Light is measured in nanometers (Nm). 1 nanometer = 1 millionth of a millimeter.
Light is made up of 3 ranges of waves:• Ultraviolet rays: short waves from 180 to 380 Nm in length.
• Visible light: medium waves from 380 to 780 Nm.
• Infrared: long waves from 780 to 1 800 Nm.
ULTRAVIOLET RAYS (U. V.).
(5% of solar radiation)Most UVs are absorbed by the atmosphere. The quantity filtered is very variable: it is only slightly filtered near the equator and at high altitude where the air is thinnest. The extent of the effect of UVs also increases if the rays reflect off snow, sand or water..
Failure to protect the eyes from UVs can cause an ophtalmia and temporary or permanent blindness and even irredeemable damage to the conjunctiva and cornea, reducing vision by as much as one-tenth. It should be noted that UVs are present even in cloudy weather.
VISIBLE LIGHT
(39 % of solar radiation)As its name indicates, this light is perceived by the brain.
It is a good idea to protect the eyes from dazzle caused by excessively bright light. Sunglasses which partially absorb visible light are a comfort concept, and may in fact damage your eyes.
INFRARED RAYS
(56 % of solar radiation)They release heat and, in fact, the transparent part of the eye absorbs IR radiation quite naturally as they contain water. In extreme conditions, the cornea is most at risk from this heat.
