The answer is absolutely yes. It's very harmful and easily to give rise to eye infection if you wear dirty contact lenses. The eyes is the most fragile part in our body. As we all know, eye infections are caused because of the bacteria, virus, etc. Meanwhile, the bacteria and virus are easy to get in touch with our eyes to lead to red eyes, floaters and bloodshot or else through the dirty contact lenses. What's worse, dirty contact lenses will make it uncomfortable to wear and we can't see clearly through them. Therefore, in consideration of your eyes, you'd better replace your contact lenses with a new one as soon as possible.