4.1.5 Dispensing Multiple Lens Forms Flashcards
1
Q
Fitting requirements for under 4
A
- make sure ear points aren’t sticking out
- dropped side should be long to keep frame hooked in place but not excessive
- if px looking through the centre of the frame then heights not always required as low risk of differential prism
2
Q
Do children need AR coating
A
- can become scratched easily
- parent may want coating
- children don’t need them
3
Q
Most important aspects to frame selection for under 4
A
- make sure lenses sit in front of eyes as centrally as possible
- should be comfortable and stable
4
Q
What frame measurements to consider for under 4
A
- crest height
- splay angle
- frontal angle
- bridge projection
- head width
- angle of side
- LTB
- Vertex distance
5
Q
Materials for under 4 frames
A
- cellulose acetate
- silicone rubber
6
Q
Varifocal advantages and disadvantages
A
Advantages
- clear vision at all distances
- more convenient
- cosmetically look like SV
- no image jumps
- no accommodation fluctuation
Disadvantages
- distortions in the periphery
- Smaller NV area
- narrow intermediate area
- adaptation period
- cost
7
Q
What is a hard design
A
- large distance area, narrow intermediate, wider reading
- aberrational astigmatism confined to nasal and temporal areas
- distance virtually aberration free
- good for prev bifocal wearers
8
Q
What is a soft design lens
A
- distortion extends to distance portions
- px has to move head more
- larger intermediate zone
- narrower reading
- good fit for first time presbyopia
9
Q
What is a soft design lens
A
- distortion extends to distance portions
- px has to move head more
- larger intermediate zone
- narrower reading
- good fit for first time presbyopia
