Posted on 25 Mar 2013 22:14
You are probably aware of many of these myths about the eyes and the sense of sight. Many of us grew up with them. These myths have been passed from one generation to the next and despite ever-increasing access to accurate information, many of them still persist.
1. Reading in the dark will hurt your eyes and could make you go blind.
Not true, reading in the dark does not damage your eyes at all. It just makes it hard to see and it will tire your eyes out more quickly.
2. If you cross your eyes they will get stuck that way.
No (but you knew that). The same muscles that move your eyes to the left and the right converge them in the middle. Therefore, if crossing your eyes could make them get stuck, then moving them to the left should make them get stuck to the left (or right).
The medical term for cross-eyed is esotropia. You many not know that the opposite condition, the eyes sitting in an outwards facing position, is called wall-eyed (like your looking at the walls), and the medical term for this is exotropia. The muscles that move the eyes work together in highly complex ways so that the eyes are held in position or moved together. If your eyes are out of alignment in any way, it is most likely due to a problem with one of the cranial nerves that innervate the eye muscles, or a restriction of a muscle. For example, if the lateral rectus muscle, which is responsible for abduction, moving the eye to the side, is inactive, the eye will tend to sit in a position of adduction, turned toward the middle. If the same muscle is inactive on both sides, the result would be a cross-eyed appearance. New-born baby's sometime exhibit a temporary cross-eyed appearance, freaking out their worried parents! But this is just baby's eye muscles learning the ropes.
3. Don't let your child sit too close to the television set because it will damage his or her eyes.
Many of us grew up on this one and heard it a million times. There is no evidence to support it and no reason to believe it true. Your child's eyes will not be damaged by sitting too close to the television.
Staring at a computer screen all day can certainly lead to tired eyes and eye strain. Rest your eyes ever so often and make sure that the light is adequate and does not produce a glare on the screen. Sometimes people staring at screens do not blink as often, making their eyes dry out. Make an effort to blink more often.
4. If you only have one working eye you should rest it often lest it become overworked because of having to take up all the slack for the missing eye.
The truth is that an eye cannot 'work harder'. It does what it does in a constant way and one eye will not work harder because the other stops working. It cannot.
5. Cataracts improve vision.
Cataracts cloud the lens so that could not possibly improve vision. But, sometimes people with cataracts find that they can read without glasses. This is because people with cataracts can undergo a myopic shift, so that they see better closeup…are more nearsighted. Problem is, things get more blurry further away. Eventually, though, as the cataract thickens, it will become harder to see anything, period.
6. Wearing glasses or contacts will make your eyes worse.
There are two reasons people think this. One is that once your vision becomes bad enough that you need glasses, your eyes are in the process of progressively becoming worse. They would have continued to become worse whether you had gotten glasses or not, but since having glasses often involves going back to the doctor for a new, stronger prescription, it seems as if the glasses made your eyes worse.
The other reason is simply because, if your vision gets blurry over a period of time, you may not notice it. But if you do get glasses, and then you suddenly have clear vision, this blurry difference becomes striking once you take the glasses off. It is the comparison that fuels your perception that the glasses are making your vision more blurry, when in fact, they were always blurry and the clear vision the glasses give you provide a baseline for comparison.
This myth leads people to believe that you should take a break from wearing glasses or contacts to "rest" your eyes. There is absolutely no need for this and not wearing your glasses is what will strain your eyes. However, this does not mean that the reverse is true and that not wearing your glasses will damage your eyes or make them worse.
7. You become farsighted as you get older.
Yes, people do often find it harder to see close up as they get older, but this is not the same as farsightedness. Farsightedness, which means you see well far off but badly close in, is caused by a shortened eye length and this is present throughout life. The loss of near sight, and the difficulty in reading, as you grow older is called presbyopia and this has to do with losing the ability to focus close up as get older.
8. Beta carotene, like from carrots, improves your vision.
This is not true. If your vision is blurry, beta carotene will not improve it. Only if you have a vitamin A deficiency will this possibly improve your night vision. The vitamin A from vegetables like carrots and other vegetables such as leafy greens is important to your eye health. So are some other micro-nutrients. But taking any nutrients in the form of supplements will not correct vision problems once they occur.
9. 20/20 is perfect vision.
The fact is there is not such thing as "perfect" vision. 20/20 vision is actually average or normal vision, and basically means your eye can make out a certain sized image from 20 feet away. Some people can see better than this, such as 20/15. Often, when we get glasses or contacts, the correction gives us better than 20/20 vision. Since you cannot be better than perfect, it makes no sense to call 20/20 perfect vision.
10. When you go blind or your vision becomes impaired, your other senses, like hearing, strengthen to make up for the loss.
Actually, it is impossible for your hearing, or any other sense, to improve because of a vision loss. What really happens is we pay more attention to the information from these other senses. Our brains grow more adept at processing the information and promotes more resources to them. The sense of hearing is the same, but what we do with the information changes. Vision, when it is normal, is a distraction from these other senses. This is why we often close our eyes to concentrate on something, whether it is listening to a sound or just thinking about something.
Bonus Myth: Doing Eye Exercises will Improve Your Vision and Delay the Need for Glasses
Your eye health and vision depends on many factors. Primary are the shape of the eye and the condition of the actual tissues of the eye. Muscular exercises will not have any significant effect on vision and will in no way delay your need for glasses.