Protect the eyes of children in this back to school season and in the mountains too from Zenni Optical ( also see Zenni Optical on TV!!!)
There are few risks or complications related to ophthalmic cold or altitude, as it remains “reasonable”. Indeed, stays in the mountains at an altitude less than 2000 or 2500 meters are well supported and do not trouble or eye damage, even if children enter the sea level
Beyond this altitude, hypoxia (lack of oxygen) may be responsible for retinal vascular lesions in the context of mountain sickness, but it is unusual that parents bring their young children to such an altitude.
Similarly, the cold has no bearing on the camera eye. You just need to remember that the hot metal conduit as the cold. We must be careful to frostbite, which can occur due to contact of metal glasses (or branches strapping glasses) with the skin.
In addition it is recommended in children, especially for sports sources falls, select resistant sunglasses not likely to break, either in glass or frames.
Subject to this caution, the risk of eye trauma is no more important in the mountains in other places, although anecdotal cases of accidents have been reported in specific activities performed in the mountains, as the mountain bike. But there is not specific advice to give, if it is to monitor the children, which is more difficult when it comes to (pre) adolescent …
UV exposure
This is not the case for UV exposure, including gray weather, combined with the reverb on the snow. This exposure to the “light” can cause severe complications and severe. They affect either the cornea and conjunctiva and are reversible, the retina and may be definitive.
Physical data
UV is the main enemy of the eyes of children and adults during the holidays in the mountains, but also to the sea, by definition, UV rays are not, and it is sometimes difficult to be aware of the presence of radiation, whether direct or reflected. There are three kinds of UV, UV A, UV-B and UV C. The atmosphere, especially the ozone layer, plays a protective role against UV. Latter stops all rays of very short wavelengths, including UV-C, and filter LUV B. But such filtering depends on the path of radiation through the atmosphere. Thus, the ray path is shorter when the sun is high in the sky when it is low on the horizon and is also shorter in height as the thickness of the atmosphere decreases with altitude. It is estimated that the UV index, which expresses the intensity of radiation liv and risk to the eyes and skin, increasing by about 10% when the altitude increases to 1,000 meters.
Most UV through the fog with little attenuation. The effect of clouds on the radiation intensity varies UV pass through clouds altitude without losing their physical properties, since the attenuation is only 5 to 10%, white clouds can even increase UV radiation because of the reverberation induced. The risk of burns related to UV is also important when the sun is obscured by a large sunny. The false sense of security given by a gray time is often the cause of accidents, especially when the cloud cover and / or fog diminishes the brightness and temperature, because then it seems unnecessary, if not ‘is disturbing, to put in tinted glasses.
The direct effects of radiation are increased by the radiation reflected. Snow returns 40 to 90% of UV radiation, rather than water (10 to 30%) or sand (25%). The danger associated with this indirect influence is much more important in the mountains and the seaside or during a boat trip.
There is debate about whether the blue light whose wavelength is similar to UV can also be harmful. Current data do not point to a possible toxicity of this portion of the spectrum of visible light. However, glasses générament decrease in the transmission.
Consequences eye
They are of several kinds. UV exposure can have adverse consequences in three main structures of the eye: the cornea, lens and retina. The deleterious effects of UV on the retina would be greater in children than in adults. This greater severity of the action of UV result of better transparency of the eye circles, which will not mitigate the intensity of radiation delivered. Moreover, the danger of UV radiation is more important for the eyes: the quantity of pigment in the iris stroma is lower than for the eyes and part of the radiation can pass through the iris to the retina. The iris is also very little pigmented in young children, who are therefore more vulnerable.
Keratitis or snow ophthalmia This keratitis, impressive for the patient, is the consequence of exposure of the eye at high UV intensities. This results in destruction and eration of cells of the corneal epithelium. This destruction of epithelial cells, which are not imme diately replaced, resulting in a few hours the formation of small “defects” or “holes”, highlighted in the corneal surface in blue light excitation after instillation of a drop of fluorescein. The intensity of clinical signs of superficial keratitis that is more or less severe.
The epithelial layer is highly innervated, the patient complained of pains associated with intense photophobia, watery eyes and a sometimes a blepharospasm. Visual acuity is also reduced due to the loss of transparency of the cornea and tearing. The conjunctiva is hyperhémiée. The keratitis heals normally within a few hours without any sequelae.
Lésion conjunctival cells of the conjunctival epithelium may also be affected by exposure to UV with a mechanism and pathogenetic consequences identical to those of the keratitis. The clinical signs are limited to a discomfort and a sensation of foreign body in the eye. ” Clinically, the patient has a marked conjunctival hyperemia. Again, the cure is obtained within hours.
UV Cataract, and mainly the UV, can cause or accelerate the onset of cataracts, first cortical, ie located at the periphery of the lens. Secondarily, these cataracts are complementary. Of course, there is no danger of developing a cataract in a child returning from a stay in the mountains due to excessive sun exposure, but the effects of UV on the lens are cumulative. Moreover, the risk of subsequent cataract occurrence is increased by the lengthening of life expectancy and the reduction of the ozone layer. Thus, the WHO points out that a decrease of 10% of the total ozone layer would be responsible for 1.7 million cataract per year worldwide.
Atteintes retinal light has a deleterious effect is also cumulative, on the retina. It has been shown that the risk of macular degeneration related to age is higher in populations exposed to strong lights. In subjects with genetic predisposition, high sun exposure may be the triggering factor for retinal degeneration, a hereditary pigmentary retinopathy or Stargardt disease.
Prevention
It is based primarily on the goggles adjusted. It is often difficult in the mountains to avoid exposing children to the sunny periods, since the days are shorter and the temperatures drop in the absence of sun can cause other problems. It is sometimes advisable to wear hats with wide visors, but this solution interesting in terms of eye protection, does not always dermatologists, since leaving out the ears and back of the neck.
Two points are clear in terms of protection glasses ( High Five to Zenni Optical ), one for frames and other quality filtration of glasses:
* The mounts must be adjusted in the face of the child, ie that for toutpetits, they must be to bridge the bottom to prevent slippage on the nose. They must not cause frostbite in cold weather and be resistant to shocks.
* The glasses must be unbreakable to avoid any accidents during falls, which occur not only skiing but sometimes toboggan or simply walking on a icy sidewalk.
The glasses should protect laterally to reduce the indirect radiation reflected frequent when there is snow. They should therefore be sufficiently broad and possibly a little rounded. European standards require manufacturers to have a CE mark indicating inter alia the amount of light blocked by the glass, with a scale ranging from O to 4, but this value does not, unfortunately, the percentage of UV or infrared arrested. We must look for glasses arresting at least 90% of UV-A and 95% of UV-B, which is theoretically always the case. In high mountain areas on the ice or snow, the protective index 4 should be strongly recommended, whereas the 3 may be sufficient on average mountain. Most sunglasses filter some of the radiation in the wavelengths of blue, which we discussed the possible deleterious effect on the eye. And about the price? you can check here $ 8 Rx eyeglasses .
