According to numerous scientific studies, reading in dim light will not damage your eyes, although some studies have linked poor lighting conditions with myopia. However, reading in dim light can cause eye strain, which could make the reader uncomfortable, and therefore it is a good idea to set up a well lit reading space to make reading more enjoyable. You may also want to talk to your eye doctor if you have specific concerns, because you could have a unique eye condition which requires special attention.

In 2007, two doctors published a study debunking a series of well known medical myths, including the idea that reading in dim light causes eye damage. Rachel Vreeman and Aaron Carroll looked at numerous studies on eyesight and reading and found that the effects of reading in dim light are temporary, not permanent. In other words, someone who reads in low light levels may experience discomfort which makes the experience less enjoyable, but this discomfort will cease as soon the the person puts down his or her books.

The eye often finds it hard to focus in dimly lit conditions, which can be a cause of eye strain for someone reading in these conditions. People also tend to blink less while reading in dim light, which can result in a dryness of the eye which feels unpleasant. People who do a lot of reading at night often probably notice these problems, and try to counteract them by creating a well lit space with no glare for the purpose of reading at night in comfort.

Some doctors, however, believe that reading in dim light may make myopia more severe. This claim is backed up with evidence such as the fact that many academics suffer from myopia, and they often read and work in poorly lit conditions. There may of course be other reasons for increased myopia among academics. Other studies have also linked myopia and IQ, for instance, although this is a classic example of a situation in which correlation may not equal causation.

Ophthalmologists believe that reading in dim light does not change the function or structure of the eyes in any permanent way. That said, there is no reason to read or work in poorly lit conditions, as temporary eye strain is still irritating and unnecessary, especially when it can be easily avoided with better lit conditions. The best lighting conditions for reading are ambient, rather than direct, and there should be no glare in a reading area.