 |
 |
8 |
 |
|
462
AM
J OPTOM
& PHYSIOL OPTICS
|
|
Vol.
65,
No. 6
|
|
increasing
the speed, the final
goal being
rapid
smooth vergence movements
at
10^/s.
At this point asthenopia and diplopia were eliminated. Voluntary or step vergence training
began
with the step jump duction
RDS program
as previously described. She rapidly developed
jump
or step abilities between
45^
BO
and
15^ B!. Home exercises using loose prisms
and
Brock
string
imagining a
bug
walking up and down the string supplemented office therapy. Binocular accommodative rock techniques using various vergence targets were performed (goal
±
2.00
D OU: BO
=
3O^ and
B!
=
15^).
Random jump duction training was done using unpredictable small stimuli
to
ensure rapid fusional
responses.
At the end of 16 sessions reevaluation showed unaided visual acuity of 6/6 (20/20) OU and orthophoria at distance and 4^ exophoria at near by cover
test.
NPC was
to
the nose. Phorometric
findings
were ortho at distance and 4^ exo at near. BO at near was >40/ 25^
and
B! X/26/20.
PRA
was
—3.00 D and NRA was +2.50
D. No symptoms were
reported.
A 1-year follow-up found no degradation of skills or recurrence of symptoms.
This boy
was a 7-year-old juvenile diabetic who
was
not
performing
at
expected
levels
academically.
His father
had a
long
history
of fa
tigue while reading and a diagnosis
of convergence
insufficiency.
The
boy stated
that he
was tired after reading
and
that
his eyes
hurt.
He thus avoided reading. He denied
a history
of headaches.
Unaided
visual
acuity
was 6/6 (20/20) each eye. No refractive
error was present.
Cover testing
elicited
8^ of exophoria at 40 cm. NPC was
8/17
cm. Extraocular muscle movements were full and concomitant.
Stereo acuity
was 20 sec
arc
on the
(original) Randot
test. Slitlamp and
fundus
examinations were unremarkable. Testing revealed the following: distance phoria
3^
exophoria B! 4/10/-3^, near phoria 9^ exophoria; near BO X/12/-3; near B! X/8/3;
PRA
=
—1.50 D,
NRA
+1.50 D,
and
accommodative amplitude was 12 D each eye.
Vectogram findings
were BO X/8/4
and
B! 2/1. Accom
modative
flexibility was
normal
with
±1.50 D.
A program of vision
training
began with traditional accommodative rock, stereograms, and
vectograms.
He became
“bored”
with these activities within two sessions. He worked with the RDS vergence program and within 5 sessions improved his BO ranges to 30^ and B! ranges
to
10^.
Repeated
vectographic training demon
strated transfer
(BO
=
X/14/10, B!
=
7/9/3). Accommodative rock with the Computer Orthopter monocular accommodative
rock pro-
|
gram used positive reinforcement feedback con
tingent
upon correct responding to improve
ac
comrnodative
facility
to +2.00 D
to
—6.00 D.
After adequate smooth (ramp) vergence ranges
had
developed,
we began
step
jump duction vergence activities. Office training
was
sup
plemented with
home
techniques. Traditional techniques
using stereograms, vectograms, and
loose prism
were
met with resistance. However,
using RDS in a jump duction technique, as described previously in
patient 1, resulted in cooperation.
After a few sessions
the boy refused
to
do the
RDS program because “it was
boring.”
Additional
motivation
was
provided by using
the highest vergence
level presented on the
screen
as encouragement “to beat his
record.”
Finally,
goals were established to
allow him to
receive a toy as reinforcement. Final
BO
ranges
were 16/
48/10k and final B! ranges
were X/12/8. He could jump from
47^
BO
to
10^
B! for 15
min
without any
signs
of
fatigue.
NPC was to the nose.
His mother
reported
that his
reading
scores had
improved, that
he was
reading
for longer periods of time,
and
that
his
attention had improved. He stated he
was
comfortable while
reading.
Though there was no control for placebo and/or Hawthorne effect we feel that the improvement was a
result
of the improvement in accommodative
and
vergence
skills
because no other therapy was being applied concurrently. A 6 month re-evaluation demonstrated no loss in subjective or objective changes acquired
during
vision training.
Success in improving vergence abilities with this
boy
was related
directly
to
the motivational
aspects
of behavior modification. Initially,
“beeps” and
“boops”
provided
strong positive
and
negative reinforcement; however, over time this reinforcement became less effective. The clinician switched reinforcement to “praise” based upon “beat your previous
score”
and performance improved dramatically.
The ability
to
control behavior
and
to
improve fusional vergence was directly dependent upon the
use
of the following: binocular stimuli which lacked monocular cues, i.e., RDS, rapid change of stimuli occurring
after a response;
and immediate reinforcement. These conditions could not be met with manual manipulation of vergence stimuli in a synoptophore, stereoscope, or with vectograms.
Research
studies have shown that computerization can improve binocular responses
and ability
in young
and
noncommunicative patients where traditional training has
fai1ed.13’4 Additionally, accommodativea and
vergence
|
|
|
8 |
|