Final answer:
A medical device that utilizes focused light of various colors and wavelengths for treating conditions like excessive hair and spider veins is known as a laser.
Step-by-step explanation:
Understanding Laser Applications in Medicine
A medical device that uses multiple colors and wavelengths of focused light to treat conditions such as excessive hair and spider veins is commonly referred to as a laser. Lasers provide intense light and emit a very pure wavelength of electromagnetic radiation, which can be precisely controlled for various medical purposes. The precision of lasers is due to their ability to emit light at a specific wavelength strongly absorbed by the targeted tissue, resulting in precise effects like cutting or coagulating tissue.
For instance, in laser surgery for eye conditions such as nearsightedness, a 193 nm wavelength UV laser removes corneal tissue to correct vision with high accuracy. Similarly, for a detached retina, a green argon laser is used to create scar tissue that helps to reattach the retina. The choice of laser and wavelength is essential, as it is dependent upon the tissue's absorption characteristics to effectively treat the intended area.