Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

B2 Methods > Cover Test > Flashcards

Cover Test Flashcards

1
Q

Cover test is done to determine:

A

Presence of a deviation (phoria or tropia)
Laterality/which eye (unilateral or alternating)
Frequency of the deviation (constant or intermittent)
Direction of the phoria or tropia
Magnitude (size) of the deviation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is orthophoria?

A

The perfect alignment in the absence of a stimulus for fixation

Eyes are aligned.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is heterophoria (or just phoria)?

A

The tendency for the eyes to deviate away when fusion is blocked.

Small phoria is common in most people, overcome by fusion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

“Posture” slightly inward

A

Esophoria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Posture slightly outward

A

Exophoria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a decompensating phoria?

A

When motor fusion is no longer enough the overcome a phoria.

Could result in discomfort or diplopia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Heterotropia/tropia is….

A

a manifest deviation.

Visual axes of both eyes do not intersect at fixation.

Leads to diplopia or suppression of the deviated eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Tropia could be due to:

A

Anisimotropia (difference in refractive errors between the two eyes)

Abnormality of the extraocular muscles or strabismus

Eye disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cover-Uncover Test (Unilateral Cover Test)

A

Helps differentiate:

  • Presence of a deviation (phoria or tropia)
  • laterality/which eye (unilateral or alternating)
  • frequency of the deviation (constant or intermittent)

This is done first.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Alternating Cover Test

A

Used to determine:

  • direction of phoria or tropia
  • magnitude (size) of deviation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is a cover test done at distance or near?

A

BOTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The “Cover” in Cover-Uncover

A

Used to show if the deviation is a phoria or a tropia.

Evaluates visual axis of each eye with both eyes are viewing a target.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

While using a Cover, it will be a Phoria if…

A

The visual axis of both eyes are aligned on the target with both eyes open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

While using a Cover, it will be a Tropia if…

A

The visual axis of one eye is aligned on the target while the other is misaligned with both eyes open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The “Uncover” in Cover-Uncover

A

shows is a tropia is alternating or unilateral tropias

*focus on the eye that is not occluded to determine if it picks up fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Unilateral tropia

A

When one eye usually fixates when both eyes are open

17
Q

Alternating tropia

A

When the pt is able to keep either eye on a target with both eyes open

18
Q

Equipment for cover test

A

Visual acuity chart for fixation at distance
Near point target for fixation at near
Occluder/paddle
Horizontal and vertical prism bars or loose prisms
Habitual correction (CT will be done w/ and w/out HC in some cases)
Well lit room

19
Q

How to explain the purpose of a cover test to a patient:

A

“I want to make sure your eyes are aligned properly”

20
Q

Distance Cover Test

A

Isolate a letter that is one or 2 lines larger than the best corrected VA in the poorer seeing eye

Could be between 20/25 and 20/40

21
Q

Near Cover Test

A

Hold an accommodative target at 40 cm

It could be a letter that is one or two lines larger than the BCVA of the poorer seeing eye

Could be a target of comparable detail/size (about a 20/30 size)

Patient may hold target.

22
Q

When the occluder is removed, how long should you wait for allow both eyes to resume their normal relationship?

A

About 2-3 seconds

23
Q

If there were no movements seen when either eye was covered, the patient has a ______

A

Phoria

24
Q

Alternating Cover Test

A

Determines the direction and the size of the deviation

25
Q

Measuring the deviation

A

Put prism in front of one eye and watch the other

Continue to move the occluder back and forth while increasing the prism until you no longer see movement

The deviation is neutralized at the amount of prism where both eyes appear aligned and there is no more movement on alternate CT

26
Q

Prisms to neutralize:

  1. Exo
  2. Eso
  3. Hypo
  4. Hyper
  5. Ortho
A
  1. BI
  2. BO
  3. BU
  4. BD
  5. Verify using BI and then BO
27
Q

Recording a Cover Test

A

Indicate if it was done with prescription (cc) or without correction (sc)

Record distance (D) and near (N) findings separately

Record the amount of prism that was required to neutralize the deviation

Record the direction of deviation

  • E for eso
  • X for exo
  • RH for right hyper, LH for left hyper
  • Ortho for no deviation

Record if it’s phoria/tropia
- R/L/Alt

Record an intermittent tropia with a parentheses (T)

Record the amount of prism measured in Prism Diopter

28
Q

Comitancy

A

Deviation size remains same (or within 5pd) in all positions of gaze

Implying no muscles are underacting or overacting

29
Q

Noncomitancy

A

Deviation size changes in different positions of gaze

Due to an overaction or underaction of one of multiple muscles

30
Q

how to correctly determine comitancy

A

CT is done in all positions of gaze

31
Q

Hirschberg test

A

Rough objective estimate and measurement of a deviation/strabismus.

Useful in young and uncooperative patients

Penlight is held straight in front of patients face, pt is instructed to fixate on the penlight with both eyes open

In the absence of strabismus, the corneal reflex should be centered in both eyes. In the presence of strabismus, the reflex will not be in the center of the deviated eye.

For 1 mm of estimated deviation, it is approximately a deviation of 22 prism diopters

32
Q

Krimsky Test

A

This is the combination of the Hirschberg test with prisms to determine the angle of deviation.

Prisms are placed in front of the fixating eye until the corneal reflexes are symmetrical.

Base Out prism is used for esotropia Base In prism is used for exotropia

In the Prism Reflection Test, the prism is held in front of the deviated eye until the corneal reflex is symmetrical.

B2 Methods (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions