toric fitting and aftercare

Question 1

PX:
RE 7.75 along 90 and 8.00 along 180
LE 7.80 along 90 and 7.80 along 180

What is the astigmatism in both eyes and is it WTR or ATR?

Answer 1

RE = WTR astigmatism of 1.25D
LE = no ast

Question 2

If there is lenticular astigmatism, which is the best lens option?

Answer 2

toric SCL or front surface RCL

Question 3

what is a disadvantage of a front surface RCL?

Answer 3

poor stability

Question 4

what are the 3 different toric lens designs or RCLs?

Answer 4

front surface toric
back toric
bi-toric

Question 5

what are the 2 diff scl toric designs?

Answer 5

prism ballast
dynamic stabilisation

Question 6

what are the diff types of prism ballast?

Answer 6

traditional
peri-ballast
reverse prism

Question 7

what are the 2 diff types of dynamic stabilisation?

Answer 7

dual thin zone
acceleration stabilisation

Question 8

what are the 2 most important things in H&S in toric aftercare?

Answer 8

• address stability of vision with your patients
• how does it compare to specs

Question 9

which type of RCL is useful in residual astigmatism?

Answer 9

front surface toric

Question 10

what is the most important part of assessment of toric fit?

Answer 10

stability of lens

Question 11

what are some signs of unstable rotation?

Answer 11

vision fluctuation and increased lens awareness

Question 12

What does LARS stand for?

Answer 12

L- left
A - add
R - right
S - subtract

Question 13

what is different about a toric over refraction

Answer 13

normal o/r, when changing power of cyl, adjust in steps available for the fitted lens
check vision with specs to compare acuities

Question 14

why is the keratometry/prescription relationship less important in soft toric lenses?

Answer 14

these drape over the cornea

Question 15

how does dual thin zone work?

Answer 15

double slab off
thinner areas fit under the lids

Question 16

what manufacturer uses dual thin zone stabilisation technique?

Answer 16

Alcon dailies toric

Question 17

how does accelerated stabilisation work?

Answer 17

4 active zones with a thicker profile in the mid-periphery wihch minimise lens rotation
thinnest portion rest under lids

Question 18

which manufacturer uses accelerated stabilisation?

Answer 18

J&J

Question 19

how long do you need to wait for the lens to be stable?

Answer 19

5 mins (byki)

Question 20

if the lens is stable after 5 mins what do you do?

Answer 20

order with any axis compensation if neede

Question 21

if the lens is unstable after 5 mins what do you do?

Answer 21

fit diff type of lens - unlikely to improve with time

Question 22

if there is a rotation of aroud 5 degrees - what could this indicate and what would you do to fix it?

Answer 22

LOOSE LENS - use a steeper BOZR
(clinical pearl from byki)