SPECTACLE MAGNIFICATION AND FIELD OF VIEW IN DISPENSING Flashcards
1
Q
What are the 5 types of magnification?
A
Angular, maximum. linear, nominal, spectacle
2
Q
What is aniseikonia?
A
an ocular condition where there is
a significant difference in retinal image sizes
3
Q
If we increase the vertex distance of a plus lens what happens to the angular field of view?
A
It reduces
4
Q
If we increase the vertex distance of a minus lens what happens to the angular field of view?
A
It increases
5
Q
What is ring scotoma?
A
A ‘jack-in-the-box’ effect where objects viewed in the periphery will disappear as they enter this ring scotoma and then seem to suddenly reappear as they exit the scotoma.
6
Q
What can eliminate a ring scotoma?
A
An aspheric lens or blended lenticular could eliminate the ring scotoma
7
Q
What is another name for colour fringing?
A
Chromatic aberration
