Sunglasses do not too much curvature

Recently, the temperature gradually increased, 　more and more sun glare, sunglasses while going out to become one of essential goods. But faced with an array of sunglasses, a lot of people because I do not know how to choose. 23, the reporter interviewed the director of Changchun Municipal People's Hospital of Zhao-Hui Li, Minister Li said that good sunglasses are three criteria: UV blocking is much less visible light block, corneal curvature similar design.

Now sunglasses quality varies greatly,   many sunglasses block the light not only the paint quality problems, arc designed to be not science. Curvature of the lens is too large (close to spherical) or small (close to the plane) will affect the refractive index of the lens of the light, so that objects rugged, long-term wear makes the eyes tired, dry, damaged eyesight. In general, corneal curvature between the center and edge of about 10 to 15 degrees, so the curvature of the lens are the best within this range. Curvature of the lens to ensure no problems, coupled with the face to choose. 　Are advised to wear a short face frame to strengthen the next frame transparent type, long face down box for those who have strengthened glasses, square face, square lenses are suitable, pointed face is suitable for butterfly sunglasses