W7 Unwanted HORIZONTAL Prism

Question 1

when the horizontal factors of between the two eyes cause images to be seen on different planes. If the OC distance is different than the patient’s desired PD the pair has horizontal imbalance.

Answer 1

Unwanted horizontal imbalance

Question 2

how will you know if the pair has unwanted horizontal prism

Answer 2

When measuring the PD, if the PD is different than the requested PD the pair has unwanted horizontal prism.

Question 3

Measure the PD on the glasses and compare it to the patient’s requested PD.

Perform the prism test if the difference is greater than 2.5mm.

Induce 0.33^ of prism in each eye by moving in the direction of the wearer’s PD.

Measure the distance between the new spots (where the total 0.67^ of prism was induced).

Answer 3

How to measure Unwanted horizontal prism

Question 4

can be used to describe any visual discomfort experienced by the wearer?

Answer 4

Asthenopia

Question 5

When inducing 0.33^ tolerance in each lens for horizontal prism

Answer 5

If wearer’s Pd is ;larger than the glasses pd induce prism so that the lens is moved toward the temple. If thewearer’s PD is smaller than the glasses PD induce prism so that the lens is moved toward the nasal