PRELIM QUIZ Flashcards
Inventor history of eyeglasses
(1216-1294)
Roger bacon
Salvino d’ Amarti (marco polo)
Greek
Chinese
Druids
Glass making
-it was a luxury and people could afford it.
-the first glass making manual from the Library of the ASSYRIAN KING “ASHURBANIPAL” (669-626 BC) DATES BACK AROUNG 650 BC
The discorvery of new technique
Around the end of the 1st century and was a revolutionary event in the history of glass making
Glass blowing
An amorphous substance made primarily of silica fused at high temperature with borates and phosphate
GLASS
Natural glass material
Obsidian
Fulgurite
Tektite
OPTICAL PROPERTIES
REFRACTIVE INDEX
ABBE VALUE
SPECIFIC GRAVITY
It is a ration of speed of light in a vacuum to its speed in a specific medium
REFRACTIVE INDEX
High refractive index
-thinner lens-more chromatic abbreviation -more reflection
-The degree to which a given lens material will dispense light
-chromatic abbreviation is inversely proportional to abbe value.
-ernst abbe
ABBE VALUE
It is a glass material made from lightning striking sand
FULGURITE
It is a glass material made from a METEORITIC impact on earth
Tektite
It is a glass material made from a METEORITIC impact on earth
Tektite
When a lens cannot bring all wavelength to a single point is called
Chromatic abbreviation
Abbe value named after
Ernst abbe
What is a refractive index of crown glass
1.523
What is the refractive index of dense barium?
1.616
What does pmma stand for?
Polymethyl Methacrylate
PMMA ALSO KNOWN AS?
LUCITE, PLEXIGLAS AND PERSPEX
It is the most common ophthalmic lens material
CR-39
It has high impact resistance with an index refraction of 1.586 or 1.59
Polycarbonate
What movement is observed when looking through a cylinder lens
Scissors
What movement is observed when looking through a convex lens
Against
What movement is observed when looking through a convex lens
Against
It is a type of lens that has a D-style design on the lower part of the lens
FLAT TOP
A lens type with round segment on the lower part
Krptok
Who first designated the bifocal lenses
Benjamin Franklin
