Vision Correction
Presbyopia
What is Presbyopia?
Presbyopia is an age related condition where the eye develops difficulty in focussing on close objects or reading. It is a natural, gradual occurrence that can affect people around the age of 40 although this can vary from person to person. Presbyopia will affect eyes that are myopic (short-sighted), hyperopic (long-sighted), astigmatic or even eyes that have never had a sight prescription (refractive error) diagnosed before.
Causes
The ability for our eyes to focus automatically from distant objects to closer ones is something we take for granted when our eyes are young. This is because the crystalline lens inside the eye, which helps us focus, is flexible and can easily change shape in order to provide more power to view close objects, such as reading or threading a needle.
As the eye gets older, gradual changes to the lens means that it loses some of its flexibility and therefore the muscles that control the lens shape are working extremely hard. At a certain age, this will mean that in order to help the eye focus on near objects, additional power is required.
Symptoms of Presbyopia
The telltale symptom of presbyopia is blurred vision while reading, using a mobile phone, or doing anything that requires near vision especially in poor lighting.
If uncorrected, other symptoms include:
• Eye strain
• Headaches
Treatments for Presbyopia
During a sight test, the optometrist will place a series of lenses in front of the eye until a clear focus is obtained as part of a normal sight test. This will include the tests required to measure myopia, hyperopia and astigmatism.
With presbyopia, additional positive power is then added where the strength of this prescription normally correlates to age e.g. somebody new to presbyopia would expect to have a near vision addition of +0.75 dioptres, whereas for an adapted presbyope it can be +2.00 dioptres, although this can vary from person to person.
Treatment options then can be:
- Spectacles – The most common treatment for presbyopic eyes. The spectacle lenses required can be made in many forms. These include single vision, bifocals or varifocal lenses.
- Contact Lenses – Now becoming more and more popular are soft multifocal lenses. These are generally suitable for a wide range of prescriptions, however may not be suitable for prescriptions with astigmatism of over 1.00dioptre.
- Gas permeable lens designs can also correct for presbyopia and offer a good solution for higher astigmatic presbyopic prescriptions.
A note about ready-readers: These are magnifying spectacles that are easily available at most large retailers and supermarket. These assume that both eyes require the same amount of magnification to see near print. This is not often the case, so it is very important to see an optometrist for a full sight test if any symptoms of presbyopia are noticed.
These symptoms can also be a sign of other eye conditions. If you have any of the symptoms, please check with your eye care practitioner.
