Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
SASSES FOR USE TN TI3E TREATMEN~/DTAONOSTS
o~ eERTAZ~T MAl<~tJ~r~T~o~s of THE EYE
TeChr~iaal Field
This invention relates generally to the
optometry art, and more specifically concerns an article
for treatment/diagnos~.s of certain malfunctions of the
to eye, in particular the phenomenon of suppression.
Backa~rou~d of the Invention
At least two s3.gn~.fiGant eye malfunctions,
strabismus (crossed-eye) and amblyopia (lazy eye),
i5 involve the phenomenon of suppression, which is a
sensory malfunction in which one of the eyes in effect
is "blind" although it has the capacity for vision.
The vision in the crossed ox lazy eye is suppressed so
that it does not interfere with the «good" eye.
20 Typically, the suppression in strabismus and amblyopia
is constant. In other asses, not involving strabismus
or amblyopia, one or both eyes may be suppressed
intermittently, which is referred to generally as
intermittent central suppression (ICS). ICS occurs at
z5 various rates and for various time intervals, typically
in the range of 12 to so timers per minute.
The treatment of constant suppression involves
the corxeation of the crossed or ~.azy eye so as to make
them, in ,effect, normal in ~unatian and appearance,
34 thereby providing the total victual benefit of both eyes
(binocular v~.~ion). While the effect of constant
suppression on vision is known (one: eye is in effect
(, ~ .~. ,~~~ e,. .;
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2
blind), the effects of ICS are less well known.
Presumably there a.s sopae effect on binocular vision.
There is also a strong possibility that Certain visualxy
mediated functions, in particular reading, are
detrimentally affected by ICS. It has been, suggested
that the intermittent nswitching off~~ of visii~rl in one
eye due t.v ICS results in the intermittent obscuring of .
the text mater~.al being read, so that reading becomes
difficult because the same wards may look different
depending upon whether suppression is present or not,
i.e. the timing of the ICS.
While malfunctions such as strabismus and
amblyopia are relatively easy to diagnose, the accuxate
diagnosis of ICS is more difficult. There are a number
~,~ of tests which have been used for ICS, most o~ which,
however, have proven to be unreliable in the accurate
diagnosis of ICS.
one of the traditional treatments used to
correct suppression involves the use of binocular
devices such as prisms and stereoscopes which in affect
force each eye to see a geparate~ portion of a "complete"
image. The two partial images are then 3.ntegrate~d by
the brain to produce a complete image. Each image path
can be alternately lighted in order to stimulate esach
eye separately. Light ~lashera Whioh impinge d~.reGtly
upon the eye have also been used. However, the
significant disadv~;z~tage to such a treatment approach is
that the treatment can anTy be, accomplished in a
practitioner's office, because of the equ~.pment
necessary. Such treatment is thus inherently time
limited. While improvement in the suppression condition
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3
is often possible with such treatment, frequently it is
relatively slow and not reliable.
Another common technis,~ue for treatment of
suppression is patching of the suppressed eye. While
~ typically an effective technique, the appearance
presented by an eye patch is usually so u~adesi~abZe that
only a small part of the population, i.e. vexy young
children, will wear a patch for an extended period of
time. Hence, patching is not perceived to be practical
1o for the general population.
rn at least one condition, i.e. strabismus,
surgery can be used as a last resozt to prevent the eye
from crossing. In amblyopia, as in ICS, however, there
is no real need far surgery, and thus the indiv~.duaJ.
15 with those conditions is left to tolerating either the
lack of true binocular vxs~,an, in the case of amblyopia,
yr the disadvantages of intermittent suppression, such
as reading difficulties and intermittent loss of
binocular vision.
20 Hence, there is a demonstrated need,
langstanding in the art, for an eff~ctive and reliable
treatment for the suppression phenomenon, bath constant
and for IGB, as well as more recently, a need to
accurately diagnose the existence of intermittent
25 central suppression (ICS).
Disclosure of the Invention
Accordingly, the ~prgsent invention is an
article far treatment and/or disgno~sis of certain eye
3o malfunctions, .including eyeglasses having at least one
lens which is treated sv as to be changeable between a
generally opaque condition and'a generally transparent
~~~~.~._~~
condition, under the control of an electric: signal and
means for producing an electric signal capable of
switching the treat~d lens between its?~opaque and
transparent conditions and for applying ~e electric
signal to the treated lens at a selected rate.
Flri~f Tlg~r_.r~~~~n Of thB Drawincts .,
Figure 1 is a representational?view showing
the article of the present invention i,n :place on an
individual user.
Figure 2 is a schematic view =showing the
art5.ale of the present invention in Wn operating
canditian with one lens opaque and the other
transparent.
figure 3 is a block diagram of the electrical
control circuit of the present invention.;
~.est Mode for Garrving Out the TnyeD,~~,c~~, _"
Figure 1 shows the article of the present
invention in a schematic ar representational form in
place on an actual user. The article comprises treated
eyeglasses which are electrically controlled to produce
alternating opaque, ~..e. acaluded (dark) and transparent
(clear) conditions in they two lenses. Thm arti.c~.e is
2~ shown generally at 10, and includes a conventional
eyeglass frame 12 with two ~,enses 14 and 16. The lenses
themselves may either be clear glass or may have
conventional correction ~ for nearsightedness,
farsightedneSS or other conditions. Also, the lenses
3p could be tinted, if desired.
The front surface of each lens 1~ and 16 is
coated with a thin film 1~, 2t? which is responsive to an
' "v .~
electrical signal to switch, i.e. change, between an
opaque state in which vision through the lens .is
partially or completely prevented, and a clear or
t~rar~spaxent state in which there is no interference with
5 the vision through the lens. .
This film z8, 20 wall be explained in more
detail in the folxowing paragraphs, as will be the .
electrical circuit, shown generally at 22, which
controls the state of the film on each lens. Whale
circuit 22, which contains a battery and a
signal-generating portion, is shown in general block
form in Figure 1 as part o~ the glasses frame, similar
to those glasses which incorporate a hearing aid, it
should be understood that control circuit 22 could be
separate from the glasses themselves and could be
attached to the car in some fashion vx contained in a
small unit adapted to be carxied by the user, such as in
a chest packet. In such a case, electrical leads would
extend from the eyeglass frame to the circuit.
In the embodiment shown, the film layers 18
and 2o consist of a thin interior (3-18 m3.ls) layer of
electro-optical liquid crystals between adjac~nt
exteriox layers of metalixed mylar. The film is
commercially available; for exa~aple, the product,
currently marketed undex the name "translight", is
available from Linear Optics Company. When the film is
not electrically stimulated, i.e. when an electrical
potential is not applied (the "off" state), the film
will scatter any light which impinges thereon, giving it
a cloudy, somewhat whitish, appearance, In the off
state, vision is prevented lay the opaque film.
Different color films are readilx possible, as well as
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different tints, which may in themselves be useful in
treating other eye ct~nditions. Colored films may help
in making the switching between opague and transparent
cry»ditions less noticeable, as we~.~, as possibly having
desi.rabl~s treatment effects. Also, the degree of light
scattering can be varied so 'that a partial occlusion can
be obta~,ned, if desired. Still further, it is possible
to cover only a portion of the lapses with the film.
i3pon the application of an electrical signal,
in the range of 30-60 VAC for the specific film material
described above, an electric field is establf~shed
between the metalized mylar conductors, having the
effect of aligning the liquid crystals, and resulting in
the film baaoming transparent. This is the °'on" state
7.3 for the lens.
Referring to Figure 2, lens 24, which is
opaque, has no electrical potential applied thereto, and
is therefore off, while lens 16 does have an ~slectric
potential applied to it, r~sulting in the film becoming
transparent, as shown, and is therefore an.
The film has relatively low power
requirements, i.a. 1/1o watt per square foot. The
required switching time isc appxQximately 1 millisecond
from off to on (to transparent), and approximately 25
milliseconds from on to off (ta opaque). These
switching times are sufficiently fast for the required
frequencies described abov~ to accomplish the
treatment/diagnosis of suppression.
The control circuit for the present invention
is shown in Figure 3. ~t includes a conventional 9-volt
battery 26, which is connected to a controlled timer 28
as well as an inverter 30. The timer 28 controls the
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frequency of the change of lens condition and the
frequency may be either adjustable or fixed, depending
upon the particular application of the glasses. The
outputs of the timer 28 and inverter 30 are applied to
a switch 32. The output of switch 32 is applied through
electrical leads 34 to the film 18 on one lens 14, a3~d
through leads 36 to the film 2Q an lens I6. When the ,
battery 26 is on, switching will occur at a
predetermined xate. Although the circuit is designed to
provide a relatively wide frequency range, in the
embodiment shown, the typical frequency fox treatment of
suppression will be in the range of 6-lSHz with the most
desirable rate being approximately 7Hz, while for
diagnosis of zCS the frequency wi~Ll be within the range
of 4-120 cycles per minute.
Hence, an article has been disclosed which
takes the form of specially treated eyeglasses,
operative such that the eyeglass lenses alternate
between opaque and transparent car~ditions, at a selected
frequency. The glasses are effective in the treatment
of suppres$ion, and may be conveniently warn by the user
for extended p~riods of time.
Although a preferred embodiment of the
~.nventian hag been disclo~ed herein far illustration, it
should be understood that variou~x ~ahanges, modifications
and substitutions may be incorporated in such embodiment
without departing from the spirit of the invention which
is defined by the claims which follow.
