Cover Test

Question 1

What does the Cover Test determine?

Answer 1

• presence of a deviation
• laterality(which eye)
• frequency of the deviation
• direction of phoria or tropia
• magnitude of deviation

Question 2

Orthophoria

Answer 2

-the perfect alignment in the absence of a stimulus for fixation

Question 3

Heterophoria/phoria

Answer 3

• the tendency for the eyes to deviate when fusion is blocked
• small phoria is common for most people
• usually overcome by fusion
• if no movement with cover/uncover test when either eye was covered

Question 4

Esophoria

Answer 4

-“posture” slightly inward

Question 5

Exophoria

Answer 5

-“posture” slightly outward

Question 6

Decompensating phoria

Answer 6

• when motor fusion is no longer enough to overcome the phoria
• can result in discomfort or diplopia

Question 7

Heterotropia/tropia

Answer 7

• MANIFEST deviation
• visual axes of both eyes do not intersect at fixation
• leads to diplopia or suppression of the deviated eye

Question 8

Anisometropia

Answer 8

• difference in refractive errors between the two eyes

- can result in tropia

Question 9

Why tropia?

Answer 9

• anisometropia
• abnormality with extraocular muscles
• eye disease

Question 10

Cover-uncover test

Answer 10

• unilateral cover test
• helps differentiate..
• presence of a deviation
• laterality
• frequency
• THIS TEST IS ALWAYS DONE FIRST
• DONE IN ALL POSITIONS OF GAZE

Question 11

Alternating cover test

Answer 11

determines. ..
- direction of deviation
- magnitude of deviation
- cover one eye to break fusion, the alternate between covering eyes to observe movement/direction
- WATCH UNCOVERED EYE FOR REFIXATING AND DIRECTION

Question 12

What do you do test?

Answer 12

DO NEAR AND DISTANCE BOTH EVERY TIME

Question 13

“cover” in cover-uncover test

Answer 13

• shows if deviation is phoria or tropia
• evaluates the visual axis of each eye when both eyes are viewing a target
• look at the eye that is not covered

Question 14

Cover-uncover results

Answer 14

phoria-the visual axis of both eyes are aligned on the target with both eyes open
tropia- the visual axis of one eye is aligned on the target while the other is misaligned with both eyes open

Question 15

Uncover in cover uncover test

Answer 15

• shows if tropia is alternating or unilateral
• focus on eye not covered to determine if it picks up fixation
• shows if tropia is constant or intermediate

Question 16

Uncover test results

Answer 16

unilateral tropia: right or lef, one eye usually fixates when both are open
-the tropic eye only fixates when the preferred fixating eye is covered

alternating tropia: patient is able to keep either eye on the target with both eyes open

Question 17

where should you sit?

Answer 17

-you can see both eyes, but you do not block the patients fixation on the target

Question 18

Distance?

Answer 18

• at distance, isolate letter that is 1 or 2 lines LARGER than the best corrected VA in poorer seeing eye
• at near, hold target 40cm
• patient may hold target if they start to lose focus

Question 19

Assess fixation

Answer 19

• determine if the patient is able to fixate with the right eye when the left eye is covered and then check left
• OBSERVE ANY MOVEMENT OF THE RIGHT EYE AS SOON AS THE LEFT EYE IS COVERED. IF NO MOVEMENT, THE RIGHT EYE WAS FIXATING WHEN BOTH EYES ARE OPEN

Question 20

fusion

Answer 20

• binocular vision
• when switching occluder between eyes, allow a couple seconds to let eyes resume their relationship with each other
• BRING BACK FUSION

Question 21

Measuring the deviation

Answer 21

• put prism in front of the eye and watch the other
• move occluder back and forth and increase prism until you no longer see movement
• deviation is neutralized at the amount of prism where both eyes appear to be aligned and there is not movement on alternative CT

Question 22

Exo

Answer 22

-correct with base in

Question 23

Eso

Answer 23

-correct with base out

Question 24

Hypo

Answer 24

-correct with base up

Question 25

Hyper

Answer 25

-correct with base down

Question 26

Ortho

Answer 26

-verify by sing BI and then BO

Question 27

Recording!

Answer 27

- cc or sc(if they come in with glasses, make them wear them) - Distance and Near(use prime) - amount of prism in prism diopters - E for eso - X for Exo - RH is right hypertropia - ortho for no deviaion - P or T - R,L, alt - only record vertical phorias and tropias - () for intermittent

Question 28

Comitancy

Answer 28

- deviation size remains the same (within 5 diopters) in all positions of gaze - implies no muscles are underreacting or overreacting

Question 29

Noncomitancy

Answer 29

- deviation size changes in different positions of gaze - more than 5 diopters - due to over action or under action of one or multiple muscles