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Long-sightedness

Long-sightedness is known medically as hyperopia or hypermetropia. Another name for it is far-sightedness.

When it develops in older people it is called presbyopia. It means that you can't focus on close objects, which makes them look blurred. It's a common vision problem that often starts in childhood and improves with age.

  • About long-sightedness
  • Symptoms
  • Causes
  • Diagnosis
  • Treatment
  • Further information
  • Sources
  • Related topics

About long-sightedness

Long-sightedness is a refractive error, like short-sightedness (myopia). That means there is an error in the amount that your eye bends light rays.

To understand what long-sightedness is, it helps to know how our eyes focus. The diagrams below show normal vision, long-sightedness and corrected long-sightedness.

Normal vision

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

Long-sightedness or hyperopia

In long-sightedness, light rays are focused behind the retina, because the eyeball is too short, the cornea is not curved enough or the lens not thick enough. Eyeball length is the most important factor. Close objects seem fuzzy or blurred. Distant objects don't look blurred, because the light rays enter the eye at a slight angle. This means they focus on the retina properly.

Corrected hyperopia

The bottom diagram shows how a convex lens - from a pair of glasses or contact lenses - refocuses light rays onto the retina, returning your vision to normal.

Symptoms

Symptoms of long-sightedness are listed below:

  • Close objects appear fuzzy or blurry, while distant objects remain in focus.
  • Headaches or tired eyes. In young people with long sight, the eyes can still focus on near objects, for example when reading a book. But the muscles in the eye have to contract more to allow this. So you might find that you get headaches when you read, write or do other near work, and that your eyes feel tired.
  • Squints. In some children, a squint can develop, where one eye points inwards more than the other. If a squint is not treated in a baby or young child, it can lead to permanent vision problems. It's important that you take your child to see a GP if you're worried that he or she has a squint.

Causes

Long-sightedness may develop in childhood. You're more likely to develop it if there's a history of it in your family.

Between the age of 45 and 65, the lens in your eye becomes stiffer. This means you might not be able to focus on near objects as well any more, but can still see distant objects clearly. This is called age-related long-sightedness or presbyopia.

Diagnosis

If you can see far objects more clearly than near objects, you should visit an optometrist and get your eyes tested.

It's important to have regular eye tests. As well as diagnosing any vision problems, they can reveal other serious illnesses, like diabetes or high blood pressure. The College of Optometrists advise that you should have an eye test at least every two years. Depending on your age, or if you have any known sight problems or illnesses that affect vision, you may need them more frequently - ask your optometrist or GP for more advice.

Treatment

Glasses and contact lenses

Long-sightedness can usually be corrected by wearing glasses or contact lenses. Some people wear contact lenses, while others feel more comfortable in glasses. Your optometrist will discuss with you what options are available.

Contact lenses tend to be more expensive than glasses, and you have to be comfortable touching your eyes to use contact lenses. Some people find they see better with contact lenses than glasses. Speak to your optometrist about the pros and cons of different types of lenses.

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

Glasses are usually recommended for children. They're also easier than contact lenses for elderly people. Glasses are a better option for those who find contact lenses fiddly and don't like touching their eyes.

Surgery

Laser refractive surgery

Laser surgery to correct refractive errors such as long-sightedness has become increasingly popular. Laser refractive surgery isn't suitable for everyone, and you'll need to talk to an ophthalmic surgeon to find out if it's right for you.

A laser is used to make alterations to the cornea, so that light rays are correctly focused onto the retina. There are various types, which differ according to how the surgeon gains access to the cornea. These include PRK (photorefractive keratectomy), LASEK (laser epithelial keratomileusis) and LASIK (laser in situ keratomileusis). Another option, called thermokeratoplasty, is available for mild long-sightedness.

The operation is carried out under local anaesthetic, so you're awake throughout. It only takes a few minutes.

Depending on the exact procedure you have, your vision may stabilise in anything from one week to several months. Laser surgery is still a relatively new procedure and the long-term outcomes are still not fully known. For more information see Related topics.

Further information

Royal National Institute for the Blind (RNIB)

The College of Optometrists

Sources

  • Simon C, Everitt H, Kendrick T. Oxford Handbook of General Practice. 2nd ed. Oxford: Oxford University Press, 2006: 950
  • Long sight. British Orthoptic Society. www.britishorthopticsociety.co.uk, accessed 15 May 2007
  • 10 reasons For Having an Eye Examination. The College of Optometrists. www.college-optometrists.org, accessed 22 May 2007
  • A Patients' Guide to Excimer Laser Refractive Surgery. The Royal College of Ophthalmologists. www.rcophth.ac.uk, accessed 22 May 2007
  • Young TL, Metlapally R, Shay A. Complex Trait Genetics of Refractive Error. Arch Ophthalmol. 2007; 125:38-48
  • Contact Lenses. The College of Optometrists. www.college-optometrists.org, accessed 16 May 2007
  • Photorefractive (laser) surgery for the correction of refractive errors. Interventional procedure guidance 164. NICE 2006

Related topics

  • LASIK
  • Short-sightedness