4.1.1 Anisometripa

Question 1

What are the vertical and horizontal tolerances

Answer 1

Vertical
- 1 prism diopter differentia; prismatic effect biinocularly

Horizontal
- up to 10 diopters out and 4 diopters in for Distance
- up to 7 diopters out and 7 in for near

Question 2

How to calculate differential prism

Answer 2

P = cF

Question 3

Why to take mono PDs in these patients

Answer 3

• can induce horizontal prism imbalance
• may induce head turn

Question 4

General solutions to anisometriopia

Answer 4

• 2 pairs of specs, different centrations
• head position, for NV drop head to look through distance OCs
• drop specs down nose to look through distance OCs
• slab off, removing base down in more negative eye, line coincides with lower limbus
  
  • minimum slab off 2 diopters
• prism controlled, segment on a prism segment blank is depressed from the back surface of the distance portion
• contact lenses