Have you ever noticed that it is very easy for you to read a book, but you cannot read a street sign until you are very close to it? Maybe your friend is capable of watching a hawk flying high from a distance of a mile, but he/she cannot read a text message without leaning forward. Such differences are the reason that the eyes of every person refract the light differently, a complicated condition that is not always favorable. The culprit? Refractive errors are the main reason for most of us to wear glasses or contact lenses.
If your eyes are perfect, they will behave like well-functioning cameras. The light enters through the transparent front surface (the cornea) and the lens and shall be bent to the minimum part to hit the retina, the eye’s visual signal-sending part. That’s how you get clear, precise pictures, whether you are peering over a canyon or checking out a recipe. However, the National Eye Institute states that for more than 150 million Americans, this precise coordination is not correct.
So what’s occurring when your vision blurs? That’s where refractive errors are involved. The most prevalent varieties—nearsightedness and farsightedness—are essentially about where light ultimately focuses within your eye.
Nearsightedness (Myopia): Missing Far, Seeing Near
In nearsightedness, your eyeball could be slightly longer than normal, or your cornea could be too steep. This makes light fall in front of the retina rather than directly on it. Close objects remain clear, but distant objects become a blur. This condition is particularly prevalent in children and adolescents as their eyes continue to mature, and it is likely to result in frequent adjustments to their glasses. Symptoms that you may be nearsighted are squinting to read distant signs or screens, eye fatigue, or headaches after attempting to read signs or screens far away from you. Coastal Eye Surgeons estimate that around 30% of Americans have myopia.
Farsightedness (Hyperopia): Far is Fine, Close is a Struggle
Farsightedness is the opposite problem. Here, the eyeball may be slightly shorter than average, or the cornea may be flat. This means light falls behind the retina rather than on it directly, causing close-up objects to be blurry but far-off ones to be clear. Hyperopia is present in many people at birth, and during childhood, the eyes will often adapt on their own. As adults, however, the symptoms become increasingly difficult to overlook—constant eye strain, difficulty focusing on near tasks, and headaches are all telltale signs. Coastal Eye Surgeons estimates that about 60% of Americans struggle with some level of farsightedness.
Other Common Refractive Errors: Astigmatism & Presbyopia
Another common problem is astigmatism. It’s created by an irregular shape in the cornea or lens, scattering light and focusing at various points. This means everything—near, far, whatever—may seem bent or fuzzy. And then there’s presbyopia, which typically begins insidiously in your mid-40s. It’s a normal aging process where the eye’s lens becomes less flexible, so it becomes more difficult to focus on things that are near, even though your eyes were fine previously.
How to Know Something’s Off
The most apparent warning sign is blurry vision, yet refractive conditions can also present with double vision, halos around lights, headaches, or simply fatigued eyes—particularly after reading or screen use. Many individuals adapt to these symptoms, unaware that they can see much clearly.
Why Regular Eye Exams Matter
The best that you can do to keep on top of your eye health is with regular checks. A complete eye exam is swift and painless. You’ll probably read off a vision chart, and your doctor might dilate your pupils so they can take a closer peek inside. Even if you’re already wearing corrective lenses but still have trouble seeing clearly, you might only need a new prescription.
The Good News: It’s All Fixable
The overwhelming majority of refractive errors can be corrected easily. The easiest solution is glasses and contact lenses, which assist in bending light so that it strikes the retina perfectly. For a permanent solution, surgeries such as LASIK or PRK can tailor your cornea to correct focus permanently. The secret is catching the issue early—so you can keep your world in pristine focus.