WAVELENGTHS & UV LIGHT
We receive wavelengths through two organs; we see light through our eyes and we capture sound through our ears. From radio waves to gamma rays, wavelengths gradually constrict, causing their frequency to increase and making them consume more and more energy. Hence, waves gradually increase in intensity and therefore are more dangerous for the eyes. The sun emits three types of light waves and without the correct eye protection each in its own way can seriously affect the eye. • Ultraviolet Light Rays: 5% of the sun’s energy reaches the earth in this form. UV rays (invisible “tanning” rays) can cause serious damage to the unprotected eye including the development of cataracts and corneal blistering.
• Infrared Light Rays: 50% of the sun’s energy reaches the earth as heat or infrared. Some IR rays will be absorbed by the cornea creating a drying effect – an issue of importance to contact lens wearers. • Visible Light Rays: 45% of the sun’s energy reaches the earth in what the eye perceives as colour. Blue Light waves are the most difficult to see. When the unprotected eye strains to focus on it, all other colours can be distorted. After two to three hours in bright sunlight, eyes can have trouble adjusting to night vision. The human eye is not able to identify the various elements of a ray – it only sees the results, which are a function of the different wavelengths and their respective light intensity. The human eye can only see wavelengths within the “visible spectrum” (between 380 and 780 nanometres).
380 NM
10 -13 NM
Gamma
X rays UV
IR
Micro waves
Radio
10 -13 NM
780NM
COMPLETE SPECTRUM
VISIBLE SPECTRUM
CONSEQUENCES OF VISIBLE U.V AND I.R RADIATION ON THE EYE
INVISIBLE SPECTRUM - U.V
VISIBLE SPECTRUM
INVISIBLE SPECTRUM - INFRARED
U.V.C
U.V.B
U.V.A
INDIGO PURPLE BLUE GREEN YELLOW ORANGE RED
NEAR INFRARED
MIDDLE INFRARED
RADIATIONS UVC 100nm to 280nm UVB 280nm to 315nm UVA 315nm to 380nm Blue light 380 to 780nm Visible light 380nm to 780nm Near IR 780nm to 1400nm Middle IR 1400nm to 2000nm
ORGANS AFFECTED Cornea
LENS LESIONS Lesions of the Cornea Premature Aging of the Lens
CONCEQUENCES ON SIGHT Conjunctivitis / Partial Blindness Cataract / Conjunctivitis / Partial Blindness Cataract / Conjunctivitis / Partial Blindness Partial or Total Blindness Visual Complaints / Uneven Perception Pigmentary Retinitis / Cataract / Blindness Cataract / Partial Blindness
Cornea and Lens Cornea and Lens Retina Retina Lens and Retina Lens
Degeneration of the Retina Photoreceivers Photo Traumatism in the Case of Intense Glare Macular Degeneration Lens Opacification
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