wk6: BV - BV3 Diagnosis of Binocular Vision Disorders Flashcards
Describe how the fixation disparity approach works
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
What is fixation disparity?
Fixation disparity (FD) is the small misalignment of the eyes under binocular conditions from exact bifoveal fixation
How many profiles/types of fixation disparity are there?
- I, II, III, IV.
fixation disparity plots to indicate the binocular vision problem from among the 4 types
Is fixation disparity practical clinically? Explain
No because it is time consuming
When should we use fixation disparity?
Only use if prism is being considered in the management plan
Is graphical analysis practical clinically? Explain (2)
No. It is cumbersome and time consuming having to graphically plot findings
What is sheard’s criterion?
Reserve = 2 x phoria. So if reserve is less than 2 x phoria then you’re likely to have a BV problem
What is percival’s criterion?
Phoria = 1/3rd reserve
What is Morgan’s normative analysis?
Groups of BV data are analysed and profiles of patients are formed based on typical presentations
What is the disadvantage of Morgan’s normative analysis?
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
How many practitioners use OEP analytic analysis?
Not many
Is OEP analytic analysis an evidence based approach?
No. However it is consistent
What type of system does OEP analytic analysis use?
21 point system which relates to the 21 things you need to do in clinical settings
What are the disadvantages of OEP analytic analysis? (2)
Very rigid/strict approach
All behind phoropter (so no consideration of proximal cues)
Which approach is the most widely used clinically?
Integrative analysis approach
List 4 advantages of the Integrative analysis approach
- compares individual test results against expected published values
- identifies any patterns or characteristic signs that indicate a particular profile of an accommodative-vergence problem
- integrates this with patient’s symptoms, hx, risk factors, visual demands
- narrows and proposes possible diagnosis/diagnoses
(5. flexible, accurate)
How flexible is the Integrative analysis approach?
Quite flexible approach and more likely to produce an accurate representation of patient problems
Explain the Integrative analysis approach in 3 points
- compare test findings to a table of expected normative data
- group the findings that are outside the normal range to look for patterns
- identify the possible diagnosis based on the pattern especially if symptoms and signs fit
How does the Integrative analysis approach differ from Morgan’s normative analysis approach?
Integrative analysis approach analyses results one by one instead of as groups of data like normative approach
Integrative analysis is the circles inside circles thing. Starting from inner most circle outward, what are the important features we want to integrate? (4)
- patient symptoms
- patient needs + demands
- risk factors
- clinical findings, characteristic features
List 8 typical symptoms a patient with BV problems may experience (not there are more)
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
List another 7 typical symptoms a patient with BV problems may experience
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
What broad visual tasks should you consider for patients? (3)
Work requirements (computer, fine detail) School requirements (whiteboard, laptop) Hobby requirements (playing pool, music, shooting)
What conditions should you consider when thinking about a patient’s visual demands? (3)
Time
Lighting
Environment
What BV problem might fatigue/prolonged near work/near stress be a risk factor for? (3)
Accom insufficiency
Excess convergence insufficiency
Convergence excess
What BV problems might genetic predisposition be a risk factor for? (4)
Converg Ins.
Converg. Exc.
Diverg. Exc.
Diverg. Ins.
What BV problems is uncorrected Rx a risk factor for? (3)
Converg. excess
Basic esophoria
Accomm. ins.
What BV problems might systemic predisposing factors (diabetes, MG, graves, parkinson’s, hypothyroid) be risk factors for? (3)
Accomm ins.
Excess binocularity problems (EOM)
Vergence disorders
What BV problems is trauma (A, B, I) a risk factor for? (2)
Accommodative spasm
Convergence insufficiency
What BV problems are certain medications like for ADHD, antidepressants, and epilepsy a risk factor for? (2)
Accommodative insufficiency or excess
List 6 risk factors for BV problems
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)
What is the minimum battery of clinical tests you must do in a BV workup? (8)
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
List the 5 approaches for making a binocular vision diagnosis
Graphical analysis (donder's diagram) Morgan's normative analysis Fixation disparity Analytic analysis Integrative analysis
How does myopic CL wear compare to spectacles in terms of accommodative and vergence function?
Generally poorer accommodative and vergence function
If a patient has both CLs and glasses, should you assess accommodation and vergence function with both or just one?
Both
What diagnostic layers need to be ruled out when assessing BV problems? (3)
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
What will you expect to see in a patient with convergence insufficiency? (5)
Near exo greater than distance Low AC/A Abnormal remote/Receeded NPC Reduced PRC and BO facility at near Low NRA
What will you expect to see in a patient with divergence excess? (4)
D exo > N
High AC/A
High tonic exophoria
Large exophoria/tropia at distance (intermittent D exotropia)
What will you expect to see in a patient with basic exophoria? (3)
Exophoria at distance = exophoria at near
Normal AC/A
Low NRA
What will you expect to see in a patient with convergence excess? (5)
N eso > D Low AC/A High tonic esophoria Low PRA Reduced NRC and BI facility at near
What will you expect to see in a patient with vergence insufficiency? (3)
Normal AC/A
Restricted fusional vergence amplitudes
Steep fixation disparity curve
What will you expect to see in a patient with basic esophoria? (3)
Esophoria at distance = esophoria at near
Normal AC/A
Low PRA
What will you expect to see in a patient with vertical phoria? (2)
Classify as either comitant deviations or noncomitant deviations (old demcompensated 4th nerve palsy, newly acquired 4th nerve palsy)
What will you expect to see in a patient with accommodative insufficiency? (7)
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
What will you expect to see in a patient with ill-sustained accommodation? (5)
Verg amp: BO blur at near may be low Fails negative acc. facility Slow verg facility Low PRA High MEM (high variable lag)
What will you expect to see in a patient with accommodative excess? (4)
Verg Amp: BI blur at near may be low
Fails positive acc facility
Low NRA
Low MEM (no lag,may have a lead)
What will you expect to see in a patient with Divergence Insufficiency? (5)
D eso > N Reduced PRC at distance D blur/diplopia Low AC/A High tonic esophoria
What will you expect to see in a patient with Accommodative spasm? (3)
Abnormal lead
Reduced VA or distance blur (pseudo myopia)
Fails positive facility
What will you expect to see in a patient with accommodative infacility? (1)
Slow accommodative facility
What will you expect to see in a patient with vergence infacility/fusion vergence dysfunction? (2)
Reduced BI/BO facility and/or
Reduced fusional reserves
