The idea that reading in dim light ruins your eyes isn’t my favourite wives' tale about “leisure activities” causing blindness, nor is it the most obscene! In any case, it’s simply not true.
I’ll begin my expose´ with a brief explanation of how we see.
The eyes are equipped to catch the light reflected off, or generated by, objects in our world. When light enters our eyes, it’s focussed by the front layers of the eye onto the retina – a delicate layer of just a few rows of cells, less than half a millimeter thick – which sits at the back of the eye.