RGP and astigmatism

Question 1

a patient with SUBJ of Plano -2.00 x 180 and Ks of 42.50@180/46.00 @ 090 OD is fit with a spherical RGP. What is the magnitude of the cylinder power expected on the over refraction?

Answer 1

-1.50

Question 2

who can get spherical RGPs

Answer 2

no corneal astigmatism or corneal astigmatism <2.50D

Question 3

who can get back surface toric RGPs

Answer 3

corneal cyl >2.50D and spec cyl=1.5 x corneal cyl

Question 4

who can get front surface toric RGPs

Answer 4

lenticular and corneal astigmatism < 2.50D

Question 5

who can get bitoric RGPs

Answer 5

corneal cyl >2.50D and spec cyl does not equal 1.5 x corneal cyl

Question 6

topo pattern for WTR

Answer 6

figure 8 of steepness

Question 7

NaFL of WTR with a spherical RGP

Answer 7

dumbell shape of touch (or figure 8 of staining)

Question 8

topo pattern of ATR

Answer 8

dumbbell shape of steepness

Question 9

NaFL of ATR with a spherical RGP

Answer 9

figure 8 of touch (or dumbbell of staining)

Question 10

flexure

Answer 10

only occurs on the eye

controlled by increasing the thickness, decrease the Dk, flattening the lens

Question 11

SCLs and flexure

Answer 11

they demonstrate complete flexure on the eye

Question 12

piggy back lens staining

Answer 12

the fit can be evaluated with high molecular weight NaFL that will not stain the soft lens portion of these lenses