关于视力的几个常见误解 上
MYTH #1: IF YOU CROSS YOUR EYES, THEY'LL STAY THAT WAY.
Crossed eyes occur when your eyes don't look the same way at the same time. There are six muscles attached to each of our eyes that, guided by signals from the brain, control their movements. When your eyes don't align, the brain gets two different images. Over time, this can cause more serious vision issues. That's a real problem, but it's not caused by making your eyes cross on purpose for short periods of time.
MYTH #2. EATING CARROTS WILL HELP YOU SEE IN THE DARK.
Well, carrots certainly aren't bad for your eyesight. They contain plenty of beta-carotene, which your body converts into vitamin A, a crucial vitamin for vision. But carrots don't do anything exceptional for your nighttime vision.
MYTH #3: THE BIGGER YOUR EYES, THE BETTER YOUR EYESIGHT.
When you're born, your eyeballs are approximately 16 millimeters in diameter, reaching 24 millimeters as an adult. But your eyes getting larger does not necessarily mean that your vision is getting better. In fact, excessive growth in human eyes can cause myopia, or nearsightedness. If the eyeball is too long, the eye's lens can't focus the light in the right part of the retina to process images clearly.
MYTH #4: PUPIL DILATION OCCURS ONLY IN RESPONSE TO CHANGES IN LIGHT.
Sexual arousal, solving a complicated mental math problem, fear, and other cognitive and emotional events can provoke changes in pupil size, though the precise reasons why are not yet clearly understood.
MYTH #5: UV RAYS CAN ONLY DAMAGE EYES WHEN THE SUN IS SHINING.
Even on cloudy and foggy days, ultraviolet (UV) radiation can cause eye damage. Years of exposure can increase your risk of developing cataracts.
MYTH #6: WEARING GLASSES TOO MUCH CAN MAKE YOUR EYESIGHT WORSE.
Giving the correct prescription "reduces the progression of myopia."
MYTH #7: READING IN DIM LIGHT WILL DIMINISH YOUR EYESIGHT.
While reading in semi-darkness may put a temporary strain on your eyes, it's not going to permanently damage your eyesight.