should see your ophthalmologist regularly. Usually you will be invited for an examination every 3-6 months, but it depends on the kind of treatment.

How is glaucoma treated?

The effects of glaucoma are irreversible, so it is important to start treatment as early as possible. Medications or surgery help to stop further damage to the optic nerve.

Medication. Eye drops are commonly used to control glaucoma. Used every day, they lower intraocular pressure. Some medications reduce aqueous humour, while others speed up aqueous humour removal through the drainage corner, and thus reduce the pressure in the eye.

Glaucoma medications help preserve vision, but can also produce side effects. Some medications cannot be taken at the same time with other drugs, so be sure to tell your doctor about any drugs you take regularly. If your glaucoma medication is causing side effects, tell your ophthalmologist.

Never stop treatment for glaucoma and do not change anything without consulting an ophthalmologist. If you are about to run out of medication, see your ophthalmologist for a new prescription.

Laser treatment for glaucoma. There are two types of laser surgery to treat glaucoma. These procedures help humour drain from the eye better.

• Trabeculoplasty/selective trabeculoplasty.. This procedure is intended for the treatment of open-angle glaucoma. Ophthalmologist uses a laser to make the drainage angle function better for aqueous humour to flow out properly. As a result, the pressure in the eye is reduced.
• Iridotomy. This procedure is intended for treating angle-closure glaucoma. With a laser beam, the ophthalmologist creates a tiny hole in the iris which helps fluid flow to the drainage corner.

Surgery. In some cases, to treat glaucoma, a new channel should be created to drain the fluid.

Trabeculectomy.The eye surgeon creates a small flap in the sclera (the white of the eye) and a bubble or pocket in the conjunctiva called a filtration bleb. It is usually not visible under the upper eyelid. Through the flap, aqueous humour enters the filtration bleb, where it is absorbed by tissue around the eye, lowering intraocular pressure.

Drainage devices. A small device can be implanted in the eye. The fluid will enter a special container – a reservoir formed by an ophthalmologist beneath the conjunctiva (a transparent membrane which covers the white of the eye and the inside of the eyelids). The fluid is then absorbed into the nearby tissue.

Outcomes

Glaucoma is a disease which damages the optic nerve. This nerve suffers from increased pressure in the eye caused by excess fluid accumulation. Damage to the optic nerve can lead to blindness.

Ophthalmologists use medications or surgery to treat glaucoma. Glaucoma has no symptoms, so it is important to see your ophthalmologist regularly to check for eye and vision changes.

If you have questions about eyes or vision, be sure to see an ophthalmologist. The ophthalmologist will make every effort to protect your vision.