Presbyopia - age related long sightenness
What is presbyopia?
Presbyopia is the medical name given to age-related long-sightedness. Most people develop presbyopia and it is a natural part of the ageing process, rather than a medical condition. The condition is caused by a refractive error, which means that light is not refracted in the normal way and is focused onto the retina incorrectly, causing images to become blurred. Other types of refractive error include hyperopia (long-sightedness), myopia (short-sightedness) and astigmatism.
What causes presbyopia?
Presbyopia is part of the accepted ageing process and causes images to become blurred as a consequence of the lens becoming less supple as we age. When we look at items that are close-by, the lens accommodates (gets thicker) and becomes more curved, which enables the light to be drawn into sharp focus on the retina at the rear of the eye. The lens must change shape in order for an individual to see close-up images clearly. However, as the lens starts to lose flexibility it can become increasingly difficult to see things up-close.
A majority of people begin to notice symptoms of presbyopia at about 40 years of age, and most will need to wear contact lenses or glasses by the age of 45. If you already suffer from long-sightedness, you may experience symptoms of presbyopia earlier. Exposure to sunlight and doing close-up actions regularly can also cause premature presbyopia.
Types of presbyopia
There are five types of presbyopia, which include:
- Incipient presbyopia: the early stage of presbyopia. Symptoms are usually mild and include experiencing difficulty reading very small print.
- Functional presbyopia: symptoms have usually developed by this stage and you may find it increasingly difficult to read things up-close or focus on detailed activities.
- Absolute presbyopia: this occurs when the eyes are not capable of focusing on objects and images up-close.
- Premature presbyopia: this form of presbyopia affects people below the age of 40.
- Nocturnal presbyopia: this occurs when people experience difficulty focusing on objects in dull or dim lighting.
How is presbyopia diagnosed?
Presbyopia can usually be diagnosed during a routine eye test. During the assessment your optometrist will check your vision, inspect your eyes and ask you if you have had any difficulties with your vision or experienced changes in your sight. You will be asked to do some simple vision tests (such as reading things up-close and far away). If you wear glasses or contact lenses you must bring these along to the test, as you will be asked to do the test wearing glasses or contact lenses and without them. If you are diagnosed with presbyopia you will be told to go to regular eye appointments, so that your optometrist can check your prescription and ensure that you are wearing the right glasses.
Symptoms of presbyopia
Initially symptoms tend to be mild and include the eyes feeling slightly strained or tired after doing close-up activities for a prolonged period of time and experiencing trouble reading small print. Other symptoms may include:
- Blurred vision.
- Becoming increasingly reliant on wearing glasses.
- Double vision.
- Difficulty focusing on close-by objects; there can be a hold-up in focus when you switch from looking at things in the distance to things close-by.
- Having to take your glasses off at times when looking at things close to you.
In most cases wearing glasses or contact lenses can aid to make significant improvements to vision. However, laser eye treatment is not suitable for people with presbyopia because it works by reshaping the cornea and presbyopia is caused by alterations in the lens.
Glasses and contact lenses are specially made for the individual, with the lenses designed to match your individual prescription to correct sight. Contact lenses function in the same way as glasses but many people prefer to wear contact lenses since they are lighter than glasses and invisible to others.
Some people prefer to wear bifocal lenses, which allow you to see close-up and at a distance, with the bottom section of the lens designed for viewing objects up-close and the top section designed for viewing objects from afar.
It may be possible to have a surgical procedure to treat presbyopia, by way of an operation called PRELEX (presbyopic lens exchange). This type of surgery incorporates the removal of the old lens and replacing it with a new, artificial one. The procedure is carried out under local anaesthetic, which means you will be awake during the procedure, but you should not experience any pain because your eye will be numbed.
Eye tests and preventing presbyopia
It is impossible to prevent presbyopia but you can take steps to protect your eyes and ensure that you get treatment as quickly as possible. Protective methods include:
- Going to regular eye tests (if you are aged above 40 you should attend regular eye tests, and you should also do so if you have a history of eye conditions in your family).
- See an optometrist if you experience alterations in your vision.
- Eat a healthy, balanced diet.
- Protect your eyes from the sun by wearing sunglasses.
Eye test are available free of charge on the NHS for children, individuals aged above 40 and those who have a elevated risk of eye conditions, such as glaucoma.