Presbyopia

Presbyopia is the commonest visual problem among Spaniards over 40, and it is becoming more prevalent.

An estimated 40 % of Spaniards are affected today — around 18 million people — and within ten years, thanks to longer life expectancy, more than half the Spanish population will have it.

Until recently, people with ageing eyesight had to rely on bifocal or varifocal glasses or multifocal contact lenses. These were workable solutions, but they reduced quality of life. Laser treatment and intraocular lenses now offer a better answer.

What is presbyopia?

Presbyopia is difficulty focusing at close range as a result of ageing. It is what people commonly call «tired eyes» and it usually appears around the age of 40 to 45. It is a natural physiological change, not a disease.

At rest, the normal eye is set for distance vision. When we need to see something close — a book, a phone screen, a restaurant menu — the eye has to change focus through an effort called accommodation, and it is the crystalline lens that does the work.

The crystalline lens sits behind the iris and focuses images, much like the zoom on a camera.

Over the years the lens loses its elasticity and with it the ability to accommodate, which inevitably brings on presbyopia: the inability to see clearly close up. That elasticity does not disappear overnight but declines gradually from the age of 40 to 45 over roughly ten years, until it is gone completely.

Causes

It is the natural consequence of age-related muscle change. The eye has a muscle, the ciliary muscle, which adjusts the crystalline lens so that near images are sharp. Like every other muscle in the body, it loses elasticity over time and, with it, the ability to focus the lens for close work.

Symptoms

The first symptoms are very specific: close objects look out of focus, you have to hold text further away to read it, and you need more light. It affects short-sighted and long-sighted people alike — though the long-sighted tend to notice it earlier — as well as those who have never worn glasses.

Treatments

Optical correction

• Standard reading glasses: they correct near focus but blur intermediate and distance vision.
• Bifocals: they make it easier to switch between near and distance vision, focusing both — near through the lower part of the lens and distance through the upper part.
• Varifocals: they allow vision at any distance by tilting the head. The structure is the same as a bifocal, but without the visible line between the near and distance portions.
• Contact lenses: multifocal lenses work on the same principle, though monofocal lenses can also be used, with one eye set for near and the other for distance.

Presbyopia can be corrected surgically

At ICOA we offer two alternatives: laser treatment and the multifocal intraocular lens.

• Laser treatment (blended vision) is similar to the technique used to correct myopia; we call it blended vision or monovision. It corrects presbyopia and markedly improves intermediate and near vision. Although we look with both eyes, one is better suited to distance (the dominant eye) and the other to near work (the reading eye). Blended vision laser treatment enhances that natural specialisation without disturbing the sense of binocular vision at near and far.
• Intraocular lens treatment (multifocal vision) involves removing the crystalline lens, which has lost or is losing its ability to focus close up, and replacing it with a multifocal intraocular lens that acts as an artificial lens. Through what is known as pseudoaccommodation — it offers three fixed focal planes: distance, intermediate and near, with the brain selecting the most suitable one for each situation — it gives patients a full range of vision, from reading a book to driving, all without glasses.

The aim of these techniques is to remove dependence on glasses and contact lenses: no longer needing them for distance vision, and achieving enough near vision for everyday life.

Both treatments are day-case procedures with a fast recovery. During your consultation the ophthalmologist will assess your case and advise which treatment suits you best.