Glasses – are frames bearing lenses worn in front of the eyes, normally for vision correction or eye protection.

• Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation.
• Sunglasses allow better vision in bright daylight, and may protect against damage from high levels of ultraviolet light.
• viewing visual information (such as stereoscopy)
• just for aesthetic or fashion values.

The inventor of the first spectacle lenses is unknown. Roman tragedian Seneca (4 BC -65AD) is said to have used a glass globe of water as a magnifier to read ”all the books of Rome”. The 13th century Venetians glass blowers are known to have produced reading stones made of solid glass that was put into hand-held, single lens-type frames made of horn or wood.

Most historians believe that the first form of eyeglasses was produced in Italy by monks or craftsmen in Pisa (or perhaps Venice) around 1285-1289. These magnifying lenses for reading were shaped like two small magnifying glasses and set into bone, metal, or leather mountings that could be balanced on the bridge of nose.

Bifocal glasses – In 1784, Ben Franklin developed bifocal glasses. He was getting old and was having trouble seeing both up-close and at a distance. Getting tired of switching between two types of glasses, he devised a way to have both types of lenses fit into the frame. The distance lens was placed at the top and the the up-close lens was placed at the bottom.

• Contact lens (also known simply as a “contact”) is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye. The inventor of the first contact lens that could be worn on eyes was German ophthalmologist Adolf Gaston Eugen Fick. He constructed and fitted first contact lens in 1887.

• Smart Glasses Help the Blind Navigate – Assisted Vision, is developing a pair of glasses that collects visual information using sensors and relays it back to the wearer using OLED (Organic Light Emitting Diode) screens and headphones. The cameras collect subsequent images to determine whether objects are static or moving. While gyroscopic information indicates the movement of the user, which in-turn helps to distinguish between objects that appear to move because of the user’s movement and objects that are actually moving. At the same time, the headphones use text-to-speech software to provide spoken assistance, which can be used in conjunction with the GPS to dictate navigation instructions.

I can see clearly now
The story behind your glasses – Eva Timothy (video 4:37)
Corrective lenses are used to correct refractive errors of the eye by modifying the effective focal length of the lens in order to alleviate the effects of conditions such as nearsightedness (myopia), farsightedness (hyperopia) or astigmatism.

• Ask – What are refractive errors? How can there be corrected?
• Imagine – With curved glass lens
• Plan, Create – The power of a lens is generally measured in diopters. Glasses correcting for myopia will have negative diopter strengths, and glasses correcting for hypermetropia will have positive diopter strengths. Glasses correcting for astigmatism require two different strengths placed at right angles in the same lens.
• Improve

Do it
Now it is your turn. Here are some challenges for you to work on…

• suggest some useful vision improvements or enhancements that depend on technology. Does the technology exist? Can an existing technology be adapted for this use?
• find some curved glass or other material and determine how it could be used to assist in viewing objects and print.

Learn more…

• OrCam camera device (video 2:27) attaches to eyeglasses and is wired to a portable computer in the wearer’s pocket. Using bone conduction technology, it “speaks” text (menus, street signs, grocery labels, newspapers) as well as bus numbers and other objects that the user points to. It can even recognize faces and monitor traffic lights.

• How eSight’s Vision Aid System Works – Zoom, contrast, brightness, and color can all be controlled by the user to optimize sight for many situations. The controller even allows the user to freeze frame, which is perfect for reading or enjoying a view. The zoom feature allows for 1.5 – 14x zoom, giving the user the ability to focus on anything from a theatre stage to a book. Furthermore, the contrast dial and six custom color combinations allow the user to adjust their view to better distinguish objects and words.