Costco (Hillsboro, OR 97124-5008)

• What is the material that sunglasses are made from?

  Sunglass frames are made from metal, plastic or beryllium. Metal frames, particularly expensive ones, are often made of mixtures of nickel and other metals such as silver. Plastic frames contain various materials, such as zyl,cellulose acetate propionate,nylon and castor oil. Beryllium, a steel-gray metal, is a lower-cost alternative to titanium eyewear.

• What is the doctor testing when he asks me to follow his finger with my eyes?

  In the eyes exam, doctors are may ask you to follow his finger in the process of Slow tracking, or ""pursuits"" in which the examiner's finger traces an imaginary "double-H", which touches upon the eight fields of gaze. These test the muscles of the eye, as well as the oblique muscles.

• Should I get bifocal glasses or two separate glasses?

  It is decided by your own preference. For bifocal glasses, you need time to get used to them, because they have two centers with the upper part to see the far distance, with the lower part to see the near distance. For two seperate general wear, you have to change between those two pairs, it is not so convenient.

• Can I wear sunglasses at night?

  You can wear sunglasses at night even it is hard to look clear at night. These following are 5 reasons for you to wear sunglasses at night. 1)Most people wear them to look cool and nonchalant; 2) Some of them wear to hide the emotions in your eyes; 3) to intimidate and to play a trick on someone 4) for health reasons; 5) to hide from paparazzi, especially for stars and celebrities.

• Will it make a big differentce when wearing glass glasses or plastic glasses?

  Glasses optical clarity is the best and as such glass lenses will have little to no distortion.Adding to that, it is the most scratch resistant optical material.However, glass will almost certainly shatter on impact. Plastic lenses are mainly made from polycarbonate and CR-39 plastic material. Polycarbonate is popular for lenses because of its high resistance to impact. polycarbonate lenses also have the highest distortion compared to any other material. CR-9 is another type of optical plastic. It has little distortion compared to polycarbonate. It is thinner and lighter than glass too.plastic being a lighter material makes plastic lenses much lighter than glass and therefore they are less likely to cause indentations. Source:http://www.differencebetween.net/object/difference-between-plastic-and-glass-lenses/

• Can the sea salt damage your eyes?

  Sea salt won't damage your eyes permanently. Just put sunscreen on your face skin before going out to sea, and wear a face mask over your sports goggles to prevent the splash of salty water from getting into your eyes.

• Can I go swimming with my contacts in?

  You'd better not.If your contacts fall into the water,I guess there is no way to find them out.

• Can I wear prescription sunglasses over prescription contact lenses?

  You'd better not, under this situationm the prescription will be added to a strong power which is relatively higher than that of your original power, thus to lead you to more serious vision problem. But it is OK to wear prescription sunglasses over non-prescription contacts or to wear non-prescription sunglasses over prescription contacts to add UV protection, fashion element and convenience.

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