Table 1.
Eye tissue | Wavelengths absorption | Percentage of blue light passing through the eye structure | Potential mechanisms | References |
---|---|---|---|---|
Ocular surface (tear film, corneal epithelial tissue, conjunctival tissue) | Ultraviolet B (< 295 nm) | Transmits all wavelengths ≥ 295 nm |
Ocular surface inflammation Oxidative stress damage Cell apoptosis |
[4, 5, 36–39] |
Lens |
Ultraviolet A and B (295 to –390 nm and a part of the near infrared wavelengths In young adults; peak of absorption around 365 nm At 60 or 70 years old; peak of absorption around 400 nm |
In young children, around 80–90% of blue light at 450 nm passes through the lens At about 25 years old, 20% of the light between 400 and 460 nm and 50% of wavelengths between 400 and 500 nm are transmitted to the retina; In the elderly, the transmission of blue light to the retina is notably reduced due to the yellowing of the lens absorbing most of the blue light |
Photobiological damage Oxidative stress Cell apoptosis |
[4, 41–43, 48] |
Retina |
Visible (380–780 nm) Near infra-red (780–1400 nm) |
Photomechanical damage, caused by high irradiance and short exposure independently of the wavelength of light (e.g., therapeutic laser with YAG for iridotomy and capsulotomy); photothermal damage, caused by long exposure (e.g., therapeutic laser photocoagulation); photochemical damage, caused by incident radiation with wavelength in the high-energy portion of the visible spectrum, mainly blue light; Increase in ROS production (loss of photoreceptors, lipid peroxidation, and cell apoptosis); Activation of inflammatory reactions, DNA damage, inhibition of mitochondria, and lysosome function |
[51] [52] |
DNA deoxyribonucleic acid, LED light emitting diodes, nm nanometer, ROS reactive oxygen species