Yes, watching some certain TV can help people, especially the children, grow well. However, when you watch too much television, there will be some side effects for you. In a world, there are both the physical and physiological effects on children from the television. Based on the physical effects, you know if the kids watch TV too much, they will not prefer to do some exercise outside, which will result in the poor health. Besides, during watching TV, the television will release much radiation which will be harmful for the eyes. Then the children's vision will get affected or become nearsighted. In addition to the physical side effects, there are some physiological effects on the kids. As we all know that there are many advertisements showed on TV, and some of the advertisements are not healthy for kids, when the children watched them, they cannot growth healthily at the physiological side. Consequently, what your mother told you is right.
It seems to me that you like to watch TV shows on a regular basis. So, as a matter of fact, sitting in front of a TV or computer for too long would do damage to your eyes, causing some problems like myopia, dry eyes, eye strain, even some infections. Therefore, what you should know is to take care of your eyes, try to take some breaks at intervals, try to get some healthy food for your eyes, and better yet, watch less.
There are many side affects when you watch too much TV. Your eyes will get dryness if you watch tv for a long time. What's worse, your eyes will get short sighted if you watch tv for a long time with no rest in the dark environment. You'd better not watch tv for a long time.
One most common and negative effects of watching too much tv is influence of eye vision. When you are sitting in front of tv for a prolonged period, it makes your eyes to be fatigue easily. And the eye muscle are tired after watching objects for a prolonged period. Meanwhile, the myopia would come if you always watch too much tv. On the other side, you would stay in the coach without any movement or exercise, thus your head or shoulder would be tired as well, even it can make you overweight. What is more, image and color flickering affects function of heart, because the frequencies of flickering can correspond to the frequencies of the heartbeat, which support functioning of human heart and brain. It is especially dangerous for a human organism.