Final answer:
A CO2 laser beam can damage the cornea, causing immediate severe pain and potential vision damage due to the high sensitivity and concentration of pain receptors in the cornea.
Step-by-step explanation:
The CO2 laser beam can cause immediate damage to the cornea and result in immediate pain. The cornea is the clear front surface of the eye, which acts as a protective covering for the iris and pupil. It also plays a key role in focusing your vision. Because the cornea is highly sensitive and has a high concentration of pain receptors, exposure to a CO2 laser can be extremely harmful, resulting in pain, burns, and potential vision damage if not properly protected.