Age-related long-sightedness

Published by Bupa's health information team, July 2008.

This factsheet is for people who have age-related long-sightedness (presbyopia), or who would like information about it.

Age-related long-sightedness happens when your eyes gradually lose the ability to focus on near objects. This makes tasks such as reading small print difficult. Its medical term is presbyopia.

Almost everyone is eventually affected by presbyopia - it's a natural part of the ageing process. It usually begins at around the age of 40, and most people will need glasses or contact lenses by the time they are 45.

• About age-related long-sightedness
• Symptoms of age-related long-sightedness
• Causes of age-related long-sightedness
• Diagnosis of age-related long-sightedness
• Treatment for age-related long-sightedness
• Further information
• Questions and answers
• Related topics
• Sources

About age-related long-sightedness

The different parts of the eye

Normal vision

When you look at something, light rays from the object pass into your eye through the cornea - the clear structure at the front of your eye - 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 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 the lens tighten causing it to change shape. This allows the lens to become thicker and more curved bringing light rays and close objects into sharp focus on the retina. This is called accommodation. To focus on objects in the distance, the lens returns to its natural resting state.

Age-related long-sightedness or presbyopia

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

There are five types of age-related long-sightedness.

• Incipient presbyopia is presbyopia in its very early stages. You will notice that reading small print or doing close up work requires a little extra effort.
• Functional presbyopia is the gradual loss of the eyes ability to focus on near objects. You will begin to noticeably struggle to focus on near objects.
• Absolute presbyopia is when the eyes can no longer focus on near objects. The lens in the eye is no longer able to focus light rays of near objects on the retina.
• Premature presbyopia is when symptoms of presbyopia begin earlier than usual (before the age of 40).
• Nocturnal presbyopia is difficulty focusing on near objects in dim light.

Symptoms of age-related long-sightedness

Common symptoms of age-related long-sightedness include:

• blurred vision and difficulty when looking at objects close up
• a delay in focusing from a near object to something in the distance
• needing brighter lighting when reading
• sore, tired eyes
• headaches
• double vision
• squinting
• tiredness or drowsiness after doing close up work
• finding that you need to remove your glasses to read (if you are short-sighted)

Causes of age-related long-sightedness

Presbyopia is not a disease - it's the result of the normal, expected changes that happen to your lenses as you get older. It will affect almost everyone, regardless of whether you already wear glasses or contact lenses.

As you would expect, the most common cause of presbyopia is ageing. Changes to the lens in the eye typically begin at the age of 40 and are completed by 60. By the age of 43, you may begin to notice changes in your vision (such as blurred or double print when reading).

You may be at risk of developing presbyopia at a younger age (premature presbyopia) if you have a job that requires close up work or if you live in a hot climate with a high level of sun exposure. Also, being long-sighted (hypermetropic) and wearing corrective glasses or contact lenses is a common cause.

Diagnosis of age-related long-sightedness

An optometrist (a health care professional who examines eyes, tests sight and dispenses glasses and contact lenses) will be able to diagnose presbyopia. They will focus especially on your near vision and will ask about any difficulties you have been having with your eyesight.

Treatment for age-related long-sightedness

Glasses and contact lenses

Presbyopia can be corrected by wearing reading glasses or contact lenses.

If you already wear glasses, you may be prescribed bifocal or varifocal lenses. These lenses will contain different strengths in different parts of the lens. For example, in bifocal lenses, the top half of the lens corrects for viewing distant objects whereas the bottom half corrects for near vision.

If you already wear contact lenses, you may be prescribed bifocal contact lenses or reading glasses (as well as your contact lenses). Another option is monovison lenses, where one contact lens corrects for near vision and the other for distance vision.

It's important to have check-ups with your optometrist every two years. This will ensure that your glasses or contact lenses stay the correct strength for you.

Surgery

Lens replacement surgery

Lens replacement surgery can be used to treat presbyopia. This is when the lens in your eye is replaced with an artificial one. The procedure is called Presbyopic Lens Exchange (PRELEX) and uses a lens implant to replace your natural lens.

This type of operation is usually performed under a local anaesthetic. This completely blocks feeling from the eye and you will stay awake during the operation.

Scleral expansion surgery

Scleral expansion surgery is a procedure that was used in the past to treat presbyopia. It involves making small incisions in the eye and inserting bands to stretch the part of the eye that controls focusing.

However, the National Institute for Clinical Excellence (NICE) have recommended that this procedure should no longer be used as it has not proved to be effective and there are potential risks involved.

Laser eye surgery

Laser eye surgery (such as LASIK) has been used to successfully treat long-sightedness for many years. However, it can't be used to treat presbyopia. Laser eye surgery changes the shape of the cornea to correct vision. As presbyopia is caused by changes in the responsiveness of your eye's lens, such treatment will have no effect.

Further information

• The College of Optometrists
  020 7839 6000
  www.college-optometrists.org

Related topics

• LASIK
• Long-sightedness
• Short-sightedness

Sources

• Collier J, Longmore M, and Scally P, Oxford handbook of clinical specialities. 6th ed. Oxford: Oxford University Press, 2003
• A systematic review of the safety and efficacy of elective photorefractive surgery for the correction of refractive error. National Institute for Health and Clinical Excellence (NICE), April 2005.
• Optometric clinical practice guidelines: Care of the patient with presbyopia. American Optometric Association. www.aoa.org, accessed 15 January 2008
• Getting an eye test. Royal National Institute of Blind People (RNIB). www.rnib.org.uk, accessed 18 January 2008
• Eyesight Problems. The College of Optometrists. www.college-optometrists.org, accessed 15 January 2008
• Focus on presbyopia. The Eyecare Trust. www.eye-care.org.uk, accessed 17 January 2008
• Laser Refractive Surgery. The Royal College of Ophthalmologists. www.rcophth.ac.uk, accessed 17 January 2008

This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.

Publication date: July 2008.