Week 1.05 Soft CL Fitting Flashcards
1
Q
0.05mm difference in keratometry =
A
0.25D in power
2
Q
7.40 @ 20; 7.60 @ 110
How much corneal astigmatism
A
- 7.60 – 7.40 = 0.20 (larger number always flattest K)
- 0.20/0.50 = 4
- 4x0.25 = 1D corneal astigmatism
3
Q
How does TD affect lens fit if altered
A
Larger TD - less lens movement improved centration
Smaller TD - more lens movement improved centration
4
Q
How can you improve the fit of a loose fitting lens
A
Increase TD
Thinner lens
More flexible lens
Steeper BOZR to aid centration
5
Q
How to improve a tight fitting lens
A
Decrease TD - maintain corneal coverage however
Try thicker or less flexible lens to increase lid interaction
