Which part of the eye is damaged by UV within the 200 to 350 nm range and mid to far infrared radiation in the 1400 nm to 1 mm range?

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

Answer: (B)

The front surface of the eye, the cornea, is the structure most affected by these ranges. Ultraviolet light in the 200–350 nm band is strongly absorbed by the cornea, where it can cause immediate irritation and injury (photokeratitis) if exposure is intense. Mid to far infrared radiation (about 1400 nm to 1 mm) is also absorbed by the water-rich corneal tissue, where the energy converts to heat and can damage the corneal epithelium and stroma. Because the cornea is the first optical element encountered, it bears the brunt of both UV and IR heating, protecting deeper structures. The retina is protected by the cornea and lens from these wavelengths, and the pupil is an opening rather than a tissue that sustains damage.