Economic, practical but harmful to the eyes. Glasses are low-cost readily available around at the stalls of street vendors.
We sought the opinion of Dr. Paolo Vinciguerra, head of Humanitas Centre of Ophthalmology.
Glasses low cost in what they differ from those of quality?
"These products are structured according to a correction simmetricadei two eyes and that's not good because in most cases the subjects have asymmetries that must be corrected ad hoc. Also, to give a comforting vision optical center nell'occhiale should fit in as much as possible to the center of the pupil, ie the distance between the two eyes must be individualized according to the characteristics of the person. In mass production, instead, it is calculated a distance between the two eyes average, around 62-63 mm. "
What risks can lead to vision lens wear low cost?
"Often those who buy cheaper lenses may be subject to headaches enausea caused by the poor quality of materials and deformation sometimes induced by these lenses. A part of the balance, in fact, is regulated from the visual: when you see evil, the brain gets a feeling "deformed" and you are susceptible to illnesses. The choice of lenses, therefore, is by no means be underestimated. Today lenses of good quality sonoantiriflesso. If the lens, besides not having the anti-reflection also has a refractive index not ideal, the focus is less than perfect. A patient, then, with the same visual defect, may perceive a difference in quality of light. To compensate for the defect the pupil dilates more and consequently the average quality of the optician worsens and the depth of focus is reduced. "
Even lenses for glasses solepossono be risky?
"They can even make color blind because some sun lenses low-cost not only stop excessive light but change colors. It's like if you become partially blind to certain colors. Sunglasses ideals should block all harmful radiation and pass only those that help us to see. Glasses of poor quality can also stop in those useful vision by reducing visual potential. "
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