Hypermetropia

Page last reviewed: 13/07/2011

Long-sightedness, or far-sightedness, is a sight problem that affects your ability to see close-up objects. People who are long-sighted can usually see distant objects clearly, but nearby objects appear blurred.

The medical name for long-sightedness is hyperopia.

Who is affected

Long-sightedness can occur at any age, but it becomes more noticeable after the age of 40, when the lens of the eye becomes stiffer and starts to lose its focusing power This age-related long-sightedness, known as presbyopia, can get worse with age.

Some children are born with long-sightedness, although this normally corrects itself as they grow older and their eyes develop. However, it is important that children have regular eye tests as long-sightedness that does not correct itself can lead to other eye problems such as crossed eyes (strabismus) or lazy eye (amblyopia).

Some cases of hyperopia may run in families.

Outlook

Long-sightedness can be easily corrected with glasses, contact lenses or corrective surgery. Laser surgery is an increasingly popular option, but is not suitable for everyone.



Page last reviewed: 13/07/2011

Adults

Signs that you may have long-sightedness include:

  • Nearby objects appear fuzzy and out of focus but distant objects are clear.
  • You find you have to squint to see clearly.
  • Your eyes feel uncomfortable after an activity that involves close focusing, such as reading, writing or working on a computer.
  • You experience pain or burning in your eyes.

Children

Children with long-sightedness often do not experience any problems with their eyesight. This is because the lenses of children's eyes are usually more flexible and can adjust to compensate for long-sightedness.

However, it is important that young children have regular vision tests to check for conditions such as long-sightedness. If left untreated, long-sightedness can lead to eyesight complications such as crossed eyes (strabismus) or lazy eye (amblyopia).

If a child has severe hyperopia, they may experience problems with their eyes, such as:

  • red or tearful eyes
  • squinting when they look at close objects
  • blinking and rubbing their eyes more than normal 
  • problems with reading

Page last reviewed: 13/07/2011

Long-sightedness occurs when:

  • The eyeball is too short.
  • The cornea is not curved enough.
  • The lens is not thick enough.

Any of these factors mean that light rays from nearby objects are not focused on the retina, so they appear blurry.

Genetic inheritance

Hyperopia is thought to be an inherited condition that some people get from their parents. However, with the exception of a rare form of hyperopia called nanophthalmos, no specific genes for long-sightedness have been identified. Further research is needed.

Age

Age-related long-sightedness, or presbyopia, occurs later in life when the lens in your eye becomes stiffer and loses its focusing power.

Underlying condition

Rarely, hyperopia can be caused by other conditions. These include:

  • diabetes
  • microphthalmia, or small eye syndrome, when a baby's eyes do not develop properly during pregnancy
  • tumours around the eye (known as orbital tumours) 
  • foveal hypoplasia, a condition where there is a problem with the blood vessels in the retina

Glossary

Genetic
Genetic is a term that refers to genes- the characteristics inherited from a family member.

How the eye works

The eye is made up of:

  • the cornea and lens
  • the retina
  • the optic nerve

Rays of light travel through the transparent cornea and through the lens, which focuses the rays onto the retina, a light-sensitive film at the back of the eye. The image that forms on the retina is converted into electrical signals, which the optic nerve transmits to the brain. This tell us what we are seeing.

Page last reviewed: 13/07/2011

It is important that your child has regular eye examinations as they grow up. Routine vision tests are given at birth, aged three and before your child starts school, but you can go to an optician at any time for an eye test if you are concerned about your child's sight. Eye tests for children are free up to the age of 16.

Most eye conditions can be successfully corrected, but if left untreated they could cause more serious complications and affect your child's vision permanently.

It is also important that adults visit their optician regularly. The College of Optometrists recommends at least every two years. Regular eye check-ups will identify conditions such as long-sightedness early on so that corrective treatment can be given.

Having an eye test

An eye test is carried out by an optometrist and usually takes between 20 and 30 minutes. Your sight and the health of your eyes will be checked. An eye test usually includes:

  • checking history and symptoms
  • examining the eye
  • a vision test

Checking history and symptoms

An optometrist will start by asking if you have any specific problems with your sight and, if so, how long you have had them for. They may ask you about your general health, including any medication you take and your lifestyle.

Examining the eye

An optometrist needs to check that your eyes are healthy and that you are not suffering from any underlying medical problems.

The inside of your eye is examined using an opthalmoscope, a torch that shines light through your pupil. This also tests your pupil reflexes (whether your pupils shrink in response to light).

Eye movements and co-ordination are also checked to make sure that both of your eyes are working together.

Other tests may be carried out depending on your age and medical history. Eye conditions that your optician will be looking for include glaucoma (pressure changes in the eye, which can damage the optic nerve) and diabetic retinopathy (where high blood pressure and high blood sugar levels cause new blood vessels to be produced in the eye, which can obscure vision).

Vision test

Your vision will usually be tested both with and without your glasses or lenses (if you wear them), so remember to take these with you.

Your optometrist will usually assess your distance vision, your near vision (for reading and close work) and your intermediate vision (for using a computer). A simple 'visual acuity' test helps the optometrist to assess how good your vision is. You will be probably asked to read from a "Snellen chart", which is a series of letters that become progressively smaller on each line. If you can only read the top line of the Snellen chart, you may be eligible to register as blind or partially sighted.

Your optometrist will then carry out tests to work out the extent of your problem and exactly what kind of glasses you need.

After your eye test

At the end of your eye test your optometrist will discuss your results with you and the best course of action. This is usually a prescription for glasses or contact lenses to correct any problems with your sight.

If your eyesight is fine, you will receive a statement confirming that your eyes do not need correction. If you need medical treatment, you may be referred to your GP or hospital.

Children with long-sightedness who have a squint need to be monitored carefully to avoid a lazy eye (amblyopia) developing.

Eye specialists

Optician (optometrist) is a specialist in the diagnosis and treatment of poor eyesight. Depending on their training, they may also screen for some eye disorders and treat eye conditions. They work either in a hospital or clinic in the community.

Ophthalmologist is an eye consultant who usually specialises in eye surgery. They work in a hospital.

Orthoptist is a specialist in the diagnosis and treatment of eye disorders. They usually work in a hospital.

Page last reviewed: 13/07/2011

The most common treatment for long-sightedness is the correction of your eyesight using glasses or contact lenses. Laser surgery to correct long-sightedness is also becoming increasingly popular.

Glasses

Long-sightedness can usually be corrected using glasses made specifically to your prescription. Convex (thinner at the edge than at the centre) lenses are used to correct long sight. The curvature of the lens, its thickness and weight will depend on how long-sighted you are. Wearing a lens made to your prescription will ensure that light rays fall onto your retina and you can focus accurately.

The lens of the eye becomes less flexible with age, so you may need to increase the strength of your prescription as you get older. If you are both long- and short-sighted, you may need to wear two different pairs of glasses. Alternatively, some people use varifocal or bifocal lenses to see objects clearly that are both close up and far away.

Contact lenses

Contact lenses can also be used to correct vision in the same way as glasses. People often prefer contact lenses to glasses as they are lightweight and almost totally invisible.

There are two types of contact lenses available:

  • rigid gas-permeable
  • soft

However, there are many different lens materials and designs. Lenses can be worn on a daily basis and discarded each day (daily disposables) or disinfected and re-used, or worn for a longer period of time and kept in overnight. Your optometrist can advise you on the most suitable lens for you.

If you choose to wear contact lenses, it is important to maintain good lens hygiene to prevent eye infections developing.

Surgical treatment

A number of surgical techniques have been developed to treat long-sightedness. The most reliable uses laser surgery.

Surgical treatment for long-sightedness involves increasing the curve of the cornea to increase its focusing power. This is done by removing some tissue from the edge of the cornea.

The benefit of laser surgery over traditional surgery is that instruments do not have to enter the eye and the risk of damage or infection in the eye is much lower.
There are three main types of laser surgery:

Photorefractive keratectomy (PRK) 

A small amount of the surface of the cornea is removed, and a laser is then used to remove tissue and change the shape of the cornea. The amount removed depends on how poor your eyesight is and is controlled by a computer. The surface of the cornea is then left to heal.

Laser epithelial keratomileusis (LASEK)

This is a similar procedure to PRK, but involves using alcohol to loosen the surface of the cornea before it is lifted out of the way. A laser is then used to change the shape of the cornea, as with PRK. Once the treatment is finished, the surface of the cornea is put back into place and kept in place by natural suction.

Laser in situ keratectomy (LASIK)

This is similar to LASEK, but only a small flap of the cornea is involved. An instrument is used to cut a flap in the surface of the cornea, which is then folded back rather than removed, and a laser is used to change the shape of the cornea. When the laser work is finished, the flap is folded back down to its original position and kept in place by natural suction.

The laser surgery operation

Laser surgery is typically done on an outpatient basis. This means you will not have to spend time overnight in hospital, but will have one or more appointments at a clinic. The treatment takes around 30 minutes to an hour.

LASIK is normally the preferred method as it causes almost no pain and your vision recovers within one to two days. However, you may experience some fluctuations in your vision after this. It can take up to a month for your vision to stabilise entirely and for you to feel the full benefits of the operation.

LASIK treatment can only be carried out if your cornea is thick enough. If your cornea is thin, there is too great a risk of complications and side effects, such as loss of vision.

LASEK and PRK may be possible if your cornea is not thick enough for LASIK surgery. Recovery time tends to be longer using these techniques; it can take up to six months for your vision to stabilise after PRK surgery.

Who cannot have laser surgery

You should not receive any sort of laser surgery if you are under 21 because your vision will still be changing and it would be dangerous to alter the structures of your eyes at this stage.

Your vision can also change if you are over 21. Your clinic should check your glasses or contact lens prescriptions to confirm that your vision has not changed significantly over the last two years.

Laser surgery may also not be suitable if you:

  • Have diabetes. This can cause abnormalities in the eyes that can be made worse by laser surgery to the cornea.
  • Are pregnant or breastfeeding. Your body will contain hormones that cause slight fluctuations in your eyesight and focusing power, making precise surgery too difficult
  • Have a condition that affects your immune system, such as HIV or rheumatoid arthritis. This may affect your ability to recover after surgery.
  • Have other problems with your eyes such as glaucoma (a condition that can cause blindness) or cataracts (where the lenses of the eye harden and become cloudy).

Risks of laser surgery

As with all surgical procedures, laser surgery carries some risks. Possible complications of laser surgery are outlined below.

  • Following surgery, your vision may get worse if the surgeon misjudges the amount of tissue taken from your cornea (this is known as a correction error).
  • The flap cut into your cornea begins to grow into the main part of the cornea when replaced (this is known as epithelial in-growth, which can cause problems with your vision and may require further surgery to correct).
  • Your cornea becomes too thin and your vision is reduced or lost (this is called ectasia).
  • Your cornea becomes infected (known as microbial keratitis).

All of the above risks are extremely rare.

Glossary

Retina
The retina is the nerve tissue lining the back of the eye, which senses light and colour and sends it to the brain as electrical impulses.

Page last reviewed: 13/07/2011

Complications of long-sightedness are rare in adults. The condition is likely to get worse as you get older but a prescription for stronger glasses or contact lenses allows most people to retain normal vision.

In children, severe hyperopia can cause a child to "over-focus", leading to double vision. This in turn can cause one eye to turn away, which can lead to two possible conditions:

Strabismus (crossed eyes)

Strabismus is when the eyes are not properly aligned with each other, so they both focus on different things. It can lead to problems with judging how far away objects are from you - known as depth perception. It can also cause your brain to ignore the output of one eye, which can weaken the eye and lead to amblyopia (see below).

Amblyopia (lazy eyes)

Amblyopia occurs when one eye becomes dominant over the other, either as a result of strabismus or another condition such as cataracts. If a child only uses one eye to focus, their other eye will get weaker and weaker. Left untreated, the weaker eye could eventually lose all vision.

How they are treated

Ambylopia and strabismus can normally be treated by making the child wear a patch over their stronger eye. This forces their brain to start using the weaker eye, making it stronger. Glasses can also be prescribed to help balance the vision of both eyes. In more severe cases, surgery may be required to realign or strengthen the muscles of the eye.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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