Presbyopia
Children have incredibly good near sight vision and can read print placed only a few centimeters from their eyes. By the time you have reached 30 years of age you can still read small print however you will need to hold it about 20 cm from your eyes. By your early 40’s you may now have to hold the print at arms’ length (or your arms may not be long enough!)
What is Presbyopia?
This loss of close vision is called Presbyopia.
It is not fully understood but it affects all of us and is a natural consequence of the ageing process.
What are the side effects of Presbyopia?
Presbyopia, if uncorrected, can be debilitating. And, can lead to:-
- Loss of confidence at work or in any situation where you need to carry out near vision tasks – reading or measuring etc.
- You may not be able to carry out your job properly
- You may lose your job for the above reason
- Inability to operate machinery or to read instructions could result in serious workplace accident or injury.
What are the root causes of Presbyopia?
As we age the collagen fibers in our skin become less springy or less elastic. This leads to a change in the appearance and the feel of our skin. I.e. wrinkles and sagging!
You may have noticed that when you pinch the skin of a younger person the skin immediately springs back. If you do the same to some in their 40’s or 50’s the skin takes much longer to return to its original condition.
Getting back to your eyes, before you are born your eyes actually start off part of your skin cells. They eventually differentiate into clear transparent tissue of the cornea and lens.
So there is a close link between our skin and our eyes.
Crystalline Lens
The part of your eye that allows you to focus on things up close is a small clear disc located just behind your iris or the coloured part of your eye. It is roughly the size and shape of a Panadol tablet.
This small disc is called the Crystalline Lens and it allows you to zoom in on whatever you want to look at whether it is 10 meters away or only a few centimetres from our faces.
The Crystalline lens does this by flexing and changing its shape in response to signals from our brain. We can focus or defocus our crystalline lens! It is in effect like the zoom lens in a very expensive camera.
The lens is vital to our ability to see things clearly at any distance from far away to up close and personal– it is constantly working a gives us incredibly sensitive and flexible control over our vision.
Like the rest of our skin the lens is made of Collagen. However it is very special type of collagen. Unlike the skin covering the rest of our body which is opaque the Crystalline lens is Crystal clear! It is an amazing structure as is not only allows the passage of light to the retina but it also finely controls the focus of the images that we see!
So why does this lens stop working as we get older?
Sadly, as mentioned before the collagen in the lens like the collagen in our skin loses its elasticity over time. And after 40 years of age rapidly becomes less flexible and cannot zoom in and out of focus as effectively.
By the age of 60 the lens has almost zero flexibility!
Presbyopia is caused by the loss of Lens flexibility.
A major problem facing today’s ageing (but effective) workforce
Presbyopia, if untreated, can result in:-
- Loss of confidence –reading measurements
- Poor work performance
- Loss of employment –can’t do the job
- Has the potential for catastrophic workplace accidents and resultant injuries!
How can this problem be addressed?
There is no medical treatment available to stop or reverse Presbyopia.
You need to see your Optometrist. He or she will give you a choice of treatment options. These options can involve one or a combination of the following:-
- Reading Glasses. Half eyes or larger frames, they are good but have a very limited range of focus you may find yourself craning your neck forward to bring print into focus 80 cm away.
- Bifocals have been around for a long time – the first bifocal is thought to have been invented by Benjamin Franklin some 200 years ago. The benefit of bifocal is that it gives you have distance and near vision in the one pair. The disadvantage is that you have a line across the middle which some wearers find annoying. Another problem with bifocals is that they don’t give you any intermediate focus at 80-100cm from your eyes which are where most Computer monitors are usually positioned. They also make you look 200!
- Progressive Addition, Multifocal or invisible bifocals give you a continuous focus from distance to near, and they look like normal lenses- no lines. Disadvantages are peripheral field of vision can be distorted narrow area for reading (point your nose). And can cause straight lines to look curved-bad for building industry.
Presbyopia Summary
Other treatment options include extended focus reading glasses for computer operators, contact lenses and Laser surgery which will discuss on a later program.
Readers, Bifocals and Progressive glasses are all great options however we recommend that you see your Optometrist for advice on which option or combination that best suits your needs.
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