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Eye to summer! 01 October, 2015 - Comments (0)

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To give value to the hours spent in open air and safeguard eyes' health, it is fundamental to protect them against sunlight with sunglasses: those should not necessarily be trendy. It is necessary, instead, that frame fits our face, and ,above all, that solar filters are high quality.

Sunglasses protect from dangerous solar radiation and lessen the light that enters into the eye . Sunglasses with filters or high quality filter lenses are the best way to protect eyes from damages induced by sunlight .To be high quality they have to eliminate UV rays, reduce in a significant way transmission of IR rays ,reduce intensity of visible radiation and not alter the chromatic balance of visual perception.Classification of protective solar filters and, indeed of sunglasses, consider the level of protection and use. The standard EN 1836/1997 consider five classes, called protection categories ,that are estalished depending on the quantity of light that the filter allows ( transmittance) : the higher the number is , the more the filter absorbs the light radiation .

The use of sunglasses with high quality filters is of fundamental importance during holidays (the sand on the beach or the snow on ski runs) transmit high doses of UV rays and blue light towards the eye; but it is also appropriated for the city, and it is a good rule to wear them also when the sky is not so bright. If filters are of high quality, they protect against damages and safeguard the skin around the eye against premature aging, contributing in delaying wrinkles development. If filters are of low quality, they are not only useless, but also damaging because they facilitate a major pupil opening (mydriases) and, as a consequence, an increase of passage of blue and UV radiations.

In case of sun, the most risky category is those of children, in which protective action of crystalline isn't effective yet nei quali A part of their parents undervalues prolonged sunlight exposure, and do not provide their children with adequate sunglasses. The purchase of high quality glasses is indeed the starting point for a correct visual prevention; if opportunely adapted to the size of child's face, they will not bother him and they will guarantee safety and protection when exposed to the sun. Children's eyes are sensitive and delicate and so it is a lot more important to protect them with high quality sunglasses.

Through: ProfessionalOptometry

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China: 90% of popoluation is shortsighted 29 September, 2015 - Comments (1)

cina e miopia

In Eastern countries, difficulty of far seeing is spreading in exponential way.It is not about a circumscribed epidemy, even if in Asia is more serious: in West incidency on new generations has doubled ( and it is not in decrease amongs adults). Research has located the causes of this defect , infact today it is not only possible to cure it, but also to prevent it.

Far east – Shangai, Singapore, Hong Kong and Korea – it is on the top of evaluations of the education systems in 65 countries carried out by Pisa- ocse program . the extraordinary school results of asian children are not due to particular characterics of educational system, there are other reasons. Pushed by the pressure of excelleance , kids from East Asia spend on books until 14 hours per day, agains 5-6 of westers students.The result? The shortsightdeness wave indeed. Sixty years ago, shortsighted

Even if it is not so dramatic, also in West it is registered a growth of young shortsighted , both in USA and in Europe.In the 70s of past century , 25% of Usa population was shortsighted , nowadays it is 40% . italy does not make an exception : 40 years ago 13% of Italians under 30 years of age was shortsighted , nowadays 25-30% : fifteen millions of italians.

A decade of years ago two australian eye doctors , Katryn Rose from University of Sidney and Ian Morgan from University of Camberra, selected 2.367 twelve years old students from Sidney: they made them eye examinations and a test about daily activites , neglecting time spend on books. The lowest rate of shortsightedness was linked to the major number f hours spent in fresh air , while the highest rate has been founded amongst the kids who spent less time out of their homes. The study was published in 2008 on scientific magazine Ophtalmology and, from that time, all the consecutives kept on confirming that, the major is the duration of the stay at open air, minor is the risk of developing shortsightedness. Therefore, light has a protective effect against shortsightedness. But, how much is it needed?

Unit of measurement of brightness is lux that is equivalent to the brightness of a candle at a distance of 3 meters. Morgan calculates that, to protect them against shortsightedness , children have to stay in open air about 3 hours per days, exposed to a brightness of 10thousand luxes , measured at the shadow of a tree in a summer day when sun is brilliant, wearing dark glasses.

What if we cannot cure kids shortsightedness in time? During adolescence, to reduce the evolution of the defect, it is possible to wear rigid glasses for orthokeratology: we can wear them at night and they modify the bending of cornea by reducing daily shortsightedness. After 25 years of age, refractive surgery can be used to definitely correct the defect . Serious difficulties can be infections, corneal ulcers, increasing of intra-ocular pressure and glaucoma. For these therapies, nevertheless, long term results are still not known. It is better to prevent.