Session 8 Flashcards
1
Q
What is sagittal depth (sag)?
A
The height or depth of a given segment of a circle.
Distance between apex and chord diameter.
2
Q
Practice 5 examples of the sag formula for Front and back surface
A
3
Q
Look at diagram PAGE 263 SOD for ET + CT forumla’s etc
A
4
Q
CT-ET=S1-S2
CT=S1-S2+ET
ET=CT+S2-S1
A
5
Q
What is relationship between CT + ET in a convex lens?
A
Centre thickness is more then Edge thickness
6
Q
What is relationship between CT + ET in a concave lens?
A
Centre thickness is less than ET
