Management of Strab - Prism

Question 1

This type of prism completely eliminates vergence demand; Corrects for the entire deviation.

Answer 1

Corrective/Neutralizing Prism

Question 2

This type of prism is used to decrease vergence demand to help stabilize normal fusion.

Answer 2

Relieving prism

- not giving all of correcting prism, just enough

Question 3

This type of prism is used to treat ARC.

Answer 3

Overcorrecting Prism

Question 4

This uses the opposite needed prism to train increasing fusional vergence ablity. A type of passive therapy.

Answer 4

Inverse training prism

Question 5

This type of prism improves the cosmesis of strabismus.

Answer 5

Inverse cosmetic prism

• we want to displace image of the EYE to make them look better
• eye moves 1mm per 8pd

Question 6

In what 3 situations are yoked prisms used?

- ex. BO and BI

Answer 6

1. Non-comitant deviation
2. Nystagmus
3. VF loss

Question 7

Prims is Rx’d for pxs with ____ sensory fusion and _____ motor fusion.

Answer 7

normal sensory fusion

inadequate motor fusion

Question 8

What test is used for dissociated prism criteria to prescribe relieving prism?

Answer 8

ACT

Question 9

To determine the prism prescribed based on the dissociated measure, what does the percentage criteria state?

Answer 9

Give percentage of the total dissociated deviation

-ex: CT = 9pd, give 3pd

Question 10

If a px has an ET of 6-20pd, how much residual vergence should be left over?

Answer 10

4-6pd

Question 11

If a px has an XT of 20-30pd, how much residual vergence should be left over?

Answer 11

10-15pd

Question 12

If a px has a hyperdeviation of 3-10pd, how much residual vergence should be left over?

Answer 12

2-4pd

Question 13

If patient with 15Δ Esotropia, how much prism should you prescribe based on Carlosos?

Answer 13

9-11pd
15-6 = 9pd
15-4 = 11pd
**leave behind 4-6pd

Question 14

This is the amount of prism that gives a fusion response. What test do you check with?

Answer 14

• Fusion Prism

- W4D or stereo testing

Question 15

This is a small vergence error within Panum’s area.

Answer 15

Fixation disparity

Question 16

This is the amount of prism needed to eliminate fixation disparity

Answer 16

Associated phoria

Question 17

The patient must have what 2 things for corrective prism to work?

Answer 17

1. NC

2. normal peripheral sensory fusion

Question 18

What type of pxs do well with correction of associated phoria?

Answer 18

IXT or DIXT (distance intermittent exotrope)

Question 19

A positive prism adaptation test is suggestive of what type of correspondence?

Answer 19

AC