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Question 1

what are possible errors in a prescription

Answer 1

out of date rx
rx with >+/- 4.00D with no BVD
options name/signature missing
one eye is in plus cyl form and other is in minus cyl form
prism BU on both eyes

Question 2

what is aniesekonia

Answer 2

significant difference in the perceived size of images

Question 3

what is aniesemetropiaa

Answer 3

significant difference in refractive error between the meridians in both eyes of more than 1.00D

Question 4

what are the types of anisometropia

Answer 4

1) simple - one eye is affected while the other eye has no rx- eye can b emyopic/hyperopic

2_ composite - Bothe eyes have rx although difference is over 2D which causes one eye to see blurrier image

3) mixed both eyes heavy etc
1 eye myopic+ 1 eye hyperopic

Question 5

what causes unwanted prismatic effects

Answer 5

• inappropriate position of the OCS leading to decentration
  -prismatic effect and relative prismatic effect between the 2 eyes

-vertical FR 2-4 Dip= amount of prim that can be placed before niocular vision breaks down and diplopia occurs.

vertical FR is small -so small amounts of unpresctivrrf relative vertical prism - cause asthenia/blurring/dip

• prismatic effects should be below 1 dip

Question 6

why is prismatic effect induced in bifocals

Answer 6

bif segment positioned I’m periphery

px will experience prismatic effect

px forced to look away from the oc to read

Question 7

why does a px experience diploma when reading and not in the distance with bif

Answer 7

• vertical differential prim not issue in SV lenses and px can move head to look through OC
  = NO PRISMATIC EFFECR

vertical differential proms considered in MF lenses where rex had to look away from oc of the lenses
as the NVP does not coincide with oc

Question 8

sol to anisemetropia

Answer 8

1)separate spex- correctly centred - inoncvienient
2) Franklin split bif distance portion+near potion in frame

3) different segment sizes - larger segment size is placed in front of more positive power lens
- uses round down curve set- larger set produces more BD

4) slab off done one one lease- more negative less
when minus lenses are slabbed off BD prism is removed
when positive lenses are slabbed off BU prism is offed

5) CL- NO PE

Question 9

anieskonia