ABO Binocular Vision & Strabismus 2

Question 1

In a patient with exotropia, the deviating eye turns in which direction?

Accepted Answer

Outward (temporal)

Answer

Exotropia is an outward (temporal/lateral) deviation of the eye, often called 'wall-eye.'

Question 2

The Maddox rod test is primarily used to assess:

Accepted Answer

The magnitude and direction of a phoria

Answer

The Maddox rod converts a point light source into a streak, completely dissociating the eyes so that any phoria can be measured with neutralizing prisms.

Question 3

Anisometropic amblyopia develops primarily because:

Accepted Answer

A significant refractive difference between the two eyes causes chronic blur in one eye

Answer

A large interocular refractive difference results in one eye receiving a chronically defocused image, leading to cortical suppression and amblyopia despite proper alignment.

Question 4

Clinically normal stereoacuity is typically defined as a threshold of:

Accepted Answer

40 arc seconds or better

Answer

A stereoacuity of 40 arc seconds or better (on tests such as the Randot or Titmus) is considered within normal limits for bifoveal stereopsis.

Question 5

The Worth 4-Dot test uses red and green filters to evaluate:

Accepted Answer

Suppression and the quality of binocular fusion

Answer

By presenting red dots only to one eye and green dots only to the other, the Worth 4-Dot test reveals whether the patient is fusing, suppressing one eye, or experiencing diplopia.

ABO - American Board of Optometry Practice Test

ABO - American Board of Optometry Practice Test

ABO Binocular Vision & Strabismus 2