During a vision or refraction exam, your ophthalmologist or optometrist will assess how light bends as it moves through your cornea and the lens of your eyes. This will help them determine whether you have a refractive error and need corrective lenses. 20/20 is considered optimum or perfect vision. Anything other than 20/20 vision indicates you have a refractive error and will need corrective lenses to compensate.

At NeoVision, we offer vision exams as both an independent service and as a part of our comprehensive eye exam.

What is a refractive error?

A refractive error is a type of vision problem that makes it hard to see clearly. Specifically, it means the shape of your eye keeps light from focusing correctly on your retina which causes distortions in your vision. Refractive errors include nearsightedness, farsightedness and astigmatisms.

Myopia (nearsightedness)

Someone with myopia or nearsightedness can see objects close by clearly but will struggle to see objects at a distance. Distant objects may appear blurry or fuzzy.

Hyperopia (farsightedness)

On the other hand, someone with hyperopia or farsightedness has no trouble seeing objects that are far away. However, objects close at hand will appear blurry or unfocused. This is often referred to as “mild hyperopia”. In more advanced cases of hyperopia, vision can be blurry at all distances.

Presbyopia (loss of near vision with age)

After age 40, the lens of the eyes becomes less flexible which makes it more difficult for the eye to focus and change focus fluidly. Presbyopia is perfectly normal and just another part of the aging process. Even people who already have myopia, hyperopia or astigmatism can get presbyopia.


Astigmatism occurs when the front surface of the eye, the cornea, has an asymmetric curvature. Normally the cornea has a smooth and equal curvature which allows light to enter the cornea evenly. Someone with astigmatism may have vision that appears wavy or distorted, much like a funhouse mirror. Usually, astigmatism causes blurred vision at all distances.

Detecting Refractive Errors During a Vision Exam

Dr. Tandon or one of our other trained eye care professionals will first assess how light bends as it moves through your cornea and the lens of your eyes. They may use either an ophthalmoscope or an autorefractor.

Afterward, if your eye doctor does detect a refractive error, they will then determine what prescription of corrective lenses you need. Each of your eyes will be tested independently as the degree of refractive error can differ from eye to eye. Finally, they will prescribe you corrective lens designed to give you better, clearer vision.

Vision Exam Frequently Asked Questions

How do I know if I have a refractive error?

Only a licensed eye care professional can accurately diagnose a refractive error during a vision exam or comprehensive eye exam.

What does “20/20” vision mean?

20/20 is one of many measurements of sight and refers to optimum or “perfect” vision. Specifically, it means that someone with 20/20 vision can see writing at 3/8 in (9.525 mm) font size at 20 ft away. So, someone with 20/40 vision can only be 20 ft away from an object to see what a person with 20/20 vision can see at 40 ft away. And similarly, someone with 20/400 vision can only be 20 ft away from an object to see what a person with 20/20 vision can see at 400 ft.

Most states require 20/40 or better in at least one eye to get a driver’s license without glasses or contact lens restriction.

On the path to better eyesight? We can help you.

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