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
NSUCO (Maples test)
NSUCO Saccades
NSUCO Pursuits:
NSUCO scoring criteria:
- NSUCO saccades:
- 2 targets, 20 cm apart
- Binocular - Horizontal Saccades
- Wolff wands or different colored pens
- Instruction: only look at the color instructed to.
- Pause maintaining fixation on the target - assess fixation
- 5 round trips
- NSUCO Pursuits:
- Pursuit = follow One target
- Two clockwise rotations and two counterclockwise rotations
- 20 cm diameter circular path
- Instruction: Don’t ever take your eyes off it”
- NSUCO scoring criteria:
- Ability to perform the task - Accuracy of performance
- Saccades = overshoots or undershoots
- More over/undershoot - less accurate the accuracy score
- Eye movements in isolation - HEAD still - High score
- *Overshoot** = eyes initially go past target, needs to refixate
- *Undershoot** = eyes lag in front of the target, have to make corrective saccade to target
But there seems to be more head and body movements when we are younger
o Less and less head and body movements as we age, around 10-11 years of age
- Eye movements are not very accurate at young agesàlevel off at 10-11 years of age
Eye Movement tests Visual-Verbal tests:
- Simulation of a reading environment
- Calling out numbers = verbal component of test
- Reading the numbers = visual component of test
- *eye movement problem or difficulty naming numbers?**
DEM:
o DEM test can distinguish if the patient has a number naming problem vs an eye movement problem
- Normed for 6-14 years old - peds test, can use in adults who have suffered a head injury too
DEM
- Diff reading the numbers in the vertical columns (cards A and B) AND the horizontal rows (card C)àit is a number naming difficulty
- perfect vertical columns (cards A and B)Diff reading horizontal rows (card C) it is an eye movement problem
Errors
- Omission omits a few numbers or entire rows
- Addition numbers added or repeated
- Substitution numbers read incorrectly and not immediately
- Transposition numbers called out of sequence
Setup
- If > 3 errors are noted in the vertical portion = repeat ONCE MORE
- If >3 errors persist, STOP testing further
-
Compute
- Total vertical time
- Horizontal adjusted time
- Adjusted time = Time x [80/(80 – omission + addition)
- Total errors
- Total errors = (s+o+a+t)
- _entire line omitte_d is counted as 1 for TOTAL ERRORS
- Ratio
- Horizontal Adjusted time / Vertical time
-
Errors:
- entire line is skipped, count those 5 omitted numbers as 5 when using the formula for adjusted time
- _entire line omitte_d is counted as 1 for TOTAL ERRORS
- If pt has symptoms use 0.5 SD
- If pt is Asymptomatic use 1.5 SD
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
Eye Movement testing
King-Devick test:
- 3 test plates containing lines of numbers
**This test fails to control for automaticity**
King-Devick test:
- 3 test plates containing lines of numbers
- fast and accurate as possible - Each test plate is timed
- TOTAL time compared to norms
- ## **This test fails to control for automaticity**
Uses:
- Increasingly used as a sideline screening tool for concussion
- Eye movement screening in Parkinson’s, Alzheimer’s etc.
- DEM has more clinical value
Objective Eye movement recorders:
Uses infrared eye tracking system
Visagraph/Readalyzer
RightEye
-
Visagraph/Readalyzer
- Horizontal/vertical saccades (maybe pursuits)
-
RightEye
- Pursuits, saccades
- Pt sits 50cm from the screen
Benefits:
- Sophisticated measures
- Fixation
- Duration of fixation
- Regression
- Reading rate
- Not dependent on examiner skills
- Gives both graphical and quantitative results
Disadvantages:
- COST
- Difficult to use in inattentive/hyperactive patients
Fixation Disparity:
- Failure to maintain targets on both fovea but still have fusion (within fusional area)
Slight vergence slip but still binocular
Fixation Disparity:
- Evaluates binocular vision under associated conditions
- Helpful for determining prism Rx = does not overestimate!
- Not part of routine exam, don’t perform on every single patient
Clinical tests:
o Saladdin card
o Wesson card
Types of Accommodative dysfunction:
- Duke-Elder classification
-
Accommodative insufficiency
- Ill-sustained accommodation
-
Accommodative infacility
- Paralysis of accommodation
- Spasm of accommodation (excess)
Accommodative insufficiency
- 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)
Accommodative infacility
- difficulty changing the accommodative response level
- Latency and speed of response (dynamics) are abnormal
- Key signs:
- Amplitude - Normal
- Response - Normal (i.e. MEM will be normal)
- Facility - Difficulty clearing BOTH (+) and (–) lenses on MAF KEY DIAGNOSITC SIGN
Accommodation (excess)
- Difficulty with relaxing accommodation
- Accommodative response is greater than stimulus
- Key signs:
- Amplitude - Normal
- Response - Low MEM (will get plano or (-) / LEAD of accom
- Facility - Difficulty clearing (+) lenses on MAF
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
Accommodative infacility:
- Patient experience difficulty changing the accommodative response level
- Latency and speed of response (dynamics) are abnormal
- NOTE - Normal amplitudes - If only AA or response is measured but not facility, infacility can easily be missed
- Key signs:
- Amplitude - Normal
- Response Normal (i.e. MEM will be normal)
- Facility - Difficulty clearing BOTH (+) and (–) lenses on MAF
-
Supporting sings:
- Difficulty with (+) and (–) lenses on BAF
- Reduced NRA/PRA (narrow range)
Neither added lenses NOR prisms will be of any benefit to accommodative infacility
Treatment
-
Correction of refractive error
- Head trauma Pts benefit more from Small 7A
- Small hyperopia/astigmatism/anisometropia
- Vision therapy
Accommodative excess (AE):
- Difficulty with relaxing accommodation
- Accommodative response is greater than stimulus
-
AKA
- Spasm of the near reflex - miosis, convergence, accommodation
- accommodative spasm
- pseudo-myopia
- Key signs:
- Amplitude Normal
- Response - Low MEM (will get plano or (-) - LEAD of accom
- _West Coas_t = LEAD of accom = against motion or (-) value on MEM • So plano would NOT be considered a LEAD of accom
- East Coast = LEAD of accom = plano and anything less than plano
- Facility - Difficulty clearing (+) lenses on MAF
-
Supporting signs:
- Difficulty clearing + lenses on BAF
- Low NRA
Pt will report first sustained blur very QUICKLY on NRA b/c they are unable to relax their accommodation with higher plus lenses
Treatment
-
Correction of refractive error
- Small hyperopia/astigmatism/anisometropia
-
Vision therapy
- Added lenses and prisms do NOT help accommodative excess
DDX
Accommodative Insufficiency
Accommodative Infacility
Non-functional causes to rule out AI or Accommodative infacility
-
Drugs
- Alcohol
- Antihistamines
- Phenothiazides
- Cycloplegics
- CNS stimulants
- Marijuana
- Diseases – adults
- DM
- Anemia
- MS
- Botulism
- Myotonic dystrophy
- Malaria
- Typhoid
- Eye diseases – adults
- Iridocyclitis
- Glaucoma
- Iris sphincter tear
- Blunt trauma
- Scleritis
- Diseases – children
- Anemia
- Mumps
- Measles
- Tonsilitis
- Whooping cough
- Lead/arsenic poisoning
DDX
Accommodative Excess
Non-functional causes to rule out AE
- Drugs
- Cholinergic drugs
- Morphine
- Sulfonamides/CAI
- Diseases – adults
- Encephalitis
- Syphilis
- Trigeminal neuralgia
- Diseases – children
- Encephalitis
- Meningitis
- Influenza
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
Persuits and Saccadic
Pathways
Pursuits
- Control centers of pursuits is believed to be the occipitoparietal junction
- Supranuclear control of pursuits are ipsilateral
- Occipitoparietal junction. – midbrain – nuclei of the EOMs
Saccades
- Control centers of saccades originate in the frontal eye fields (Brodmann’s area 8)
- Supranuclear control of saccades are contralateral
- Frontal eye fields – midbrain pons – nuclei of the EOMs
Differential diagnosis of Pursuit dysfunctions:
- Serious underlying disease to rule out:
Cogwheeling
Slow pursuit gain
- Differential diagnosis of Pursuit dysfunctions:
- Serious underlying disease to rule out:
- Cogwheeling (step-like/staccato movement)
- Possible causes:
- Basal ganglia disease
-
Parkinson’s disease – caused by dopamine deficiency, leads to impaired neural inhibition
- Signs:
- Muscle rigidity
- Slowness of movements
- Tremors
- Signs:
- Cerebellar disease
- Possible causes:
- Slow pursuit gain
- Aging
- Tranquilizers
- Anticonvulsants
Differential diagnoses of Saccadic dysfunction
- Disorders of velocity
- Disorders of accuracy
- Disorders of initiation
- Inappropriate saccades
Differential diagnoses of Saccadic dysfunction:
- Disorders of velocity
-
Saccades too slow
- Ocular motor nerve paresis
- Internuclear ophthalmoplegia
-
Saccades too fast
- Internuclear ophthalmoplegia
-
Truncated saccades (shortened in duration/extent)
- Myasthenia gravis
-
Saccades too slow
- Disorders of accuracy
- Dysmetria – over or under shooting
- Disorders of initiation
- Reaction time differences
- Inappropriate saccades
- Interfere with foveal fixation
- Saccadic intrusion syndrome
CASE Ddx
Found nystagmus in superior gaze during EOMs
- Ask about headaches, nausea, dizziness, diplopia, tingling arms and legs, change in appetite, unintended weight gain/lossàneurological questions
- Further neurological testing:
- Cover test, Color vision, Fields, DFE o Were all negative
multiple sclerosis
Blurry vision, nystagmus, optic neuritis were the presenting signs of MS
Dx: saccadic intrusion syndrome secondary to her acquired brain injury
- Inappropriate saccades that disrupts fixation
- Prescribed Gabapentin (aka Neurontin, for anti-seizure, diabetic neuropathy, control of migraines, overall used in a lot of neurological incidences) with no relief
- jumping of the target in all positions with a decrease in superior gaze
- High velocity spontaneous horizontal saccadic intrusions were observable in all positions of gaze with a decrease in superior direction
Largest improvement was reported and observed while wearing plano with 6pd yoked BD prism OU
Drug effect on eye Movement
Developmental OMD:
- Patient with overall delay of development
- Birth history
- Prenatal
- History as an infant
- Environment
- Nutrition
- Prematurity
- Perinatal
- Unknown
Craniosynostosis - Abnormal head development due to premature closure of seams in skull
Crouzon syndrome - - most common, premature fusion of skull bones
Can turn down lights so less distracting for stimulus to gauge eye movements
Symptoms Associated with OMD
- Loss of place of omission of words when reading
- Skipping lines
- Difficulty copying from the blackboard
- Poor comprehension
- Slow reading speed
- Poor attention, easily distractible
- Fatigue when reading
- Vertigo, dizziness
- Motion sickness
- Poor performance in sports
- Excessive head movement
- ASK ABOUT USING FINGER TO GUIDE WHILE READING!!
Muscle actions
Primary - Secondary - Tertiary
Eye movements:
Pursuits
to maintain a moving object on the fovea
Pursuits = to maintain a moving object on the fovea
- Significant role in sports and driving
- Not as much associated with reading
Fixation = to evaluate the ability of the patient to maintain steady fixation
- Measure of EOM control as well as attention
- Duration of fixation on a piece of information ~ 200-250 ms
- Children learning to read and poor readers tend to make more and longer fixations
- Abnormal fixation results in square wave intrusion – due to lack of EOM control
Saccadic eye movements:
To bring an off-foveal object onto the fovea
Saccadic eye movements:
- To bring an off-foveal object onto the fovea @ 10% of reading time
- Average saccade is 8-9 characters (can range 2-15 characters)
- Duration of the saccade is a function of the distance covered
- Between saccades, the eye is relatively still in fixational pause
- The perfect saccade is a single eye movement that rapidly reaches and abruptly stops at the target of interest
Inaccuracies:
-
Undershooting - most common
- Stops just before the target
- Eyes either then glide towards the target or make another saccade to reach target
-
Overshooting - less common
- Eyes go past the target, have to come back
Regressions
Right-left eye movement (backtracking)
- the reader overshoots the target
- misinterprets the test
- has difficulty with comprehension of reading material
Children with reading or learning difficulties have high prevalence of eye movement anomalies
- *Regressions:** - Right-left eye movement (backtracking)
- Can occur when the reader overshoots the target, misinterprets the test, or has difficulty with comprehension of reading material
- Increases as difficulty of reading material increases
-
Normal readers
- 10-20% of all saccades during reading are regressions
-
Poor readers
- 35-40% of all saccades during reading are regressions
- Objective methods are most accurate to measure regressions
- Readalyzer
o But hard to separate cause and result
o Important to ask about SCHOOL HISTORY!
i.e. is your child reading on grade level? Any difficulty reading? Are they receiving any additional educational resources? à determined if there any types of learning difficulty that the doctor should look into further
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
Phorias
Also evaluate the Qaulity / Type instead of only the Magnitude
- Phorias at D and N = look for magnitude difference but ALSO quality/type of deviation
EXAMPLE:
- CT at distance–8XP , CT at near – 6IXT
- If you just look at the numbers, it seems that distance is worse than near = would assume basic EXO
- But if you look at the quality as well, the patient has worse control of their deviation at near (b/c intermittent exotropia) than at distance (latent phoria)
CI b/c deviation is worse at near than distance
Low AC/A Conditions:
Convergence insufficiency
Divergence insuficiency
Convergence insufficiency (CI)
- Key signs:
- EXO Near > Distance
- Receded NPC
- Low AC/A
- Low PFV at near
- Difficulty with BO on vergence facility
- BO demands convergence
- Supporting signs:
- Difficulty clearing (+) on BAF
- (+) lenses trigger accom relaxation and PFV
-
Low MEM = LEAD of accom
- Pts with convergence problems (low PFV) often have to rely on their accommodative vergence to focus at near More accommodation = lead of accom
- Low NRA (+ lenses)
- Difficulty clearing (+) on BAF
Convergence insufficiency (CI)
+
Accommodative Dysfunctions
Convergence Insufficiency
- CI + A-Excess
- Difficulty with (+) on MAF testing
- CI + A-Insufficiency
- Difficulty with (-) on MAF testing
- Low amps
- Possible improvement in NPC with plus lenses at near
Convergence insufficiency (CI)
TYPES
Types:
- True CI
-
Pseudo CI
- Underlying accommodative insufficiency leading to reduced accommodative effort and greater exophoria at near
- CI can be secondary to AI
- Mild improvement in NPC with plus lenses
Convergence Insufficiency
Treatment
Treatment:
True CI
-
Correct refractive error
- Hyperopia consideration - significant hyperopia may wish to correct it EVEN if the EXO gets worse
-
Prisms (base-in) Relieving Prisms
- Relieves the demand on fusional vergence (convergence)
- Amount determined by:
- Sheard’s criterion
- Fixation disparity
- Vision therapy = preferred treatment of choice (both young pts and adults
Pseudo CI
- Plus lenses at near
- VT as needed
§ **Correct any PRIMARY vertical deviation**
- A primary vertical deviation exists even under fused conditions (binocular), as a fixation disparity
- Secondary deviations manifest when pt is dissociated = don’t have to treat because it disappears when patient is fusing
True for ALL VERGENCE ANOMALIES
- An uncorrected vertical deviation can impede the treatment of horizontal deviations
- The compensating fusional skills are different in horizontal and vertical deviations
Prescribing Prism
SHEARDS Criterion
Near cover test - 16 XP’
Near Base OUT - x/16/10 - always use Blur value unless not measured
Sheard’s:
Amount of Prism = 2/3(phoria) - 1/3(compensating fusional vergence)
= 0.66(16) - 0.33(16)
=5.3 BI
