Smartphones have become an essential element in daily life, as they have become affordable and thus more people can access them. In fact, smartphones are useful for almost everything, as they take quick photos and have programs for chatting and video calls, and this increases the hours of use as well. Many jobs require people to sit in front of computer and phone screens for more than 40 hours a week, and this increases the risk of blue light to the eyes. Blue light is the light emitted from phones, tablets, and laptops, and it has negative effects on eye health. Studies show that blue light can lead to macular degeneration, which is damage to the retina. It is also thought to affect central vision because it kills photoreceptor cells. In the retina, unlike some other cells in the body, once these cells die, they cannot regenerate.