Accommodation is the ability of the eyes to focus the image of an object on the retina in spite of variation of the distance between the object and the eye. While walking on a road, for distant objects ciliary muscles remain relaxed, the lens becomes thin and focal length increases, so distant vehicles, signals and road directions are focused on retina. For nearer objects ciliary muscles contract, the lens becomes more convex, focal length decreases and the nearby object (like stones, pedestrians) is also focused on the retina, which helps to avoid road accidents.