glaucoma
Dr Uwakwe-mangse Hanna (MBBS, MRCS), Monday Columnist

Do you or anyone related to you suddenly lost or have a reduced vision? Is there such a history in your family?

I will be talking about this illness in a nutshell today but my main focus will be on recognising the sins and symptoms of glaucoma and where to seek help.

Glaucoma is an eye condition where the optic nerve, which connects your eye to your brain, becomes impaired, or damaged. It can lead to loss of vision if not detected and treated on time.

It usually occurs when the fluid in the eye cannot drain properly, which increases the pressure inside the eye and puts pressure on the optic nerve.

Glaucoma is a common condition, but many people won’t realise they have it because it doesn’t always asymptomatic or goes unnoticed at the beginning.

It can affect people of all ages, including babies and young children, but is most common in adults in their 70s and 80s.


There are different types of glaucoma but the main types are:
•primary open angle glaucoma – the most common type that often has few symptoms. In this type of glaucoma, the part of the eye where fluid drains away (called the “angle”) isn’t blocked, but the fluid doesn’t drain properly. This leads to increased pressure in the eye. One normally starts losing side vision first with this type until the whole vision is lost. It is also painless.
•primary angle closure glaucoma – a less common type that can cause sudden, severe symptoms. It occurs when the part of the eye that drains fluid becomes blocked, causing pressure to build up in the eye.
•secondary glaucoma – an uncommon type caused by another eye condition
•childhood glaucoma – a rare type that affects babies and young children. It is usually the result of a problem in the development of the eyes, which causes fluid and pressure to build up inside them.

 

SYMPTOMS
Symptoms can include:
•intense eye pain
•a red eye
•a headache
•tenderness around the eyes
•seeing halos or “rainbow-like” rings around lights
•blurred vision and gradual loss of peripheral vision
•feeling and being sick
Sometimes these symptoms may last for a few hours before disappearing.
If you experience sudden symptoms, go to your nearest eye clinic or accident and emergency (A&E) department as soon as possible. I know Nigeria may not have such facility in their emergency department and if such is the case go to the nearest eye clinic.
In children it may be difficult for them to express their symptoms but the following can be noticed:
•larger eyes than usual
•dislike of bright lights
•uncontrollable blinking
•red, watery or cloudy eyes
•rubbing their eyes frequently
Remember to take them to the eye clinic as quick as possible.

CAUSES
Glaucoma can occur for a number of reasons though most times it’s unclear what the actual cause is. Many cases are caused by a build-up of pressure in the eye.
The eyeball is filled with a watery substance called aqueous humour, which creates pressure in the eye to give it shape. In healthy eyes, this fluid constantly flows in and out of the eye.
Glaucoma can occur if fluid is unable to drain from the eye properly, resulting in a build-up of fluid and pressure in the eye. This increase in pressure then damages the optic nerve (the nerve connecting the eye to the brain).

A number of things are thought to increase the risk of acquiring it and they are
•Age – glaucoma becomes more likely as you get older; the most common type (primary open angle glaucoma) affects up to 2% people over 40 and around 10% people over 75, a huge number I must say
•Ethnic origin – people of African, Afro-Caribbean or Asian origin are at increased risk of developing certain types of glaucoma, so technically being Nigerian increases ones chance of getting glaucoma
•Family history – if you have a close relative, such as a parent, brother or sister who has glaucoma, you’re at increased risk of developing it yourself
• Other medical conditions – conditions such as short sightedness, long-sightedness and diabetes can increase your risk of glaucoma

Known causes
In a small number of cases, a cause for glaucoma is found and they are:
•a build-up of deposits in the drainage tubes in the eye – a common example is a condition called pseudoexfoliation glaucoma
•new blood vessels growing inside the eye that block the drainage of fluid
•uveitis (inflammation of the middle layer of the eye)
•long-term use of steroid eye drops
•eye injuries or previous eye surgery
•a problem with the way the eyes developed – this can cause glaucoma in babies and young children.

DIAGNOSIS
Most people get diagnosed following routine check-ups.
It’s important to have regular eye tests so problems such as glaucoma can be diagnosed and treated as early as possible. Early treatment can help stop your vision becoming severely affected.
You should have an eye test at least every two years. If you’re at a higher risk of glaucoma, for example if you have a close relative with it, you may be advised to have more frequent tests.

Various Test used for diagnosis is:
Eye pressure test
An eye pressure test (tonometry) uses an instrument called a tonometer to measure the pressure inside your eye.
A small amount of anaesthetic (painkilling medication) and dye is placed onto the front of your eye. A light from the tonometer is gently held against your eye to measure the pressure inside.
High pressure in your eye can be a sign that you have glaucoma or are at increased risk of developing it.
Gonioscopy
This is an examination of the front outer edge of your eye, between the cornea (transparent layer at the front of your eye) and the iris (the coloured part of your eye).
This is the area where the fluid should drain out of your eye.
A gonioscopy can help to determine whether this area (called the “angle”) is open or closed (blocked), which can affect how fluid drains out of your eye.
Visual field test
A visual field test – sometimes called perimetry – checks for missing areas of vision.
You may be shown a sequence of light spots and asked which ones you can see. Some dots will appear in your peripheral vision (around the sides of your vision), which is often affected by glaucoma to begin with.
If you can’t see the spots in your peripheral vision, it may indicate the glaucoma has damaged your vision.

Optic nerve assessment
The optic nerve (the nerve connecting your eye to your brain) can become damaged in glaucoma, so an assessment may be carried out to see if it’s healthy.
For the test, eye drops will be used to enlarge your pupils. Your eyes are then examined with a slit lamp (a microscope with a bright light) to assess your optic nerve.
The eye drops used to widen your pupils could temporarily affect your ability to drive, so you’ll need to make arrangements for getting home after your appointment.

Optical coherence tomography
Optical coherence tomography (OCT) is a type of scan where special rays of light are used to scan the back of your eye and produce an image of it.
This can help detect any damage to the retina (the light sensitive layer at the back of the eye) or optic nerve caused by glaucoma.

Referral to a specialist
If glaucoma is picked up during an eye test, you should be referred to an ophthalmologist (eye doctor) for further tests.
Your ophthalmologist will confirm your diagnosis and find out:
•how far the condition has developed
•how much damage the glaucoma has done to your eyes
•what may have caused the glaucoma

TREATMENT
There are several different treatments for glaucoma, including eye drops, laser treatment and surgery. The best treatment for you will depend on your circumstances.
Your treatment largely depends on which type of glaucoma you have.
For example:
•primary open angle glaucoma is usually treated with eye drops, or laser treatment or surgery if drops don’t help
•primary angle closure glaucoma often needs immediate treatment in hospital with medication to reduce the pressure in the eye, often followed by laser treatment
•secondary glaucoma may be treated with eye drops, laser treatment or surgery, depending on the underlying cause
•childhood glaucoma often requires surgery to correct the problem in the eye that led to the build-up of fluid and pressure
You will also often be advised to attend regular follow-up appointments to monitor your eyes and check that treatment is working. It’s important not to miss any of these appointments.

In conclusion, Glaucoma can be managed effectively if diagnosed early and if the right treatment is instituted. Don’t lose your vision.
See you next week.

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