Which type of laser poses the greatest risk of eye injury?

Class IV lasers pose the greatest risk of eye injury due to their high power levels and the ability to cause damage to the retina with relatively short exposure times. Unlike lower-class lasers, which either emit non-hazardous levels of light or are only hazardous under prolonged exposure, Class IV lasers can generate significant heat and present serious hazards not only to the eyes but also to skin and even flammable materials.

Class I lasers are safe under all conditions of normal use, making them the least risky. Class II lasers, which are visible light lasers, can also be hazardous, but they typically have a blink reflex protection that provides some safety against exposure. Class III lasers range from low to high power but still generally pose a lesser risk than Class IV lasers, which are capable of causing severe retinal burns very quickly and often require stringent safety measures due to their potential for immediate and significant harm.