If you've lost the ability to focus on objects up-close, you're not alone. Presbyopia – the technical name for this condition – is a normal (and unpreventable) part of the aging process. Most people begin to notice it in their mid-40s, often when reading becomes difficult. If distance vision is still good, then presbyopia may be fixed with reading glasses; for patients who already wear glasses, bifocals or trifocals may be used.

If you have presbyopia and don't like wearing glasses or contact lenses, then you may be considering LASIK surgery. It's a common choice for people with nearsightedness, farsightedness, or astigmatism. However, while LASIK can be used for presbyopia, it's a little different than simply correcting focal length.

What's Special About Treating Presbyopia

Because presbyopia is a problem with adjusting vision, surgically correcting a patient's vision to 20/20 doesn't eliminate their need for glasses; their eyes still can't change from seeing something correctly at twenty feet to reading something correctly at one foot.

Some people choose to have their vision corrected anyway and wear reading glasses; LASIK surgery, in this case, can at least eliminate the need for bifocals. However, there's a second option for fixing presbyopia: monovision LASIK.

How Monovision LASIK Works

Monovision takes advantage of the brain's natural flexibility in an interesting way; instead of correcting both eyes to 20/20, you will have each eye corrected separately. One eye, usually your dominant eye, will be corrected to see properly at a distance, while the other eye is corrected to see close objects properly. This way, you no longer rely on your eyes to change their focal length. Instead, your brain learns to switch between one eye and the other depending on what you are looking at.

Why You Need Contact Lenses First

Because LASIK means making a permanent change to your eye, it's crucial to start with monovision contact lenses first. Not everyone reacts well to having their eyes at different focal lengths. In addition, it can take a few weeks for the brain to adjust. By testing out the process first with contact lenses, you can find out whether monovision will work for you.

When To Choose Regular LASIK

If you are unable to adjust to monovision contacts, that doesn't mean that you can't have LASIK. It just means that LASIK surgery won't remove your need for glasses; most commonly, your distance vision will be corrected, and you will need to wear reading glasses to look at objects close to you.

However, while it can be very freeing to no longer need glasses, it's important to note that monovision does have a couple of disadvantages that might cause you to choose regular LASIK even if your brain can adjust properly. Monovision results in decreased depth perception and night vision; if these are important to you, regular LASIK and reading glasses might be preferable.