What harm does laser light do to eyes?

The damage of laser to eye tissue is related to the wavelength of laser. Ultraviolet light below 300nm can not penetrate the refractive medium of the eye, but is almost completely absorbed by the cornea, which can cause electro-optic ophthalmia; 300 nm ~ 400 nm ultraviolet light is mainly absorbed by crystals, which can cause radiation cataract; Visible light of 400 nm ~ 800 nm and near infrared light of 800nm~900nm can reach retina through refractive medium and be absorbed by pigment cells, causing retinal burns and even bleeding. Infrared light above 950nm can be absorbed by the refractive medium of the eye and damage the surface tissues of the eye, such as cornea and lens, in the form of thermal radiation. The damage of laser to eye tissue is also related to other factors. For example, the greater the laser energy, the greater the damage to the eyes; The smaller the angle of laser irradiation on the eyes, the greater the damage, because the smaller the incident angle, the smaller the spot on the retina and the more concentrated the energy density; If the eyes look directly at the laser beam, the laser beam will focus on the central recess of the retina, which has a great influence on vision; It is easier to cause retinal damage at night than during the day, because the pupil is dilated at night, and the retina receives more laser energy when the laser with the same energy density irradiates the retina.