Eyesight vs Vision
Our visual perception or the sense of seeing is what helps us most in interpreting the world around us. Eyesight and vision are two of the many words used to refer to this perception. Visual perception is possible not just with our eyes as it also involves our brain to make sense of things in our immediate environment and our learning and culture. Many people think eyesight and vision to be the same or synonymous though there are also differences that will be talked about in this article.
When you start to have trouble reading a newspaper or clearly reading the text or faces on television, you go to an eye doctor called ophthalmologist or an optometrist who checks your eyesight by making you look at a chart with numerals and alphabets written over it in many lines and asking you to identify them from a distance wearing different glasses. He is the person who decides the power of the lenses or glasses that we ought to wear to have clear images formed by our eyes. We have good eyesight when we see clear images formed at the back of our eyes. Our visual acuity is tested both from a distance (20 feet) as well as near (reading distance of 16 inches). When we are able to see clear images from a distance of 20 feet, we are said to have a 20/20 eyesight that is so called on the basis of a fraction developed by Dutch ophthalmologist Snellen. If you have eyesight of 20/40, it means your eyesight is only half as good as normal eyesight as 20/20 is just 50% of normal eyesight.
If you have 20/20 eye sight, it does not guarantee you have a vision that is perfect. This is because reading a chart containing letters and numerals in different light conditions is just a specific task, whereas our eyes have to perform many different and challenging tasks in our daily lives. There is a term called binocular vision that refers to the fact of our eyes working as a team to make sure we see clearly in all conditions. This is why we can have a poor vision even though we may have 20/20 eyesight if our eyes are not aligned properly as they should be. It is possible for people with 20/20 eyesight to have a blurred vision or to suffer from headaches because of this problem. Different reading tasks require our eyes to work in tandem according to different principles. For example, the principle of convergence is at work when we are working at computers as it requires our eyes to be pointing slightly inward. Reading from newspapers and watching movies in a dark room requires our eyes to change focus quickly and from one place to another. This is called accommodation.
What is the difference between Eyesight and Vision?
• Though eyesight and vision are related concepts, eyesight refers to clarity of images formed by our eyes whereas vision is what our eyes and brain make out of our surroundings, and this is dependent upon many other things apart from eyesight.
• We go to get our eyesight tested when we have trouble reading books or watching TV or other objects from a distance.
• 20/20 eyesight does not mean we have a perfect vision as there can be other problems leading to a blurred vision or even headaches.
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