COT Basic Ocular Motility

You are performing a Hirschberg test. What measurement is indicated in the following (Figure 3-3)?

60 prism diopter RET

Stereopsis can be measured in which of the following patients?

8 diopters intermittent XT

You are performing and Hirschberg test. What measurement is indicated in the following (Figured 3-2)?

90 prism diopters LXT

Which of the following is most likely to develop amblyopia in the right eye?

A 3-year-old with a refractive error of +4.00 sphere OD and +1.25 sphere OS

The Hirschberg test alone mat be appropriate for all the following situations except:

Cooperative binocular patients

The Krimsky measurement combines the Hirschberg method with:

Correcting prisms

Decreased elevation of one eye may be due to all of the following except:

Duane's syndrome causes a horizontal deviation.

Anisometropia at birth is more likely to result in:

Exotropia

In a patient with ARC, the images:

Fall on the fovea of one eye and on a nonfoveal point in the other eye

You are measuring a patient with a vertical deviation. The Maddox rod should be placed so that the light forms a:

Horizontal line

In the Bielschowsky head tilt test:

Hypertropia with head tilted right, then left, is measured

Which muscles are elevator?

IO and SR

The Bielschowsky 3 step test (B3ST) is used in vertical deviation to:

Identify with cyclovertical muscle is at fault

Which muscle is weak in the following B3ST example? Step 1: RHT Step 2: worse in right gaze Step 3: worse in left tilt

RIR

Judging the NPC by having the patient report diploia may not always be accurate because the patient might be:

Suppressing

You are holding the red filter in front of the patient's left eye, and she says that she sees only a single white light. This indicates:

Suppression, OS

Which of the following indicates the better stereo vision?

25 seconds of arc

Prism and cover testing in a head tilt position is done to evaluate:

Testing in head tilt position is done to test vertical deviations. Accommodative deviations and A/V patterns are associated with horizontal deviations.

The Maddox rod test will be accurate in which of the following situations?

The binocular patient

You have placed the Maddox rod before the patient's left eye with the ridges running horizontally. That the line is to the right of the light. This indicates:

The ridges are horizontal, creating a vertical line for checking horizontal deviation. You have placed the rod in front of the left eye, and the line is to the right. This indicates a left exotropia. If the line were to the left, a left esotrpia would be indicated

The most common cause of a V pattern is:

The secondary and tertiary action of the OI are elevation and abduction. Because the OI has its action in upgaze, an overaction would likely increase abduction, hence the V pattern.

The measurement described in the above question refers to:

The secondary deviation

You want to check the action of the LIO. Where do you direct the patient to look?

Up and right

Which pattern is most common?

V pattern ET

All of the following are true regarding the prism and cover test except:

The prism must be placed in front of the deviated eye

When performing a prism and cover test in a head tilt position, the bottom edge of the prism should:

The prism should be tilted with the head; that is, the bottom edge of the prism should be parallel to the floor of the orbit.

The deviation of a tropic patient is neutralized with a 15 diopter prism, base up, in front of the right eye and a 5 diopter prism, base up, in front of the left eye. This patient has a:

10 diopter LHT

Your patient has an esodeviation that is worse at near than at a distance. This is classified as:

A convergence excess means that the eyes overconverge for near viewing. Thus, an estropia would be worse at near in this situation.

Pseudoesotropia most often is caused by:

A flat nasal bridge and epicanthal folds

Which of the following in appropriate when testing a preschooler for amblyopia?

A full line of figures

A patient with fusion might report all of the following on W4D testing except:

A patient who fuses may report any of the listed combination except for seeing one red light on the bottom and three green lights (on top, left, and right). Additionally, sometimes the bottom light might be seen as yellowish, a sort of blended red and green.

As the patient fixates on a light, the red filter is held in front of one eye. If the patient is fusing, she will see:

A patient who is fusing will see a pink light or alternately, a blended red and white light. If only a white light is seen, then the eye behind the filter is suppressing. If only a red light is seen, then the other eye is suppressing. If two lights are seen, diplopia is present, indicating that fusion has been broken or does not exist.

If your patient has suppression and no binocular vision, he will see:

A patient who sees a single line in suppression and does not have binocular vision. Seeing two lines that do not cross is considered a diplopic response with NRC.

If your patient has ARC and suppression, the Bagolini targets will appear as:

A patient with ARC and suppression will report with a solid line crossed by a line with a gap

With the red lens over the right eye, a patient with fusion will report seeing:

Again, by convention, the glasses are placed on the patient with the red lens over the right eye. (I remember this by the R's: Right Red.) The patient with fusion will report seeing four lights.

All of the following can cause amblyopia except:

Alternating strabismus

You are testing divergence and the patient is looking at a 20/40 letter. The patient reports "breaking" at 20 diopters. You should:

Ask him if he can pull the images together

To test divergence, the prism is placed:

Base in

In order for a patient to be able to perform the W4D test, he must:

Be able to count objects

Clinically, amblyopia is diagnosed when the:

Best corrected vision of each eye differs by two or more acuity lines

Bifoveal stereopsis is defined as:

Better than 67 seconds of arc

A common deviation found following head trauma is:

Bilateral SO palsy

All of the following are commonly associated with horizontal deviation except:

Blow-out fracture of the orbit

Stereopsis differs from depth perception in that:

Depth perception is monocular or binocular

Step 3 of the B3ST involves:

Determining if the hypertropia is worse in head tilt left or right

Step 2 of the B3ST involves:

Determining if the hypertropia is worse in left or right gaze

Step 1 of the B3ST involves:

Determining which eye is hypertrophic primary position

The purpose of covering one eye with an occlude for strabismus testing is to:

Disrupt fusion

If the eyes have normal version movements, all of the following will exist except:

Divergence is when the eyes move in opposite directions, away from each other. In versions, the eyes are moving together in the same direction.

In paralytic strabismus, the measurement taken with the patient fixating with the affected eye is:

Greater than the measurement take with the patient fixating with the unaffected eye.

If a patient has a difficulty in telling what she sees during the Bagolini test:

Have her draw the pattern that she sees

The most accurate way to measure NPA is to:

Have the patient wear full distance correction

Your patient has tested orthophoric, and reports seeing a cross during the Bagolini test. This means that:

He has NRC

The compensatory head posture of a patient with a RSO palsy would most likely he:

Head tilt left and down

Your patient has an exodeviation that is more divergent at near than at a distance. This is evidence of:

If convergence is insufficient, the patient is not able to pull eyes inward for near viewing. Thus, the deviation is greater at near than distance. Note: Convergence insufficiency also can occur in orthophoria.

You have placed the Maddox rob before the patient's right eye with the ridges running vertically. Which response would indicate that the patient has a RET?

If the rod is placed so the ridges are vertical, then the line is running horizontally, which checks for a vertical deviation, not a horizontal deviation such as an ET.

Patients with a new vertical deviation will complain of double vision where the images:

In a vertical deviation one eye is higher than the other, thus the doubled images are one above the other or possibly diagonal to each other. A horizontal deviation causes doubled images that are beside each other.

The Maddox rod test can be done:

In all fields of gaze

A and V patterns are types of horizontal deviations that:

In an A pattern, the eyes are more converged in upgaze and more diverged in downgaze. A V pattern is more diverged in upgaze and more converged in downgaze. They can be measured with prisms.

The red glass test can be used: In the diagnostic positions of gaze:

In the diagnostic positions of gaze

Pseudostrabismus usually is seen in:

Infants

Adduction means the eye is turning:

Inward (towards the nose)

Which of the following regarding NPC is not true?

It is more remote with children vs. adults

An advantage to the Bagolini test in that:

It is the least dissociating of all the fusion tests

When vergences are measured, it is important to:

Measures divergence first, and measure distance first

Your child patient has an abnormal head position. In order to help determine if this due to strabismus, you should?

Move the child's head in the opposite direction, watching for a change in alignment

When performing the alternate (cross) cover test, it is important to:

Move the cover rapidly from one eye to the other

Ductions refers to:

Movements of one eye

The near point of accommodation (NPA) measures the:

NPA measures the amount of accommodation, in diopters, that a patient has available for near viewing. It is not a measurement of the bifocal add. Answer b relates to NPC.

The near point of convergence (NPC) is reached when:

NPC is the point at which the eyes cannot maintain fusion on an object at near. The closer an object is to the eye, the more convergence is required fuse. Eventually fusion is no longer possible and breaks down, and one eye drifting out.

Normal retinal correspondence (NRC) is the situation in which:

NRC occurs when the fovea of each eye is receiving the same image and the brain can blend the images. A patient with a constant deviation cannot be using the foveae simultaneously.

A compensatory head tilt is most often adopted when the muscle involved is a(n):

Oblique muscle

The Bagolini lenses are placed in a trial frame so that:

One lens is at axis 135 and the other is at axis 045

A 3-month-old may be tested for amblyopia by any of the following except:

Rating central, steady, and maintained

Testing ductions is useful in different cases of:

Restrictive strabismus

Which muscles are primarily torsional muscles?

SO and OI

NPA should be measured:

Separately for each eye

Your patient has tested esotropic, and reports seeing a cross during the Bagolini test. This indicates that:

She is fusing

When measuring a patient with an RHT, the correcting prism could be placed:

The patient has an RHT; the right eye is higher, so the apex ("arrow") should point up. This puts the base down. You could put the prism in front of the left eye, too, but the left is the lower eye so the apex would point down (ie, base up). This was not offered as an answer.

In vergence testing, stronger prism is added until:

The patient reports seeing two images

In pseudostrabismus:

The prefix "pseudo" means false. Thus, pseudostrabismus is false strabismus: the eyes falsely appear to be crossed although they are straight.

When measuring a patient with the Maddox rob:

The correction prism goes over the Maddox rod

With the red lens over the right eye during W4D testing, the patient reports seeing only two red lights. This represents:

The eye looking through the red lens (usually OD) will see the red light as red, and the white light as red. The two green are not seen. The eye looking through the green lens usually (OS) will see the two green lights as green, and the white as green. The single red light is not visible. Thus, the patient in the example is suppressing with the left eye.

You have covered the patient's right eye. When you uncover it, the right eye moves inward. Now you cover the left eye. When you uncover it, the right eye moved inward. You can deduce that the patient has an:

The eyes must have drifted out under the cover if they make inward movements when uncovered, so an exodeviation is present. You were not given enough information to differentiate between a phoria and tropia. For that, you need to know what the uncovered eye is doing, as well

Cover testing can be useful in all of the following patients except:

The monocular patient

As a tertiary action, both oblique muscles:

The obliques abduct as a tertiary action. (Memory hint: oBliques aBduct.)

The deviation of a tropic patient is neutralized with a 15 diopter prism, base up, in front of the right eye and a 5 diopter prism, base out, in front of the left eye. The patient has a:

The patient has a 15 diopter ET. The prisms are base out, with the apexes "pointing" to the nasal. This indicated that you are dealing with the esodeviation. The power of the prisms is additive, hence 15 diopters.

If the deviation described above is measured using the unaffected eye to fixate, the measurement is referred to as:

The primary deviation

Your patient is a fully corrected 30-year-old myope. With glasses on, you measure his NPA, OD, to be 12 cm. This translates to:

To convert distance to diopters, first get the distance in cm. Then divide the cm into 100. In this case, 100/12 cm = ~8.00 diopters.

Vergence testing examines the ability of the eye:

To move in opposite direction to maintain fixation as an object move closer or farther away

You are testing an intelligent 12-year-old with the Titmus dots, and suspect that he is either a good guesser or a cheater. You should:

Turn the test 180 degrees

The power of a Riley prism is changed by:

Turning a thumbscrew

The patient tilts her head to the right. The compensatory muscle movements:

With head tilt right, the eyes will compensate to remain upright by intorting OD and extorting OS. The muscles that intort OD are RSR and RSO. The muscles that exort OS are LIO and LIR.

All of the following muscles take part in ductions except:

Yoked muscles are muscles in both eyes that act to move the eyes in the same direction (ie, versions rather than duction). For example, the RMR is yoked to the LLR for left gaze. The other answers are in the same eye (see question 129). The agonist is the muscle in one eye that is the primary mover for a given gaze.