If you didn't leave out any Chinese characters of what Huitailang's wife said, some punctuations should be added like this:
近视了不是?让你平时别躺床上看书,你就是不听!
"近视了不是?" looks like a question, but actually isn't. It means "It doesn't surprise me that you get nearsighted"
The following sentence "让你平时别躺床上看书,你就是不听!" states the reason why she was not surprised.
Here's another example of "...不是" :
感冒了不是? 叫你穿上外套,你就是不听!
It doesn't surprise me that you catch a cold. I told you to put on your coat, but you just wouldn't listen.
As you may have seen, "... 不是" implies that the person you are talking to is to blame for something bad that has just happened to himself/herself.