Even though people with presbyopia need reading glasses, it shouldn’t be thought of as a vision defect. Instead, it’s a natural consequence of aging: they eye’s lens loses flexibility, and it’s no longer able to change shape to focus on objects at different distances – a process known as accommodation.
Everybody is affected by it, irrespective of whether they have refractive errors or other visual disturbances. If someone has an eye with its natural, crystalline lens, in place it will eventually succumb to presbyopia and stiffen.
People start to notice the onset of presbyopia at around the age of 40–45 years, and the stiffening of the lens tends to be complete by the 65 years of age. Presbyopia occurs in all people; those with normal vision and in patients with visual disturbances.
Presbyopia cannot be reversed, but there are some options to mitigate its effects on vision, and we list these here. It is important to note that no perfect solution exits to treating presbyopia: all involve some form of optical compromise. But it is possible to make you as spectacle independent as possible for everyday life; so you can see at both far and near without needing glasses.
Using contact lenses, we can exploit the fact that if you have two eyes, you have two optical systems to work with in these eyes; one eye receives a contact lens that is focused for distance; the other is focused for near.
A single lens corrects near and far. one optical zone focuses a sharp image from near objects on the retina; another optical zone focuses a sharp image of objects that are far away on the retina. This comes with a cost: reduced contrast sensitivity.
If you can tolerate monovision with contact lenses (one eye “tuned” to near, the other to far), then you can make these adjustments in the cornea with an excimer laser, meaning that contact lenses are no longer necessary.
Whatever the contact lenses can do, the excimer laser can do too (and with micron-level precision too) – and this also applies to multifocality. If a patient tolerates multifocal contact lenses, then they can tolerate multifocal optics created with the laser.
Rather than wait for a cataract to develop (as a natural consequence of aging) before removing the lens and replacing it with an artificial intraocular lens, it’s possible to replace both lenses early and simultaneously correct the eye for both near and distance vision.
These are small rings that are introduced into the cornea with the help of a femtosecond laser – it acts by helping exclude light that comes in from far away, and significantly improves near vision in the eye it’s implanted in (at the cost of reduced contrast sensitivity).
We will discuss this question in detail with you after a detailed examination.