Plus, Minus, Prism, and Therapy: Managing Accommodative and Vergence Dysfunction

American Academy of Optometry Meeting, Boston 2011

Kristine B. Hopkins, OD, MSPH, FAAO
University of Alabama at Birmingham School of Optometry
Kbhopkins@uab.edu

Case History
Onset: Sudden vs. gradual; Longstanding vs. recent
Frequency: every day, only school/work days, mornings, afternoons
Duration: minutes vs. hours
Eliciting factors: associated with near work, computer work, lighting, etc.
Pertinent medical history/medications: accommodative side effects?
Symptom Checklist or patient/parent survey

Functional Vs. Organic Lesion

Functional Organic
Etiology Reduced function not related to Neurological lesion or other organic defect
organic lesion source of decreased function
Symptoms Typically longstanding without precise Typically sudden onset, often severe
onset. May be unilateral or bilateral
Typically bilateral
Signs Not associated with neurological loss, Typically associated with other neurological
systemic illness, or medications signs, systemic illness, or medication use.
EOM palsy, pupil abnormality, visual field
defect, ptosis.

Initial exam should rule out significant refractive error and ocular pathology. If significant
refractive error present, Rx and return to re-test BV and accommodation with new Rx (4-6
weeks later).

Significant Refractive Error (patients 6 years and older):

Myopia -1.00D or greater
Hyperopia +2.50D or greater*
Astigmatism -1.00D or greater
Aniosmetropia 1.00D difference or greater
*May prescribe for lower amounts of hyperopia in presence of BV/accomm dysfunction

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Binocular, Accommodative, and Ocular Motor Testing Battery and Norms

BV Alignment and Vergences

Test Age Condition Expected Value
Cover Test Any Near 3 XP (±3)
Distance 1 XP (±1)
AC/A Any 3/1 to 5/1
CA/C Any 0.5D per 6Δ
Smooth Vergences Any Near BO 17/21/11
Near BI 13/21/13
BI/BO ranges in Distance BO 9/19/10
phoropter with Risley Distance BI X/7/4
Prisms
Step Vergences Child 7 to 12 Near BO 23/16
Near BI 12/7
BI/BO ranges with Adult 12 Near BO 19/14
prism bar Near BI 13/10
Distance BO 11/7
Distance BI 7/4
Vergence Facility Any 3BI/12BO 15 cpm
Fused prism
NPC Children With accomm tgt 6 cm (minimum 10cm)
Adults With accomm tgt 5/7 cm (minimum 10cm)
Adults With R/G tgt 7/10 cm

Accommodation
Test Age Condition Expected Value
Amplitude Any Any Minimum=[15-(age/4)]-2
Monoc. Facility 8-12 yo ±2.00 flipper 7 cpm (±2.5): at least 4 cpm
13-30 yo ±2.00 flipper 11 cpm (±5): at least 6 cpm
Binoc Facility 8-12 yo ±2.00 flipper 5 cpm (±2.5): at least 2 cpm
13-30 yo Scaled flipper 10 cpm
13-30 yo ±2.00 flipper Approx 8 cpm
NRA Any +2.00 to +2.50

PRA Any -2.37 to –3.37

Accom Response Any MEM +0.25 to +0.50

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Accommodative Insufficiency
Symptoms Associated with near work: blur (text “comes in and out of focus”),
headaches, tired or sore eyes, poor reading comprehension, fatigue,
blinking or squinting to read.
Signs Reduced amplitude of accommodation
 [15-(age/4)]-2
May or may not show higher lag on MEM
Critical Tests Accommodative Amplitude
 Push-up (highest value and lowest repeatability)
 Pull-away
 Minus lens amps (lowest value but best repeatability)
 Objective amps with retinoscope (over estimates amps)
Treatment Options Additional plus at near
 Plus build up—subjective
 MEM method—for patients with high lag on MEM, add plus
until MEM normalizes
 NRA/PRA midpoint—accounts for vergence ranges but doesn’t
always indicate need for additional plus
 BCC—subjective
For young patients: Rx FT at lower pupil margin, PAL 2-3cm high, or
NVO specs (multifocal CL’s?)
Vision therapy
 Often best choice if AI is also associated with BV dysfunction

Accommodative Infacility
Symptoms Blur (may be distance or near), difficulty copying from the board,
headaches, fatigue, eye strain
Signs Reduced monocular and binocular accommodative facility
 Difficult with + and – sides of flipper
May also show decreased NRA/PRA
Critical Tests Monocular Accommodative Facility
 Reduced binocular facility not specific to accommodative
infacility (may also indicate poor vergences)
Treatment Options Additional plus at near if NRA is high enough (see AI)
Vision therapy

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Accommodative Excess/Spasm
Symptoms Blur (may be distance or near) worse after prolonged near work,
headaches, eye strain, fatigue, diplopia (if associated with ET)
Signs  Neutral or lead with MEM
 Difficulty clearing plus with monocular facility testing
 Reduced NRA
 Dry ret/auto may show more minus than wet
Critical Tests  MEM
 Monocular accommodative facility
 Wet retinoscopy
Treatment Options Vision Therapy
Cycloplegic agents for extreme spasm
 Spasm of the near reflex: lead on MEM, ET, and pupil miosis
 Consider 1% Atropine OU twice/week with near add (wean
over time)
Bifocal lenses not indicated (low NRA—patient will not accept plus)

Binocular Vision Dysfunction: Making the Diagnosis

 Begin with measurement of ocular alignment at distance and near to make Duanne’s
classification and generalization about AC/A.
 Look at tests that belong to compensating testing group for depressed findings to
support diagnosis
o For an exo deviation, the tests that measure Positive Fusional Vergence (PFV)
findings would need to be normal or high to prevent symptoms. Depressed PFV
findings along with symptoms support the diagnosis and need for treatment.
o For an eso deviation, the tests that measure Negative Fusional Vergence (NFV)
findings would need to be normal or high to prevent symptoms. Depressed NFV
findings along with symptoms support the diagnosis and need for treatment.
 If symptoms and signs are present, recommend treatment

Deviation Compensating Group Tests

Exo Deviation Positive Fusional Vergence Group BO (PFV) ranges (smooth or step)
BO ability with vergence facility
NPC
NRA
Binocular Plus with accommodative facilty
MEM (may show lead?)
Eso Deviation Negative Fusional Vergence Group BI (NFV) ranges (smooth or step)
BI ability with vergence facility
PRA
Binocular minus with accommodative facility
MEM (may show lag?)

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Expanded Duanne’s Classifications
Cover Test Duanne’s Classification AC/A Supporting Signs
Greater eso at near Convergence Excess (CE) High Reduced NFV findings at near
than distance
Greater exo at Divergence Excess (DE) High May show reduced PFV findings at
distance than near distance (but often normal)
Greater eso at Divergence Insufficiency (DI) Low Reduced NFV findings at distance
distance than near
Greater exo at near Convergence Insufficiency (CI) Low Reduced PFV findings at near
than distance
Similar eso at Basic Eso Normal Reduced NFV findings at distance
distance and near and/or near
Similar exo at Basic Exo Normal Reduced PFV findings at distance
distance and near and/or near
Nearly ortho at Fusional Vergence Dysfunction Normal Reduced PFV and NFV at distance
distance and near and/or near

Convergence Excess
Symptoms Headaches and eye strain with near work, blur, diplopia at near, fatigue
with reading, slow reading, poor reading comprehension, words moving
on page, avoidance of reading
Signs  Greater eso at near than distance
 High AC/A
 Low NFV group findings
 May show high lag with MEM
Critical Tests  Cover Test
 NFV group tests
 MEM
Treatment Options Additional Plus at near
 High AC/A responds well to low amounts of plus
 Rx amount of plus that reduces near phoria to near ortho
(maximum plus to correspond with working distance)
Base Out Prism
 May be needed if small eso present at distance and near add
still leaves residual eso with symptoms
Vision Therapy
 Not generally first line of treatment. May be necessary of
optical management alone does not resolve symptoms or if
patient unable/unwilling to wear optical correction

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Divergence Excess
Symptoms Cosmetic concerns about outward eye turn (often IXT), rarely diplopia,
rarely near point symptoms
Signs  Parent/patient report of IXT (may not manifest with CT)
 Greater exo at distance than near
 PFV and NFV ranges may be normal at distance and near
 May show suppression or ARC at distance when the eye is XT
 High AC/A by calculation but may not be truly high with gradient
Critical Tests  Cover Test
 PFV data (although may be normal)
 May do prolonged CT to rule out Pseudo-DE
Treatment Options Over minus lenses
 Recommended for young patients (under 6) with true high AC/A
 Trial over minus in office
 Rx for FTW generally up to -2.50 over minus
Vision Therapy
 DE IXT’s generally respond well to VT and often first line of tx
 Emphasize diplopia awareness and vergence ranges
Prism
 Horizontal prism not generally beneficial
Occlusion
 FT occlusion for as long as 2 months may decrease suppression
and improve fusion
 More popular with ophthalmology
Surgery
 Considered for very large (>35-40), frequent deviations that fail
to respond to more conservative treatment

Divergence Insufficiency
Symptoms Longstanding intermittent diplopia at distance, headaches, ocular
fatigue, difficulty focusing from far to near
Signs  Greater eso at distance than near (phoria or tropia)
 Reduced NFV group findings at distance
Critical Tests  Cover Test
 NFV group tests (at distance)
 EOM’s (rule out 6th Nerve Palsy)
Treatment Options Prism
 BO prism often treatment of choice for low magnitude deviation
Vision Therapy
 Improving NFV ranges and vergence facility often helpful
Surgery
 Last resort if deviation cannot be managed with prism and VT

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Convergence Insufficiency
Symptoms Symptoms occur while doing near work: headaches, eye strain, blurred
vision, diplopia, movement of print, poor reading comprehension
Signs  Greater exo at near than distance
 Receded NPC
 Reduced PFV group findings
 Low AC/A
Critical Tests  Cover Test
 NPC
 PFV group tests
Treatment Options Vision Therapy (office based)
 Most effective treatment for CI
 Emphasize PFV’s and NPC as well as accommodative amps and
facility
Vision Therapy (home based)
 Use of HTS or similar computer system may be beneficial but will
likely take longer than office based treatment
 Pencil push-up therapy alone is not effective
BI Prism
 Not generally effective for long term treatment of CI

Basic Eso
Symptoms Symptoms may be associated with distance and/or near work:
headaches, eye strain, blur, diplopia, poor reading comprehension
Signs  Similar eso at distance and near
 Reduced NFV group findings at distance and near
 MEM may show higher than normal lag
Critical Tests  Cover test
 NFV group tests
 MEM
 EOM’s (rule out 6th Nerve Palsy)
Treatment Options Additional Plus at Near
 Although AC/A normal, low amounts of plus may reduce EP
enough to eliminate near symptoms
 Rx least amount of plus necessary
BO Prism
 BO relieving prism should be considered when plus not well
tolerated or not effective.
 Eso’s generally respond more favorably to prism than exo’s
Vision Therapy
 Therapy to improve NFV ranges at near and then distance often
helpful

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Basic Exo
Symptoms Symptoms may be present with near or distance work: eye strain,
headaches, blur, diplopia, poor reading comprehension, movement of
print
Signs  Similar exo at distance and near
 Reduced PFV group findings at distance and near
 Receded NPC
Critical Tests  Cover test
 PFV group tests
Treatment Options Vision Therapy
 Responds favorably to therapy (similar program to CI)
 In-office therapy recommended when possible, home therapy
may also be effective
Prism
 BI relieving prism may be considered
 If vertical deviation present, vertical prism may be helpful
Surgery
 Rarely necessary but may be considered for large deviations that
do not respond completely with therapy and/or prism

Fusional Vergence Dysfunction

Symptoms Symptoms associated with near work: Headaches, eye strain, blur, poor
reading comprehension, avoidance of reading
Signs  Normal phoria at distance and near
 Reduced BO and BI ranges at near and/or distance
 Reduced PRA and NRA
 Reduced binocular accommodative facility but normal
monocular facility
Critical Tests  Fusional vergence ranges (BI and BO)
 Accommodative facility testing
 NRA/PRA
Treatment Options Vision Therapy
 Training improves vergence ranges
 In-office vs. home

Reference: Scheiman M, Wick B. Clinical Management of Binocular Vision: Heterophoric, Accomodative, and Eye
Movement Disorders, 3 ed: Lippincott Williams & Wilkins, 2008

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