Session 9 Flashcards
1
Q
What are the 3 lens categories?
A
Single vision
Segmented Bifocal
Progressive addition
1
Q
What is a single vision lens? 3
A
Contain rx for one distance.
distance, intermediate or reading
can be spherical or spherocylindrical
2
Q
What is a segmented multifocal? 2
A
contains more than one power located in distinct area of the lens with a clear line
3 categories - bifocal, trifocal, blended bifocal
3
Q
What is the most common bifocal?
A
Round seg - rseg22mm
flat top - dseg28mm
4
Q
How are trifocal heights written
A
7x28
7=Intermediate height
28=reading width
5
Q
What are occupational multifocals?
A
specialised segmented multifocals designed for specific use
6
Q
What are progressives? 3
A
For presbyopic px
lenses have no lines
progressively have more plus
