How the type of lighting affects the view
The human eye is an organ sensitive to external factors such as light, whether natural (solar) or artificial. Specifically, it is on the retina where light can have the most harmful effects. And it is that in this membrane there are two types of very delicate receptors: rods (susceptible to the intensity of light) and cones (responsible for color vision). Damage occurs mainly from exposure to intense light received in a short period of time and from continuous exposure to moderate light intensity. This article explains what are the main risks of light in the vision, how they affect different lighting systems, and what effects the screens have.
The risks of light in the vision
The main risks that light produces on vision are of three types, according to the website of the Advanced Ophthalmology Area of Dr. Carlos Vergés:
Structural: they are caused mainly by laser radiation.
Thermal: caused by brief exposures that increase the temperature of the ocular tissue from 10ºC to 20ºC above room temperature.
Photochemical: they occur after a longer exposure time and low intensity and are associated with some retinopathies related to sun exposure generated by activities in very bright environments such as skiing, sailing, or flying airplanes.
Light has also been associated with other physiological aspects, not just visual, such as the circadian rhythm. The human being has a biological cycle that repeats approximately every 24 hours (circadian rhythms) and that is closely linked with the brain's internal clock. It is therefore decisive in the sleep/wake cycle. In different studies, it has been shown that exposure to light at night, and especially if it is rich in blues, decreases or eliminates the secretion of melatonin, the hormone responsible for regulating the sleep/wake cycle and basic in the immune system.
Light bulbs, fluorescent, halogen ... Lighting systems have evolved significantly over the years. Each of them, with its advantages and disadvantages.
Inexpensive fluorescents, with warm light, are not very effective from a visible light point of view. The halogen lights, with a whiter light, it is considered that can emit more ultraviolet light radiation old bulbs. Energy-saving lamps, while they consume less and last longer, may contain mercury, are larger, and the light is not as warm.
What about LED systems? This white light source, increasingly used for its low consumption and high efficiency, provides, in addition to greater durability, some drawbacks. According to this specialist, the main problem with this type of lighting is the high intensity and more proportion of blue light. LED light causes glare, if there is overexposure, you look directly at the light stimulus or if it comes closer than 20 centimeters.
Children, people with problems or alterations in the retina such as macular degeneration, and people exposed to this type of lighting such as electrical installers are very sensitive to blue light. However, for the Federation of National Associations of Manufacturers of Luminous and Electrotechnical Equipment of the European Union (CELMA), LED lighting complies with current European regulations and correct use does not pose a particular risk to health.
Tired eyes: are glasses with a blue light protective screen necessary?
The eyestrain, or asthenopia, is the answer to a prolonged muscular effort. It is caused by the use of electronic books and computers and even by reading for many hours on paper.
The main signs of eye fatigue are stinging, redness, tearing, and increased sensitivity to light or wind. Visual disturbances such as blurred vision or seeing spots can also occur, as well as problems such as dizziness, headache, or neck pain.
In most cases, these symptoms appear as a result of inappropriate habits, such as maintaining a bad posture in front of the computer, exceeding the hours of use, having poor lighting, or the presence of too many reflections on the screen. They can also arise after doing activities that require a lot of concentration, such as sewing or drawing. The experts from the optician's colleges speak of problems, not of diseases, as long as they are corroborated by reviews that rule out other ophthalmological alterations. The American Academy of Ophthalmology, admits that the signs of visual fatigue are exacerbated when there is a lack of sleep.
The Spanish Society of Ophthalmology recognizes that there is no scientific evidence to show that the blue light emitted by screens damages the eye. Therefore, it maintains that the use of blue light shields cannot be widely recommended to avoid harm not demonstrated in real-world conditions and in humans by devices, such as computers or tablets. These are therefore not harmful to the eye; Yes they are, on the contrary, habits.
To help prevent symptoms, it is important to have good lighting; avoid reflections on the screen; look away from the screen every 20 minutes or so and focus at a distance of about twenty feet; position yourself well in front of the computer screen; force blink; and avoid very dry environments.
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