Categories of Laser Hazards
- Beam related: laser energy exposure to eye and skin
- Non-beam related
- Fire
- Smoke plume
- Electrical
- Chemical
Explosion
Beam-related injuries
The main concerns over laser use are the possibility of eye and skin injury.
Eye Injury
The eye is the organ most sensitive to light. Laser radiation effects will depend on the laser wavelength and the part of the eye it affects.
The cornea is the transparent layer of tissue covering the eye. Damage to the outer cornea may be uncomfortable (like a gritty feeling) or painful but will usually heal quickly. Damage to deeper layers of the cornea may cause permanent injury.
The part of the eye that provides the most acute vision is the fovea centralis (also called the macula lutea). This is a relatively small area of the retina (3 to 4%) that provides the most detailed vision and color perception. This explains why eyes move when you read, since the image has to be focused on the fovea for detailed perception. If a laser burn occurs on the fovea, fine vision (reading and working) may be lost. If a laser burn occurs in the peripheral vision, it may produce little or no effect on vision.
Blink and aversion response
Fortunately, the eye’s blink and aversion response acts as a self-defense mechanism by closing the eyelids or moving the head to avoid exposure to bright light. The aversion response is assumed to happen within 0.25 seconds, but only defends the eye from lower-power, visible lasers. With high-power lasers, the damage can occur in less than a quarter of a second.
Signs of Eye Exposure
Symptoms of a laser burn in the eye include:
- Headache shortly after exposure,
- excessive watering of the eyes, and
- sudden appearance of floaters in your vision.
Skin Injury
Laser radiation injury to the skin is considered less serious than injury to the eye, since functional loss of the eye is more debilitating than damage to the skin. However, the possibility of skin exposure is greater than that of eye exposure because of the skin’s greater surface area.