Lighting is the application of light sources in a way that considers factors like placement, amount of light, color, and shadows. As people age, they need more light but it must be balanced, uniform and shielded to avoid glare. Energy-efficient lighting produces the most light while using the least energy, such as fluorescent and LED lights which use less energy and last longer than incandescents. Lighting for universal design adapts to people's changing needs and allows them to navigate spaces safely as they age.