wk6: BV - BV3 Diagnosis of Binocular Vision Disorders

Question 1

Describe how the fixation disparity approach works

Answer 1

plots the amount of prism required to eliminate FD. This is the associated phoria and can be used to determine amount of prism required to treat some BV disorders

Question 2

What is fixation disparity?

Answer 2

Fixation disparity (FD) is the small misalignment of the eyes under binocular conditions from exact bifoveal fixation

Question 3

How many profiles/types of fixation disparity are there?

Answer 3

4. I, II, III, IV.

fixation disparity plots to indicate the binocular vision problem from among the 4 types

Question 4

Is fixation disparity practical clinically? Explain

Answer 4

No because it is time consuming

Question 5

When should we use fixation disparity?

Answer 5

Only use if prism is being considered in the management plan

Question 6

Is graphical analysis practical clinically? Explain (2)

Answer 6

No. It is cumbersome and time consuming having to graphically plot findings

Question 7

What is sheard’s criterion?

Answer 7

Reserve = 2 x phoria. So if reserve is less than 2 x phoria then you’re likely to have a BV problem

Question 8

What is percival’s criterion?

Answer 8

Phoria = 1/3rd reserve

Question 9

What is Morgan’s normative analysis?

Answer 9

Groups of BV data are analysed and profiles of patients are formed based on typical presentations

Question 10

What is the disadvantage of Morgan’s normative analysis?

Answer 10

As this approach has not been modified to include more recent clinical tests, it falls short and fails to identify some accommodation and vergence problems

Question 11

How many practitioners use OEP analytic analysis?

Answer 11

Not many

Question 12

Is OEP analytic analysis an evidence based approach?

Answer 12

No. However it is consistent

Question 13

What type of system does OEP analytic analysis use?

Answer 13

21 point system which relates to the 21 things you need to do in clinical settings

Question 14

What are the disadvantages of OEP analytic analysis? (2)

Answer 14

Very rigid/strict approach

All behind phoropter (so no consideration of proximal cues)

Question 15

Which approach is the most widely used clinically?

Answer 15

Integrative analysis approach

Question 16

List 4 advantages of the Integrative analysis approach

Answer 16

1. compares individual test results against expected published values
2. identifies any patterns or characteristic signs that indicate a particular profile of an accommodative-vergence problem
3. integrates this with patient’s symptoms, hx, risk factors, visual demands
4. narrows and proposes possible diagnosis/diagnoses
   (5. flexible, accurate)

Question 17

How flexible is the Integrative analysis approach?

Answer 17

Quite flexible approach and more likely to produce an accurate representation of patient problems

Question 18

Explain the Integrative analysis approach in 3 points

Answer 18

1. compare test findings to a table of expected normative data
2. group the findings that are outside the normal range to look for patterns
3. identify the possible diagnosis based on the pattern especially if symptoms and signs fit

Question 19

How does the Integrative analysis approach differ from Morgan’s normative analysis approach?

Answer 19

Integrative analysis approach analyses results one by one instead of as groups of data like normative approach

Question 20

Integrative analysis is the circles inside circles thing. Starting from inner most circle outward, what are the important features we want to integrate? (4)

Answer 20

1. patient symptoms
2. patient needs + demands
3. risk factors
4. clinical findings, characteristic features

Question 21

List 8 typical symptoms a patient with BV problems may experience (not there are more)

Answer 21

Headache with near work
Blurry vision
Diplopia, closing or covering one eye
Avoidance of near tasks
Inability to sustain near tasks
Difficulty concentrating on near tasks 
Symptoms after prolonged near work
Eyestrain/fatigue during reading/desk work

Question 22

List another 7 typical symptoms a patient with BV problems may experience

Answer 22

Near/distance blur when changing fixation
Words moving or running together
Blinking, tearing, redness
Squinting, rubbing with near work
Poor attention and conc. when doing homework
Loss of place, slow reading speed, uses fingers to read
Poor reading comprehension, avoiding reading, learning concerns

Question 23

What broad visual tasks should you consider for patients? (3)

Answer 23

Work requirements (computer, fine detail)
School requirements (whiteboard, laptop)
Hobby requirements (playing pool, music, shooting)

Question 24

What conditions should you consider when thinking about a patient’s visual demands? (3)

Answer 24

Time
Lighting
Environment

Question 25

What BV problem might fatigue/prolonged near work/near stress be a risk factor for? (3)

Answer 25

Accom insufficiency Excess convergence insufficiency Convergence excess

Question 26

What BV problems might genetic predisposition be a risk factor for? (4)

Answer 26

Converg Ins. Converg. Exc. Diverg. Exc. Diverg. Ins.

Question 27

What BV problems is uncorrected Rx a risk factor for? (3)

Answer 27

Converg. excess Basic esophoria Accomm. ins.

Question 28

What BV problems might systemic predisposing factors (diabetes, MG, graves, parkinson's, hypothyroid) be risk factors for? (3)

Answer 28

Accomm ins. Excess binocularity problems (EOM) Vergence disorders

Question 29

What BV problems is trauma (A, B, I) a risk factor for? (2)

Answer 29

Accommodative spasm | Convergence insufficiency

Question 30

What BV problems are certain medications like for ADHD, antidepressants, and epilepsy a risk factor for? (2)

Answer 30

Accommodative insufficiency or excess

Question 31

List 6 risk factors for BV problems

Answer 31

Fatigue/near stress/prolonged near work Genetic predisposition Uncorrected Rx Systemic predisposing factors (e.g. diabetes, MG, graves, parkinson's hypothyroid) Trauma (A, B, I) Some medications (e.g. ADHD, antidepressants, epilepsy)

Question 32

What is the minimum battery of clinical tests you must do in a BV workup? (8)

Answer 32

``` Cover test NPC Stereopsis Phorias (distance, near) NPA/amplitude of accommodation (monocular) Accommodative facility (+/-2 at near) Vergence facility (12BO/3BI at near) MEM dynamic retinoscopy ```

Question 33

List the 5 approaches for making a binocular vision diagnosis

Answer 33

``` Graphical analysis (donder's diagram) Morgan's normative analysis Fixation disparity Analytic analysis Integrative analysis ```

Question 34

How does myopic CL wear compare to spectacles in terms of accommodative and vergence function?

Answer 34

Generally poorer accommodative and vergence function

Question 35

If a patient has both CLs and glasses, should you assess accommodation and vergence function with both or just one?

Answer 35

Both

Question 36

What diagnostic layers need to be ruled out when assessing BV problems? (3)

Answer 36

Headaches: could have multiple causes Anterior eye: could have dry sore eyes due to tear film, allergies, infection, inflammation Attentional/Developmental: could be other factors affecting abnormal findings and symptoms

Question 37

What will you expect to see in a patient with convergence insufficiency? (5)

Answer 37

``` Near exo greater than distance Low AC/A Abnormal remote/Receeded NPC Reduced PRC and BO facility at near Low NRA ```

Question 38

What will you expect to see in a patient with divergence excess? (4)

Answer 38

D exo > N High AC/A High tonic exophoria Large exophoria/tropia at distance (intermittent D exotropia)

Question 39

What will you expect to see in a patient with basic exophoria? (3)

Answer 39

Exophoria at distance = exophoria at near Normal AC/A Low NRA

Question 40

What will you expect to see in a patient with convergence excess? (5)

Answer 40

``` N eso > D Low AC/A High tonic esophoria Low PRA Reduced NRC and BI facility at near ```

Question 41

What will you expect to see in a patient with vergence insufficiency? (3)

Answer 41

Normal AC/A Restricted fusional vergence amplitudes Steep fixation disparity curve

Question 42

What will you expect to see in a patient with basic esophoria? (3)

Answer 42

Esophoria at distance = esophoria at near Normal AC/A Low PRA

Question 43

What will you expect to see in a patient with vertical phoria? (2)

Answer 43

Classify as either comitant deviations or noncomitant deviations (old demcompensated 4th nerve palsy, newly acquired 4th nerve palsy)

Question 44

What will you expect to see in a patient with accommodative insufficiency? (7)

Answer 44

``` Verg Amp: BO blur at near may be low Low accomm amplitude (low NPA) Fail negative acc. facility Slow facility Abnormal lag Low PRA High MEM ret ```

Question 45

What will you expect to see in a patient with ill-sustained accommodation? (5)

Answer 45

``` Verg amp: BO blur at near may be low Fails negative acc. facility Slow verg facility Low PRA High MEM (high variable lag) ```

Question 46

What will you expect to see in a patient with accommodative excess? (4)

Answer 46

Verg Amp: BI blur at near may be low Fails positive acc facility Low NRA Low MEM (no lag,may have a lead)

Question 47

What will you expect to see in a patient with Divergence Insufficiency? (5)

Answer 47

``` D eso > N Reduced PRC at distance D blur/diplopia Low AC/A High tonic esophoria ```

Question 48

What will you expect to see in a patient with Accommodative spasm? (3)

Answer 48

Abnormal lead Reduced VA or distance blur (pseudo myopia) Fails positive facility

Question 49

What will you expect to see in a patient with accommodative infacility? (1)

Answer 49

Slow accommodative facility

Question 50

What will you expect to see in a patient with vergence infacility/fusion vergence dysfunction? (2)

Answer 50

Reduced BI/BO facility and/or | Reduced fusional reserves