Answers
What is a plastic frame example? - answer Zylonite
Zylonite (plastic) - answer Zyl, highly flammable, most commonly used plastic,
inexpensive, not hypoallergenic, brittle with age, they come in many colors, harder to
make a vertex adjustment
Half eye glasses - answer These are for people who need help with a reading
correction but no correction for distance.
Rimless mountings - answer These glasses frame hold the lenses in place only at
their nasal edge.
Optyl (plastic) - answer Inexpensive, easily adjusted, hypoallergenic, brittle with age,
slightly higher in cost, can't adjust nosepad, harder to make a vertex adjustment
Nickel (metal) - answer Inexpensive, easily adjusted, not hypoallergenic,weight,react
with sweat, turning people's frames and their skin green where the frame touches the
face
Titanium (metal) - answer very lightweight, most hypoallergenic material, expensive
Memory metal - answer most flexible, durable, lightweight, expensive, not easily
adjustable
Nylon - answer highly flexible, brittle with age,
Polyamide/copolyamide - answer nylon based material, hypoallergenic,
Grilamid - answer nylon based, usually used for sports and performances, wide
amount of color variety,
Carbon fiber - answer carbon fiber and nylon, can be made thinner,
Polycarbonate - answer used for elastic sports glasses, impact-resistant
Kevlar - answer mixed with nylon, strong and lightweight,
Rubber - answer nylon and rubber
frame front - answer chassis
, Measuring Frames - answer •The eyesize.
•The bridge size.
•The temple length
1 mm = - answer .039 inches
Pupillary Distance - answer distance between the centers of a person's pupils in
millimeters
distance PD - answer the distance between the pupil centers when the person is
looking in the distance
near PD - answer which is the pupil distance when the person is looking close up
Bifocals - answer Little segments placed toward the bottom of the lenses
What do lenses do? - answer They bring an image to a single point of focus at a
desired distance away from the lens.
When does Refraction occur? - answer refraction occurs when images pass through
a material of one index of refraction and into a material of a different index of refraction .
Refracting power - answer how much lens that will refract an image
what are the three ways of changing the refracting - answer 1. Greater the difference
of index in refraction
2. Thicker the lens the greater the refracting ability
3. Changing the curvature
Units of diopters - answer power of lenses
F=1/d - answer F is the power of the lens (diopters) small d means focal point
plus power - answer these lenses bring images to a focus behind the lens
negative power - answer this lens has a focal point in front of the lens and causes
light to disperse instead of come together as it passes through the lens
single vision lens - answer The entire lens is set with one power or focal point.
Trifocal - answer Three distinctive powers: distance reading and intermediate tasks.
Prescribed to people over 40.