Strabismus – common in children but can occur at any age

Strabismus

Strabismus

A squint, also called strabismus, is where the eyes point in different directions. It’s particularly common in young children, but can occur at any age.

One of the eyes may turn in, out, up or down while the other eye looks ahead.

This may happen all the time or it may come and go.

Treatment is usually recommended to correct a squint, as it’s unlikely to get better on its own and it could cause further problems if not treated early on.

This page covers:

Causes

When to get medical advice

Get advice if:

your child has a squint all the time

your child is older than three months and has a squint that comes and goes - in babies younger than this, squints that come and go are common and aren't usually a cause for concern

you have any concerns about your child's vision - signs of a problem can include regularly turning their head to one side or keeping one eye closed when looking at things

you develop a squint or double vision later in life


Your GP, health visitor or local opticians service can refer you to an eye specialist for some simple tests and treatment if necessary.

Treatments and surgery for a squint

The main treatments for a squint are:

Glasses - these can help if a squint is caused by a problem with your child's eyesight, such as long-sightedness.

Eye exercises - special exercises for the muscles that control eye movement may sometimes help the eyes work together better.

Surgery - this involves moving the muscles that control eye movement so the eyes line up correctly. It may be recommended if glasses aren't fully effective on their own. Read more about squint surgery.

Injections into the eye muscles - these weaken the eye muscles, which can help the eyes line up better. But the effect usually lasts less than three months.

If your child has a lazy eye as a result of their squint (read about possible further problems below), it may need to be treated first.

Treatment for a lazy eye usually involves wearing a patch over the unaffected eye to help improve vision in the affected eye.

Problems that can occur if a squint isn't treated

It's important not to ignore a squint that happens all the time or occurs after three months of age.

It could lead to further problems if left untreated, such as:

persistent blurred or double vision

lazy eye - where the brain starts to ignore signals coming from the affected eye, so your child doesn't develop normal eyesight

embarrassment or low self-esteem

Surgery can help improve the alignment of the eyes even if a squint has been left untreated for a long time, but any vision problems may be permanent if they're not treated at a young age.

Causes of squints

The exact cause of a squint isn't always known.

Some people are born with a squint and others develop one later in life. Sometimes they run in families.

In children, a squint is often caused by the eye attempting to overcome a vision problem, such as:

short-sightedness - difficulty seeing things that are far away

long-sightedness - difficulty seeing nearby objects

astigmatism - where the front of the eye is unevenly curved, causing blurred vision

Rarer causes of a squint include:

certain infections, such as measles

some genetic conditions or syndromes, such as Down's syndrome

developmental delays

cerebral palsy

other problems with the brain or nerves

A squint can also sometimes be a symptom of a rare type of childhood eye cancer called retinoblastoma. Take your child to see your GP if they have a squint to rule out this condition.

44% of us over 35 experience eye strain at least once a week, yet over half surveyed do nothing to alleviate the effects

Eye strain

Eye strain

 

Extended use of digital devices such as smartphones and electronic reading devices means eye strain is more prevalent than ever in UK adults.

New research released today has found that 44% of UK adults over 35 experience eye strain at least once a week but over half (52%) do nothing to alleviate the effects.

In addition, the research by Magnivision, which has been released during National Eye Health Week, found that 1 in 10 Brits over 35 say that staring at their digital devices every day causes them to experience the effects of eye strain.

The symptoms of eye strain can be caused by:[1]

 

Extended use of digital devices: TVs computers, and smartphones.

Exposure to bright light/glare.

Long periods of activities that demand focus and concentration.

Straining to see in very dim light.

Extended use of digital devices such as smartphones and electronic reading devices along with long periods of time spent in front of a computer (desktops, laptops and tablets) focusing on bright screens has led to the pervasiveness of digital eye fatigue. We normally blink 15 times a minute but staring at digital screens slows our blinking down from half to a third of the normal frequency[2], resulting in scratchy dry and itchy eyes.

The growing phenomenon of digital eye fatigue or digital eye strain, technically referred to as computer vision syndrome[3] which first began being diagnosed after the use of personal computers became more common.

 

The common eye condition ‘Presbyopia’ which is long-sightedness or difficulty with close up vision caused by the loss of elasticity of the lens of the eye occurring typically in middle and old age –  it effects an estimated two billion people worldwide.[4] Regular eye checks and the right prescription for your reading glasses can help alleviate the effects of eye strain that may stem from undiagnosed presbyopia.

 

Other common effects of eye strain including tired eyes, blurred vision, frequent headaches and pain in neck, shoulders or back.

Consultant Eye Surgeon Alex Shortt said: “As a consultant eye surgeon it astonishes me how people fail to look after their eye health. Regular eye tests are a must, especially after the age of 30. This is because the demands of modern life, particularly the use of computers and smartphones place a significant strain on the eyes. “I frequently see patients with computer vision syndrome, also known as digital eye strain, who require treatment to alleviate their symptoms”

 

Whilst amongst those surveyed who have taken action to alleviate the effects of eye strain, 44% have bought reading glasses.

[1] https://coopervision.co.uk/digital-eye-fatigue

[2] Source: https://www.aao.org/eye-health/tips-prevention/computer-usage

Other sources:

The Vision Council: https://www.thevisioncouncil.org/content/digital-eye-strain

Consumer Survey for Magnivision by Opinion Matters, July 2017

[3] https://www.college-optometrists.org/oip-resource/computer-vision-syndrome–a-k-a–digital-eye-strain.html

[4] Essilor Investor Materials and 2013 Infomarche (45+)

Macular hole – Know more about this eye problem

Macular hole

Macular hole

A macular hole is a small gap that opens up at the centre of the retina, in an area called the macula.

The retina is the light-sensitive film at the back of the eye. In the centre is the macula – the part responsible for central and fine detail vision needed for tasks such as reading.

In the early stages, a macular hole can cause blurred and distorted vision. Straight lines may look wavy or bowed, and you may have trouble reading small print.

After a while, you may see a small black patch or a “missing patch” in the centre of your vision. You won’t feel any pain and the condition doesn’t lead to a total loss of sight.

Surgery is usually needed to repair the hole (see below). This is often successful, but you need to be aware of the possible complications of treatment. Your vision will never completely return to normal, but it’s usually improved by having surgery.

Why does it happen?

We don’t know why macular holes develop. The vast majority of cases happen spontaneously (without an obvious cause). They most often affect people aged 60-80, and are twice as common in women as men.

One possible risk factor is a condition called vitreomacular traction. As you get older, the vitreous jelly in the middle of your eye starts to pull away from the retina and macula at the back of the eye. If some of the vitreous jelly remains attached, it can lead to a macular hole.

A few cases may be associated with:

retinal detachment – when the retina begins to pull away from the blood vessels that supply it with oxygen and nutrients

severe injury to the eye

being slightly long-sighted (hyperopic)

being very short-sighted (myopic)

persistent swelling of the central retina (cystoid macular oedema)

What should I do?

If you have blurred or distorted vision, or there’s a black spot in the centre of your vision, see your GP or optician as soon as possible. You’ll probably be referred to an ophthalmologist (a specialist in eye conditions).

If you do have a macular hole and you don’t seek help, your central vision will probably get gradually worse. After a year, you’ll be unable to read even the largest print on an eye test chart.

There’s evidence that relatively early treatment (within months) gives a better outcome in terms of improvement in vision.

There’s a very small chance the hole may close and heal by itself, so for this reason, your ophthalmologist may want to monitor its progression before recommending treatment.

What is the treatment and how successful is it?

Vitrectomy surgery

A macular hole can often be repaired using an operation called a vitrectomy, with inner limiting membrane (ILM) peel and gas.

If you’ve had the hole for less than a year, there’s around a 90% chance the operation will be successful in closing it. More than 70% of people successfully treated will be able to read two or three additional lines on a standard vision chart, compared to before the operation.

Even if surgery does not achieve this degree of improvement, your vision will at least become stable, and you may find you have less distortion of vision.

In a minority of patients, the hole doesn’t close despite surgery, and the central vision can continue to deteriorate. However, a second operation can still be successful in closing the hole.

Ocriplasmin injection

If a macular hole is caused by vitreomacular traction, it may be possible to treat it with an injection of ocriplasmin into the eye. The injection helps the vitreous jelly separate from the back of the eye and allows the macular hole to close. This treatment is successful at closing a macular hole in around 40% of cases.

The injection takes a few seconds and you’ll be given local anaesthetic  as eye drops or an injection, so you won’t feel any pain. You’ll also be given eye drops to dilate your pupil, so the ophthalmologist can see the back of your eye.

An ocriplasmin injection is usually only available in the early stages, while the macular hole is less than 400 micrometres wide, but causing severe symptoms.

Ocriplasmin can cause some mild side effects, which usually go away, such as:

temporary discomfort

floaters

flashing lights

dimming of vision

yellow tinge to the vision

A small number of people may develop more severe side effects, such as a noticeable loss of vision, enlargement of the macular hole or retinal detachment. Surgery is usually needed to correct macular hole enlargement or retinal detachment.

You won’t be able to drive after the injection, as the eye drops cause your vision to be blurry. However, you should have normal, comfortable vision the day after.

If the ocriplasmin injection fails to close the macular hole, which happens in around 60% of cases, vitrectomy surgery will be needed to close the macular hole and improve the vision.

What does vitrectomy surgery involve?

Macular hole surgery is a form of keyhole surgery performed under a microscope.

Three small incisions (one millimetre in size) are made in the white of the eye and very fine instruments are inserted.

First, the vitreous jelly is removed (vitrectomy) and then a very delicate layer (the inner limiting membrane) is carefully peeled off the surface of the retina around the hole, to release the forces that keep the hole open.

The eye is then filled with a temporary gas bubble, which presses the hole flat onto the back of the eye to help it seal.

The bubble of gas will block the vision while it’s present, but it slowly disappears over a period of about four to eight weeks.

Macular hole surgery usually takes 45-90 minutes and can be done while you’re awake (under local anaesthetic) or asleep (under general anaesthetic). Most patients opt for a local anaesthetic, which involves a numbing injection around the eye, so no pain is felt during the operation.

You may be able to go home the same day, but most patients need to stay in hospital overnight.

What can I expect after the operation?

Temporary poor vision

With the gas in place, the vision in your eye will be very poor – a bit like having your eye open under water.

Your balance will be affected and you’ll have trouble judging distances, so be aware of steps and kerbs. You may have problems with activities such as pouring liquids or picking up objects.

In the 7-10 days after the operation, the gas bubble slowly shrinks. As this happens, the space that was taken up by the gas fills with the natural fluid made by your eye and your vision should start to improve.

It generally takes six to eight weeks for the gas to become absorbed and for vision to improve.

Mild pain or discomfort

Your eye may be mildly sore after the operation, and will probably feel sensitive.

Contact your ophthalmologist immediately or go to your nearest eye accident & emergency (A&E) department if at any time:

you’re in serious pain

your vision gets worse than it was on the day after the surgery

Protective dressing

When you wake up, your eye will be padded with a protective plastic shield taped over it. The pad and shield can be removed the day after the operation.

Getting home

If you’ve had a general anaesthetic, you will not be able to leave the hospital unless a responsible adult is there to help you get home.

Medication

You’ll usually be prescribed two or three types of drops to take after surgery:

an antibiotic

a steroid

a pupil-dilating agent

You’ll be seen again in the clinic about two weeks after the operation and if all is well, the drops will be reduced over the following weeks.

Do I need to position myself face down after the operation?

Once at home, you may have to spend several hours during the day with your head held still and in a specific position, called posturing.

The aim of lying or sitting face down is to keep the gas bubble in contact with the hole as much as possible, to encourage it to close.

There’s evidence that lying face down improves the success rate for larger holes, but it may not be needed for smaller holes.

If you’re asked to do some face-down positioning, your head should be positioned so the tip of your nose points straight down to the ground. This could be done sitting at a table or lying flat on your stomach on a bed or sofa. Your doctor will advise you on whether you need to do this and, if so, for how long.

You may find it helpful to read Moorfields Eye Hospital’s instructions for post-operative posturing (PDF, 1.7Mb).

If face-down posturing isn’t advised, you may simply be told to avoid lying on your back for at least two weeks after the surgery.

Sleeping

You’ll need to sleep with your head on one side, resting on an ear. You may be asked to avoid sleeping on your back for at least one month after your operation, to make sure the gas bubble is in contact with the macular hole as much as possible.

If you can’t lie on your side, you should sleep propped up with pillows so you’re at a 45-degree angle.

If you have concerns about sleeping positions, speak to your doctor or nurse.

Am I able to travel after macular hole surgery?

You must not fly or travel to high altitude on land while the gas bubble is still in your eye (up to 12 weeks after surgery).

If you ignore this, the bubble will expand at altitude, causing very high pressure inside your eye. This will result in severe pain and permanent loss of vision.

What if I need another operation shortly after my treatment?

If you need a general anaesthetic while the gas is still in your eye, it’s vital you tell the anaesthetist, so they can avoid certain anaesthetic agents that can cause expansion of the bubble.

Can I drive after the operation?

No – the gas bubble will still be present in your eye for six to eight weeks after your surgery, so during this time you can’t drive a vehicle of any sort.

None of these exclusions apply once the gas has fully absorbed. You’ll notice the bubble shrinking and will be aware when it has completely gone.

How much time will I need off work?

Most people will need at least two weeks off work, although this will depend to an extent on the type of work you do and the speed of recovery. Discuss this with your surgeon.

What are the possible complications of macular hole surgery?

It’s unlikely that you’ll suffer harmful effects from a macular hole operation.

However, you should be aware of these six possible complications:

Failure of the hole to close. This happens in 1-2 out of 10 patients. If the hole fails to close, your vision may be a little worse than before the surgery. It’s usually possible to repeat the surgery.

Cataract. This means the natural lens in your eye has gone cloudy. You’ll almost certainly get a cataract after the surgery, usually within a year, if you’ve not already had a cataract operation. The cataract may be removed at the same time the hole is being repaired.

Retinal detachment. The retina detaches from the back of the eye in 1-2% of patients having macular hole surgery. This can potentially cause blindness, but it’s usually repairable in a further operation.

Bleeding. This occurs very rarely, but severe bleeding within the eye can result in blindness.

Infection. This is also very rare, occurring in an estimated 1 in 1,000 patients. Infection needs further treatment and could lead to blindness.

Raised eye pressure. An increase in pressure within the eye is quite common in the days after macular hole surgery, usually due to the expanding gas bubble. In most cases, it’s short-lived and controlled with extra eye drops or tablets to reduce the pressure, protecting the eye from damage. If the high pressure is extreme or becomes prolonged, there may be some damage to the optic nerve as a result.

How successful is macular hole surgery?

The most important factor in predicting whether the hole closes as a result of surgery is the length of time the hole has been present.

If you’ve had a hole for less than six months, there’s about a 90% chance your operation will be successful (9 in 10 operations will successfully close the hole).

If the hole has been present for a year or more, this success rate drops to about 60%.

Most people have some improvement in vision after they’ve recovered from the surgery. At the very least, the operation normally prevents your sight from getting any worse.

Your doctor will speak to you in more detail about what results you can expect from the surgery.

Even if surgery doesn’t successfully correct your central vision, a macular hole never affects your peripheral vision, so you’d never go completely blind from this condition.

Can I develop a macular hole in my other eye?

After carefully examining your other eye, your surgeon should be able to tell you the risk of developing a macular hole in this eye.

In some people this is extremely unlikely, in others there’s a 1 in 10 chance of developing a macular hole in the other eye.

It’s very important to monitor any changes in the vision of your healthy eye and report these to your eye specialist, GP or optician urgently.

AMD – the causes of macular degeneration

Symptoms of macular degeneration

Symptoms of macular degeneration

The exact cause of macular degeneration isn’t known, but the condition develops as the eye ages.

Age-related macular degeneration (AMD) is caused by a problem with part of the eye called the macula. The macula is the spot at the centre of your retina (the nerve tissue that lines the back of your eye).

The macula is where incoming rays of light are focused. It helps you see things directly in front of you and is used for close, detailed activities, such as reading and writing.

Dry AMD

As you get older, the light-sensitive cells in the macula can start to break down. This tends to occur gradually, often over many years.

Waste products can also begin to build up in your retina, forming small deposits called drusen. Drusen are a common feature of dry AMD and tend to increase in size as the condition progresses.

As dry AMD progresses, you’ll have fewer light-sensitive cells in your macula, causing your central vision to deteriorate. A blurred spot will develop in the centre of your vision, making your central vision less well-defined. As a result, you may need more light when reading and carrying out other close work.

Wet AMD

In cases of wet AMD, tiny new blood vessels begin to grow underneath the macula. It’s thought these blood vessels form as an attempt by the body to clear away the drusen from the retina.

Unfortunately, the blood vessels form in the wrong place and cause more harm than good. They can leak blood and fluid into the eye, which can cause scarring and damage to your macula.

The damage and scarring causes the more serious symptoms of wet AMD to develop, such as distorted vision and blind spots.

Increased risk

It’s unclear what triggers the processes that lead to AMD, but a number of things increase your risk of developing it. These are described below.

Age

The older a person gets, the more likely they are to develop at least some degree of AMD.

Most cases start developing in people aged 50 or over and rise sharply with age. It’s estimated 1 in every 10 people over 65 has some signs of AMD.

Family history

AMD has been known to run in families. If your parents, brothers or sisters develop AMD, it’s thought your risk of also developing the condition is increased.

This suggests certain genes you inherit from your parents may increase your risk of getting AMD. However, it’s not clear which genes are involved and how they’re passed through families.

Smoking

A person who smokes is up to four times more likely to develop AMD than someone who’s never smoked.

The longer you’ve been smoking, the greater your risk of getting AMD. You’re at even greater risk if you smoke and have a family history of AMD.

Read more about how to stop smoking.

Ethnicity

Studies have found rates of AMD are highest in white and Chinese people, and lower in black people. This could be the result of genetics.

Other possible risk factors

The following things may increase your risk of developing AMD, although this hasn’t yet been proven.

Alcohol

It’s possible drinking more than four units of alcohol a day over many years may increase your risk of developing early AMD.

Sunlight

If you’re exposed to lots of sunlight during your lifetime, your risk of developing macular degeneration may be increased. To protect yourself, you should wear UV-absorbing sunglasses if you spend long periods of time outside in bright sunlight.

Obesity

Some studies have reported being obese – having a body mass index (BMI) of 30 or greater – may increase your chance of developing AMD.

High blood pressure and heart disease

There’s some limited evidence that having a history of high blood pressure (hypertension) or coronary heart disease may increase your risk of developing AMD.

Macula
The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.
Retina
The retina is the nerve tissue lining the back of the eye. It senses light and colour and sends it to the brain as electrical impulse