Device for determining and measuring monocular pupillary deviations in a patient's eyes

The invention provides a simple and accurate device for determining and/or measuring monocular pupillary deviations in a patient's eyes that is, the distance in normal distant or near sight between the center of the pupil of each eye and the plane of virtual symmetry of the patient's face. The device comprises a cross bar carrying two adjustable reticles; the bar is formed of two casings which can move telescopically in relation to each other and each of which contains a runner capable of moving inside it under the control of an outside regulating knob and connected to a removable reticle-holder pin, each said telescopic casing comprising a downward-pointing arm held against the corresponding inside or outside surface of one of the arms of the spectacle frame, by at least one spring exerting force on each casing, the aforesaid device being characterized by the fact that each casing comprises an internal extension enabling the two casings to fit telescopically inside each other and which includes a supporting device for one end of a compression spring so that the force of the spring causes the casings to move away from each other and presses the downward arms against the inside surface of the spectacle arms.

This invention concerns a device for determining and/or measuring monocular 
pupillary deviations in a patient's eyes, i.e. the distance in normal 
distant or near sight between the centre of the pupil of each eye and the 
plane of virtual symmetry of the patient's face, corresponding in practice 
to the plane of symmetry of the spectacle frame worn by the patient. 
Many appliances already exist to measure these pupillary deviations. Some 
extremely simple ones are in the form of a ruler, but these are not 
accurate enough to allow proper centring of the lenses in the frame, 
particularly in the case of progressively variable-focus lenses, which 
require high-precision fitting. Other devices, such as the 
corneal-reflection pupillometer described in French patent No. 1 506 352 
of Aug. 4, 1966, are very accurate, but rather expensive. 
It is also possible to use a photographic mensurator, which provides a 
straightforward way of determining the position of the centre of the pupil 
of each eye in relation to the inside circumference of the corresponding 
frame aperture. However, this type of photograph shows only one kind of 
pupillary deviations in either near sight or far sight. This is not enough 
to allow a progressively variable-focus lens to be centred and angled 
precisely on an apparatus for edging and bevelling operations, prior to 
insertion into the spectacle frame. 
This invention offers a way of overcoming the disadvantages of the existing 
art, by providing a simple, accurate device capable of determining and/or 
measuring monocular pupillary deviations in the eyes of a patient who is 
looking at a distant or close object; such a device may be used in 
combination with a photographic mensurator, in order to record either of 
these two forms of pupil deviation on a photograph. 
This new device, to determine and/or measure the monocular pupillary 
deviations in a patient's eyes, comprises a cross-bar, carrying two 
adjustable reticles, to determine and/or measure the distance between the 
pupil of each eye and the plane of virtual symmetry of the patient's face, 
the said bar being formed of two casings which one move telescopically in 
relation to each other, and each of which contains a runner capable of 
moving inside it under the control of an outside regulating knob, and 
connected to a removable reticle-holder pin, each such telescopic casing 
further comprising a downward-pointing arm, held against the corresponding 
inside or outside surface of one of the arms of the spectacle frame worn 
by a patient by at least one spring exerting force on each casing, the 
said device being characterized by the fact that each casing comprises an 
internal extension which enables the two casings to fit telescopically 
inside each other, and which includes a supporting surface for one end of 
a compression spring, in such a way that the force of the spring causes 
the casings to move away from each other, and presses the downward arms 
against the inside surface of the spectacle arms. 
The cross-bar is thereby accurately positioned in relation to the frame to 
which lenses are to be fitted, because the extension rests on the 
corresponding frame aperture, so that the oculist can adjust the reticles 
precisely, by bringing them into line with the patient's pupils while he 
is looking at either a distant or a close object, by means of a mirror 
device, as described in French patent No. 2 384 232 of Mar. 15, 1977, 
filed by the same applicant. 
In another embodiment of the invention, each runner comprises a projecting 
element, which fits into one of the turns of the threads on a revolving 
shank inside the casing, connected to a knob, thereby allowing the 
position of the runner in the casing to be controlled. This projecting 
element takes the form of a tooth forming an integral part of the runner, 
to which it is connected by an elastic bracket, acting as torque limiter, 
so that the tooth can separate from the threading if the runner is jammed 
or pressing against another surface, and so that it can be reinserted into 
the threading by rotating the control knob. 
In one particularly economical and attractive embodiment of the invention, 
each runner moves along the cross-bar in an internal groove, the 
cross-section of which is entirely surrounted by the casing, except for an 
opening at the bottom, to provide a passage for an extension of the 
runner, to which the reticle-holder pin is attached. The groove preferably 
has a polygonal cross-section, and the cross-section of the runner 
comprises surfaces in contact with each surface of the groove. 
It will be easier to fit each runner inside its casing if the runner 
possesses a hollow rectangular cross-section, with a through shaped lower 
part, containing the bottom opening, and a lid-shaped upper part, glued, 
welded, screwed, or attached together in any other way, to complete the 
groove cross-section and enclose the runner inside the groove. 
The downward-pointing arm of the runner may contain several holes into 
which a double-L shaped reticle-holder pin can be inserted from below, in 
order to bring the reticle closer to the centre of the cross-bar in 
relation to the runner. Each reticle may be oblong, and to it may be 
attached, by snap-on action a vertically sliding clip comprising two or 
three elastic arms, as well as a handle and a horizontal bar.

The device illustrated in FIG. 1 comprises a cross-bar 1, composed of two 
casings 2 and 3, which slide partly inside each other, so that the minimum 
and maximum distances between the downward-pointing arms 4 designed to 
rest on the surface of the arms of a spectacle frame are approximately 120 
and 146 mm, thereby allowing it to be used with any size of frame. 
The bottom of each casing 2 and 3 carries a short projecting portion 6, 
which rests on the top of the appropriate frame opening, so that the whole 
device can be fitted to the frame. 
Two reticles 7 and 8, which are on a vertical plane when the device is 
placed on the spectacle frame, and at an angle on this plane, as shown in 
FIG. 2, to allow for the average angle of frames, are attached to two 
runners 9, which can slide inside grooves 10 provided for the purpose at 
the end of each casing. 
In FIG. 5, a spring 27 in the middle of the cross-bar 1 pushes the two 
casings away from each other to the right distance, depending on the size 
of the spectacle frame. The ends of this spring rests on surfaces 28 and 
29 on extensions 30 and 31 inside each casing. These extensions 30 and 31 
enclose the spring 27 inside a cavity, formed together wih the bearing 
surfaces 28 and 29. This spring 27 may be helical traction or compression 
spring, to push the two casings apart or draw them together, depending on 
whether the arms 4 rest on the outside or inside surface of the spectacle 
frame arms. 
FIG. 3 shows the system of regulation of the sliding movement of each 
runner 9 inside the matching groove 10. In this system, a tooth-shaped 
projection 11 meshes with the thread 12 on a shank 13, which revolves on 
bearings 14 and 15 inside the casing 3, and is connected to a knob 16. 
This system is used to adjust the position of the runner 9 inside the 
casing 3. The knob projects beyond the edges 5 of the cross-bar 1, where 
it is easily accessible to the oculist. 
The projecting tooth which fits into the threading 12 may be semicircular 
in section, and preferably forms an integral part of the runner 9, with 
which it is moulded in a single piece from a suitable material, such as 
plastic. The tooth is highly elastic, and acts as torque limiter when the 
runner 9 is in either of its end positions inside the groove 10. This 
prevents the runner from being jammed or blocked in either of these 
positions, which could damage the threaded shank 13. When the tooth has 
become separated from the thread, the shank 13 merely needs to be given a 
turn to readmit the tooth into the threading. 
FIG. 4 shows a more detailed view of the inside groove 10 and corresponding 
runner 9. The groove, which has a rectangular overall cross-section, is 
made up of a trough-shaped lower part 17, and a lid-shaped upper part 18, 
fitted together in order to enclose the runner 9 inside the groove 10. The 
two parts 17 and 18 may be assembled by any method, for example by gluing 
or welding, when they are moulded from plastic. The runner 9 is entirely 
surrounded by the casing except, for an opening 19 in the bottom of the 
lower part 17, through which projects an extension 20 of the runner. A rod 
21, carrying the reticle 7 or 8, surrounded by a ball 22 to prevent 
injuring the patient accidentally fits into this extension 20. This 
reticle-holder rod, which is double-L shaped, may be inserted into one of 
several openings 23 in the runner, as shown in FIG. 4. The runners contain 
surfaces in contact with each surface of the groove 10. A passage 25 
inside each runner contains the threaded shank 13, which meshes with the 
tooth 11, supported by an elastic bracket 26, and forming an integral part 
of the runner 9. 
FIG. 6A shows a reticle 7 or 8, which preferably has an oblong 
cross-section, and to which is attached, by snap-on action, a clip 32, 
with two or three elastic arms 33 and 34, allowing it to slide vertically 
on the reticle. FIG. 6B shows such a clip in perspective. It is provided 
here with a handle 35 and a horizontal opening 36. When the clip is 
brought level with the patient's eye, and this horizontal opening is made 
to coincide with the pupil of the eye, vertical co-ordinates for the pupil 
can be obtained, in relation to the upper and/or lower portions of the 
spectacle frame opening. 
The device described above functions as follows. 
The cross-bar 1 is positioned on the spectacle frame worn by the patient, 
by placing the projections 6 against the corresponding spectacle frame, 
and allowing the casing 2 and 3 to slide telescopically until the arms 4 
come into contact with the frame arms. The oculist then adjusts the 
reticles 7 and 8, by turning the corresponding knobs 16, which cause the 
runner 9 to move along inside the groove 10, through the connection 
between the tooth 11 and the threaded shank 13, until each reticle 
coincides with the appropriate pupil of the patient's eye. When each 
reticle has been set to measure monocular pupillary deviations in near 
sight, and each horizontal opening 36 has been set by sliding the clip 32 
vertically on the reticle, the oculist places a photographic mensurator 
opposite the patient, and asks him to look at a distant object, such as an 
infinite point produced by the mensurator, then takes the photograph. This 
photograph will show, in addition to the spectacle frame, the patient's 
pupils in the far sight position, and two vertical images of the reticles, 
showing each monocular deviation in near sight, and two horizontal lines 
reproducing the horizontal openings 36, showing the vertical position of 
the pupils in near sight. 
This new device can naturally be used on its own. The cross-bar 1 comprises 
a double measuring scale to left and right, each casing 2 and 3 being able 
to slide in relation to this scale, so that the originating point of the 
scale remains fixed, whatever the distance between the casing ends. In 
this embodiment, an indicator fixed to each carriage 9 and/or reticle 7 
and 8 moves along the scale. 
This invention is obviously not confined to the embodiments described and 
illustrated above: many variants are possible for someone skilled in the 
art, without any departure from the spirit of the invention.