Diagnostic testing Flashcards
Symptomology
Symptoms are associated with near visual tasks
asthenopia symptoms
- Headaches
- Eye strain/fatigue
- Blurred vision
- Diplipia
- Loss of place while reading
- Diff sustaining near tasks
- Avoiding near tasks
Headaches
- Location = brow region, frontal
- Aggravated = by sustained near visual tasks
- Worse at end of the day
- NO nausea/vomiting a - more migraine related, neurologically associated
Eye strain/fatigue
- Tired, droopy lids
Blurred vision (ACCOMODATIVE PROBLEM)
- Near to Far vice-versa
- Delay/latency in accommodative system
- perceived as blur by the patient
- Common symptom of accommodative dysfunction
Symptoms are associated with near visual tasks
asthenopia symptoms
- Headaches
- Eye strain/fatigue
- Blurred vision (ACCOMODATIVE PROBLEM)
- Diplipia (VERGENCE PROBLEM)
- Loss of place while reading
- Diff sustaining near tasks
- Avoiding near tasks
DIPLOPIA = vergence problems
- Onset sudden (weeks) or gradual (months)
- Pts with heterophoric vergence issues will have double vision problems that are GRADUAL
- Monocular or binocular true double vision is binocular
- Causes of monocular double vision:
- Astigmatism
- Dry eye
- Media opacity/cataracts
- Constant or intermittent
- Constant = progressive problem, strabismic
- Intermittent = unable to manage phoria problems
- Distance or near
- Depends on underlying condition
- more frequent at distance or near
-
Horizontal vs vertical
- Horizontal double vision is = convergence/divergence issues
- Oblique double vision = both horizontal and vertical components - oblique EOMs dysfunction
• Beware: sudden onset double vision associated with nausea, vomiting, loss of balance, headaches, tingling of extremities
frequently associated with neurological type double vision - Needs to be referred for imaging
Symptoms are associated with near visual tasks
asthenopia symptoms
- Headaches
- Eye strain/fatigue
- Blurred vision (ACCOMODATIVE PROBLEM)
- Diplipia (VERGENCE PROBLEM)
- Loss of place while reading (SACCADIC DYSFUNCTION)
- Diff sustaining near tasks
- Avoiding near tasks
Loss of place while reading
- use finger on the page as they read
- Reading laborious and frustrating
- Common in patients with oculomotor problems (i.e. saccadic dysfunction)
Difficulty sustaining near tasks
- Pt reports frequent breaks in between tasks
Avoiding near tasks
- No Symptoms because Px avoiding reading
- Decreased academic performance
- Usually presents later on in the exam
Abnormal exophoria at near but pt does not report any difficulty reading = they may be avoiding reading
Symptom Questionares
CISS
Convergence Insufficiency Symptom Survey (CISS)
Convergence Insufficiency Symptom Survey (CISS)
- Validated questionnaire
- Score is tabulated based on f_requency of symptoms_
- Higher score = more frequent symptoms = additional testing
- Lower score = less symptoms § Validity:
- Not valid for children under 9
Kids (9-18)
- Normal binocular vision(NBV)score = 8.4 ± 6.4
- Convergence insufficiency (CI) score = 30.8 ± 8.4
- CISS ≥16 = Requires additional testing
Young adults (19-30)
- NBVscore =11 ± 8.2
- CI score = 37.3 ± 9.3
- CISS ≥ 21 = Requires additional testing
Symptom Questionares
Brain Injury Vision Symptoms Survey (BIVSS)
Concussion Patients
Concussion patients
- Visual symptoms 30-85% of TBI pts
- Asthenopia
-
Difficulty with motion perception UNIQUE to head trauma patients
- Walking into supermarket is arduous (supermarket syndrome) § Due to optic flow problems
- As you walk down an aisle, peripheral visual information contains NOISE and makes it difficult to process
- i.e. trouble following a moving object (will make them dizzy) o May see stationary objects as moving
-
Peripheral awareness difficulty
- ignore objects in periphery
- Patients would prefer looking at objects with less noise (i.e. blank backgrounds)
-
Issues with depth perception
- visual-spatial imbalance
-
Light sensitivity very common in head trauma patients
- Will ask you to turn lights down and slow down talking
- Treated with filters
Brain Injury Vision Symptoms Survey (BIVSS)
- Validated in patients with self-reported mild traumatic brain injury (mTBI)
- More detailed than CISS
- Score ≥ 31 is suggestive of TBI like symptoms
Systemic Patient history
Dyslexia
ADHD (link to symptomatic CI)
Dyslexia
- Accommodative, vergence, and oculomotor deficits were more prevalent in children with developmental dyslexia
- Association, NOT causation
ADHD
- Children with symptomatic convergence insufficiency** + **ADHD = reduced academic performance
- Ask about asthenopia with near work
- Headaches
- Eyestrain
- Ask about history of concussion!àif so, administer symptom questionnaire
- Ocular alignment and AC/A ratio
- Tests of accommodation:
- Amplitude § Dynamics § Response
- Tests of eye movements:
- Pursuits § Saccades
- Sensorimotor status:
- Stereopsis § Worth 4 dot test
- Tests of vergence
- Amplitude § Dynamics
- Fixation disparity
Prerequisite to testing
- Determination of refractive error (static retinoscopy or autorefraction)
- MPMVA refraction
-
Cycloplegic evaluation (1% cyclopentolate x2 5min apart)
- first-time pediatric patients
- Latent hyperopia!
- Adults with wavering refractions/possibility or an overminused prescription
- If objective and subjective findings do not match
o Tropicamide better for older kids and adults
Ocular alignment
- Cover test
- Modified Thorington
- Von Graefe
AC/A ratio testing
- Gradient AC/A
- Calculated AC/A
Ocular alignment
-
Cover test - _w/ accommodative targe_t
- Document magnitude + direction of phoria at distance and near
- Modified Thorington MOST RELIABLE METHOD, free space technique
- Von Graefe
Ocular alignment
Cover test
Modified Thorington
Von Graefe
AC/A ratio testing
Gradient AC/A
Calculated AC/A
Calculated >>Gradient Why?
AC/A ratio testing:
- change in accommodative convergence when accommodation changesby 1D
- Important for determining final diagnosis and appropriate treatment sequence
Examples: Convergence excess is a high AC/A ratio
- ESO > N than D
- Treatment - Added plus lenses work extremely well
Convergence insufficiency is a low AC/A
- EXO > N than D
- Treatment - Does NOT respond well with added lenses
- Should work with prisms and vision therapy
Two methods of testing:
-
Gradient AC/A
- Von Graefe or Modified Thorington at 40cm
- repeat test at same distance using -1.00D lenses OU
- -1.00 lenses stimulate accommodative convergence § AC/A = change in phoria measurement/lens power
-
Calculated AC/A
- AC/A = IPD (cm) + NWD (m) (Phn –Phd)
- Phn = near phoria (eso = plus, exo = minus)
- Phd = distance phoria (eso = plus, exo = minus)
- AC/A = IPD (cm) + NWD (m) (Phn –Phd)
-
Expected value (norms) = 4:1 – 6:1
- High AC/A > 7:1
- Low AC/A < 3:1
- Rule of thumb = high AC/A means MORE ESO or LESS EXO at Near
Calculated AC/A >> Gradient AC/A (why)
- Proximal vergence = the near phoria measured for calculated AC/A will be impacted by proximal vergence (more eso or less exo)
- In gradient AC/A phoria is measured TWICE at same distance but with different lenses, so proximal vergence is held constant
- Shifts in direction of eso
-
Lag of accommodation = we generally underaccommodate for a given accommodate stimulus
- Since -1.00 is typically used for gradient AC/A, the accommodative convergence triggered is LESS than expectedàthis may cause the gradient AC/A to be LOWER than calculated
Sensorimotor tests:
- non-strabismic conditions (heterophoria), the ability to maintain fusion and depth perception
- Important tests to determine prognosis and sequence of treatment
3 types of fusion:
- Superimposition (simultaneous fusion) - 1st degree
-
Flat fusion - 2nd degree
- W4D tests this
-
Stereopsis fusion - 3rd degree
- Global and contour (local) stereopsis
Stereopsis
- Global and contour (local) stereopsis
- Global = no monocular cues (True stereo RANDOT)
-
Local = monocular cues present
- not high quality but still tests for stereopsis in pts with limited stereopsis
- Start with global testing
- <60 arc sec = peripheral stereoàcoarse stereo
Worth four dot (W4D)
- Test distance and near
-
Near W4D tests peripheral fusion due to the large area of retina the image subtends
- significant XP, if they have good peripheral fusion, they will be able to fuse the W4D images • 40cm
- Distance W4D tests central fusion due to the small area of retina the image subtends • 20 feet
4 balls normal second-degree fusion
- Normal correspondence (retinal image falls on both foveas)
-
Depth of suppression evaluated by adjusting room illumination
- Normal room illuminationàtest natural viewing conditions
- Dim room illuminationàdifficult to maintain suppression in unnatural viewing conditions
If suppression is reported with room lights off, then it is DEEP ROOTED
SUPPRESSION in strabismic patients
Not indicated if you do not suspect suppression
Tests of accommodation
- Done with best subjective correction
- Evaluate each aspect of accommodation
Amplitude = measures maximum amount of accommodation stimulated for a given stimulus (in one direction)
Facility = measures ability to stimulate and relax accommodation repeatedly for a given stimulus (more dynamic)
Amplitude:
- Push-up
- overestimation by 2D - dt Relative dist magnification
- Pull Away
- Young children
- Minus lens to blur
- Monocular
- 2D less ant Push up
Facility
-
MAF
- Tests only accomodative facility
-
BAF
- Tests accommodation and vergence dynamics keep image clear + single
- Plus - ability to relax
- Minus - ability to stimulate
- Higher amount of cycles better facility
Accomodation Tests
Amplitude
Push up
Pull away
Minus lens to blur
AMPLITUDE of ACC
-
Push up
- with 7A in free space
- Concerns:
- Relative distance magnificatio - as the target is moved closer, it is magnified in the retina
- Overestimation of amplitude by 2D
Norms - Hofsetter’s Formula
- Avg amplitude = 18.5 – 0.3(age)
- Min. amplitude = 15 – 0.25(age)
- Pull away.
- with 7A free space
- technique in young children (non-seeing to seeing)
- upper lid lash - pull the target away until first noticed clear
- Minus lens to blur
- 7A phoropter - Done monocularly
- Procedure:
- Add -0.25D until first sustained blur
- Test distance 33cm
-
Correction factor Add 2.50D (accounts for minification due to minus lenses)
- i.e. pt reports blur at 8th click (2D)àAmp = 2D + 2.50D = 4.50D § Norm:
- 2D less than that for push-up
Accomodation Tests
Facility
Measures ability to stimulate and relax accommodation repeatedly for a given stimulus o Lens flipper is utilized to test the dynamics
§ Plus lenses = evaluates ability to relax accommodation
§ Minus lenses = evaluates the ability to stimulate accommodation
MAF
asseses ONLY Accomodative Facility
BAF
Asseses Accomodative and Vergence Facility
Facility
- Plus to minus = 1 cycle (1min test)
- The higher number of cycles, the better the accommodative facility
Monocular Accommodative Facility (MAF)
- Only tests accommodative facility
- Diff plus lens = difficulty relaxing accommodation
- Diff minus lens = difficulty stimulating accommodation
Binocular Accommodative Facility (BAF)
- Tests accommodation and vergence dynamics = keep image clear + single
-
Plus lens side = behave as base OUT prisms
- Relaxes accommodation
- Positive fusional vergence required to maintain binocularity (convergence)
-
Minus lens side = behave as base IN prisms
- Stimulates accommodation
- Negative fusional vergence is required to maintain binocularity (divergence)
- Efficient to start with BAF, if fails, do MAF
• BAF is good screener test (determines if problem is with accommodation or vergence)
Accomadative facility
MAF & BAF
test and rational
-
Test setup:
- 40 cm test distance
- Accommodative target 2 lines above BCVA
- Vertical line
- 7A / Age of pt: 0-30 +/- 2.00 flipper / Test distance 40 cm
- > 30 years - Scaled Facility
- based on pt’s amplitude of accommodation
- Binocular test first, if abnormal then do monocular testing
- Rationale:
- BAF - assess accommodation and vergence
- if normal, likely normal facility
- Fails lenses in BAF = accommodative or vergence problem
- Fails BAF but passes MAF = vergence problem
- Fails BAF and MAF = likely accommodation problem
Testing procedure:
- Start with + side
- Instructions: letters clear and single as quick as possible
- Single not appropriate for MAF
- What to observe:
-
Is one lens easier than the other?
- Accommodative insufficiency (AI) patients have difficulty with minus lens
- Is one eye better than the other? (monocular test)
- Accommodation should be steady and equal to both eyes - anisometropic amblyopia exeption
- could not clear one side? (>5 sec to clear for each lens)
- If more than 5 sec, just flip to other side
-
half a cycle does not count as cpm
• Record results as = 0 cpm, fails (-) lens OR 0 cpm, fails (+) lens
BAF - Scaled accomadative Facility
Amplitude scaled facility (>30 years)
For determining flipper lens power § Binocular procedure
- PUSH UP - binocular amplitude of accommodation.
-
45% of that dioptric value as the TEST DISTANCE
- Convert to cm and round to nearest 0.5 cm
-
30% of that dioptric value as the lens flipper RANGE
- Round to nearest 0.25D
- The flipper power used = range/2
Example: 20D amplitude
- 45 (20) = 9D = 11 cm test distance
- 30 (20) = 6D / 6D/2 = + 3.00 flippers
Accommodative Response:
Assessment of accuracy of accommodative response to a stimulus - At 40cm, the accommodative demand is 2.5D
Norm = slight accommodative lag
Objective assessment:
Monocular Estimation Method (MEM)
Nott retinoscopy
Book Reinoscopy
Monocular Estimation Method (MEM) retinoscopy
- very reliable
- Used when prescribing Near ADD
- Working distance:
- Adults habitual reading distance
- Children Harmon distance (distance from elbow to middle knuckle)
- Age-appropriate cards
- Ret the amount of plus or minus to neutralize
- With motion (WM) = lag of accommodation (+)
- Against motion (AM) = lead of accommodation (-)
- Always abnormal / dont neutralize
Normal value = +0.50 + 0.25D, range of + 0.25D to +0.75D slight lag of accommodation
- If pt’s lag = +1.50 pt is UNDERACCOMMODATING by more than 0.75D for that distance
- Use +1.50 or +1.00 lens as add, check for change in accommodation / new scope should only be +0.50D
- Lenses are used in 2 ways:
- Measuring lenses loose lenses < 1⁄4 of a second to NOT stimulate accommodation
- Probe lenses flippers - long enough to induce accommodation
Examples:
- Neutrality/plano in OD, with-motion in OS
- Plano is bordering a LEAD in accommodation, not normal
- Could be due to
- Anisometropia
- uncorrected astigmatism in one eye
- incorrect binocular balance
Plano in OD, against-motion in OS
- Both eyes are showing a lead response
- Caused:
- over-minus
- uncorrected astigmatism in one eye
Assessment of accuracy of accommodative response to a stimulus - At 40cm, the accommodative demand is 2.5D
Norm = slight accommodative lag
Objective assessment:
Monocular Estimation Method (MEM)
Nott retinoscopy
Book Reinoscopy
Nott retinoscopy
- very reliable
- Response measured without lenses
- changes dist space to determine neutrality
- Patients selection: sensitive around their face, do not like trial frames/lenses, being touched, Down’s syndrome, sensory system overload, etc.
- Target remains at test distance
- If “with motion” detected - MOVE AWAY till neutral
- The dioptric difference in space between the PATIENT to TARGET and the PATIENT to SCOPE represents the lag of accommodation
- Distance neutrality is obtained (in diopters) = accommodative response (AR)
- Distance of target (in diopters) = accommodative stimulus (AS)
- Lag of accommodation = AS – AR
Assessment of accuracy of accommodative response to a stimulus - At 40cm, the accommodative demand is 2.5D
Norm = slight accommodative lag
Objective assessment:
Monocular Estimation Method (MEM)
Nott retinoscopy
Book Reinoscopy
(NOTT + MEM ret most acurate for Lag)
- *Book retinoscopy**
- *QUALITY of response** as pt is presented with a reading material
- Grade response based on COLOR of reflex
- patient reads for comprehension - appropriate material is obtained, probe lenses are used
- As accommodation increases: Reflex against-motion
Stage 1 = Free Reading (IDEAL)
Pt comprehension with little effort
o Reflex is BRIGHT (whitish-pink) and is neutral to low with-motion (WM)
Close to neutrality, fast streak
Stage 2 = Easy Instructional Level
Comprehension with some effort
o Reflex is BRIGHT PINK and essentially neutral with minor shifts to WM and AM
Stage 3 = Difficult Instructional Level
hard to maintain/achieve comprehension
o Reflex is DARK REDDISH PINK and is fluctuating AM (-0.25D to -1.25D)
Stage 4 = Nonreading/complete frustration level
Comprehension not possible
o Reflex is DULL BRICK RED and has high with-motion HEAVY LAG o Also seen if no effort is put forth regardless of demand
Tests of Vergence:
Amplitude measures range of amount of convergence/divergence pt is able to exert
Dynamic measures fluidity of moving from convergence to divergence
Measures the change in vergence direction within a specific amount of time uses prisms
Amplitude:
NPC
Step / Smooth vergence
Dynamics
Near vergence Facility
Dist vergence Facility
Near Point of Convergence (NPC)
maximum convergence amount - Recommended: two measures
-
Accommodative target – Burnell fixation stick
- Norms = 5cm/7cm
- Emphasis on break, not blur
- Start where target is CLEAR AND SINGLE
- Monitor for suppression OBJECTIVE result
-
Penlight and red/green glasses
- Norms = 7cm/10cm
- OD - red light, OS - green light
- adds stress to the disparity vergence system general to keep the target single
Red/green glasses intentionally adds stress to the system to see if NPC recedes
Difference in norms are especially evident in patients with CI
Tests of Vergence:
Amplitude measures range of amount of convergence/divergence pt is able to exert
Dynamic measures fluidity of moving from convergence to divergence
Measures the change in vergence direction within a specific amount of time uses prisms
Amplitude:
NPC
Step / Smooth vergence
Dynamics
Near vergence Facility
Dist vergence Facility
Step/smooth vergence
Measures vergence range (convergence and divergence) using prism bars or prisms in phoropter
Done at distance and near
- Step vergence
- Free space, allows us to monitor the eyes with increasing prism
- No blur value
- Smooth vergence
- phoropter
- CT findings are normal - use this technique
- Norms are different = are physiologically different tests
- Smooth vergence = smoothly and slowly increase vergence demand
- Step vergenc indiscrete increases in vergence demand (not the same size steps)
If performed one method pre-treatment, USE same for post-treatment evaluation
Tests of Vergence:
Amplitude measures range of amount of convergence/divergence pt is able to exert
Dynamic measures fluidity of moving from convergence to divergence
Measures the change in vergence direction within a specific amount of time uses prisms
Amplitude:
NPC
Step / Smooth vergence
Dynamics
Near vergence Facility
Dist vergence Facility
Vergence Dynamics:
- Near vergence facility
-
3BI / 12BO (stacked prism)
- BO ranges are generally larger than BI ranges
- Binocular test @ 40 cm
- Target = single column of 20/30 letters
- Start with Base In prism
- shown to differentiate between symptomatic vs non-symptomatic patients
-
Norm=15cpm+3cpm
- 12 cpm means abnormal
- trouble clearing ONE SIDE of the prism
- Decline over time
-
3BI / 12BO (stacked prism)
- Distance vergence facility
- sensitive measure in CI and concussion patients
- Also helpful in conditions such as divergence excess
- Norm=15cpm+3cpm
Summary of vergence tests:
- In a busy primary care practice, consider:
o NPC
o Near vergence facility
differentiate symptomatic from asymptomatic patients
Tests of Eye movements:
Pursuits, Saccades, Fixation
- Loss of placement during reading, skipping or omitting lines/words, using their finger to guide during reading
- indicate a saccadic or pursuit dysfunction
saccadic dysfunction - HATE reading - task of reading is difficult and tedious
- Direct observation of eye movement
- Northeastern State University College of Optometry (NSUCO)/Maples test
- Visual-Verbal
- Developmental Eye movement test (DEM)
- King-Devick test
- Objective eye movement recordings
- Visagraph
- Right eye
NSUCO (Maples Test):
- Components assessed:
- Saccades / Pursuits / Head movement / Body movement
- Developmentally - do not exhibit eye movements without head or body movements
- Ages: 5 years and above
- Test distance: Harmon distance / no farther than 40cm
- Set up: patient stands directly in front of the examiner
- No instruction given on whether or not to move head
DEM
Interpretation of results
-
Type I = normal
- Pt has normal number naming ability and eye tracking ability
-
Type II saccadic dysfunction
- Pt has normal number naming ability but eye tracking has significant issue
-
Type III. automaticity (number naming difficulty)
- Pt has normal eye tracking ability
- vertical and horizontal components, the time will be HIGH for BOTH
-
Type IV combo of type II and type III
- Pt has number naming issues and saccadic dysfunction
Accommodative insufficiency (AI):
- Difficulty in stimulating accommodation
- Key signs:
- Amplitude - reduced amplitude of accommodation
- < 2D less Hofstetter’s minimum or more
- Response - High lag (> +0.75D) on MEM
- Facility - Difficulty clearing -2.00 flippers on MAF (minus lenses stimulate accommodation)
-
Supporting signs:
- BAF Difficulty with -2.00D flippers binocularly
- Reduced PRA
TREATMENT (preferred) - Visual therapy for AI
Treatment:
- Vision Therapy for AI
- Preferred treatment to normalize accommodative amplitude
- Added plus lenses are NOT preferre - DOES NOT improve symptoms
- 12-14 in-office visits with home reinforcementà~3-3.5 month treatment
-
Correction of refractive error
- Small hyperopia/astigmatism/anisometropia > 1.00 should prescribe 7A
- Cycloplegic evaluation
- ATR and oblique astigmatism lower thresholds for refractive correction (Pt Might need -0.50 comfort)
-
Added plus lenses (aka near ADD or near vision spectacles)
-
Does NOT rectify the insufficient amplitude
- symptomatic if NVO are stopped - Passive treatment
- Considerations:
- krutch - VT to mitigate symptoms
- Pt refuses vision therapy
-
Does NOT rectify the insufficient amplitude
How to prescribe? Added plus lenses
- MEM
- Determine plus needed to bring the value down to normal lag (+0.50 to +0.75D)
- repeating MEM with tentative ADD
MEM: OD +1.25D, OS +1.25D = Possible near adds: +0.50 or +0.75
- NRA/PRA
Summary table
Accommodative Dysfunctions
Ocular Motor Dysfunction:
- Ocular motor control clinically develops more SLOWLY than accommodative and vergence systems
- Basic research data à normal levels by 1-2 years of age
- Clinical research data = development continues through elementary school (mostly end of third grade)
- Eye movements are thought to be related to higher cognitive processes (attention, memory, visual processing)
TYPES:
Types of ocular motor dysfunction:
-
Pathological
- Disease
- Trauma
- Drugs
-
Functional
- Accommodative and/or vergence dysfunction
- Actual non-path OMD
- Role of attention and cognition
-
Relationship to school and sports
- Eye movements in reading
- Eye movements in sports
- Developmental
Drug effect on eye Movement
Muscle actions
Primary - Secondary - Tertiary
Classification: Vergence Anomalies
3 main categories based on AC/A ratio:
- Low AC/A ratio
- Convergence insufficiency
- Divergence insufficiency
- Normal AC/A ratio
- Basic exophoria
- Basic esophoria
- Fusional vergence dysfunction
- High AC/A ratio
- Convergence excess
- Divergence excess
Modified Duane’s Classification:
Is phoria greater at distance or near?
-
N > D = convergence problem
- ESO = high AC/ = CE
- EXO = low AC/A = CI
-
D > N = divergence problem
- ESO = low AC/A = DI
- EXO = high AC/A = DE
-
D = N = basic
- ESO = normal AC/A = basic eso
- EXO = normal AC/A = basic exo
- Normal AC/A = fusional vergence dysfunction
Phorias may be normal, need to look at other conditions
