Optometric management with prisms, spheres, exercises

T H E I N S T I T U T E O F O P T O M E T RY
Treating orthoptic anomalies in
optometric practice
Prof Bruce Evans
BSc (Hons) PhD FCOptom DipCLP DipOrth FAAO
Director of Research
Visiting Professor
Private practice
Shareholder
“The Institute of Optometry is unique in being an independent self-financing charity dedicated to
the promotion of clinical excellence, research, and education in optometry.”
Roberson (1989)
WHEN TO TREAT AMBLYOPIA:
conclusions of literature review
Most results are of passive occlusion
Institute of Optometry
City University
Brentwood, Essex
Optometric Educators Limited
Reference: Pickwell’s Binocular Vision Anomalies, 5th Edition,
Elsevier, 2007.
WHO SHOULD TREAT: differential
diagnosis
optic nerve hypoplasia
For strabismic amblyopes:
Age matters
No sharp cut-off, best to treat before 7-12 yrs
For best results, treat as early as possible
retinal pathology
neural pathology
For anisometropic amblyopes:
Age does not matter
Try with Rx first, ideally CL, patch if necessary
Evans (2007) Pickwell’s Binocular Vision Anomalies, 5th edition, Butterworth-Heinemann, Oxford
WHO SHOULD TREAT AMBLYOPIA:
WHO SHOULD TREAT AMBLYOPIA:
general principle
differential diagnosis
Look for negative sign:
no abnormalities of optic nerve, fundus, pupils
Orthoptic treatment is within the scope of optometry
Only treat a condition if you have appropriate skills
If you lack appropriate skills, refer to an appropriately skilled
optometrist or to HES
Look for positive sign:
Strabismus
Anisometropia
An optometrist or ophthalmologist MUST be involved
Treat decisively
Refer soon if unsuccessful
Monitor ocular health at every visit
1
TREATMENT OF AMBLYOPIA (a)
TREATMENT OF AMBLYOPIA (b)
Flow chart based on review of recent RCTs in Evans et al. (2011; OPO)
Many cases of amblyopia can be cured by refractive correction alone;
20% don’t need occlusion (Gibson, 1955; Pickwell, 1984; Stewart et
al., 2004; West & Williams, 2011)
Contact lenses are likely to be best (Evans, 2006)
RCTs show that occlusion is unsuccessful in 17-37% (Simons, 2005)
If treatment fails, re-evaluate your diagnosis (Evans, 2007)
Treated amblyopic eyes on average 2 lines below fellow (Repka et al., 2005)
Remember that the child may be partially sighted during occlusion
It is not always better to do something than nothing at all (Jennings, 2005)
Record informed consent
Many cases never require
full-time occlusion
Penalisation is a viable
alternative to occlusion
If 6/9 to 6/25, 2h occ. ≡ 6h
West & Williams (2011)
If ≤ 6/30, 6h > 2h
Avoid full time occlusion for
orthotropic anisometropia
There is a dose-response
relationship in patching
(Stewart et al, 2004)
Timings approximate
Eye patch is best but
compliance poor & they will
cheat!
See patients frequently during
the treatment of amblyopia, to
begin with every 4-6 weeks
ACTIVE AMBLYOPIA THERAPY
Active treatment for brief periods of
occlusion in adults
TREATMENT OF MOTOR DEVIATION
Nelson (1988)
Motor deviation
Refractive correction / modification
(Mallett, 1977; Campbell, 1978)
Prisms
Eye exercises
RCT of IPS show 1 line improvement for
adults, but recidivism (Evans et al., 2011)
Binocular sensory adaptations
Perceptual learning methods look
promising, but needs major RCT
Polat (2008)
(Polat, 2008; Levi & Li, 2009; Evans et
al. 2011; Astle et al., 2011)
Phoria: foveal suppression is rare
Strabismus: consider both sensory &
motor
PEDIG group pilot study of vision therapy
for amblyopia is promising (Lyon et al., 2013)
Virtual reality methods may make
treatment more engaging
(Eastgate et al., 2006)
OVERVIEW:
SEQUENCE OF TREATMENT
in heterophoria:
if significant motor deviation treat first,
usually any foveal suppression (rare) is
eliminated
if (rarely) no significant motor deviation but
only foveal suppression, then treat this
OVERVIEW:
SEQUENCE OF TREATMENT
in strabismus:
only treat motor or sensory if you are
sure that both can be corrected
if can correct refractively / prismatically
easy to check that Rx will not cause
intractable diplopia
usually sensory factors eliminated with Rx
if treat sensory factors before motor deviation
corrected then will need occlusion
if good sensory adaptations then treatment
usually inappropriate
2
MOTOR DEVIATION:
REFRACTIVE CORRECTION: OVERVIEW
MOTOR DEVIATION:
REFRACTIVE CORRECTION: SPECIFICS
• Mandatory in accommodative esotropia
• Also possible to treat exo-deviations
with negative lenses & convergence
excess with multifocals
• determine sphere that
– eliminates strabismus (no diplopia)
– eliminates FD on Mallett Unit
• Can check (2 mins) don’t adapt (North & Henson,
1985)
• limited by 4 factors
– angle of deviation
– refractive error
– accommodation
– AC/A ratio
• prescribe, try to reduce approx. every 3-6/12
• negative adds and bifocals/varifocals can work well
MOTOR DEVIATION:
REFRACTIVE CORRECTION: MYTHS
• negative adds might cause myopia
– overminus lenses do not induce clinically significant myopic
changes (Rutstein et al., 1989; Paula et al., 2009)
• patient likely to adapt to the over-correction
– if abnormal BV, tend not to adapt (North & Henson, 1985)
• bifocals might reduce children’s ability to accommodate
– smooth muscle; 14D-3D=11D
– BF don’t reduce amplitude of accommodation (Fresina et al,
2010)
MOTOR DEVIATION:
REFRACTIVE CORRECTION: CASE STUDY: D1542
• 11/5/96, female, age 8y, 1 headache a fortnight
– wearing full cyclo plus (c. +2.00, R=L)
– cover test: D: 8∆ SOP
N: 10∆ RSOT
– with +2.00 add: N 4∆ RSOT with +2.50 add: N ortho
Date May 96 July 96 Mar 97 Jun 97 Sep 97 Jan 98 Apr 98 Jun 98 Sep 98
+3.00 +2.50
+2.00 +1.75 +1.50 +1.00 +0.50 None
Add +2.50
• accommodative (hyperopic) esotropia will not need glasses in
later life
– after 10 yrs, 97% still need Rx (Rutstein & Marsh-Tootle, 1998)
MOTOR DEVIATION:
PRISMATIC CORRECTION: OVERVIEW
MOTOR DEVIATION:
PRISMATIC CORRECTION: SPECIFICS
• preferred treatment in
small/moderate vertical deviations
• determine prism that
– eliminates strabismus (no
diplopia)
– eliminates FD on Mallett Unit
• may also help in small/moderate
horizontal deviations if not
amenable to refractive modification
or exercises
• limited by angle of deviation /
cosmesis of prism
“There I was, asleep in this little
cave here, when suddenly I was
attacked by this hideous thing with
five heads!”
• unlikely to adapt to prism if
abnormal BV (North & Henson,
1985)
• But can check (2 mins) don’t adapt
(North & Henson, 1985)
3
MOTOR DEVIATION:
PRISMATIC CORRECTION: EVIDENCE
MOTOR DEVIATION:
PRISMATIC CORRECTION: MYTH
Small RCT (mostly esophoria) shows
Mallett prism is preferred to no prism
patient might “eat up prisms”
"Based on our results, one would not expect to
find a significant preference for prism
prescribed according to Sheard's criterion.“
(Payne et al., 1974)
prism adaptation usually abnormal in orthoptic
anomalies
(North & Henson, 1981)
exceptions can occur
Prism prescribed using Sheard’s criterion
is no better than placebo for children
with CI
(Scheiman et al., 2005)
e.g., myopes with decompensated esophoria
O’Leary and Evans (2006)
RCT shows Mallett prism improves
reading speed
(O’Leary & Evans, 2006)
Prismatic glasses (8BI) as effective as
computer orthoptics at improving reading
(Dusek et al., 2011)
0.5PD
0.8
Sensitivity (Hit rate)
Presbyopes with CI have less symptoms
with BI prism
(Teitelbaum et al., 2009)
1
0.9
0.7
1.5PD
2PD
1PD
0.6
0.5
0.4
0.3
0.2
0.1
3PD 2.5PD
0
0
0.2
0.4
0.6
MOTOR DEVIATION:
PRISMATIC CORRECTION: CASE STUDY: F6123
•
•
0.8
1
1-Specificity (false alarm rate)
8/4/97, male, age 6y, ? dyslexia
– symptoms: words move, sore and tired eyes
– motility full, +0.50DS BE, cover test ortho., D=N, NPC=nose
– Dissoc. tests: D: 3∆ SOP, 2∆ L/R
N: 3∆ XOP, 3∆ L/R
– Align. prism:
D: LE supp.
N: 1∆ in, 1∆ up R
– Rx: plano, 1∆ up R
5/7/97
– symptoms: with Rx no eyes hurting, D & N clearer
– no slip with glasses, other findings as above
MOTOR DEVIATION:
FUSIONAL RESERVE EXERCISES:
OVERVIEW
•
preferred treatment in small/moderate
horizontal deviations, if px co-operative
• Work well in those aged 11-19y, even if
strabismic (Pickwell & Jenkins, 1982)
•
•
in exo-deviations improve ability to converge
in eso-deviations improve ability to diverge
•
try to assess progress using a method
different to the treatment technique
•
there is some supporting evidence from RCTs
– Ciuffreda & Tannen (1995)
– Scheiman & Gwiazda (2011)
It was over. But the way the
townsfolk called it, neither
man was a winner.
FUSIONAL RESERVE EXERCISES:
FUSIONAL RESERVE EXERCISES:
EVIDENCE IN THE LAST 10 YEARS - RCTs
EVIDENCE IN THE LAST 10 YEARS - RCTs
In-office VT better than placebo or home
pencil push-ups (Scheiman et al., 2005; CITT, 2008)
[15min a day + 60min weekly > 15min a day]
Seems to be better to exercise convergence
and accommodation independently of one
another than together (Horwood & Toor, 2014)
But this study looked only at normals
Systematic review supports VT for CI; lack of
evidence for other disorders
(Cacho Martinez et al., 2009)
Other studies (not listed) have not included a
matched treatment for the control group
Treatment for 12+ weeks may be optimal
(Scheiman et al., 2010)
But did not control for treatment dose
Systematic review suggests in-office VT better
than at home
(Scheiman & Gwiazda., 2011)
But don’t seem to have controlled for
treatment dose
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FUSIONAL RESERVE EXERCISES:
MOTOR DEVIATION:
FUSIONAL RESERVE EXERCISES:
EVIDENCE IN THE LAST 10 YEARS – objective measures
Small trial indicates VT for CI improves
convergence, phoria, peak velocity
convergence, and fMRI measures
SPECIFICS
• haploscopic instruments / anaglyphs / vectograms /
free-space methods
(Alvarez et al, 2010)
Children with vergence insufficiency & vertigo
show improved vergence response with training
– feedback helps, as in computer-orthoptics
(Jainta et al., 2011)
It is the transient (open-loop) phase of
vergence that changes, not the tonic
(closed-loop)
– varying targets & conditions helps
Alvarez et al. (2010)
– a key factor is practitioner enthusiasm
–
Jainta et al. (2011)
(Horwood & Toor, 2014)
– with a PC & printer anyone can design their own
exercises
ORTHOPTIC EXERCISES: The
elderly
Retrospective study of 161 presbyopes with
asthenopia and conv. Insuff./decomp.
phoria
Most needed <10/52 of therapy, max.
15/52
97% had symptoms cured, 92% +
improved optometric status
CONVERGENCE INSUFFICIENCY:
OVERVIEW
• an exophoria/tropia at a close viewing distance
• exercises to extend the binocular range into the
monocular range
• often need brief top-up (maintaining) exercises
• RCTs support training of positive fusional reserves
After 3/12, 77 needed further VT
Gresset & Meyer (1994)
CONVERGENCE INSUFFICIENCY: SPECIFICS
Treatments (in order of increasing complexity)
simple push up (bead on string if very remote)
jump convergence
push up with physiological diplopia
jump convergence with
physiological diplopia
free-space stereograms
RCT shows intensive programme of exercises better than
home push-up
Scheiman et al. (2005)
15min a day + 60min weekly > 15min a day
“Whether synoptophore or jump vergence stereocards are
used…the critical variable is the length of time it is
maintained”
Vaegan (1979)
“Convergence exercises independent of accommodation
were the most effective treatment”
Horwood & Toor (2014)
BEAD-ON-STRING EXERCISES
Patient holds card, C,
close to nose
Bead, B, is on string
tied to card
Patient fixes bead,
sees card in crossed
physiological diplopia
String appears as X
In suppression, part of
X is missing
This approach does
not exercise relative
accommodation or
relative convergence
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FUSIONAL RESERVE EXERCISES:
COMPUTER ORTHOPTICS
APERTURE RULE TRAINER
HTS
Wide range of vision therapy
For fusional reserves, amblyopia
& much more (if wanted!)
In-office
•Single aperture to train convergent
reserves
•Double aperture to train divergent
reserves
At-home
Reproduced with permission from
Vision Training Products, Inc. (Bernell
Division)
Orthoweb
Patient “visits” web site to do exercises
http://www.academy.org.uk
Designed by Andrew Field
PHYSIOLOGICAL DIPLOPIA
Patient looks at A
PHYSIOLOGICAL DIPLOPIA
Cats at arms length: patient fixes pencil
B is seen in crossed physiological diplopia
Patient looks at B
A is seen in uncrossed physiological diplopia
INSTITUTE FREE-SPACE STEREOGRAMS
(IFS)
A new version of an old approach
Bruce Evans
Director of Research, Institute of Optometry
Pencil position adjusted until middle two cats fused
Patient asked to see cats clearly: exerting negative relative
accommodation
DECLARATION OF INTEREST
• Institute of Optometry is a registered charity
• IOO Marketing raises funds for Institute of Optometry
• Markets equipment
• Pays an incentive to staff to invent equipment
• Bruce Evans receives 0.85p for each set of exercises
sold
Acknowledgment: Anita Lightstone entered 5 patients into
trial
Colleagues at the Institute for comments on early versions
Reference: Pickwell’s Binocular Vision Anomalies, Fifth
Edition, Elsevier, 2007.
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DEVELOPMENT OF IFS: Primary goal
IFS EXERCISES: USES
• To maintain the
patient in an overconverged posture for
10-20 mins a day
without them
becoming bored
• IFS exercises can be used to treat:
• decompensated exophoria at near
• binocular instability
• convergence insufficiency
• To provide a variety of
stimuli to help any
benefit translate into
everyday life
• intermittent exotropia at near
• experienced practitioners can also use the exercises
to treat constant comitant exotropia at near, usually
as part of a more detailed treatment regimen.
• Declaration of interest
DEVELOPMENT OF IFS: Details
Goal
Design feature
Affordable
Easy to understand
Fun to do
Printed h ome e xercise s
Comp reh ensive instru ction s
Novel 3-D images
Varied tasks
Encou rag e pa re nt/child te am
One or two 10’ sessions dai ly
Check in 3-4 weeks
10 self-test que stion s
18 targets with step and ramp
Diffe ren t si ze stimuli
Diffe ren t sh ape stimu li
Vergence angles: 3-30∆
Physi olog ical dipl opic images
Monocular markers
ste reo psis
Motivating
Checks on progress
Variety of stimuli
Con trol/treat sup pre ssion
DEVELOPMENT OF IFS:
Card 1
• Teaches physiological diplopia
& introduces 3-D perception
Card 1: Learning How to Use Double Vision to Develop 3-D Vision
On the “Card 1” that accompanies these notes there are three "exercise pictures". These
pictures look very simple. But don't be fooled! As you will come to realise, these exercises
will involve you doing some very clever things with your eyes.
Card 1: First Exercise: Dots
Stage 1: Seeing Four Dots
The first of the three exercises on Card 1 consists of two dots, about 1.5 cm apart. The aim of
these dots is to teach you how to use double vision to improve your control over your eyes.
These dots are like those drawn below.
. .
Look at the dots, then try and make your eyes "go cross-eyed" (try imagining that you are
looking at something on the tip of your nose. When you do this you should notice that the
dots go double, so that you see 4 dots instead of 2, as drawn below. At the moment, don't
worry if the dots become blurred.
. .
DEVELOPMENT OF IFS:
DEVELOPMENT OF IFS:
Card 2
• Builds fusional reserves (step &
ramp)
• Controls for & treats suppression
Card 2: Improving 3-D Vision: Mega 3-D !
After completing card 1 you will not be surprised by the pictures on card 2. What you can see
is 5 pairs of targets, each target is made up of 2 rings, with other shapes as well. Before long,
these shapes will be floating off the page towards you, in a type of “virtual reality”. The
smaller targets are at the top of the page; and the targets become further apart towards the
bottom of the page. Surprisingly, the smaller top two targets are actually easier to do than the
larger ones. So start with the smaller targets.
Stage 1: The Smallest Targets
For now, try to ignore the larger targets and just concentrate on the smallest size at the top of
the page. Don’t think about the shapes: at this stage just concentrate on the rings. The
procedure is exactly the same as for the circles on Card 1. However, there are no dots so you
have to make your eyes go cross-eyed without using the dots.
As before, make your eyes go cross-eyed (you can use a pencil if you have to) until you see 4
blurred targets instead of 2. Then, change how cross-eyed you are until you see 3 targets. The
inner rings on the central target should look like they are closer to you than the outer ones. IF
THE INNER RING SEEMS FURTHER AWAY THEN STOP DOING THE
EXERCISES AND TELL YOUR EYECARE PRACTITIONER.
Practice keeping three targets instead of two or four. You may need to twist the page to keep
the targets level. Try to keep the targets as clear as possible. When you can see 3 targets and
keep them clear for most of the time then go on to Stage 2.
. .
FREE SPACE STEREOGRAMS
Card 2: Improving 3-D Vision
Card 3
Card 3: Now to Magic!
Unlike Cards 1 and 2, Card 3 should be turned on its side
to be viewed, so the heading is at the top. When you look
at Card 3 you will probably not be able to see a lot, except
for a few eyes looking out at you from near the top of the
picture. Believe it or not, when you can do this exercise
you will be able to clearly see letters on this sheet. What’s
more, these letters will appear in 3-D.
The type of picture on Cards 3 and 4 is called an
autostereogram. Recently, the autostereogram method of
seeing 3-D images has become very popular, and you
have probably seen posters, postcards, books, and even
videos using this type of picture. It may be that you have
already experimented with these images, and you may or
may not have managed to see them in 3-D.
• Builds fusional reserves
• Controls for suppression
• Card 4 similar, but different
autosterogram
With this type of picture there are in fact 2 ways of seeing
the image in 3-D. The way most people use is to underconverge the eyes. Because your eyes naturally underconverge, this method will be easiest for you. If you can
already see 3-D images in this type of picture then it is
almost certainly because you use the under-convergence
method. However, the under-convergence method will
not help your eye problem. The stages described below
will teach you a new way to see the 3-D images, by overconvergence. This method is similar to that used on
sheets 1 and 2 and will help your eyes to become better at
working together.
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OPEN TRIAL: Fusional reserves &
NPC (N=20)
OPEN TRIAL: Effect of treatment on compensation
• Divergent reserves
(control) did not
change significantly
(p=0.6)
Mean Fusional Reserves (to break)
initial
final
16.00
• Convergent
reserves improved
significantly
(p=0.004)
Criterion
Before
Af t e r
Chi-sqar.
Wilcoxon
Mallett
Sheard
8 passed
7 passed
14 passed
14 passed
0.006
0.001
0.035
0.025
14.00
12.00
10.00
Prism
Diopters
8.00
6.00
• Mean NPC
improved from 6 to 4
cm (p=0.015)
4.00
2.00
0.00
convergent reserve
divergent reserve
Evans (2000)
Conclusions about orthoptic exercises
•
Decompensated exophoria and convergence insufficiency are
readily treatable in optometric practice
• Treatment does not need to take up a lot of “chair time”
• Treatment improves fMRI measures (Alvarez et al., 2010)
•
Treatment with orthoptic exercises is appropriate for optometric
practice
•
Strabismus can also be treated with exercises (Pickwell & Jenkins,
1982)
• Treating strabismus with exercises seems less common now
(Piano & O’Connor, 2011) than Pickwell might
have wished...
A sceptical view of Behavioral Optometry
Non-standardised
“no randomised controlled
trials”
(Jennings, 2000)
“a large majority of
behavioral management
therapies are not evidencebased”
(Barrett, 2008)
Validated
VT for convergence insufficiency
Yoked prisms in neurological patients
Visual rehabilitation after brain
disease/injury
Controversy: training saccades in dyslexia
Saccades are not unique to reading
To
SpL
D
Evans (2000)
Voltaire: “Practical therapeutics is the art of
keeping the patient entertained until nature
effects a cure”
3-D displays are popular but unnatural
Vergence changes but accommodation does not
Abnormal saccades when reading more
likely to be a consequence than a cause
of dyslexia
Loss of spatial resolution (but may help)
Loss of temporal resolution
The DEM is not an eye movement test:
Unusual degrees of stereopsis
DEM test has no correlation with
objective eye movements measures
(Ayton et al, 2009)
Abnormal DEM ratio is an effect not a
cause of reading difficulties
(Medland et al., 2010)
OR
Possible mismatch between various depth cues
Howarth (2011)
the DEM is not a measure of saccadic
eye movements (Webber et al., 2011)
Attention deficit disorder (ADD) is an
important confounding variable
8
How many people will not perceive 3-D content?
Strabismus
Uncorrected anisometropia
Monovision
Stereo-blind
Poor or distorted vision in one eye
Total
2.5-4%
0.5-1.5%*
0.4%*
<0.1%*
v rare in young*
3.5-8%
CONCLUSIONS
Always be on the lookout for pathology
refer if no significant improvement
BUT pathology is very rare
It is possible to treat amblyopia in optometric practice
patients will need good instructions & regular checks
Many comitant ocular motor anomalies are treatable
How many people may have discomfort with 3-D?
Under-corrected refractive error
Decompensated heterophoria
11-30%*
possibly, 1-10%*
plus for eso and minus for exo are under-used treatments
Vision therapy for convergence insufficiency is evidencebased, but there is a need for more research for other
forms of vision therapy
*more common in older people
Could be reduced with better eyecare
Some famous people who were
dyslexic
Thomas Edison, Albert Einstein,
Michael Faraday, Willem Hollenbach,
Orlando Bloom, Tom Cruise, Danny
Glover, Whoopi Goldberg, Keanu
Reeves, Oliver Reed, David Bailey,
Leonardo da Vinci, Tommy Hilfiger,
Pablo Picaso, Auguste Rodin, Andy
Warhol, Duncan Goodhew, Cher,
John Lennon, King Carl Gustav,
Winston Churchill, Michael Heseltine,
John F Kennedy, Nelson Rockefeller,
George Washington, Hans Christian
Anderson, Agatha Christie, F. Scott
Fitzgerald, Richard Branson, F.W.
Woolworth, Walt Disney, W.B. Yeats.
“We find comfort
among those who
agree with us –
growth among those
who don’t.”
Frank A. Clark
Handout from www.bruce-evans.co.uk
for regular tweets on optometric research
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