Test Review 5 Flashcards
What two design changes might be helpful in centering a high riding myopic lens?
Hyperflange lenticular
Prism ballast
Rigid gas permeable lens flexure may be eliminated by:
a) Reducing sagittal vaulting
b) Increasing center thickness
c) Choosing a lower Dk material
d) All of the above
d) all of the above
A low riding high plus lens on a 40.00 @ 180 / 40.75 @ 90 cornea could be corrected with:
A myoflange lenticular
Mike, a welder whose Rx is -6.00 +2.00 x 180, has been advised to trade his PMMA lenses of 20 years for a
modality that allows more oxygen to the cornea. The first lens of choice would be:
a) Soft spherical lens
b) Low to mid Dk RGP
c) High Dk RGP
d) Aspheric lens
b) Low to mid Dk RGP
A technique for correcting a high riding rigid minus lens may be to use a
Prism ballasted lens
To increase tear exchange with a rigid gas permeable lens, all of the following should be attempted
Reduce the overall lens diameter
Flatten the peripheral curves
Decrease the optic zone
Which of the following polishing compounds should not be used with gas permeable lenses?
Silvo
It contains ammonia
To correct a flat fitting rigid gas permeable lens, you should:
Enlarge the optical zone
After building up her wearing time, Jennifer returned for an afternoon recheck after eight hours of lens wear.
The lenses moved <0.5 mm and her complaints were minimal, except for late afternoon burning. Which would you
suspect?
Tight lens
Which of the following will not increase the movement of a tight fitting rigid gas permeable lens
a) Enlarge the posterior optic zone
b) Decrease the posterior optic zone
c) Decrease the sagittal vaulting
d) None of the above
a) Enlarge the posterior optic zone
The average refractive power of the cornea is about
+43.00d
concave surface is read at aerial image warpage and toricity recorded at this
image
Radiuscope
In keratometer the lower right area is the
true image
Average reading between … D
42.00D and 45.00D
edge standoff means
lens too flat
