Long-sightedness

Published by Bupa's Health Information Team, June 2010.

This factsheet is for people who have long-sightedness, or who would like information about it.

Long-sightedness is a common vision problem, which means that people can't focus on close objects so they look blurred. Long-sightedness is known medically as hyperopia or hypermetropia. Another name for it is far-sightedness.

About long-sightedness

Normal vision

When you look at something, light rays from the object pass into your eye through your cornea (the clear dome that covers your pupil) then through your lens and on towards the retina at the back of your eye. In a healthy eye, your lens and cornea focus the light rays on a small area of your retina so that you can see the object clearly.

The lens of your eye is naturally dome-shaped and very flexible. This allows you to focus from a range of distances, on objects far away and those that are very close up.

To focus on near objects, the ciliary muscles at either side of your lens tighten causing it to change shape. Your lens becomes thicker and more curved, bringing light rays and close objects into sharp focus on your retina. This is called accommodation. To focus on objects in the distance, your lens returns to its natural resting state.

What is long-sightedness?

Long-sightedness is a refractive error. This means there is an error in the way that your eye focuses light rays.

If you're long-sighted, light rays are focused behind your retina. This may be because your eyeball is too short, your cornea isn't curved enough or your lens isn't thick enough. You may find that close objects seem fuzzy or blurred. Distant objects won't look blurred because the light rays don't need as much focusing power, so they focus on your retina properly.

Long-sightedness often starts in childhood.

Age-related long-sightedness

As you get older, your lenses naturally lose their flexibility, becoming stiffer and less elastic. This reduces the power of accommodation, and eventually light rays from near objects no longer focus on your retina.

Age-related long-sightedness is known medically as presbyopia. Presbyopia isn't a disease - it's a result of the normal, expected changes that happen to your eyes as you get older. Almost everyone will develop age-related long-sightedness, regardless of whether you already wear glasses or contact lenses or not.

Symptoms of long-sightedness

Symptoms of long-sightedness are:

• close objects appear fuzzy or blurry, while distant objects remain in focus
• headaches
• tired eyes

If you have presbyopia, you may also have double vision and if you're short-sighted you may need to take your glasses off to read. Some people with presbyopia find that they need brighter lighting when they are reading.

A symptom of long-sightedness in children is a squint, where one eye points inwards more than the other. If a squint isn't treated in a baby or young child, it can lead to permanent vision problems, such as a 'lazy eye'. If you think your child has a squint, it's important to contact his or her GP for advice.

Causes of long-sightedness

You're more likely to develop long-sightedness if other people in your family have it.

A common cause of long-sightedness is ageing (in which case, it's called presbyopia). Changes to the lens in your eye typically begin around the age of 40 and are completed by the time you are 60. You may be at risk of developing presbyopia at a younger age (premature presbyopia) if you have a job that requires you to do close-up work.

Diagnosis of long-sightedness

If you can see far away objects more clearly than near objects, you should visit an optometrist (a registered health professional who examines eyes, tests sight and dispenses glasses and contact lenses) to have your eyes tested.

It's important to have regular eye tests. As well as diagnosing any vision problems, they can reveal other serious illnesses, such as diabetes and high blood pressure. The College of Optometrists advise that you should have an eye test at least every two years, although some people need them more often - ask your optometrist or GP for more advice.

Treatment of long-sightedness

Glasses and contact lenses

Long-sightedness can usually be corrected by you wearing glasses or contact lenses. A convex lens - in a pair of glasses or contact lenses - refocuses light rays onto your retina, returning your vision to normal.

Your optometrist will discuss with you what options are available.

Glasses are usually recommended for children. They may also be more suitable for older people than contact lenses.

Wearing contact lenses can increase your risk of getting an eye infection. You can reduce your risk by making sure you follow all the advice of your contact lens practitioner.

If you develop presbyopia and already wear glasses, you may be prescribed bifocal or varifocal (progressive) lenses. These lenses are of different strengths in different parts of the lens. If you already wear contact lenses, you may be prescribed bifocal contact lenses or reading glasses (as well as your contact lenses). It's important to have check-ups with your optometrist every two years. This will help to make sure that your glasses or contact lenses stay the correct strength for you.

Surgery

Laser refractive surgery
A laser can be used to make alterations to your cornea, so that light rays are correctly focused onto your retina. The operation is carried out under local anaesthesia, so you're awake throughout. It only takes a few minutes.

There are various types of laser refractive surgery, which differ according to how your surgeon gains access to your cornea. These include PRK (photorefractive keratectomy), LASEK (laser epithelial keratomileusis) and LASIK (laser-assisted in situ keratomileusis). Laser refractive surgery isn't suitable for everyone, and you will need to talk to an ophthalmic surgeon to find out if it's right for you. Laser surgery can't be used to treat presbyopia.

Depending on the exact procedure you have, your vision may take anything from one week to several months to improve.

Lens replacement surgery
Lens replacement surgery called presbyopic lens exchange (PRELEX) can be used to treat presbyopia. This is an operation to replace the lens in your eye with an artificial one. This type of operation is usually performed under local anaesthesia. This blocks pain from your eye and you will stay awake during the operation.

Scleral expansion surgery
Scleral expansion surgery is a procedure that has been used in the past to treat presbyopia. It involves your surgeon making small incisions in your eye and inserting bands to stretch the part of your eye that controls focusing. However, the National Institute for Health and Clinical Excellence (NICE) has recommended that this procedure should no longer be used as it hasn't proven to be effective and there are potential risks involved.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.