The main physical effect of exposure to infrared radiation is heating. This is also true for biological tissue. In the case of the eye, there is very sensitive tissue available for exposure to IR radiation. “Near IR” (7800 Ǻ–14,000 Ǻ) is blamed for many eye cataracts. The eyes may be easily protected by the wearing of goggles. Ultraviolet (UV) radiation is that part of the EM spectrum between 100 Ǻ and 4000 Ǻ. The UV-A band of UV extends from 3150 Ǻ–4000 Ǻ and is called “black light” or “near UV.” This band can cause thermal skin burns, increased skin pigmentation, and photoreactions. It does not, in general, cause eye injury. From 2800 Ǻ to 3150 Ǻ is “mid-UV,” or erythemal region. This band produces photokeratitis and possibly skin cancer. The UV band from 1000 Ǻ–2800 Ǻ is the UV-C band. It is known as “far UV” or “short UV.” This band of UV is germicidal and viricidal, and destroys molds and yeasts as well. There is a subregion of UV-C from 1700 Ǻ–2200 Ǻ that produces ozone. The whole UV region can damage human skin and eyes. In eyes, it can cause blepharitis, conjunctivitis, keratitis, and keratoconjunctivitis. Skin exposure to solar UV can cause erythema and tanning; chronic skin exposure to solar UV leads to tanning, elastosis (dry, leathery, deeply wrinkled skin), and an incidence of non-melanoma skin cancer.

Type of radiation	Wavelength, Ǻ
cosmic	0.0005–0.005
gamma	0.005–1.4
X	0.1–100
UV	100–4000
visible	4000–7000
infrared	7000–2,000,000