according to most ophthalmologists, while reading in the dark might strain your eyes and give you a headache, the notion that it can cause lasting damage is wrong. Most people can expect to experience some decline in their vision as they age, and genetic research shows that it is family history above all else that determines to what extent your vision will weaken.
But some researchers argue that putting too much strain on your eyes as a child or young adult, like the kind caused by reading in the dark, or simply reading for prolonged periods in general, might contribute to the decline of your eyesight later in life.