Monofixation Syndrome

Question 1

To identify an amblyogenic factor, what 2 things are we looking at?

Answer 1

1. Ocular alignment

2. Refractive Error

Question 2

A patient with amblyopia will have the worst VA on what type of chart?

Answer 2

Full chart

Question 3

What 4 specific tests are performed on amblypic patients?

Answer 3

1. VA
2. Fixation (CF vs. EF)
3. Accom (Amps)
4. Saccades (NSUCO)

Question 4

If the patient has EF, under monocular conditions what portion does the patient use to fixate an object?

Answer 4

non-foveal point

Question 5

Eccentric fixation is a _______ (monocular/binocular) phenomenon.

Answer 5

Monocular

Question 6

When a patient has both eyes open, are they using their EF point?

Answer 6

No

Question 7

This is the reference used to compare all visual directions while monocular; oculocentric

Answer 7

Principle visual direction

Question 8

This is the value that each PR has that is proportionoal to the distance from the fovea.

Answer 8

Retinomotor Value

Question 9

Normally, the fovea has what retinomotor value?

Answer 9

0

Question 10

In central fixation, the ZRMV and PVD are associated with the ____.

Answer 10

• fovea

Zero retinomotor value, Principal Visual Direction

Question 11

In eccentric fixation, the ZRMV and PVD are associated with the ____.

Answer 11

• EF location/spot

- called eccentric localization

Question 12

In eccentric viewing, the ZRMV is associated with ____ and the PVD is associated with ____.

Answer 12

ZRMV = EF location
PVD = fovea
- no eccentric localization is present

Question 13

Eccentric fixation is most often associated with what type of amblyopia? what %?

Answer 13

• strabismic amblyopia (60-80%)

Question 14

How is eccentric fixation described?

Answer 14

1. Which Eye
2. Direction (which part of retina)
3. Magnitude
4. Stability

Question 15

Esotropes tend to have what direction EF?

Answer 15

Nasal EF

Question 16

Exotropes tend to have what direction EF?

Answer 16

Temporal EF

Question 17

EF is usually how many prism diopters off?

Answer 17

3-4pd or less

Question 18

What’s easier to treat: unsteady or steady EF?

Answer 18

Unsteady EF

- more peripheral = less steady

Question 19

How do we objectively measure EF?

Answer 19

Visuoscopy

• most common method
• monocular test

Question 20

How do we subjectively measure EF?

Answer 20

1. Haidinger’s brush

2. BGAIT

Question 21

The magnitude of EF in Haidinger’s Brush is determined by what conversion factor at 40cm?

Answer 21

4mm = 1pd

Question 22

For BGAIT, which eye do you flash first?

Answer 22

non-amblyopic (good) eye

Question 23

The patient must have what type of correspondence for the BGAIT to work?

Answer 23

normal correspondence

Question 24

The magnitude of EF in BGAIT is determined by what conversin factor at 1m?

Answer 24

1cm = 1pd

Question 25

What are the 2 mechanisms by which EF contribute to decreased VA?

Answer 25

1. Sensory inhibition

2. Motor (EF)

Question 26

What equation is used to determine the decrease in VA from EF ONLY?

Answer 26

20/(1+ef)(20)