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Патент USA US2118132

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May 24, 1938.
AAMS, JR, ET AL
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2,118,132
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CORRECTING OCULAR DEFECTS
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Filed oct. 2e, 19:54
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May 24, 1938.
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A. Amas, JR.. Er AL
CORRECTING
OCULAR
DEFECTS
Filed oct. ze, 1954
2,118,132
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4 sheets-sheet s
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May 24, 1938.
A. AMES, JR., El' AL
2,118,132
CORRECTING OCULAR DEFECTS w
Filed OCT.. 26, 1934
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4 Sheets-Sheet 4
2,118,132
Patented May 24, 193s .
PATENT: oFFIcE
UNITED STATES
2,118,132
`
.
CORRECTmG OCULAR'DEFECTS
Adelbert Ames, Jr.,’Gordon H. Gliddomand Ken
\ l
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Ogle, Hanover, N. H., assignors to
Trustees of Dartmouth College, Hanover, N. H.,
a corporation of New Hampshire
neth N.
Application ‘October 26, 1934, Serial No. 750,162 ’
v y12 claims.
(ci. fis-54)
Heretofore, various defects ofthe eyes have
been known and corrected in different ways ap
propriate to these defects. For example, dioptric
errors have been corrected by spherical, cylin
5 drical or torio lenses, and muscular defects or
phorias by means- of prism lenses which affect
the vergence of the eyes by changing the direc~
tion of the line of sight of an eyeball when the
ocular muscles fail to turn ‘it correctly.
More recently, a hitherto not investigated but
quite common eye defect has been found which
will be referred to as aniseikoniav and involves
diiïerences in size and/or shape‘of the ocular
images in binocular vision, also referred to as
eikonic conditions. The term “ocular image”
describes the impression formed inthe higher
brain centers through the vision of one eye. It
isA determined not only by the properties of the
dioptric image that is formed in the retina of
the eye, but also by the modifications imposed
upon that image by the anatomical properties
and physiological processes by which this image
is carried to the higher brain centers.
Methods and instruments forl evaluating
aniseikonias are for example described in the
Patent No. 1,944,871 of January 30, 1934 to _Adel
bert Ames, Jr. and Gordon H. Gliddon', and in
the Patent No. 1,954,399 of April 10, 19,34 to
Adelbert Ames, Jr. Spectacles for correcting
aniseikonias, also referred to asl iseikonic specta
.5)
~ ~
there is only one.
_
‘
Y
It is therefore one of the objects of this in
vention-,to provide a method and means’for cor
recting distortional aniseikonia by distorting the
image` formed on the retina of .an eye without
changing the direction of the line of sight'.
Such means, however, which could introduce .
corrective distortion ’without unwanted change`
of vergence, would in many cases change the 10
dioptric and/or overall and- meridional magniñ
cation properties of the eyes introducing thereby
these types of aniseikonia. It is,`therefore, an
other object of this invention to provide> methods
and means for correctively distorting the image 16
formed on the retina o! an eye, while at the same
time controlling the >dioptric and/or overall and
uniformly meridional eikonic properties o1' the
eyes.`
»
`
If prisms are used to correct» phoria only, `no
distortional aniseikonia being present, the dis
tortional effector the prisms introduces the lat
ter defect to the disadvantage of the wearer. Our
invention permits, in another'aspect thereof, a
change of vergence, or direction of lines o! sight. 25
without distorting the’image, or by introducing
a predetermined. amount of distortion and at the
same time, if required, controlling the> dioptric,
andeikonic conditions.
In its general aspect, the invention has there- '
cles, have also been developed and are described
for example in the Patent No. 1,933,578 of No
fore the object of providing a method and means '
vember 7,' 1933 to Adelbert Ames, Jr. and Gordon
H. Gliddon. Such iseikonic spectacles change
the magnification to a predetermined degree and
defects, and overall, meridional and distortional .»
aniseikonia o1' the eyes, whereby any one, sev 35
may or may not have in addition a .specified~
dioptric effect.
n
40
l
the patient to see `two objects where in reality
Aniseikonia may be of the so-called overall
type in which one image is larger than the other
in all meridians, or it may be meridional, where
one image is larger than the other in one merid
ian. Meridional aniseikonia may be uniform with
respect to that meridian, or it may have the
., form of distortional disparity >along that merid
ian, principally the horizontal one?.
'
-Disparities of the latter type correspond to the
effects of prisms, which distort an image in the
meridian in which they bend the line of sight.
Therefore, prisins can be used for compensating
or rectifying such distortional aniseikonias.
However, ordinary prisms used for correcting this
defect would change the -vergence of the eyes
and introduce a new defect equivalent to muscu
55 lar defects as phoria or tropias tending to cause
for evaluating or correctingphoria and dioptric
eral, or all of these defects may be inherently
present, `or introduced by correcting one, orsev
eral of the other defects.
'
These and other objects, features and aspects
of our invention will be apparent from the 1'ol 40
lowing detailed explanation thereof illustratingv
its genus with reference to general practical
embodiments. The description refers to drawings
in which:
i
“
Fig. 1 is a schematical representation .of the 45
distortion effect of a prism;
‘
Fig. 2 is a diagram showing the relation be
tween distortion and magniñcationzof a prism;
Figs. 3 to 6 are .diagrams explaining the effect
of prisms upon the horopter;
`
»
~
..
Fig. '7 is a diagrammatical representation of
apparatus for carrying out partition measure- p
ments;
f
,.
Figs. 8 and 9 are diagrams giving the relations
between distortion,v prism power and base cuí‘ve;
2f
2,116,132
Fig. 10 is a plan view, partly in section, showing
a spectacle frame in which is mounted one em~
bodiment oi’ our invention;
Fig. 11 isa vertical cross-section of Fig. 10
l taken along line II-Il thereof;
`
Fig. 12 is a diagrammatic view illustrating the
method of designing a distortionless prism;
' `
Fig. 13 is a vertical cross-section of a slightly
modiiled form of our invention;
lo
Fig. 14 is a horizontal cross-section of the de
.vice shown in Fig. 13, taken along the line Il-M
-thereof;
'
-
`
Fig. 15 is a diagrammatic illustration showing
our invention in position before an~ eye;
Yu
Fig.4 16 is an elevation of the principal lens
used in
trying out our invention;
.
„ Pig ¿asis a front elevation view, showing a
spectacle frame in which `is >mounted oner eni
.bodiment of our invention;
n-
l
f
Fig. 181i: a cross-section oi Fig. 17 taken along
line Il`-'-|l’thereof;
,
Fig. 19. is a cross-section o1' Fig.,17, taken along
-
line
Irl-._.k-IQ
thereof;
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,
,
I
,
Fig?èfm is’l a'partial sectional view similar to
g5 Fig. ìßiggshowing'a modification;
k
Figa-121- yis a cross-section of Fig. 20; taken along
line 2lb-_2i thereof; '
'Á
,
" ,
Fig,;22fls a >view similar to Fig. _20,_showing an
,
otherfmodiflcation;
.
`
'
.
`
n - ' Fig. 23 'is a cross-’section of Fig. 22, taken along
line 23"-2I`thereof;
'
Y
`
Fig. 24 >is a diagrammatic illustration showing
one embodiment of our invention in position'be
fore an eye; and>
ß
v
j
~
Figs. v25 and 26 show lens combinations accord
ing to Tables V1I.a.n_d_V'lII.`
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'
For a better understanding of the invention,
the distortion eii'ected by prisms, and the- dis
tortional aniselkonic defects 'of the eyes .will iirst
‘o be> discussed.l
The distortion of an eyeglass'for a given iixa
tion distance will herein be understood. to mean
the change in the per cent magniiìcation oi' the
eyeglass for increasingperipheral angles. Anal
distortion line D. The intersect Mo on the mag
niñcation axis is the overall magniiication of the
prism in the plane of the deviation, and, for pur
poses of this invention, indicates the magnitude
of magniilcation of the zero eil'ective power lens 5
necessary to counteract this magniñcation, as
will 'be explained more in detail hereinafter.
We observed that, physiologically, the path
ological distortion of 'the ocular images (prin
cipally in the horizontal meridian) vcausing the 10`
above-mentioned distortlonal aniseikonia is,'gen- f
' erally speaking, of the same nature as the just
described distortion effected by prisms. It is
further afact that, in binocular vision, the mag
nitude of the two ocular-image distortions deter- 15
mines> the shape of the longitudinal horopter.
The horopter, which may be deñned as the sur
face in space, every point on which is imaged on
corresponding retinal points, is substantially sym~
metrical with respect to a'vertical plane through 20
the medial line of sight of a 'person having no'y
eikonic defects. If, however, the ocularimages
or portions thereof have di'iîerent sizes, one and
the same object appears smaller to that eye which `
produces >a morev extended ocular image.
This 25
causes in binocular vision an apparent change in
location and/ or shape of the object. For example,
a4 diiïerence in overall size of the ocular images
produces> a rotation ofthev longitudinal horopter,
which may be describedas the intersection oi 30
the horopter surface and fans of projection lines
Afrom they m'ean nodal points of the eyes, these ,
fans being coniined in ahplane through these nodal
points. 'I‘his rotation of the longitudinal horopter
appears to take place about a vertical axis pass- 35
ing through the point of fixation at which the
eyes are looking, the- horopter portion at the side
of the eye with the larger ocular image appearing
more
distant.
`
.
~
`
Fig. 3 indicates the location of the longitudinal 40
horopter‘of a person with normal eyes, H being
thev horopter4 trace (which may be for a certain
visual distance b a straight line), and F a fixa
¿5 ogously, it will be the change inthe per cent ' tion point', determining vergence, at the distance _b
.difference'in the angular size of the kobject and from R and L, the right and left eyes, respectively, 45 .
the image produced `by'the eyeglass, reckoned
from the anterior nodal point of the eye, for
increasing values oi' the angularsize of-the ob
w ject. Thus, for a distortionless lens this change
will be kzero, while fora pin-cushion distor
tion _it will vary, increasing with ythe increase in
the angular size of thevobject.
of the observer. Fig. 4 shows the location of the
horopter trace H1 if, under otherwise similar con
ditions, the ocular image of the left.eye is larger, A
due to the interposition of a size changing lens
S before that eye, orto a corresponding patho- 50
logical diiïerence of the Ocular images.>
.
Distortional` aniseikonias, either inherent or in
troduced by prisms, have> the‘eil'ect of apparently
‘a the plane of the deviation is, within about 20’ curving the horopter, in a manner indicated in
`
of the deviation, that of a constant change asv Figs.V 5 and 6, Where H2 and Ha are the longitudi'- u
Y 'I'he type oi' distortion 'exhibited by prisms in
nal horopter traces apparent to normal eyes due
indicated in Fig. 1, where O is an object in the
form. of 'a divided square, which appears dis
torted-as shown at O’ if viewed through a prism
00 P. It will be evident that meridian d, and simi
havingv'a corresponding distortional aniseikonia
- larly- any inclined meridian, is distorted as in
. dicated at d’. Thus,- as graphically shown in
be measured with instruments of the general type
described _in the> Aabove-mentioned Patent No.
Fig. 2, the distortion vof a prism P will Vbe‘rep
resented by an approximately straight line D
" 66 _(related to the position of the prism as indicated
in Fig.v 2) in a system.“ coordinates represent
ing magniiicationv l,l and oblique angles qb, (see
Fig. 3) respectively.magnitude of the dis
vtortion, above deñnedfps the change in per cent
to prisms P2 `and P3, respectively. Abnormal eyes
produce a similar eiïect'. » Defects of this type' can
1,954,399.
A patient having aniseikonia exem
pliñed in Fig. 5 would move the points of a horop
ter instrument to actual positions indicating 65
trace H', in order to see them apparently placed
as indicatedA by ytrace H". By placing before
the patient’s eyes distorting prisms which produce
coincidence of apparent horopter and actual ho
70 magnification per do'ëree (¢)_ and herein called Y ropter instrument setting, that is, which move 70
H' and H", itis possible to correct this defect
which, even if present 'only to a very low degree,
may cause serious illness.
7g is then graphically expressed by the slopel oi the
A convenient way to measure distortional an
iseikonia quantitatively is the so-called “Multiple »75
3.
2,118,132
Partition Test" which is based on the same prin
ciple as the horopter experiments, and which is
conducted as follows: A series of object points
are also intermediate cases requiring ‘correctionv
of both distortionally eikonic and muscular de
represented by threads or wires are arranged so
that, as seen by each eye, all appear` equally sep
arated directionally. As shown in Fig. '7 in oblique
projection, a. series of- wires W, W1, W2, etc., and
W1 and Wn, etc., respectively, is placed before
each eye. Wire W serves as a fixation object and
10 may be iixed, as well as W1 and W1, the distances
W, Wi and Wr being kept constant. The other
wires are laterally movable and the patient,
looking at W, W1, W2, Wa, W4, Ws with the right
eye adjusts the wires so that they appear to bc
fects, and therefore `control of both distortion
and deviation of the lines of sight by _optical
means. Inaddition; it may'beuneçessary to cor
rect dioptric defects ‘andw'eikonic defects other
than distortion.~
~
_
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"
According to our invention, we` control the
effect of lenses including prism elements `by ap
propriately curving or bending prism compo-nents and, yif desirable, combining them with
other prism components and/0r lens elements
not directly influencing the direction of the line
oisight.I
,
M
For purposes of- our invention, it is necessary 15
equally spaced. If he has a distortional defect,the
wires will actually be unequally spaced, and their
positions provide a measure of the amount of dis
to correlate ythe various characteristics of optical
tortion, which can be checked with the aid of
prisms correcting the defect. The other eye is
for preliminary or .approximate computations.
20 similarly examined with Wires W, Wr, Wu, etc.,
and the combined effective distortion of both
eyes must correlate with the unbalanced distor
tion of the horopter.
,
The shape of the longitudinal-horopter, then,
25 is a measure of the unbalanced distortion be
tween the ocular i‘mages of the two eyes in the
prisms. While this can be done analytically,` it
was found that a more convenient way, 'at least
is to relate these characteristics graphically, as
will now be described.
'
f
~
With the above discussed unit for the prism
distortion ha, the properties of prisms have been
laid down graphically as shown in Figs. 8 and 9.
The effect of a prism depends'principally on
prism power, curvature (that is the basev curve
longitudinal meridian. Hence,- the unit describ
ing the distortion of prisms should be of _the order
. of changes of the ocular images for correspond
30 ing changes of the longitudinal horopter.
upon which the prism is ground), thickness- of
the prism, distance of prisinffrom eye, and‘de
gree of tipping with respectto the visual axis.
In these graphs, the distortion ha (already de
Thus, the unit of prism distortion may be de
fined to signify 0.1%vv magnification change per
one degree peripheral angle.` A prism having a
unit of distortion when placedV before one eye of
fined as the change in per cent magnification
per unit peripheral angle) is plotted against> the
an ideal observer at a definite fixation distance,
would cause the horopter trace of zero or un
base curves B in diopters, for various prism pow
ers A. As minus base curves are indicated Athose
which .result in lenses concave~ to the eye, 4and
asA plus ba'ses those which result in yocular sur
faces convex to the eye. Intermediate prism
balanced 4distortion (also called Vieth-Müller cir
powers are omitted for the sake of clarity. The
cle), to recede to the frontal plane. Now in
horopter theory, the distortion is defined as
curves are drawn for a distance of about 23 mm.
40
dM
from the anterior prism surface- to the -nodal
point of the eye, that surface being always per
pendicular to the line of sight. Fig. 8 showsthe
relations for infinite or relaxation kvisual dis
that-is the change in magnification per tangent
of peripheral angle, and h=2a/ b when the longi
tudinal horopter lies in the frontal plane, where
2a will be the interpupillary distance and b the
distance from the median nodal point oiî> the two
eyes to the point of fixation. If the above ideal
tance (that is, the distance betweenfnodal'point
observer is assumed to have an interpupillary dis
tance of 60 mm. and if his hcropter race is to
be taken at l m. distance from the eyes (compare
Fig. 3), then the value of h for this change is
-of Fig. 1l offrabout 1 mm. and varying center.
thickness t, but could also be computed vfor con
and theobserved object), to which a distance of L
about 6 m. is practicallyequivalent, and Fig. 9
is similarly drawn for `reading distance, of about
40 cm. For the sake of practical convenience,
the curvesr are made up for a constant trim (t'
stant t.
Similarfcharts can be made up for dif- y
>ferent distances from the eye to the prism.
These graphical representations of prism char
acteristics which, as already pointed out, are
especially convenient for purposes .of the present
The optical prism distortion is defined, however as invention, can be obtained empirically by actu
h--qg-Oñàaos
’
dM
ha _”d; X (100)
00
ally measuring prisms, or by conventional tri- 1 `
angulatìon ray tracing methods well known in
the art of optics.
While our invention provides for general c_on
trol of distortion, deviation of the line of sight`
and dioptric and eikonic defects by appropriate,
ly bending prism elements and in certaini in-v
for the values given above
stances combining them with other similar _or
different optical elements, two especially signifi
cant embodiments thereof are the correction of `
distortional aniseikonia without affecting the
It will now be evident that conventional. prisms
use_d for correcting vergence (phoria
efects
may introduce eikonic disturbances and’t‘hat, on
the other hand, conventional prisms used for
correcting distortional aniseikonía would most
likely cause a cha-nge in the relation of the lines
75 of sight of the eyes equivalent to phorias. There i
lines of sight, and of diverting the latter for
corrective purposes, without introducing distor`-4
tion. The latter is’the -»simplest ymodification
which may be called “Distortionless Prism”` and f
will first be described. Prisms of thisl type are
especially valuable in phoria cases which could Il»,
4
~2,118,182
not be corrected with conventional „prisms be
causeof the distortion» thereby introduced.
the center of rotation of the eye and perpen
dicular to a straight axis between the eye and
the object, has been found to have a practically
» In Fig. 10 there is shown a spectacle frame con
sisting of a pair of double rims l for holding the
negligible distortion.
lenses, a bridge member 2 connecting vsaid rims,
and a pair of temples 3, hinged at 4 to endpieces
5, which are in turn secured to portionsof the
rims I remote from the bridge »2.
,
,
below.
Y
_It will be obvious that any suitable well known
necessary, the spectacle frame illustrated being'
shown byy way of 'example only. Also, it is in
certain instances possible to join the lens ele
ments directly, for example by cementing, and to
,
As Üwill now „be -*evident from _the preceding
discussiony of the relation of prism power, base
curve and distortion, it is possible to ?nd prisms
having a'particulary curvature in the plane of
the base-apex line as shown at 'l and 8 on the
.
‘
In making prisms curved as above described,
it has been found that the elimination ofimage
form of lens holding means may be used, or that
a special type» of> frame may be designed if found
mount them'in a more conventional frame..
f
'I'he characteristics o1' a series of prisms of this
type, in steps of one A, are given in Table I
distortion inthe meridian of the base apex line
ofthe prism, is accompanied by a change in the
size of the image >in that meridian so that the
image would appear in its approximately correct
size in vthe meridian perpendicular to the base
apex line,Y but would appear of a different size in 15
the meridian of -the base apexline. Therefore,
such cylindrical prisms, if usedbefore one eye
only, would produce a relative `difference in the
shape oi' the two ocular images. When distor
tlonless prisms of equal power are put before each
lens 6 of Figs. 10 and 11, which prisms bend eye, no differences in the relative shape and size
the. line of sight without distorting the image in ~ of the ocular images are produced.y While such
the plane of the bending or, in other words, pairs of cylindrical prisms are of practical use,
`which have zero distortion h. together with a they have the disadvantage that, even when so
predetermined prism- power A, suited to correct used, they make objects appear broader than 25
high. In order to bring the image back to its
the ocular defect of an individual patient.
proper
proportions the lenses 6 have also been
The data of a» prism of thistype may in any curved in the plane perpendicular to the base
30
instance be found either ldirectly by means of
previously prepared graphs Asimilar to those of
apex line, as indicated in Fig. ll, so as to change
the size of the image in that meridian. In order 30
that the size of the images in both these meridians
be exactly the same,'the curvatures ofthe prisms
in the two meridians must be slightly different.
'I'hat is, the lens must beof torio form. Table III
gives- the curvatures in the two meridians neces
sary to equalize exactly the size inboth meridians
`for a series of prisms varying by steps of l` prism
Figs-8 and 9, or by a trial and error method con
sisting of two main steps.
'
' `
’
First, a prism i6 (referring> to Fig. 12) of given
parameters is laid 'out and computations are made
to determine-whether or not that particular set
of parameters gives the desired deviation.V Such
computations consist of tracing‘an axial rayV of
light i'l~ from a point i8' representing the center
of rotation of the eyethreugh the prism Vi6 at the
diopter.
angle I9 whichit is desired to cause the eye to
turn ln viewing a given object 20. This ray re
turns to, -or >intersects Athe normal line of sight
are shown for a series of prisms in Tables I and
n.
l
(angle of devianon=à=4255o
75, when placed with its first surface 40.24 mm. from
55
CoNs'rAN'rs or DrsroarroNLEss` P_Rrsns
Assuming the eye turns to take up prism power
first surface of lens is 28.83 mm. from center of
rotation.` of eye
y60
Prism power'
A
'
prism power of 7.3884
50
TABLE I
set of parameters, untill one is found which
~70 concave curvature cf 68.7983 mm. radius
.
practice such types of spherical meniscus prisms
are most useful. Theyalso have the advantage
of- being much more easily and cheaply made.
ess must be repeated, taking a prism of a different
vByway of example, a prism 5 mms-.thic `
.
difference between the ocular images if a single
prism were used before one eye, they would not
if equal prisms are placed before both eyes. In
If the two oblique rays are about equal distances
from the axial rayl at 26 and 21 (the distance of
the object from the eye), therevwill be no distor
_tion of the object. If theA distortion properties
of the‘prism prove to be unsatisfactory, the proc
~ a convex curvature of 52.6714 mm. radius '
_
While such 'variations would cause too great a
eye.
Second, the distortion is determined- for the
prism which is selected by the first step, by means
of `tracing two oblique rays 2| 'and 25, having
equal angles of Obliquity, from the point i8 re‘p
resenting the nodal point of the eyethrough the
base and apex portions of the prism respectively.
The rays are traced by the method commonly
known in the art'of optics as triangulation
‘
~
the images will be produced. These differences
2iv (along'which the eye would view the object
a, directly) .at 23, the distance of the 4object from
the eye. If the ray does not intersect at 23, the
parameters are changed until this/ray i1 does
meet the line -2| at the proper distance from the
will satisfy all conditions. '
I
If the curvatures in the two meridians are made
the same, that is if the lens is given a meniscus 40
spherical form, someY differences in the size of
Angle between the
.
Cog-"ex
ra lus
at
axis' degrees
l
2
~
two [aces of the Thick' Coâlyex
prism
1. 095
2. 190
3. ϧ
4. 373
the
»
ness
ra ius
mm.
mm.
mm.
2. 95
2. §55/
2. 95
2. 95
5l. U6
5‘0. 66
49. 66
48. 68
50. 65
49. 64
48. 65
47. 67
5. 439
2. 95
47. 73
45. 71
5. 461
4. 754
45. 53
43.90
6. 543
7. 623
8. 697
4. 75
4. 75
4. 75
45. 97
46. 42
46. 88
44. 33
44. 78
45. 25
9. 766
4. 75
47. 36
45. 73l
10. 669
4. 75
47. 78
45. l5
70
anais:
TABLE IIv
seikonia can be enacted by introducing cylindri
cal size changing components, for example by
_ .
MAGNIFICATION oF THE DIsToRTIoNLnss PrusMs 1N
making lens 9 toric, or by adding Surfaces hav
THE HORIZONTAL MIIBIDIAN AND THE VERTICAL
ing a similar effect.
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„
to 'a change in size, and in that lcase a power lens
may be added, or a lens I2 (Figs. 13 andr14)
may be substituted for lens 9 of Fig. 10. Lens I2
is of the general type -of focus and size correcting 10
lenses likewise described in the above patent and
Magnification Magnin cation
vertical
horizontal
percent
percent
Prism power A
„
desirable to provide a change in »focus in addition
First surface of lens is 28.33 mm. from center of
rotation of eye
10
.
In certain cases of ocular defects it may be
MEBIDIAN
may be designed as a singlelenswith `curves I3
Aand Il changing both magnification and size to
a prescribed degree. :
.
y
~
`
I
.
Recapitulating,` for providing> a devlation'of 15
the line of sightwithout `introducing prismatic
distortion, and at the same time accounting for
prescribed magnification and dioptric character
istics, We first determine the proper curves for
the prism lens 6 in itsapex-base meridian so that
it will bend the line of sight-the required amount
but will not distort the image in that meridian.
Next, we compute the curves necessary in the
TABLE III
25
meridian perpendicular to the apex-base merid
RADII IN THEHORIZONTAI. AND VERTICAL MERIDIANS
ian to change the size of the image in that me
To PRODUCE THE' SAME MAGNIFICATIONl IN THE » ridian by the same amount that the curved prism
HORIZONTAL AND VERTICAL MnnIDIANs
First surface of lens is 28.83 mm. from center of
'
.
lens is then ground and finished.
rotation of eye '
. _Horizontal
30
Prism
willchange it in the apex-base meridian. This
po wer Aì
Vertical
'
Next, we’compute the curves for the lens 9 or
I2 necessary to change the size ofthe deflected
image back to the desired size. ~ If the focus is
not to be changed, a lens like the lens Bis used,
but if the focus is `to lbe changed, a lens like I2
Ri
Rz ,
r
R:
mm
mm
mm.
mm
5l. 66
50. 66
49. 66
48. 68
50. 65
49. 64
48. 65
47. 67
51. 48
49. 98
48. 47
46. 99
50. 47
48. 98
47. 48
46. 00
used. After these computations have been made
and the lens 9 or I2 has,be'en ground Yand finished,
the prism lens 6 and the lens 9.or I2 are mounted
47. 72
46. 71
45. 23
44. 26
45. 53
43. 90
44.00
42.41 ‘
45. 97
46. 42
46. 88
47. 36
47. 78
44. 33
44. 78
45. 25
45. 73
46. 15
43. 74
43. 53
42. 73
42. 00
41. 23
42. 16
41. S0
4l. Z)
40. 50
39. 75
in a lens holding means', such `as thefspectacle
frame shown, by whichvthey are held in añxed 40
and proper relationwith respect to eachotherk
Rx
or an equivalent structureeiîecting both size and '
dioptric changes to `predetermined. degrees is
/
As was mentioned before with reference to Fig.
2, the prism which is curved in both directions to
the' proper degree _for avoiding partially or en
tirely all distortion, and bends the line of sight
as desired, effects in addition a change of the
size of the ocular image in all meridians. This
overall size change is equivalent to the effect of
a plane parallel plate of the thickness of the prism
at the line of sight and is, therefore, indicated
in Fig. 2 by the magnification at oblique angle
zero. If, for example, a different prism correc
tion is given for each eye, or if a different mag
niñcation is required for each eye, for example
due to inherent overall aniseikonia, the magnífi
cation properties of the prism must be corrected.
For this purpose, according to our invention, we
place in series with the prisms 6 (Fig. 10) the
and are supported in the proper positionon .the
face of the wearer.
ï
'
It will also appear that we have `provided, in 1
this embodiment of our invention, a new means 45
of changing the direction of pointing of an eye`
without distortion and with controlled magniñ
cation. In doing'this we first place-before the
eye I5 (Fig. 15) a distortionless magnifying prism Y
lens 6, and then place a secondf'lens 9 or I2 be 50.
fore the eye in series with the first, said second
lens having the proper curves. thereon to com
pensate for the change in the size introduced in
the image. This meansthatthe line of sight is
`first bent without distortion„butA with change in
55
size of the image, andrvthatuthe y_change in size is
then compensated for`_„ 'This order may be re
versed by a Vcorresponding"change in the curves
of the lenses.'
Accordingly, in Fig.
-
-
f
,points Pi and Pz, at equal
lenses 9 with curves III and II which change the
size of the imageback to its natural size or to a
distances from the linefof sightv, represent an
object which is imaged. at Pi', P2', which image
points, due to the function of the distortionless
size desired, without changing the dioptric posi
prism, are at equal distances from the deviated 65
tion of the image.
.
line of sight c', the distance P1’--P2' being equal
`
These lenses are designed to have no focal
power when they are at a specified ldistance be
fore the eye with an object at a specified distance.
By the term effective “zero power” it is meant
that the lenses do not change the vergence of
the incident light, that is the object and the
final image are at the same place.
A method
for calculating'such lenses is given in the above- v
mentioned PatentA No. 1,933,578.
It is evident that corrections of uniformly (as
75
353
distinguished from distortional) meridional ani
to distance Pi--Pz due to the effect of size element
9„,which, as indicated, retains the image plane
in the object plane. It is evident that by impart
ing a different magniñcationtoelement Y9, dis 70
tance PIL-P2’ can be increased or diminished
and that, by giving to the surfaces of 4element 9
unequal curvatures, Vergence power can be intro
duced, removing the plane of P1'--Pz’ from plane
P1--,Pz. .It is further understood that vsuch mag 76
niñcati'on and power effects can be made -sym«-
2,115,132
metrical to any meridian instead of, or in addi
The second above-mentioned speciñc embodi
tion to, corresponding overall eil’ects.
Instead of calculating the lens combination for ment, namelyr the correction of ldistortional
zero distortion, -the vprism component 6 can be aniseikonia Without bending the line of sight,
with the aid of so-called “Distortion lenses” will
chosen to have a Vpredetermined prism power to
gether with a, chosen distortion. Again, graphs now be described.
As shown in Figs. 17 and 1.8, a pair of distor- 1
similar to Figs. 8 and 9 can be used for this pur
tionless prism lenses 6 designed as above de
pose, or theprisms can be computed by conven
tional trial and error methods, in which `case, '- scribed and having curved surfaces 1 and 8, are
10 referring now to Fig. 12,> the oblique rays 24 and
mounted in series, respectively, with' a. pair of
25 will be so traced and Vselected that unequal ` prism lenses |09 having iiat or plane surfaces ||0 10
distances ‘from 20 `and 2l represent the desired and ||| thereon. These lenses areso mounted
distortion. Examples ofsuch prismatic elements that the bases of lenses 6 are opposite lthe apices
are Agiven vbelow-in Tables IV, V, and VI, which of the lenses |09. By this means, as will readily
be apparent, theimage coming to the eye will
list series of prisms having distortion in con
venient steps, each series having a constant prism first be deilected by the distortionless prismv 6.
power of one, three and ñve A, respectively. In Then, as the image passes through the flat prism
’ this case, points P1’> and Pz'of Fig. 15 would be 9 it will be deflected in the opposite direction and
20
. distorted. `Hence, the deilections cancelling one
unequally spaced in relation to v'
another, only the distortion effected by prism |09
e TABLE IV
remains. In addition, the image will be mag 20
niñed.
‘
.
‘ Drsmarrorz or Smau Pnrsn-Powna 1A
In the case of this specific embodiment called ’
“Distortion lens”, the prism powers of the lenses
25
Umu 0 r
(umion
«M 1w
am 1)
d tm,
_
o
A _`‘
u
ms" For?
P
mof
curve
dioptel’s (related
to eye)
`
h-`
6 and |09 are made the same, so that the line of
sight enters the eye with no resultant deviation.
It is, however-,clear that by'making the prism ‘ 25
powers of the two lenses 0 and |09 different, a
0. 00
0. 00
0.0015
0. 0100
0.0m
0.0125
0. 0250
0. 0315
0.0000
`
0.0500
K
--8. 40
Concave.
resultant deviation of any desired amount may
_1.54
D0.
+0. 00 Convex.
+13. 25
D0.
+2050
'
accordance with the more general
aspect of our invention.
D0.
' .
'
If. the prism powers of the two lenses, for ex
ample 6 and |09, are made the same, thenthe
TABLE v
Drsromon or Smau: PmsM-Powrm 3A
35
the lenses„but without'deviating the line of
sight.
Uma of
.
h . «0M-0%
'
A «uM-1)
l-`
Y 0n
u
d tan ¢
0.a) «
0.00
Bm,
Form oi
cum
plriïnà
(re
dmpters
negato
_8. 60
Concave
0. 0150
0. 025
_3. 15
0.050
+1.25 convex
0.015
+5.00
D0.
0 0500
0. 015
0. 100
0. 125
D0.
D0.
0 000
0.150
+1100
+15. 01
+20. 50
Y
‘
'
has been curved in both directions to the proper
degree to avoid entirely or partially all distortion,
and prism |09 bend the line of sight as desired,
but at the same time change the size of the image 40
no.
seen therethrough in all meridians. Therefore,
if a patient required a different distortional cor
Do.
45
TABLE VI
see images of. diiïerent size.
Drs'xmnox or SxNaLaPaIsu-Powna 5A
am“ h'
¿(51 1
«M 1)
_Á°
ß-`-
d0
Hand»
Ba“
For?
or
p m
curve
0.00
" 0. 00-
0. 025
0.050
0. 075
0. 100
0125
-aso
0.015
0.000
0. 045
0. 050
0.015
-5 15
--2. 15
+0. l35
+3. 00
+0.00
1.
1.
2.00...
2.25
0.000
0.125
0.120
0125V
0.150 +8.88
0.115 +1118
0.000 +14.12
0.225 +1100~
2.50....----
0 150
0.250
D0.
D0.
Convex
no.
D0.
D0.
D0.
no.
D5.
+2050
_ D0.
appropriate lens combination, are so> designed
that they change both size and focus of the image,
both by the prescribed amount'. The'procedure
somewhat, although not very considerably, with
changes of the visual.- distance, as shown Aby a
^ up for reading
of)ove.
computati n is analogous to that ` described
a
gs. 8 and 9, which _are made
position, and inñnite distance
vision, respectively. -It may sometimes be advis
10 ableto use different-corrections for these two dis
tances.V but in most cases computation for one
distance ïwhich may be dominant, concerning de
sirability of'correction, or for an intermediate
distance, for example 1.332D, is fully satisfactory.
' 'Ihe'foregoing tables are computed -for light
comingfrom infinity.
j
1
»
natural .size or to some other
size desired without changing the focus. .
Again, if it is desired to change the focus of the
concave
It should be noted that the distortion changes
65
a
chosen that they will change-the size of the image
'
0.
„
(Figs. 20 and 21) with curves ||4 and ||5 so
diopters ($19231
0
0.
0.
1.
1.
g
In such instances, we place in- series f‘with the
lenses as for example shown in Fig. 18, namely
the prism pairs 6 and | 09-1‘espectively, lenses H3
50
'unal or _ l
35
It will readily be seen- that the prism 6 which
.
0.0000
0.0450
55
30
~
_
-
arranca
It will also be apparent that we have invented
otherwise the same effect as combinations of dat
a new means for correcting adistortion verror of
an eye vwithout deviation of the line of sight and
with controlled magnification. -In doing this we
ñrst place before the eye ||9 a fiat prism |00 to
obtain the proper amount of distortion to correct
for the distortion of the eye, after which we place
a distortionless magnifying prism lens 6 of the
same prismy power as thelens |09 before the >eye
with its base Lopposite the apex of the lens |09.l 10
in order to compensate for the deviation intro#
duced by the ñat prism lens 9, _and then we place
and curved prisms, namely, one prism produces
a distortion and a deviation, and the other a.
deviation opposing that of the iirst, without dis
tortion.
.
.
r
,
.
As already mentioned, it is further possible,
according to our invention, to combine prisms,
both curved or one curved and one straight,
which produce a prescribed amount of` distortion
together ‘with a prescribed amount of deviation
of the line of sight.
_,
TABLE Vn
a third
lens I I3 or | I6 >before .the eye in series
i
DIsrolmoN LENsEs-2 Pinsus or EQUAL ` PRISM , withk the lenses |09 and 6 to compensate for the
POWER
e change inv size introduced by . lenses 6_ and |09.
15
una» of
distortion
«uM-0%
nl“ ' 414,-“
.
«uM-1)
h1 tan ¢
Base cum
lst powerk
Bm ¿um
2nd power
Form of
prismV
5A on o
5A on o
Fig. 25.'
20
coo _____ -_
20
o. oo
0.00
base.
0. 60..... ..-
0. 03
L@..... _-
0. 06
1.50 ..... -_
0. 09
0. 05
EA‘` 0n -3
0.10
5A 0n -ß
,
,
’
base.
.
5A 0n +3
ase.
-
Fig. 26. l
.
base.
ase.
0.15
'
5A on +6
Do. ~
base.v
6A on -9
base.
v
6A on +9
k
zoy
Do.
base.
25
TABLE VIII
Dls'roa'rIoN LEN sas-_2 PBIsMs oF EQUAL PRISM
PowEa
30
`
30
Iì’àii';
d(M-1)%
_d(M-1)
curve oi `
0.00---.
0. 125.-0. 250.--
0.00
0.0075
0.0150
0.00
0.0125
0. 0250
0.00_.'._
0.00
0.00
3 A on 0 base_-_. 3 A on 0 base__._ Fig. 25.
0. 25.--0. 50---.
0.015
0. 030
0. 025
0. 050
3 A on --1.50base
3 A on »4.50base
40 0. 76---.
0. 045
0. 060
0. 075
0.100
3 Aon _6.00 base 3 A 0n +9 base..
3 A on ~-7.50 base 3 A on +12 base-
:mien h" __Q-4, _ h“ d tan ¢
35
Base curve of
lst prism
Form of
2nd prism '
prism
(i A Prism)
_ -
l A on 0 base_..- l A on 0 base-_-». Frg. 25.
1‘A0n ---1.50baSe 1 A on +6 base.; Fig. 26.
1 Aon _3.00 base 1 A on +12 base.
Do.
(3 A Prism)
1.00----
«
(6 A Prism)
_
3 A on +3 base.- Fig. 26. ,
3 A On +0 base..
Do.
’
I
0.00..-.
0.00
0.00
0.50-.-1.00-...
0.03
0. 06
0.05
0. l0
5 A on -~3 base.- 5 A on +3 base.. Fig. 26
5 A on -6 base" 5 A on +8 base;Do;
1.50.---
(),09
0.15
5 A on -9 base.- 5 A on +9 base-_.\
5Aon0baso.... 5Aon0base_.__ Fig. 25
Recapitulating, the various elements of f this
lens combination‘may be computed as follows:
First, the proper prism power andr base curve
for the prism lens |00 is determined, so that it
will produce the desired distortion. This can be
-readily done graphically as indicated, orl by trial
and error, or by computation, as discussed herein
before. It should be noted that it may be desir
able to have a greater amount of distortion than
can be produced by a ñat prism. In that case, a
prism .on a meniscus base, with the lens turned
backwar ,is used. Combinations of this type are
given in
ables VII and VIII.
Í
The next step is the computation of a distor
00 tionless prism 6 of the same prism power as the
distortion prism |09 in the manner already dis
cussed.
'
40
D0.
Do.
l
‘
,
'
Next we compute the curves vfor a lens ||3 or
IIB necessary to change the size of the distorted
65 image back to the desired size. If the focus is
not'to be changed, a lens- like the lens | |_3 is used,
but if the focus is to be changed, a lens like the
lens H6, or equivalent structure, is used. f
After all these lenses have been finished, they
70 are mounted in a lens holding means, such as the
Do.
This'means that lthe-line of sight is bent, the
image at the same timebeing magnified; that
the line of sight is bent back to its original direc,
tion but distortion is introduced; and that the
change in size is .then compensated for.
This order may be reversed by a corresponding
change in the curves of the lenses.
i f
Fig. 24, analogous to Fig. 15, illustrates such an
arrangement, the distances of points P1” and'Pz"
from axis v”, whose direction is not changed, in-'
dicating the distortion with reference to the posi
tion of object P1, P2. Size compensating yelement
| I3 does not separate object and image planes.
It will ,be evident that by giving element ||3
appropriate curvatures, any desired lmagniiica
tion can be introduced, and that a distance be
tween object and image (in Fig. 24 assumed to
be in the same plane) can be introduced by giv- »
ing element ||3 a certain vergence power in ad
dition to its magnification characteristic; It is
further evident that the magniñcation and power ~
components may be effective »in any chosen rne
ridian as Well as in all meridians, by accordingly
shaping the surfaces, if necessary by means of
composite lenses incorporating surfaces shaped
spectacle frame shown, by which‘they areheld in
to accomplish these eiïects.
y
,
face of thewearer, at >the distance from the eyes
lsight can be introduced, the kresulting effect be
Itis also understood that by making the op
e properly fixed relationwith respect to veach other , posing prism powers ofv elements 6 and |09 un
and are supported in the proper position on the equal, a predetermined deviation of- the line of
for which the lenses were computed. -
4
65
8 ,
2.11am:
ing in substance the same as that discussed above
with reference to Fig. 15. Such a distortion plus
deviation lens .comprising two prism .elements
may be’ preferable in cases where considerable
distortion is required.
„
substantially affecting
tions and given prism powers that differ in con
venient steps (Tables 1V, V,V VI), including se
ries with distortion zero (Tables I, II, III) or
-
element, the said curved surfaces producing in
said second meridian a magnification 'substan
tially _equal to said magnification introduced by
the curvatures in said first meridian without
It will ’be evident that lens series with distor
10 prism power zero (Tables V'lland VIII) are use
ful for testing eyes for eikonic and muscular de
fects, and within the scope of our invention.
It is to be understood that wherever a “mag
_tionedpmeridian so as to produce a cupped lens
saidcompensatory distor-
tion and said compensatory deviation.
l
.
3. An eyeglass for correcting ocular image dis
tortion, and deviation of the line of sightbyintro
ducing given compensatory amounts of prismatic
distortion and deviation, comprising a lens ele
ment having surfaces, _each of said surfaces hav
ing in one meridian a curvatureand being spaced
nifying” prism and a “reducing’f lens are lcalled
for in the foregoing specification vand accompa
nying claims, both the lensand the prism
l
may
tem effecting said compensatory distortion, said
including that provided by lenses 9, I2, H3 or
meridian being located withrespect to said first
relative to the other forming a prismatic lens sys- l
be either magnifying or diminishing, it being only ` compensatory prismatic deviation and a certain
necessary that the lens be such as to make the substantially zero power magnification yin said „ Í
image its proper size after its sizeV has been meridian, and a second lens element having sur
faces, one convex and the other concave, each of
changed by a prism element.
the surfaces of said second element having a
’ It is further understood that, at least in cer
curvature in’y a compensation meridian. being
tain cases especially favorable for such proce
dure, the entire size and/or dioptric correction, » spaced relative to the other and the surfaces Aof*
l It (Figs. l0, 13.20, 22) can be incorporated in
the element. or elements, having the prism eñect.
From ¿the foregoing description it will be seen
said ñrst 'lens element and said compensation
mentioned meridian to produce in said compensa
tion meridian -a magnification substantially equal
that we have provided methods and means forV to said magnification.intrcduced- by the curva
carrying out all the objects of the invention, and tures in said first meridianwithout substantially
affecting said compensatory distortion and said
that we have provided means for correcting dis
tortional‘aniseikonia and phoriaor for `correct
` >4:. An eyeglass for correcting ocular image dis
.compensatory
ing distortional errors of the eye without chang
ing the direction of the line of sight of the eye,
or for correcting the direction of the liney of
deviation.
,
.
»
y
»
-
`
f
tortion and deviation of the line of sight by intro
sight without introducing distortiom and, in all
.ducing given compensatoryamounts of prismatic
distortion and deviation, comprising a’lens ele-`
cases, at lthe same time controlling eikon'ic con-l
ing in one meridian a curvature and being spaced
ment having surfaces, each oi’jsaid surfaces hav
ditions other thanl distortional, and the dioptric
relative to the other to produce a prismatic lens
properties ofthe image, whenever it should be .system
effecting isaid compensatory distortion,
necessary.
deviation, a certain Lsubstan
It should be understood'that the present dis ` said compensatory
zero power magnification in _said meridian
closure is for the purpose of illustration only and -tially,
and a substantially zero power overall magnifica
that this invention includes all modifications and tion,
and each of said surfaces being -curved»
equivalents which fall within the scope of the
in a -meridian normal to said first-mentioned me
appended claims.
`
ridian so as to produce a cupped lens element. the
V45
We claim:
said curved surfaces producing in said second
1. An eyeglass for-correcting ocular image dis
tortion, and deviation of the line of sight by in vmeridian a magnification counteracting said
troducing given compensatory amounts of pris
matic distortion and deviation, comprising a
lens system having surface means, each of said
surface means having in one meridian a curva
ture, and being spaced relative to the other sur
face means, forming a prismatic lens system ef
55
Y fectingv said compensatory distortion, said' com
pensatory deviation and a certainfsubstantially
magnification introduced by the curvatures in
sa’idflrst meridian without substantially affect
ing said compensatory distortion and said com
pensatory deviation, and a second lens element
having surfaces one convex and the other con
50
cave, each of said surfaces having curvatures in>
two meridíans, aligned with said first-mentioned
meridiana, and being spaced relativeto the other
and to the surfaces of said first element to pro
zero power magnificationxin said meridian, and
55
said surface means being curved in a meridian duce without substantial ,change yof v'vergence
normal to said first-mentioned meridian so as to ' power a rgiven overall magnification which, to
produce in said second meridian a magnification _gether with that of said first element provides an n
substantially equal to said magnification intro->` ' eyeglass with predetermined meridional and over
s `
-'
duced by »the rcurvatures in said first meridian, all magnifications.
5.> An eyeglass for correcting ocular image dis
without substantially affecting said compensa- `
tory distortion and said compensatory deviation. tortion and deviation of the line of sight by in
troducing given compensatory amounts of pris
2. An eyeglass for correcting ocular image dis
tortion, and deviation of the line of sight by in ’ matic distortion and deviation, comprising a lens
element having surfaces, 'each of 4said surfaces 65
troducing given _compensatory amounts of pris
~matic distortion and deviation, comprising a f having in one meridian a `curvature and being
spacedrelative to the other to. produce a pris
lens element having surfaces, each of said sur
faceshaving in one meridian >a curvature, and vmatic lens section effecting said compensatory
70 being- spaced relative to the other forming a distortion, said compensatory deviation, a certain
prismatic> lens system effecting said compensa-- substantially zero power magnification inj'said 70
tory distortion, said compensatory deviation and meridian and substantially zero power 4overall
rs
a certain substantially zero power magnification ' magnification, and' each 'of said surfaces being
curved in a meridian normal to said first-men
tioned meridian so as to produce a cupped lens
curved in a meridian normal to said first-men
in said meridian, and each of said surfaces being
element, the said curved `surfaces producing in 75
'
„ à
2,118,132
said second meridian a magnification substantial
ly equal to said magnification introduced'by the
curvatures in said first meridian without substan
tially affecting said compensatory distortion and
dium of a given index of refraction and having
" surface powers computed according to said in
said compensatory deviation, and a second lens
element having parallel surfaces one convex and
the other concave, each of said surfaces having
curvatures in two meridians, aligned with said
first-mentioned meridians, and being spaced rela
tive to the other and to the surfaces of said first
element to produce substantially without change
of vergen'ce power, an overall magnification sub
stantially equal to that'of said first element, pro
viding an eyeglass substantially lWithout, merid
ional magnification and compensating the overall
15
magnification ofsaid first element.` '
6. An eyeglassk for correcting deviation of the
line of sight without ocular image. distortion by
introducing a given compensatory amount of
prismatic . deviation, comprising a lens system
dices Vand according to said spacing, with the.
surface means of each of said systems being de
pendent upon the’ other, said curvatures and
said spacing to effect in said meridian a given
distortion altering the angles subtended, at aref
erence point 'of aneye, by a fan of light rays from
object points in a plane through the object and
said point to progressively different amounts,
substantially-in proportion to said distortional
aniseikonia.
y ~
r
'9., Spectacles for correcting binocular"v vision
' for distortional'aniseikonia of~ an amount vdefined
by the tested change in magnification >ratio with
changingy peripheral angle,- said spectacles com- 1
prising a frame, and twoïlens systems mounted
in said frame before the'respective eyes, at least
one of said systems having‘surface' means, 'each
ofl said surface means being'spacedï relatively 20
to vthe other and having" in-one meridian a 'cur
f
having surface means, each of said surface means> ~ vature forming a prismatic lens 'system and'each
being spaced relative _to therotl'ier surface means of said surface means beingcurve'd in a meridian
to form a lens system having said compensatory normal to said first-mentioned meridian so as
prismatic deviation in one meridian and each of to'produce a cupped lens system; the surfaces 25
said surface means having in said meridian 'a of said two systems, v'respectively',*being in said »
25 curvature
producing at said spacing substantially frame spaced from the respective eyes, and each
zero'prismatic distortion anda certain substan
system being formed of lens medium> of a given
tially zero power magnification and each of said index ofrefractionand having `surface powers
surfacemeans being curved in a meridian normal computed according to said indices and accord
30 to said prismatic meridian to form a cupped lens ing to said spacing, with the surface means of
system, the said curved surfaces producing in said each of said systems being dependent upon the
second meridian a lmagniñcation substantially
` equal to said magnification introduced by the other, said curvatures and said spacing to ef
fect vin said first meridian a given distortion al
curvatures in said first meridian without sub
35
stantially affecting said zero distortion `and said tering the angles subtended, at a reference point
55
compensatory deviation.
of an eye, by a fan of light rays from object
points in a plane through the object and said
‘7. An eyeglass for correcting ocular image dis
tortion without substantially deviating the line‘of -point to progressively different amounts, sub
stantially in proportion to said distortional anise
sight by introducing a given compensatory pris
matic distortion, comprisingI a lens system having ikonia, and also producing a certain substantial
ly zero power magnification, and said curvature y
ing in one meridian a curvature and being spaced in said second meridian producing in that merid
relative to the other surface means forming a ian a magnificationsubstantially equal to said
prismatic lens system effecting a prismatic de
magnification introduced by the curvature in said
viation, said compensatory distortion and a cer
first meridian without substantially affecting said 45
tain substantially zero power magnification, and given distortion. j
a second lens system having surface means
10. Spectacles 4for correcting binocular vision
spaced relative toeach other and to the surface for distortional aniseikonia of an amount defined
means of said first system to produce a prismatic by the tested change in magnification `with
lens system effecting in said meridian a prismaticv changing peripheral angle and for deviating the 50
direction of at least one of the lines of sight to a
50 deviation opposite to and therefore compensating
40 surface means, each of said surface means hav
said prismatic deviation of said first system, and
predetermined degree, said spectacles compris
also effecting a certain substantially zero power
magnification, the surface means of at least one
of said elements being curved in a meridian nor
mal to said first meridian so as to produce a
ing a frame, and two lens systems mounted in
said frame before the respective eyes, at least
cupped lens system, the said curved surface
means producing in said second meridian a mag
nification substantially equal to said magnifica
one of said systems having surface means, each of 55
said surface means being vspaced relative to the
other and having in one meridian a curvature
forming a prismatic lens system, the surface
means of said two systems, respectively, being in
tion introduced by the curvatures in said first , said frame spaced from the respective eyes, and
60 merid-ian without substantially affecting 'said
each system being formed of lens medium of a
compensatory distortion and said compensated given index of refraction and vhaving surface
powers computed according to said indices and>
deviation.
~
8. Spectacles for correcting binocular vision according to said spacing, with the surface means
for distortional aniseikonia of an amount defined of'each of said systems being dependent upon theo Cl by the tested change in magnification ratio withy other, said curvatures and said spacing to> effect`
changing peripheral angle, said spectacles com
in said meridian a given distortion altering the
prising a frame, and two lens systems mounted in angles subtended, at a reference point of an eye,
said frame before the respective eyes, at least one by a fan of light rays from object points in a
of said systems having surface" means, each of plane through the object and said point to pro 70
70 said surface means being spaced relatively to gressively different amounts, substantially in pro
the other and having in one >meridian a curva
portion to said distortional aniseikonia, and to
ture forming aprismatic lens system, the sur
bend the line of sight of at least one eye to said
face means of said two systems, respectively, be
degree.
,
ing in said frame spaced from the respective predetermined
l1. Spectacles for correcting binocular vision 75
75 eyes, and each system being formed of lens me
2,118,132
vby deviating the direction of at least one ofthe
lines _of sight to a predetermined degree, without
introducing ocular. image distortion, said spec
tacles comprising a frame, and two lens systems
mountedl in said frame before the respective eyes.
at least one of said systems having _surface means,
each of said surface means being spaced relatively
tothe other and having in one meridian a curva
ture forming a prismatic lensosystem, and each
10 of said surface means having in said meridian a
and two lens systems mounted in .said frame be
forethe respectiveeyes, at least one of said sys
tems having one lens element with surface means,
each of said surface means being spaced relative
ly to the other and having in one meridian a curv
ature forming a prismaticlens system effecting
a prismatic deviation, and a second lens element
having surface means spaced relatively to each
other and to the surface means of said first ele
ment forming a prismatic lens system 'effecting 10
in said meridian a prismatic deviation opposite
zero distortion, the surface means oi'.` said two f to and therefore compensatingy said prismatic
. systems. respectively, being in said'frame spaced deviation ofl said first element, the surface means
vfrom ,thev respectiîe eyes,v >each system' lbeing of .said two systems, respectively, being in said
15 formedßof lena
of a given indexpfre
frame spaced from the respective eyes, eachsys 15
‘ fraction and having'surface powers computed lac
tem being formed 'of lens lmedium -of a given in
curvature producing at said spacing substantially
cording to said s» indices f and according to said
spacing, with the 'surface means of each _of said
systems being ,dependent upon-the other, said
dex of refraction and having `surface powers com- -
puted according Vto said indices and according to
said spacing, with the surface means of each of
curvatures and said spacing to retain in said -said systems being dependent upon the other, 20
meridian unaltered> the angles subtended, at a said curvatures and said spacing to effect in said
reference point of an eye. by a fan of iight rays
25
from object points lin a plane through the object
and said point, and to bend the line of sight of
at least ,» one eye` toI saidv predetermined degree.
12.".Spectacles for (correcting binocular vision
for-distortional aniseikonia of ‘an amount yde
fined by the tested change in magniflcationfwith
changing peripheral angle, without substantially
30 deviating the direction of at least one of the
lines of sight, said spectacles comprising aframe,
meridiana given distortion altering the anglesY
subtended, at a reference point of an eye, by a
fan lof light rays from object points in'a plane
through the object and said point to progressively
25
different. amounts, substantiallyin proportion yto ,
Asaid distortional aniseikonia, without substantial
ly bending the lines of sight of the eyes. '
,
ADELBERT AM'ES, JR.
GORDON H_GLIDDON.
KENNETH N. OGLE.
'
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