Exposure to UV in the 200-350 nm range and mid-to-far IR in 1400 nm to 1 mm harms which ocular structure?

• A. Retina
• B. Lens
• C. Cornea
• D. Pupil

Answer: (C)

Exposure to these wavelengths primarily harms the cornea because it is the eye’s outermost surface and the first tissue to absorb energy from both ultraviolet light and infrared radiation. Ultraviolet light in the 200–350 nm range is strongly absorbed by the corneal epithelium, causing photokeratitis (a painful “sunburn” of the cornea) and potential epithelial damage. Infrared radiation from about 1.4 μm to 1 mm is absorbed as heat by the cornea and anterior eye tissues; this heating can injure corneal cells and alter corneal clarity with enough exposure. Although the lens and retina can be affected by high energy exposure, the combination given directs damage to the cornea first and most directly, while the pupil is not a tissue that sustains damage from these energy ranges.