Common Vision Problems
The majority of vision correction diagnoses are one, or a combination of the following…
Commonly known as nearsightedness, you need correction to see far away. (e.g. street signs, TV, movies, sporting events, classroom chalkboard)
Commonly known as farsightedness. With a small farsighted prescription, you just need correction for reading up close (e.g. reading a book, looking at a mobile device). With a large farsighted prescription, you may need help for both far and near vision.
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The lens of your eye must stay flexible in order to adjust its focus so you can see things both up close and at a distance. With age, the lens can harden and lose its elasticity, and the muscles that control the lens can weaken, all leading to farsightedness caused by an inability to focus on nearby objects – this is presbyopia. A patient with presbyopia is an excellent candidate for progressive lenses.
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An eyeball’s cornea is not always perfectly round. The majority of us have a slight circular imperfection in our corneas – this is called an astigmatism, causing blurred vision in some cases. Astigmatism is independent of near- or farsightedness. And it is easily correctable. TWO corrections are needed for an astigmatism… CYLINDER – the backside curve of a lens corrects for the size of the astigmatism, and AXIS corrects for the orientation of the astigmatism.
In the illustration shown here, the astigmatism is at about the 45° axis. Astigmatism can occur anywhere from 1° to 180°.
All prescription eyeglass lenses can easily correct for astigmatism. The most common reason that your vision is still a little blurry looking through those cheap OTC readers you bought at the drugstore? It’s because OTC readers DO NOT correct for astigmatism. For most contact lenses, manufacturers offer versions that correct for astigmatism, including both daily and extended wear lenses
Commonly known as double vision, you need correction to have your eyes see one image instead of two. While much less common that near- or farsightedness, double vision can occur in people of any age. In most cases, this is correctable by adding a feature called “prism” to your corrective lenses. This is not a triangular piece of refractive glass – like the one that can split light into a rainbow of colors. Prism in eyeglass lenses refers to a special “bend” built into a lens that helps your eyes give your brain one image instead of two. A sudden onset of double vision can be a sign of a more serious health problem such as a stroke. In this case you should go to your nearest ER.
Prism is not available in OTC eyeglasses! If you are experiencing double vision, you need to see an optometrist.
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