Presbyopia

What are the symptoms of presbyopia?

The main signs and symptoms of presbyopia include:

• The need for more light when you’re reading.
• Blurred vision at a normal reading distance.
• The need to hold reading material at arm’s length.
• Headaches from doing close work.
• Eye strain, which makes your eyes feel sore or tired.

What causes presbyopia?

Age-related changes to your eyes cause presbyopia. During the first few decades of life, your eye’s lens is soft and flexible. It easily changes its shape when you shift your vision from something far away to something close-up. This ability (accommodation) allows light to land on your retina so you can see objects clearly.

As you get older, your lens grows less flexible and has trouble focusing light as it should. This leads to symptoms of presbyopia that begin in your 40s and level off in your mid-60s.

Think of your eye like a camera. The lens in a camera can autofocus on objects that are near or far. Your lens works together with your cornea (your eye’s clear, outer “window”) to do this job and help give you clear vision. To understand presbyopia, it helps to know a bit about this process:

1. Your cornea bends light as it enters your eye.
2. A tiny, circular muscle surrounding your lens either contracts or relaxes. These actions change the shape of your lens to bring things into focus. If the object is far away, the muscle relaxes. If it’s near, the muscle contracts.
3. Light lands on your retina. This is a layer of tissue at the back of your eye that translates light into electrical signals. Your optic nerve sends these signals to your brain, allowing you to see the image.

Your lens continues to grow as your eye ages. New layers of cells form (picture an onion). This process thickens your lens and makes it less flexible. As a result, light can’t land properly on your retina, and your close-up vision grows blurry.

Treatment

Reading glasses

If presbyopia is your only vision problem (you do not have nearsightedness, farsightedness or astigmatism), glasses may be all you need. Reading glasses help correct close-up vision problems by bending (refracting) light before it enters your eye. They can be bought without a prescription, but the specific power of reading glasses that you need should be determined by an eye exam.

Bifocals, trifocals or progressive Lenses

If you already wear eyeglasses for other vision problems, now you might need bifocals, trifocals, or progressive lenses.

• Bifocals correct for close-up and far vision. A line, which may or may not be visible, divides the lens. The bottom of the lens refracts light for close up vision. The top portion refracts light to allow you to see distant objects.
• Trifocals have three lens areas to correct for close-up, mid-range and far vision.
• Progressive lenses correct vision like bifocals and trifocals. But instead of a line that divides each refractive area, refraction changes gradually in the lens from top to bottom. 

Contact lenses

Some people prefer to wear contact lenses rather than eyeglasses. There are two types of contact lenses that help presbyopia:

• Monovision contacts. These correct one eye for distance vision and the other for close-up vision. You need to adapt to monovision lenses and train your brain to see this way. You may find you lose your ability to judge something’s distance or speed with monovision lenses.
• Multifocal contacts. These lenses have several rings or zones set at different powers. With this design, you are actually using both near and far vision at the same time. However, your brain learns to automatically select the right focus for what you want to see. You may find that using a multifocal lens makes your vision less sharp than when using a monofocal lens.