### device | lens | convex lens:

Sunglass
* All sunglasses absorb UV more strongly than visible light
  - protect eyes from the sun's ultraviolet rays
* Many sunglasses have frames and arms made of wire, as opposed to plastic.
* Most sunglasses allow some direct sunlight to enter from the top and sides of the frame.
* Some sunglasses have labels stating the degree of UV protection they provide.
* also can contribute to comfort as well as safety
  - protect the delicate skin around the eyes
* are a kind of eyeglasses that keep too much sunlight from getting in people 's eyes
  - also helpful when out in the sun all day
  - essential when walking over snow or on hot, exposed slopes
  - essentials especially when driving
  - helpful in protecting against the sun's damaging rays
  - important for protection as well
* are located in bags
  - cars
  - drugstores
  - purses
  - often more extravagant and expressive in their appearance than normal glasses
  - sold for each and every age groups and come in array of colors, shape and design
  - spectacles
  - the norm even at night
  - to be worn indoors only if prescribed by a physician or required for the job
  - used for protection
  - useful to prevent eyestrain from glare and to minimize ultraviolet light exposure
* block ultraviolet radiation.
* can also be tremendously useful as safety devices
  - help prevent some direct damage to the eye from light
  - prevent exposure to potentially damaging rays
  - filter out UV light, reducing exposure to harmful UV radiation
* can help decrease the risk of cataracts
  - on bright days
  - reduce the risk of cataracts
* come in all different sizes, colors, and prices.
* convex lens
* generally have stickers that identify what rays they block out.
* help protect the eyes from glare off the river surfaces
  - the eyes adapt to bright conditions
  - to reduce the bright winter sun's effects
  - ward off too much sunlight, as well as dust and insects
* offer little protection while snowboarding
  - the best eye protection from UV light, better than visor hats or parasols
* protect children's eyes from the UV rays and decrease the risk of cataracts in adulthood.
  - tender skin around the eyes and reduce the risk of developing cataracts
* provide eyes welcome protection from the sun year round.
+ Eyeglasses: Eye :: Optics

### device | lens | convex lens | sunglass:

Polarized sunglass
* are very helpful in distinguishing water colors.
* help reduce glare.
* stop photons swinging up and down from passing.
+ Photon, Properties: Basic physics ideas :: Electromagnetism :: Light :: Elementary particles
  * The last usable property of a photon is its polarity. If you saw a giant photon coming straight at you, it could appear as a swath whipping vertically, horizontally, or somewhere in between. Polarized sunglasses stop photons swinging up and down from passing. This is how they reduce glare as light bouncing off of surfaces tend to fly that way.

### device | lens:

Eyeglass
* are a multi billion dollar a year industry in the United States alone
  - an example of calm technology
  - corrective lenses set in frames, compensating for focussing problems of the eye
  - really just another type of lens
* are the easiest and safest method of correction
  - traditional choice for correcting the majority of refractive errors
  - usually good enough for eye protection
* can make a person look more mature as well as more intelligent and successful.
* have many models.
* made of titanium are lightweight and durable and often hypo-allergenic.
* offer minimal protection from blowing dust or sand, but airtight goggles are better.
* usually have to be replaced once a year or so.
  * have many models. So it may be worn for fashion. The glasses are not intended such as shielding and correction of vision, which are functions of the glasses. Generally, such glasses are cheap.