Presbyopia: a blurred near world
Presbyopia is better known to many as old age vision, when our ability to focus on objects up close recedes. This typically occurs around age 45. To combat this problem, many hold books and fine print further than their comfortable reading distance.
Most people have no problem holding things further, until they feel their arms are not long enough.
This is the point when most people make an appointment to see their optometrist.
Presbyopia is a natural, aging process. It occurs when the lens’ ability to focus at near decreases.
The lens is a clear structure that is positioned behind the coloured part of the eye, the iris. The lens is connected to the ciliary muscle via zonules.
The ciliary muscle contracts, which changes the shape of the lens, allowing us to focus at near. This process is called accommodation.
As we get older our lens grow and accumulates layers like an onion. The increasing size of the lens makes it more difficult for the ciliary muscle to contract and change the shape of the lens, resulting in blurred near vision.
A person who is slightly near-sighted (requires glasses to help them see far away), will experience the effects of presbyopia later than a person who is long-sighted (requires glasses to help them see closer objects).
Reading glasses are required to correct the blurred vision at near. Most people will buy cheater readers or off-the shelf readers to correct their blurred near vision.
These readers are only useful for people who have close to perfect vision in the far distance. There may be a difference in vision between the two eyes.
This can result from a difference in overall power between the two eyes, as well as the presence of astigmatism (irregular or toric curvature of the cornea or lens) in one or both eyes.
Having a large difference between the two eyes can cause eyestrain when using cheater readers.
It’s important to have regular eye exams to check whether a distance prescription is required before wearing cheater readers.
All in all, presbyopia is a natural condition that affects everyone.