Hi, in my opinion, reading on a kindle fire in dark is indeed not a good idea. Your eyes need a comfortable lighting condition to work. And this comfortable condition means both lighting strength and stability. So what is the problem with a kindle fire? It may be too strong or too light, or too weak or too dark for your eyes. And one more terrible thing is that the light from the kindle fire is always changing, to which the eyes will constantly need to adapt. So people can easily get tired by reading on a kindle fire. And that is also the reason many people get short sighted by reading on a kindle fire in dark.
Of course not, you should not read book on the kindle fire especially in the dark. When you have reading on kindle fire in the dark, your eyes have to be focus on the point, so this will make your eyes fell strain. In a long time, it will do harm to your eyes. Anyway, you should be careful about it. Besides, it all depends on your pose when you have reading. You should not read book in the bed. Also you should also pay more attention to your reading habits. For example, you'd better not read a book in a dark place. And the position and the distance of your reading are also very important, so just be careful about them. So that you can not damage your eyes.
It is bad for the eyes to read on a kindle fire in dark. Becasue the light resource is directly shining into our eyes which save the process for the eyes to reflect the lights on the retinal, it may hurt our eyes if we see on the strong light screen for a long time. We are easilly short sighted and intense the prescription if doing this often.
Not exactly that good to have something to read on a kindle fire in dark. The first hurt is your respiration system, a kindle fire will lead to oxygen lack, and the symptom is dazzling and choking sensation in chest. The secondly is the hurt to your eyes. The kindle fire will rock and leap always, the brightness will always change, your eyes will be hard to accommodate and fatigue, and finally the myopia will happen. We need the permanent light source to reading for the eyes care. Comfortable or not is the standard to say if the light will be the suitable for your eyes.