Laser Safety Protection

Laser wavelength and eye injury: Among the injuries caused by lasers, the eye in the organism is the most serious. Wavelength in the visible and near-infrared light laser, eye refractive media absorption rate is low, the transmission rate is high, and refractive media focusing ability (i.e., concentrated light force) is strong. High intensity visible or near-infrared light into the eye can pass through the refractive medium of the human eye, light accumulation in the retina. At this time on the retina laser energy density and power density increased to thousands or even tens of thousands of times, a large amount of light energy in an instant in the retina, to the retina photoreceptor cell layer temperature rises rapidly, so that the photoreceptor cell coagulation degeneration and necrosis and the loss of photoreceptor role. Protein coagulation and denaturation caused by overheating when the laser is focused on the photoreceptor cells is irreversible damage. Once the damage is done, it will cause permanent blindness of the eye.
Different wavelengths of laser light have different degrees of effect on the eye, and their consequences are also different. Far-infrared laser damage to the eye mainly to the cornea, this is because this kind of wavelength of laser light is almost all absorbed by the cornea, so the cornea damage is the most serious, mainly caused by keratitis and conjunctivitis, the patient feels eye pain, foreign body-like stimulation, fear of light, tears, eyeball congestion, vision loss and so on. When far infrared light damage occurs, it should be covered to protect the injured eye, prevent infection from occurring, and treat symptomatically.
Ultraviolet laser damage to the eye is mainly cornea and lens, this band of ultraviolet laser light is almost completely absorbed by the lens of the eye, and the middle and far to the cornea to absorb the main, and thus can lead to lens and corneal clouding.
Lasers are usually labeled with a laser warning label with a safety class number:
Class I (Class I/1): Usually because the beam is completely enclosed, e.g. in a CD or DVD player.
Class 2 (Class II/2): Safe under normal conditions of use, usually less than 1 mW, e.g. laser pointers.
Class 3 a/R (Class IIIa/3R): Power levels up to 5mW are common, and staring at such a beam for a few seconds can cause immediate damage to the retina.
Class 3b/B (Class IIIb/3B): Immediate damage to the eye is caused by exposure.
Class 4 (Class IV/4): The laser burns the skin and even scattered laser light (200W or more) can cause damage to the eyes and skin. New types of cooking tools can be created by utilizing the thermal energy of the laser.
The above scenario is what happens when the laser is directed at the eyes. If the laser light is observed indirectly, the Tyndall effect of any laser light of 200W or less will not affect the eyes.