BV

Question 1

How many Dioptres is 1mm of Hirschbirg reflex?

Answer 1

22

Question 2

What nerves innervate the ocular muscles?

Answer 2

lateral rectus= 6th nerve, superior oblique= 4th nerve, all other= 3rd nerve

Question 3

What is the muscle sequelue, what law does it follow and what time scale?

Answer 3

Primary underaction- muscle palsy- from the onset
Overaction of contralateral synergist - Hering’s law (equal innervation)- from the onset
Overaction of ipsilateral antagonist- Sherrington’s law (reciprocal innervation)- after a few months
Secondary underaction of contralateral antagonist- Hering’s and Sherrington’s law- after a few months

Question 4

What does Park’s 3 step aim to identify?

Answer 4

paralytic muscle in vertical/oblique deviations?

Question 5

How to interpret Park’s 3 step results?

Answer 5

1. Identify which eye is hyper deviated in primary gaze
2. Identify if deviation greater in right or left gaze
3. Identify id deviation greater with right or left head tilt

Highlight suspected underacting muscles and the one it points to is the palsied muscle

Question 6

What is the minimum amplitude of accommodation for a px?

Answer 6

15- (1/4 of px age)

Question 7

What is the norm for NPC?

Answer 7

break 2.5cm +- 2.5 (anything below 10cm is okay)

Question 8

What is the norm for distance heterophoria?

Answer 8

1 xop +- 2

Question 9

What is the norm for near heterophoria?

Answer 9

3 xop +-3

Question 10

What is the norm for vertical heterophoria?

Answer 10

ortho

Question 11

What is the tolerated vertical prism?

Answer 11

2

Question 12

What are the norms for distance fusional reserves?

Answer 12

BO break of 19pd, BI break of 7pd