Presbyopia generally starts around 40 with the onset of blurred vision when trying to read or work close up at a screen. This is a natural part of ageing and cannot be avoided, however there are treatment options to limit the effects on daily life.
Where the eye is concerned, a healthy eye is able to change shape easily, a process that lets you focus on objects whether they are near or far. As we reach 40 though there is a natural hardening of the lens, which makes it harder to change shape as often as we need. This is known as presbyopia.
As nearly everyone develops presbyopia it may also combine with any level of myopia (near sightedness), hyperopia (far sightedness) or astigmatism.