Vision Skills Evaluation

Question 1

True or false: it is easy to determine from a patient’s symptoms whether their dysfunction is accommodative or vergence-related in nature.

Answer 1

False; most of the signs and symptoms of both types of dysfunctions are the same.

Question 2

The Convergence Insufficiency Symptom Survey is a list of 15 symptoms associated with CI. Each symptom is rated on a scale of 0 (never) to 4 (always). A score above _____ indicates symptomatic CI.

Answer 2

score above 16 indicates symptomatic CI

Question 3

True or false: evaluation of accommodation and vergence skills should always be done through appropriate refractive compensation.

Answer 3

True.

Question 4

The primary stimulus for vergence is?

Answer 4

Binocular retinal image disparity.

Question 5

Define: tonic vergence

Answer 5

The underlying level of vergence activity in the absence of a target

Question 6

Define: fusional vergence

Answer 6

The vergence that occurs in response to binocular target disparity; used to overcome phoric tendencies

Question 7

Define: accommodative vergence

Answer 7

The vergence that occurs in response to changes in accommodation

Question 8

Define: proximal vergence

Answer 8

The vergence that occurs due to a mental or psychological awareness of target nearness.

Question 9

What tests can be used to measure vergence posture?

Answer 9

Cover test, Von Graefe, Maddox rod

Question 10

What are the expected results for vergence posture at far and at near?

Answer 10

Far: 0-2 exo
Near: 0-7 exo

Question 11

What is considered a normal AC/A?

Answer 11

3-5^/D

Question 12

What tests or devices are used to measure associated phoria?

Answer 12

Saladin card, Sheedy disparometer, computerized chart systems at far

Question 13

In terms of diagnosing vergence anomalies, what does Sheard’s criterion say? For what kind of patients does it work best?

Answer 13

The blur point of the compensating vergence reserve should be at least twice the demand (i.e., a 9^ exo patient should have at least 18^ of PRV range). This works best for exo patients.

Question 14

In terms of diagnosing vergence anomalies, what does Percival’s criterion say? For what kind of patients does it work best?

Answer 14

The demand line should be in the middle third of the total vergence range (BO blur to BI blur). This works best for eso patients.

Question 15

The following are methods of measuring vergence amplitude:
NPC
Capobianco method
Prism vergence ranges

What are the minimum values for NPC?

Answer 15

Break at 8cm

Recovery at 11cm

Question 16

The following are methods of measuring vergence amplitude:
NPC
Capobianco method
Prism vergence ranges

Describe the Capobianco method.

Answer 16

This is a variation on NPC: record the break with a penlight or transilluminator without a red lens, then again with a red lens in front of one eye. A difference of more than 2cm indicates potential symptoms.

Question 17

What are the OEP minimum expected values for blur/break/recovery for near PRV?

Answer 17

15/21/15

Question 18

What are the OEP minimum expected values for blur/break/recovery for near NRV?

Answer 18

14/22/18

Question 19

What are the OEP minimum expected values for blur/break/recovery for far PRV?

Answer 19

7/19/10

Question 20

What are the OEP minimum expected values for blur/break/recovery for far NRV?

Answer 20

X/9/5

Question 21

What are the levels of sensory fusion, in binocularity?

Answer 21

Stereopsis (highest)
Superimposition/flat fusion
Simultaneous perception
None (lowest)

Question 22

Stereopsis can be tested with random dot tests and with lateral disparity tests. Which of these requires bifixation, and which of them can be appreciated even with a small angle strabismus?

Answer 22

Random dot (global stereo): requires bifixation
Lateral disparity (local stereo): can have small angle strabismus