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What is 20/20 Vision?

It's assumed that 20/20 is known as "perfect" vision, what does that actually mean?

Perfect according to whom and why? And what about those people who say they have better than 20/20 vision? Is that even possible??

What’s actually kind of crazy is that almost half of U.S. adults don’t have 20/20 vision. Our definition of perfection is one that many people can’t reach!

How is 20/20 vision defined?

What “20/20” means, in the simplest terms, is that one can see at a 20-foot distance what one is supposed to be able to see at a 20-foot distance.

Does that sound vague? That sounds vague.

Basically, this Dutch eye doctor named Herman Snellen developed an eye chart (the Snellen chart—we’re positive you’ve seen one before) in 1862 that, at a distance of 20 feet from the viewer, displayed lines of letters that determined how good a person’s vision is. It starts at the 20/200 line (or what you see at 20 feet is what others can see from 200 feet — meaning you have to be that much closer to see what others can see at 200 feet) and has 20/20 as the goal.

It sounds kind of arbitrary, but to Snellen’s credit, he developed an eye measurement system and a language for talking about visual ability that’s still in use today. Don’t fix what’s not broken.

Perfect vision isn’t 20/20 everywhere. In fact, that’s really only what we call it in the U.S. Countries that use the metric system call it 6/6, referring to 6 meters of distance instead of 20 feet.

So 20/20 is as good as it gets?

No. You can have better than 20/20 vision.

For example, if your vision were 20/15, that means you can step back five feet and read the Snellen chart the same as someone else five feet closer.

In fact, when tested, many people who’ve undergone LASIK report seeing with better than 20/20 vision six months after the surgery.

Does that mean I could see as well as my pet falcon? (I forgot to mention, I’m a falconer.)

Oooh cool hobby! Can I pet her? No? And I should be standing further back? Oh, ok, sorry.

The answer is no. Birds of prey see about eight times as well as humans. Theirs is closer to 20/2 vision. I wouldn’t hold your breath.

More to the point, about 94% of people in a clinical study who underwent LASIK saw 20/20 or better six months after surgery. There are also possible side effects, the most common among them including dry eye or visual disturbances.

So there’s more to consider than just the possibility of 20/20 or better vision. That said, if you’re part of the almost half of American adults with less-than-ideal vision, you can talk to a LASIK doctor about your expectations and concerns and they can discuss your options.

Don’t know a LASIK surgeon? That’s ok, we do. You can find one near you here and most do consultations for free, so no reason not to call. Or if you’d rather look at puppies, we have some of that too.

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Indication:  LASIK (laser-assisted in situ keratomileusis) is a laser surgery procedure that permanently changes the shape of the cornea to reduce or eliminate nearsightedness, farsightedness, or mixed visual irregularities due to an abnormal curve in the cornea (astigmatism). Only an eye care professional trained in laser vision correction can determine if you are a candidate for this procedure. The iFS® laser is a surgical laser that can be used to create flaps for use in LASIK surgery.

Contraindications: You should not have LASIK if you have collagen vascular (such as rheumatoid arthritis), autoimmune, or an immunodeficiency disease because they affect the body's ability to heal. You should not have this procedure if you are pregnant or nursing, show signs of corneal thinning, or take medications with eye-related side effects, such as Isotretinoin (Accutane®) for acne treatment or Amiodarone hydrochloride (Cordarone®) for normalizing heart rhythm.

Warnings: LASIK is not recommended if you have diabetes, a history of herpes simplex or herpes zoster keratitis, significant dry eye, or severe allergies.

Precautions: Your doctor will examine your eyes to determine if you are a candidate for this procedure. Talk to your doctor about any eye-related conditions, injuries, or surgeries you have had, as well as any changes to your vision in the past year. These may result in poor vision after LASIK. Tell your doctor about any medications you are taking. After surgery, you may find it more difficult to see in conditions such as dim light, rain, snow, fog, or glare from bright lights at night. LASIK is for patients 21 years of age and over.

Side effects: Possible side effects include dryness, which may be severe; loss of vision or the possible need for glasses or contact lenses after surgery; and visual disturbances such as halos (hazy rings around lights), glare, starbursts, double images, and other visual irregularities that may be debilitating. Possible complications resulting from LASIK flap creation include swelling, inflammation or pain in your eye, infection, or flap-related complications. Mild to severe light sensitivity occurred in 1% of patients between 2 and 6 weeks after surgery. Some patients (0.03%) noticed a temporary spoke-like band of light in their peripheral vision.

Please consult with your eye care professional regarding the potential risks and benefits of this procedure. Results may vary for each individual patient.

The iLASIK® platform utilizes the STAR S4 IR® Excimer Laser System, WaveScan WaveFront® System, as well as the iFS® Advanced Femtosecond Laser during the LASIK procedure.

Caution: U.S. Federal Law restricts these devices to use by practitioners who have been trained in their calibration and operation, and who have experience in the surgical treatment and management of refractive errors.

For U.S. Consumers Only