Reading novels in night mode under the covers was relatively less harmful to the eyes because night mode would filter out most of the light and reduce eye irritation. In addition, it is also important to choose comfortable reading materials, such as using suitable brightness of the font, maintaining a moderate distance, avoiding excessive fatigue, etc. These can reduce the damage to the eyes. However, if one used night mode for a long time or read overly stimulating books, it might still cause eye fatigue, dryness, and other problems that required appropriate rest and adjustment.