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Plus, Minus, Prism, and Therapy:
Managing Accommodative and Vergence
Dysfunction
Kristine B. Hopkins, OD, MSPH, FAAO
Disclosure Statement
 Nothing to disclose
Meet Karley
 10yowf referred to your office for ―eye teaming‖ issues
 Symptoms/history…
 Blur and double vision while reading
 Headaches with reading
 Symptoms for more than 1 year
 4th grader
 Previous eye exam ―normal health‖
 Was given reading glasses that don’t help much
 What does this history tell us?
Functional vs. Organic Dysfunction
Functional
Organic
Etiology
Reduced function not related to organic
lesion
Neurological lesion or other organic defect
source of decreased function
Symptoms
Typically longstanding without precise
onset.
Typically sudden onset, often severe
May be unilateral or bilateral
Typically bilateral
Signs
Not associated with neurological loss,
systemic illness, or medications
Typically associated with other neurological
signs, systemic illness, or medication use.
EOM palsy, pupil abnormality, visual field
defect, ptosis.
Karley’s initial exam…
 Referred from local Doc
 VA’s 20/20 without need for Rx
 Normal pupils, EOM’s, and VF
 Normal ocular health
 Near work symptoms
 Presumed functional etiology
 Initial exam must rule out ocular pathology and need for
glasses
Significant Refractive Error
Myopia
-1.00D or greater
Hyperopia
+2.50D or greater**
Astigmatism
-1.00D or greater
Aniosmetropia
1.00D difference or greater
*
*Patients 6 years and older
**May prescribe for lower amounts of hyperopia in presence of BV/accomm dysfunction
 If a significant Rx is indicated, Rx this first and re-evaluate
BV/accomm findings 4-6 weeks later with new Rx
Comprehensive history
with BV symptoms
•Supports functional diagnosis
•Pt. symptomatic requiring
treatment
Refractive error and
ocular health
addressed
Binocular and
Accommodative Test
Battery
BV Testing
 Alignment (dissociated)
 Comparison of distance
and near phoria give intial
Duanne’s Classification
 Cover Test
 Von Graefe
 Modified Thorington
 Maddox Rod
 Alignment (associated)
 Fixation Disparity
Karley’s CT: 0rtho @ Distance, 8-10 XP @ near
Duanne’s Classification
Cover Test
Duanne’s Classification
Greater eso at near than distance
Convergence Excess (CE)
AC/A
High
Greater exo at distance than near Divergence Excess (DE)
High
Greater eso at distance than near
Divergence Insufficiency (DI)
Low
Greater exo at near than distance
Convergence Insufficiency (CI)
Low
Similar eso at distance and near
Basic Eso
Normal
Similar exo at distance and near
Basic Exo
Normal
Nearly ortho at distance and near FusionalVergence Dysfunction
Normal
Alignment—Fixation Disparity
 Alignment tested while fused (using
polarized glasses)
 Fixation Disparity
 Small error in fixation that occurs under
binocular conditions (fusion is present)
 vergence inaccuracy
 measured in minutes of arc (fractions of )



34.2 minutes of arc per prism diopter
Example: 17’ FD= approx ½ prism diopter
Most FD is less than 10’ (<1/3 prism diopter)
Fixation Disparity
Wesson Fixation Disparity Card
Fixation Disparity
Saladin Card
Fixation Disparity—Associated Phoria
 The associated phoria is the amount of prism that reduces the
fixation disparity to zero (i.e. corrects the vergence misalignment)
 This prism amount is often used to prescribe relieving prism
5BI
Lateral FD (eso/exo): Use
BI/BO prism to align vertical
vernier lines
2BU
Vertical FD (R or L hyper): Use vertical
prism to align horizontal vernier lines
Analyze Compensating Vergence Group
 If the patient is Exo, must use Positive Fusional Vergences
(Base Out) to compensate (control the exo)
 Evaluate the Base Out (PFV) group and look for low findings
 If the patient is Eso, must use Negative Fusional Vergences
(Base In) to compensate (control the eso)
 Evaluate the Base In (NFV) group and look for low findings
 Presence of abnormal eso or exo with low compensating
findings support Duanne’s classification and justification for
tx
Compensating vergence group
Motor
Alignment
PFV (BO)
Group
NFV (BI)
Group
CT @ near
PFV
smooth
NFV
smooth
CT @ dist
PFV step
NFV step
Fixation
Disparity
NPC
PRA
AC/A
NRA
Binoc
accom
MINUS
Binoc
accom
PLUS
If the patient is exophoric or
exotropic, look for low findings here
If the patient is esophoric or esotropic,
look for low findings here
Fusional Vergences
 FusionalVergences (Fusional Reserves)
 Prism Bars (step vergences)
 Risley Prism (phoropter—smooth vergences)
 Vergence facility-near (12∆BO/3 ∆BI)
 Near Point of Convergence
 Indirectly: NRA/PRA
Vergence Testing
Smooth (Risley) Vergences
Step (Prism Bar) Vergences
 In phoropter
 Hand held prism bars
 Can’t see pt
 Good visibility of patient
 Proximal cues
 More ―realistic‖
 Difficult for young pts
 Better repeatability than
Prism bar
 Repeatability (COR) at near
 PFV break (adults) 7∆
 PFV break (kids) 12∆
 Poorer repeatability
 Repeatability (COR) at
near for adults
 PFV break 15∆
 NFV break 8∆
 NFV break (adults) 7∆
•Antona et al. Ophthalmic Physiol Opt. 2008 Sep;28(5):475-91
•Rouse et al. Optom Vis Sci. 2002 Apr;79(4):254-64
Vergence Testing
 Bottom line…
 Cannot compare in phoropter ranges with prism bar
 Pick one method and stick with it
 Be mindful of normal fluctuations in measures
NPC testing—target selection?
Accommodative
target
18 controls
Transiluminator
and red lens
36 subjects
Accommodative
Target
18 CI
Transiluminator
and red lens
NPC Break
Controls
NPC Break
CI
Sensitivity
False
Positive
False
Negative
AccommTgt
4.31 cm
10.05 cm
94.4%
15%
6.25%
Trans/red
lens
4.08 cm
13.04 cm
100%
10%
0%
Pang et al. Ophthalmic Physiol Opt. 2010 May;30(3):298-303
Negative Relative Accommodation
 NRA requires good PFV
 Low NRA indicates:
 Unable to relax
Divergence would
occur with relaxing
of accomm
A
accommodation
 Low PFV (BO) ranges
target
Must use PFV
to keep fusion
Plus lenses
Positive Relative Accommodation
 PRA requires good NFV
 Reduced PRA indicates:
A
Convergence would
occur with increase in
accomm
Must use NFV
to maintain
fusion
target
 Reduced accommodative
amplitude
 Reduced NVF (BI ranges)
Minus lenses
Compensating vergence group
Motor
Alignment
PFV (BO)
Group
NFV (BI)
Group
CT @ near
PFV
smooth
NFV
smooth
CT @ dist
PFV step
NFV step
Fixation
Disparity
NPC
PRA
AC/A
NRA
Binoc
accom
MINUS
Binoc
accom
PLUS
If the patient is exophoric or
exotropic, look for low findings here
If the patient is esophoric or esotropic,
look for low findings here
BV Test Battery
Test
Cover Test
Age
Any
AC/A
CA/C
Smooth Vergences
BI/BO ranges in
phoropter with
Risley Prisms
Step Vergences
BI/BO ranges with
prism bar
Any
Any
Any
Any
Near BO
Near BI
Distance BO
Distance BI
Near BO
Near BI
Near BO
Near BI
Distance BO
Distance BI
3BI/12BO
Expected Value
3 XP (±3)
1 XP (±1)
3/1 to 5/1
0.5D per 6Δ
17/21/11
13/21/13
9/19/10
X/7/4
23/16
12/7
19/14
13/10
11/7
7/4
15 cpm
Vergence Facility
Fused prism
NPC
Children
Adults
Adults
With accomm tgt
With accomm tgt
With R/G tgt
6 cm (minimum 10cm)
5/7 cm (minimum 10cm)
7/10 cm
Child 7 to 12
Adult 12
Condition
Near
Distance
Scheiman M. Wick B. Binocular Vision Heterophoric, Accommodative, and Eye Movement Disorders.
3rd Edition. Lippincott. 2008
Summary…(bottom line)
History suggests functional
etiology
Start analysis with Cover
Test
--8-10XP @ N, Ortho @ D
Look at PFV Group and
compare to normative values
(look for low findings)
--PFV, NRA, NPC,
Make Diagnosis…CI!
Karley’s diagnosis…
 Cover Test
 Ortho @ dist, 10XP @ near Greater exo at near suggests CI
 PFV Group
 NPC: 40/75! cm (Norm = 6cm)…Low
 PFV: X/3/-5 (Norm = 23/16)…Low
 NRA: +1.75 (norm = +2.50)…Low
 Symptoms + Exo at near + low PFV group
=Convergence Insufficiency
 What about Karley’s Accommodative System?
Accommodative Test Battery
 Amplitude
 Push-up
 Pull away
 Minus Lenses
 Facility
 +/-2.00
 scaled
 MEM
 NRA/PRA
Accommodative Amplitude
 61 subjects (18-32 years)
 Measured Amps with three different methods on 2 visits
Method
Mean Amp (D)
SD (D)
COR (D)
AA by push-up
13.08
2.79
±4.76*
AA by push-down
11.25
1.77
±4.00
AA by minus lens
8.56
1.72
±2.52
*COR =5.32D for 5th and 6th graders (Rouse et al. OptomVis Sci. 2002 Apr;79(4):254-64
 Minus lens 2D< push down 2D< push up
 Minus lens gives lowest amp value and has highest repeatability
 Poor agreement between methods
Antona et al. Ophthalmic Physiol Opt. 2009 Nov;29(6):606-14. Epub 2009 Aug 3
Amp Norms?
 Hoffstetter’s Minimum
 15-0.25(age)…??
 Sterner examined push-up
amps in 6-10 year old
Swedish children OD, OS,
and OU
 Over 1/3 of the subjects
were 2D less than
Hofstetter’s minimums
 Why?
 Norms are to high?
 Swedish children all have
accommodative problems?
Minimum= [15-0.25(age)]-2
Accommodative Facility
 Traditionally +/-2.00 @ 40cm
 Facility measures 8-12 year old different than 13-30 year olds
 Facility measures not reliable under 8 years of age
 Measure OU first (pursue monocular measure only if fail OU)
Binocular
minimum
Monocular
minimum
8-12 year old
2 cpm
4 cpm
13-30 year old
8 cpm
6 cpm
Accommodative Test Battery
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
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
Binoc Facility
NRA
Any
+2.00 to +2.50
PRA
Any
-2.37 to –3.37
Accom Response
Any
MEM
+0.25 to +0.50
Back to
Karley
 Symptoms
indicate near blur
 Run accomm
test battery
 Look for low
findings
Min
(15-0.25(10))-2= 10.5D
At least 4 mono/2 binoc
NRA
+2.50; PRA
+0.50
Diagnosis: Accommodative Insufficiency (Disorder of Accommodation)
-2.50
Good VA without need for glasses
Start with CT to make
initial Duanne’s
Classification (CI)
Look for low values in the
compensating vergence group
(BO) to confirm CI
Look for low accommodative
findings to make diagnosis of
accommodative disorder (AI)
Binocular Vision Disorders
High AC/A
CE
DE
Normal AC/A
Low AC/A
CI
DI
Basic Eso
Accommodative Disorders
Accommodative
Insufficiency
Accommodative
Excess
Basic Exo
FVD
Convergence Insufficiency
 Symptoms: (occur with near work) headaches, eye strain,
blur, diplopia, movement of print, poor reading
comprehension
 Signs: Greater exo at near than distance, receded NPC,
reduced PFV findings, low AC/A
 Treatment options: In office therapy, home based therapy,
prism, pencil push-ups…
Convergence Insufficiency Treatment Trial
(CITT)


Funded by National Institutes of Health/National Eye
Institute (NIH/NEI)
$3.8 million study done with OD and MD collaboration
in 9 centers in the US
UAB
Bascom Palmer
Mayo Clinic
SUNY
NOVA
Ohio State
PCO
Ratner Eye Center
SCCO
Convergence Insufficiency Treatment Trial Study Group. Randomized Clinical Trial of Treatments for
Symptomatic Convergence Insufficiency in Children. Arch Ophthalmol. 126 (10) October 2008. pp
1336-1349.
CITT
Randomized Clinical Trial of 221 children
between 9 and 17 years of age with CI
Research Question:



Compare common treatments for CI to determine
which is most effective
Pencil
Push-ups
Office
VT/Orthoptics
Base-In
Optometrists
36%
16%
15%
Ophthalmologists
50%
5%
30%
*Scheiman, M, Cooper, J, Mitchell L et al. A survey of treatment modalities
for convergence insufficiency. Opt Vis Sci 2002;79:151-157.
CITT
 Kids (9-17yo) were randomized into one of 4
treatment groups…
221 kids
Office based vision
therapy
Placebo office
based vision
therapy
Home based pencil
push up therapy
 Primary Outcome: Symptoms
 Secondary Outcomes: NPC & PFV
Home based pencil
push up plus
computer therapy
CI Symptom Survey (CISS)
Convergence Insufficiency Symptom Survey
Name _____________________________________
DATE __/__/__
1.
2.
Primary outcome measure
Symptom score (CI
Symptom Survey)
Score less than 16
considered asymptomatic
Score 16 or greater
considered symptomatic
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Never
(not very
often)
Infrequently
Sometimes
Fairly often
Alw ays
__x 0
__ x 1
__ x 2
__ x 3
__ x 4
Do your eyes feel tired when reading or doing
close work?
Do your eyes feel uncomfortable when
reading or doing close work?
Do you have headaches when reading or
doing close work?
Do you feel sleepy when reading or doing
close work?
Do you lose concentration when reading or
doing close work?
Do you have trouble remembering what you
have read?
Do you have double vision when reading or
doing close work?
Do you see the words move, jump, swim or
appear to float on the page when reading or
doing close work?
Do you feel like you read slowly?
Do your eyes ever hurt when reading or doing
close work?
Do your eyes ever feel sore when reading or
doing close work?
Do you feel a "pulling" feeling around your
eyes when reading or doing close work?
Do you notice the words blurring or coming in
and out of focus when reading or doing close
work?
Do you lose your place while reading or doing
close work?
Do you have to re-read the same line of words
when reading?
TOTAL SCORE ___________
Symptoms
Mean adjusteda CI Symptom Survey score
35
30
25
20
15
HBPP
10
5
HBCVAT+
OBVAT
OBPT
0
Eligibility
4 week
8 week
Study examination
12 week
NPC Break
16
Mean adjusteda NPC break
14
12
10
8
6
HBPP
4
HBCVAT+
2
OBVAT
OBPT
0
Eligibility
4 week
8 week
Study examination
12 week
Positive Fusional Vergence
Break at Near
35
HBPP
a
Mean adjusted PFV blur/break
30
25
HBCVAT+
OBVAT
OBPT
20
15
10
5
0
Eligibility
4 week
8 week
Study examination
12 week
Convergence Insufficiency Tx
 Office based VT is more effective than home based pencil
push-up or home based pencil push-up plus computer
vergence training at improving symptoms and signs of CI.
 Pencil push-ups are no more effective than placebo therapy
 Home based computer therapy showed improved PFV’s over
pencil push ups but no difference in symptoms and NPC
 Compliance?
 Longer treatment time?
Home Based Computer Therapy for CI
www.visiontherapysolutions.net
Home Based Computer Therapy for CI
 Serna et al. JAAPOS 2011
 Retrospective evaluation of the efficacy of HTS computer therapy for CI
 42 patients (5 to 16 years old—mean 9 years) received combination of HTS,
BI prism, and pencil push ups
 35 PPU plus HTS
 7 HTS only
 Some subjects also received BI prism (2) and near plus (?)
 Treatment lasted between 3-30 weeks (mean 12.6; SD 6.6)
Home Based Computer Therapy for CI
 All objective findings significantly different pre and post tx
 All subjects reported improvement in symptoms (not
standardized—subjective)
 Good compliance in all but 7 subjects
Reasonable alternative to in-office VT for CI—more research coming…
Convergence Insufficiency
What about BI prism?
 CI Base-in prism study (Scheiman et al. Br J Ophthal. 2005)
65 CI patients (9 to <18yo)
31 BI-Prism reading Glasses (Sheards)
34 Plano (placebo) reading glasses
Symptom survey score improved 15 points
( 12)
Symptom survey score improved 11
points ( 13)
NPC and PFV minimally affected
NPC and PFV minimally affected
Statistically no difference between Placebo glasses and BI prism glasses
BI prism not good treatment choice for young CI patients
Convergence Insufficiency in Presbyopia
 Presbyopic CI Prism Study (Teitelbaum OVS 2009)
 29 symptomatic 45-68 year olds
Baseline Symptom Score = 30
BI Prism Glasses
Placebo Glasses
BI Prism Symptoms= 13
Placebo Glasses
Symptom
Survey
BI Prism Glasses
Placebo Rx Symptoms= 23
Significant (p<0.00001) decrease in symptoms with BI prism in presbyopic CI’s
(CISS>21 is considered symptomatic in adults)
Convergence Insufficiency Treatment
 Office based VT #1 choice
 Home based VT with computer vergences may be beneficial
but may require more than 12 weeks of treatment
 Base-in prism not effective in children but may show some
benefit in presbyopic CI patients
 Pencil push ups are not effective
Back to Karley
 CI/AI
 Why didn’t she like
her low plus readers?
 Treatment?
Karley—Final (after 12 VT sessions)
 VA: 20/20
 Accom amps: 20D
 CT at near: 4XP
 Accom fac: 22 cpm
 CT at dist: ortho
 NRA: +3.00
 NPC: TB
 PRA: -2.50
 PFV (near): >45/>45
 MEM: +1.00
 NFV (near): X/35/20
In Karley’s words:
•Love to read
•Concentrate better
•Don’t see double
•Don’t see blurry
•Don’t loose spot
•Even though it took up my time
to get here and do homework, I
knew I had to do it.
•It has made school work easier
•It has changed my life
Carolyn--Baseline
 64yo female
 Complains of dry eye stuff…oh, and she also looses her place
and has double vision when reading
VA
20/20-
CT @ distance
4XP
CT @ near
10 IAXT (trope 30%)
NPC
8/40cm
PFV @ near
x/4/1
NFV @ near
X/6/2
W4D
Crossed dip at near
CI! Recommended VT
Carolyn—Final
Baseline
Final
VA
20/20-
20/20-
CT @ distance
4XP
8 XP
CT @ near
10 IAXT (trope 30%)
6 XP
NPC
8/40cm
Nose/6cm
PFV @ near
x/4/1
X/45+/30
NFV @ near
X/6/2
X/12/10
W4D
Crossed dip at near
-
 Finished therapy in 15 visits
 Much slower progress with presbyopic patients
 No accomm therapy—push BO and NPC
 “Reading much better and no more double vision!”
Joyce--Baseline
 70 yowf referred by outside doc for ―reading difficulty‖
 Trouble with reading since July (3 months ago) when seizures
(possible stroke) began
 Can read first couple of words and then struggles to complete
 Reading improves with one eye covered
 Was seen by neruo-ophthalmologist, referred to low vision
specialist, then sent to our office
Joyce--Baseline
 BCVA 20/20 OD/OS
 CT @ D: 4XP, CT @ N: 18XP
 NPC: 25/35cm
 PFV @ near: X/16/8
 Stereo: 200 sec
 W4Dot: Fusion D and N
 VT Demo
 Brock String: Exo at near without suppression
 Stick and Straw: 12cm!
 Computer Vergences: able to appreciate RDS targets
 Recommended VT…
Joyce
 Baseline
 After 13 VT visits
 CT @ D: 4 XP
 CT @ D: 5 XP
 CT @ N: 18 XP
 CT @ N: 18 XP
 NPC: 25/35cm
 NPC: 12/16cm
 PFV: X/16/8
 PFV: X/12/2
 Stereo: 200 sec
 Stereo: 20 sec
 Hmmph!
Determining Prism Rx for exo
 Rx least amount of prism needed to relieve symptoms
 Consider Sheard’s criteria as starting point
Sheard’s:
2/3(phoria)-1/3(compensating range)
 Rx prism in trial Fresnel (test drive)
 Tweak prism power if necessary
 May consider associated phoria measurement as starting
point
BI
Joyce
 Trial 6∆ BI prism (Fresnel)
 CT @ D with prism: 2 XP
 CT @ N with prism: 18 XP
 PFV with prism: X/24/16
 (improved from X/12/2 without)
 One week later…loving the prism…Rx’d it
Sheard’s:
2/3(phoria)-1/3(compensating range)
2/3(18) – 1/3(16) = 6.67Δ
Binocular Vision Disorders
High AC/A
CE
DE
Normal AC/A
Low AC/A
CI
DI
Basic Eso
VT
VT or BI
for >45
Accommodative Disorders
Accommodative
Insufficiency
Accommodative
Excess
Basic Exo
FVD
Brook
Cover Test: more eso @ distance
than near
Compensating vergence group
(BI at distance): Unable
Divergence Insufficiency
Divergence Insufficiency
 Symptoms
 Longstanding intermittent diplopia at distance, headaches,
ocular fatigue, difficulty focusing from far to near
 Signs
 Greater eso at distance than near, reduced NFV at distance
 Treatment Options
 Base Out prism--#1 treatment option for low eso amount
 Vision Therapy—treatment to improve NVF ranges
 Surgery—reserved for larger angle eso’s that cannot be
managed with prism and/or therapy alone
Brook
 4∆ BO Fresnell Trial: gave fusion without prism adapting
 RX: Wet Ret (similar to hab Rx) with 4∆ BO split
 5 month follow up






Wearing +3.00 with 2∆ BO OD; +3.25 with 2∆ BO OS
VA good
CT @ D: Ortho
CT @ N: 8 XP
Stereo: 140 sec (no global)
W4Dot: Fusion distance and near
 2 year follow up





Same Rx with good VA
CT @ D: ortho
CT @ N: 2-4 XP
Stereo: 200 sec
W4Dot: Fusion
Trial of 2∆ BI Fresnel
caused CLET @ distance
Brook
 3 year follow-up
 Good VA with minimal change in Rx
 Good fusion and alignment with specs
 Trial of 2∆ BI Fresnel showed 2∆ ILET
present less than 50% of the time
 Trial of BI Fresnel produced
discomfort—maintained 4Δ BO in
specs
Thomas--Baseline
 82 yowm –retired
 Referred by LV specialist for dip management
 Complains of intermittent diplopia and ―distortion‖ at
distance, it’s worse at the end of the day, makes driving
difficult
 Also occasional dip at near while reading
 Ocular hx: end stage glaucoma
 Systemic hx: HTN x ―several years‖
Thomas—BV eval
 BVA 20/30+ OD, 20/20- OS (w/low cyl rx)
 Cover Test
 6 ILET at distance (70% trope)
 2 EP at near (Maddox Rod = 6EP)
 EOM’s Full, Pupils normal
 Suppression during vergence testing
 W4D at distance uncrossed diplopia
Thomas—Final
 Divergence Insufficiency (borderline?)
 Trialed prism to obtain fusion…reported fusion with 6
BO at distance and near
 Trialed 6 BO Fresnell for 3 weeks
 Rx:




-0.50-1.25X083, 3.0 BO OD
+0.50-1.50X075, 3.0 BO OS
+2.50 add
Referred back to LV specialist with recommendation to discuss
driving!
Determining prism Rx for eso’s
 Rx least amount of BO prism to provide fusion
 Fixation Disparity (associated phoria)
 Rx amount of prism that eliminates the fixation disparity
BO
 Percival’s Criteria
 1/3(greatest vergence range) – 2/3(lowest vergence range)
 Little lit support but suggests better for eso’s than exo’s
Prescribing Prism: Bottom Line
 Esophoria
 Eso’s will generally accept prism better than exo’s
 Eso’s will generally take a prism power closer to phoria measure than
exo’s (may take full amount)
 May begin with Percival’s and tweak (consider FD)
 Always trial the prism before final Rx
 Exophoria
 Generally need lower percentage of phoria compensation with prism
 Don’t typically respond as favorably to prism as eso’s and hyper
 May begin with Sheard’s and tweak (consider FD)
 Always trial the prism before final Rx
What’s gong on with
Kelsey?
 8-10 CAET at distance and near with full plus Rx and bifocal
 Trial 8 BO, CT=8 CAET (16 ET)
 Trial 16 BO, CT=8 CAET (24 ET)
 Trial 24 BO, CT=8 CAET (32 ET)
Beware of the PRISM EATERS!
Prism Adaptation
 ―Eating Prism‖
 Example:
 No prism: CT @ near = 6XP
 With 4 BI: CT @ near = 6XP
 With 10 BI: CT @ near = 6XP
 Normal vergence response to the stress of added prism
 Asymptomatic patients more likely to prism adapt and less likely to
need or accept prism
 Symptomatic patients are less likely to prism adapt and more likely
to accept prism
Prescribing prism
 Prism adaptation occurs within
minutes
 Recheck cover test after 10 minutes
of trial
 If CT returns to original deviation,
prism adaptation has occurred
 Patients with strong prism
adaptation mechanism may find
little benefit from prism Rx
Binocular Vision Disorders
High AC/A
CE
DE
Normal AC/A
Low AC/A
CI
DI
VT
BO
VT or BI
for >45
Basic Eso
VT?
Accommodative Disorders
Accommodative
Insufficiency
Accommodative
Excess
Basic Exo
FVD
Hannah
Cover Test: Convergence Excess
Compensating Vergence group
non-contributory
Accommodative measures
normal
Convergence Excess
 Symptoms—headaches and eye strain with near work, blur,
diplopia, fatigue with reading, poor reading comprehension,
avoidance of reading
 Signs—More eso at near than dist, high AC/A, low NFV
findings, may show high lag on MEM
 Treatment Options:
 #1—Additional plus at near
 Rx plus to reduce near phoria to near ortho
 Base Out Prism
 May be necessary if small eso still present at
D and N with add
 Vision Therapy
 may be helpful if Rx still leaves symptoms
(push BI training)
Hannah
 CE
 Trial + at near
 RTC 4 weeks
 Ortho with +2.25 OU
 Wet Ret:
 +1.50-1.00X105 OD
 +1.50-1.50X090 OS
 Rx: wet ret with +2.50
add
 Seg at lower pupil margin
 Glasses ―made a world of
difference!‖
 VA 20/25 OD, 20/30 OS
 CT 3 EP at dist and near
 Suppression with W4D and
stereo
Hannah—Follow-up
 6 month f/u
 VA 20/30
 CT ortho distance, 3 XP at near
 Stereo 50 sec
 MEM +1.00
 W4D Supp at distance
 9 month f/u
 VA 20/30
 CT ortho distance, 3 EP at near
 Stereo 30 sec +global
 MEM +0.25
 With glasses she reads much
better, better handwriting,
catches the ball better, -dip, headaches
Jessica--Baseline
 10wf presented for general eye exam
 CC: headaches while reading, no diplopia, no meds, sulfa
allergy
VA (uncorrected)
CT @ dist
10/10 with HOTV OU
6 IRET
CT @ near
MEM
PFV/NFV at near
19 IRET
+1.00
unable
Stereo
Dry Ret
70 sec
Plano
Jessica--Baseline
 Trial +2.00 @ near=9 IRET (less troping)
 Trial +2.50 @ near=6 IAET
 Maximum plus would be +2.50 at 40cm
 Wet Ret: Plano OD, +0.50 OS
 Ocular health: unremarkable
 Rx: plano OU with +2.50 add
Jessica—2 week follow up
 No more headaches
 VA: 10/10 OU
 CT (with Rx)
 6 IRET at distance (trope 1/8 times)
 6 IRET at near (trope 2/10 times)
 Stereo 50 sec
 Additional tx?
Emily
Cover Test and BV findings
all normal—No Duanne’s
Classification
Accommodative findings
show low amps, shifted
NRA/PRA, and high lag
Dx: Latent hyperopia with AI?
Accommodative Insufficiency
 Symptoms: blur, headaches, tired or sore eyes with reading;
poor reading comprehension
 Signs: Reduced accommodaitve amps ((15-0.25*age)-2),
MEM may be normal or show slightly elevated lag
 Treatment Options:
 #1—Additional plus at near
 Vision Therapy—often prescribed when other accommodative
and BV problems exist
Prescribing Plus for AI
 Plus build up method—subjective
 MEM method
 Useful for pts with high lag
 Trial binocular plus until MEM returns to normal (low) lag
 NRA/PRA midpoint method
 (NRA + PRA)/2= tentative add power
 Accounts for binocular condition but doesn’t always indicate the
need for an add
 BCC method—subjective and difficult with peds
Back to Emily
 Dry Refraction: plano OU
 Wet Ret: +1.25 OU
 NRA/PRA: +3.50/-1.25
(+3.50 + -1.25)/2= +1.12D Add
 Rx’d plano OU with +1.25 add
Emily
 Follow-up—Reading much easier with add
 VA 20/15 OU
 CT Ortho dist and near (Where’d the exo go?)
 Amps with add: 14D OU
 MEM: +0.50 OU
 2 years later…
 Different doc Rx’d wet ret of +1.25 DS OU (no add)
 Patient returned complaining she had to look over the glasses at
distance to see
 We returned her to the add and she lived happily ever after (5 years and
counting…)
Prescribing Plus at Near
 Convergence Excess
 High AC/A! (a little plus goes a long way)
 Rx amount of plus that reduces near phoria to ortho
 Basic Eso
 Normal AC/A
 Rx near plus to reduce eso to near normal levels
 Accommodative Insufficiency
 Low amps (pt has difficulty accommodating)
 Rx amount determined initially with MEM method, NRA/PRA
method, or build up (trial). Final Rx usually low plus
Research on near plus?
 Plus commonly Rx’d for AI but lack of evidence of efficacy
 Abdi and Rydberg 2005: Prospective study of 120 children
with AI and CI received combination of therapies (VT/plus/ )
 98% with AI had improvement in symptoms with near plus
 No standard measurement of symptoms
 Unmasked
 No placebo control
 Mazow et al 1989: Retrospective review of 26 patients (7-28
years) with AI and CI. 22 received VT, 21 received plus (+1 to
+2.50)
 Symptoms improved but objective findings did not
 No standard measurement of symptoms
 Unmasked
 No placebo control
Will plus at near result in wimpy
accommodation?
Base line Accom Amps
=8.75D (95% CI =7.99
to 9.51)
28 Convergence Excess
(AC/A =9.04±1.06)
Accom Amps after 4
years in add = 8.93D
(95% CI=8.25 to 9.6)
56 children 5-8 years old
Baseline Accom Amps =
10.96D (95% CI=10.51
to 11.42)
28 controls (ortho D &
N with AC/A=3±0.86)
Fresina M, Schiavi C, Campos EC. Do bifocals reduce accommodative amplitude in
convergence excess esotropia? Graefes Arch Clin Exp Ophthalmol. 2010
Oct;248(10):1501-5. Epub 2010 Jun 4
Accom Amps after 4
years in add = 10.68D
(95% CI=10.31 to
11.04)
Will plus at near result in wimpy
accommodation?
 Accomm amps measured
Younger group 21-30 years
Older group 38-44 years
Normal BV and amps ≥3D
before tx, immediately
after 2 months of tx, and
2 months following tx
with +1.50 reading Rx
 Amps decreased
following tx and did not
recover 2 months later
 Accom decrease was
0.65D in younger group
and 0.7D in older group
Vedamurthy I, Harrison WW, Liu Y, Cox I, Schor CM. The influence of first near-spectacle reading correction on
accommodation and its interaction with convergence. Invest OphthalmolVis Sci. 2009 Sep;50(9):4215-22. Epub 2009 Mar 5
Binocular Vision Disorders
High AC/A
CE
Near +
DE
Normal AC/A
Low AC/A
CI
DI
VT
BO
Basic Eso
VT
VT or BI
for >45
Accommodative Disorders
Accommodative
Insufficiency
Near +
VT
Accommodative
Excess
Basic Exo
FVD
Kayla
 4yo with eye turn
 Cover test
 Ortho at near
 15 IAXT at distance (60%)
 NPC: 4cm
 Vergences: unable
 MEM: +050
 Wet Ret: Plano OU
 Dx?
Divergence Excess
 Symptoms: Cosmetic concerns over IXT, rarely diplopia,
rarely near point symptoms
 Signs: Greater exo at distance than near, PFV and NFV may
be normal at distance and near, may show suppression at
distance, high AC/A?
 Pseudo DE
 Prolonged occlusion (30 mins) or +3.00 OU shows basic exo
 AC/A is normal
 True DE
 Deviation at distance remains larger than at near even after prolonged
occlusion
 AC/A may be high but often still normal by gradient
Divergence Excess
 Treatment options:
 Over-minus—recommended for young pts (under 6) with true
high AC/A
 Trial over minus in office and recheck dist CT
 Vision Therapy—may be 1st line of tx in older pts;
 stress diplopia awareness
 vergence ranges
3 targets
near
2 targets
1 targets
distance
Divergence Excess
 Additional Treatment Options
 Occlusion—FT/PT occlusion for up to 2 months to decrease
suppression and improve fusion--?
 Surgery—Considered for very large (>35-40 ) deviations that
fail to respond to more conservative tx
Kayla
 At 4 yo…
 At 6 yo…
 DE IXT (15
 Glasses un-cool for school
@ dist)
 To young for VT
 -2.00 over Rx controlled
the XT at distance for 2
years
 15-20 IXT @ dist
present >50%
 Surgical candidate?
 Rx’dVT
Amount of over minus found by in office trial
(generally -1.50 to -3.00)
Kayla (7 years)
 After 25 visits of VT, she was able
to voluntarily control her IXT at
distance
 No longer required added minus
 Over minus short term fix but may
buy time until child is old enough
for VT
One year later, still holding XT
well but…emerging myopia!
Kayla (9 years)
 2 years post VT
 Still showing excellent
alignment at distance and
near
 Wearing CL’s for myopia
Will over minus lenses cause changes
in refractive error?
 Rutstein et al. (OVS 1989)
 Retrospective review of 40 IXT’s treated with over minus
 Age 1-15 years (average age 7)
 Over minus Rx between -0.75 and -3.75 (approx 1.95D)
 Mean changes in refractive error were same for hyperopes, myopes, and
emmetropes and similar to values reported for non-exotropes
 Paula et al. (Arq Bras Oftalmol 2009)
 Retrospective review of 21 IXT’s treated with occlusion
 13 were also treated with over minus Rx
 Over minus Rx between -0.50 and -3.50 (avg 2.46D)
 No induced refractive error changes in over minus group
Cover Test: DE IXT
Compensating Vergence Group
(BO): Show only mild
reduction—suggest possibly
different mechanism than high
phoria and low BO ranges?
Accommodative testing: Normal
except for low NRA finding
Treatment options?
Denton
 Divergence Excess Treatment Options:
 Over Minus—Denton’s too old
 Occlusion—Didn’t consider
 Surgery—Deviation large enough to consider…
 Vision Therapy—Recommended therapy
 Emphasized anti-suppression/diplopia awareness
 Vergence ranges dist and near
 Final
 20∆ XP @ distance, 14∆ @ near
 BO: X/40+/40 D & N
 BI: X/35/25 D & N
Prescribing plus or minus
Consider added plus
Consider added minus
Convergence Excess
Divergence Excess
(High AC/A)
(High AC/A)
Basic Esophoria
Large Basic Exophoria
(normal AC/A)
(normal AC/A)
Accommodative Insufficiency Young age (< 6yo)
Added plus and minus not considered for low AC/A conditions:
→Convergence insufficiency
→ Divergence Insufficiency
Binocular Vision Disorders
High AC/A
Normal AC/A
Low AC/A
CE
DE
CI
DI
Near +
- Rx for
preschool
VT
BO
VT
Basic Eso
VT
VT or BI
for >45
Sx/occ?
Accommodative Disorders
Accommodative
Insufficiency
Near +
VT
Accommodative
Excess
Basic Exo
FVD
Lee--Baseline
 History
 Findings
 7 yobm presented as BV
 VA 20/20 corrected
referral
 Reported that left eye turns
in
 Wearing mild hyperopic Rx
with +1.25 add
 CT at distance 10 IAET (30%)
 CT at near 14 IAET (50%)
 W4D at distance: fusion
 W4D at near: alt suppression
 70 sec stereo
 NVF: unable
 Accom Amps 12D
 DX: Basic Eso ~CE
Basic Eso
 Symptoms: headaches, eye strain, blur, diplopia, poor reading
comprehension
 Signs: Eso similar magnitude dist and near, reduced NFV at
distance and near, MEM may show higher than normal lag,
normal AC/A
 Treatment Options
 Additional plus at near: Rx lowest power to normalize eso
 BO prism: Rx lowest amount of prism to allow fusion
 Rx prism to eliminate diplopia
 Rx associated phoria
 Vision Therapy: improve NFV at distance and near
Lee--Tx
 Original CT: 10 IAET @ D & 14 IAET @ N
 TX: Trial additional plus at near and BO prisms
 6BO with +2.25 add gave
 CT 4EP at distance and 6-7EP at near
 RX: 6BO prism (split) with +2.25 add
**At 6mo f/u, still some
symptoms…
Will
Cover Test: Basic Exo (IXT w/o Rx)
PFV Group: Low BO at near,
Receded NPC
Accommodation: Reduced
Amps
Basic Exo (IXT)
Basic Exo
 Symptoms: Eye strain, headaches, blur, diplopia, poor
reading comprehension, movement of print on page
 Signs: Similar exo at distance and near, reduced PFV findings
at distance and near, receded NPC
 Treatment options:
 Vision therapy: responds well (similar program to CI)
 Prism: BI relieving prism may be considered
 Surgery: Rarely considered for large deviations with very
frequent loss of fusion
Will—Basic Exo
 Recommended VT to improve PFV ranges
 Mid Therapy
 By visit #13, vergence ranges were normal and accommodation
normal
 Added 2
BO fresnell to glasses
 By visit #17, vergence ranges normal with additional 2
BO
fresnell
 Added another 2
BO to glasses (neutralizing the 4 BI in habitual Rx)
Will--Final
 CT w/o prism
 6XP at distance
 10-15 XP at near
 NPC: TB
 Amps: 10D X3, OD and OS
 PFV: X/24/18
 NFV: 20/24/14
 ―Now I can read for hours instead of just a
little while. I don’t need prisms and my head
never hurts.‖
General Guidelines…
 Exo’s
 Respond well to therapy
 BO ranges easier to train than BI
 Generally don’t do as well with prism
 Eso’s
 Respond well to plus and prism
 BI ranges harder to train but VT still an option
Binocular Vision Disorders
High AC/A
Normal AC/A
Low AC/A
CE
DE
CI
DI
Near +
- Rx for
preschool
VT
BO
VT
VT or BI
for >45
Sx/occ?
VT
Basic Eso
Basic Exo
Near +
VT
BO
VT
Accommodative Disorders
Accommodative
Insufficiency
Near +
VT
Accommodative
Excess
- Rx for
preschool
BI
FVD
Jake
Cover Test: Normal, equal XP
No Duanne’s Classification
Vergences: Low PFV and NFV
Accommodation: Low Amps,
Low PRA, High Lag
FusionalVergence Dysfunction &
Accommodative Insufficiency
Fusional Vergence Dysfunction
 Symptoms: Headaches, eye strain, and blur with near tasks;
poor reading comprehension, and avoidance of near work
 Signs: Normal phoria, reduced PFV and NFV ranges at near
and/or distance, reduced NRA and PRA, reduced binocular
accommodative facility
 Treatment Options:
 Vision Therapy: Training to improve vergence ranges
CPT 368.30--Binocular vision disorder; unspecified
Jake
Treatment Options:
Consider plus Rx?
Vision Therapy?
Jake completed 21 visits of therapy with excellent results!
Binocular Vision Disorders
High AC/A
Normal AC/A
Low AC/A
CE
DE
CI
DI
Near +
- Rx for
preschool
VT
BO
VT
VT
VT or BI
for >45
Basic Eso
Basic Exo
Near +
VT
BO
VT
Sx/occ?
- Rx for
preschool
Accommodative Disorders
Accommodative
Insufficiency
Near +
VT
Accommodative
Excess
BI
FVD
VT
Anna
 14yowf presents with complaints of distance and near blur.
Previous doc said she had an ―accommodative problem‖ and
gave her +1.75 readers (which didn’t help much).
 Taking thyroid and attention meds
 Family are missionaries—considering move back to Africa in 6
mos
 Father died of brain tumor 9 mos ago
Anna
 VA 20/150 OD/OS
 CT 5 EP at dist, 14 EP at near (ortho with +1.75)
 MEM -1.00 to -2.00 OD/OS
 Dry Auto/Wet Auto…Dx?...Tx options?
Accommodative Excess
 Symptoms: Blur (at distance or near) may be worse after
prolonged near work, headaches, eye strain, fatigue, diplopia
 Signs: Neutral or lead with MEM, difficulty clearing plus
with facility testing, Reduced NRA, dry ret more minus than
wet, often associated with psychological stress and may show tubular
VF
 Treatment Options:
 Vision therapy for mild accommodative excess (push plus
training and NFV ranges)
 Cycloplegic agents for more severe accommodative spasm
 Consider 1% Atropine 2x/week with near add (wean over time)
Anna
 Tangent Screen VF
Anna
 Dx: Accommodative
excess/spasm/pseudomyopia
 Tx: Atropine 1gtt
twice/week OU
 Use +2.50 OTC readers for
near work
 RTC 4 weeks
 4 week f/u
 Better with drops (it’s
been a week since last
drop)
 VA 20/20 OU
 CT Ortho at near
 MEM +0.75 to -1.00
Anna
 8 week Follow-up
 Symptoms are gone. Good VA, enjoying reading, last drop >2
weeks ago
 VA 20/20 OD, OS
 CT ortho at distance and near
 MEM -0.50 (stable)
 Dx: accomm excess resolved
 Tx: d/c Atropine, monitor
Binocular Vision Disorders
High AC/A
Normal AC/A
Low AC/A
CE
DE
CI
DI
Near +
- Rx for
preschool
VT
BO
VT
VT
VT or BI
for >45
Basic Eso
Basic Exo
Near +
VT
BO
VT
Sx/occ?
- Rx for
preschool
Accommodative Disorders
Accommodative
Insufficiency
Accommodative
Excess
Near +
VT for mild
VT
Cycloplegics
BI
FVD
VT