Optical engineering is the field of study that focuses on applications of optics. Optical engineering deals with design of optical instruments such as lenses, microscopes, telescopes, and other equipment that utilizes the properties of light using physics and chemistry. Other prominent optical engineering applications include optical sensors and measurement systems, lasers, fiber optic communication systems, optical disc systems (e.g. CD, DVD), etc. Optical engineers design and build devices which manipulate light by applying knowledge of optics. Additionally, engineers in this field of study also considers the practicality in terms of available technology, materials, costs, design methods, etc. Electrical engineers often use general computer tools such as spreadsheets and programming languages, along with specialized optical software designed specifically for the field to assist on calculations.