Patent Application
20050041209
The present invention relates to ophthalmic equipment for eye-testing and spectacle setting. More specifically the invention is concerned with an apparatus and a method for accurately determining the position of the pupils of an individual and for correctly positioning lenses with respect to a spectacle frame of the individual.
When an individual requires corrective eyeglasses, it is extremely important that the corrective lenses be positioned in proper relationship to the individual's line of vision (in alignment with the individual's pupils and a viewed object). In particular this is the case when considering bifocal or multifocal lenses (also referred to as progressive lenses). However, this information is useful also for diagnostic and research purposes.
In order to obtain correct measurements, it is important that such measurements be carried out while the individual is wearing the eyeglasses at a normal and comfortable position (corresponding with how the wearer will use the eyeglasses), such that the relative positioning of the lenses with respect to the individual's eyes is most accurate. This measurement problem is further compounded by the fact that present day eyeglass frames take a wide variety of shapes and sizes ranging from generally circular in shape to various oval configurations. Additionally, any such measuring apparatus should also be capable of accommodating the so-called frameless eyeglasses as well as wire rim frames, etc. Even more so, it is important that the lenses be fitted in the frame in correspondence with the individual's regular activities, i.e. driving, reading, computer use, TV watching, outdoor activities, etc. and that measurements be taken at different positions i.e. leaning over, walking, sitting, etc.
A variety of measuring techniques and devices were proposed throughout the years, some of which are simple but not reliable and non accurate, e.g. when using manual measuring techniques. Other techniques are complicated to use thus requiring substantial amounts of time in obtaining the desired measurement. Others of these techniques and devices do not tend to be sufficiently accurate or may result in movement of the eyeglass frames during a critical portion, of the measuring process. Still other devices may be well suited for use with a particularly shaped eyeglass frame but may be unsuitable with respect to other shapes or types of frames such as the so-called frameless/rimless eyeglasses, wire-rim frames, etc.
U.S. Pat. No. 4,653,192 to Conard et al. discloses an apparatus for use in accurately determining the vertical position for the line of demarcation between the bifocal correction lens and other corrective lens segments to be provided in eyeglass lenses. The measuring apparatus includes an elongated indicia carrying member having provided thereon adjustable clamping members specifically designed to enable the elongated member to be attached to a wide variety of eyeglass frames for purposes of obtaining a measurement of the proper height for location of the segment line. The elongated member also includes a sliding gauge which may be moved there-along and cooperates with the indicia to provide an accurate, easily determined measurement for the position of the segment line.
U.S. Pat. No. 4,494,837 discloses a pupil location gauge having an index member movable in relation to a graduated scale for use in an ophthalmic test lens holder for subjective measurement of both vertical and horizontal pupillary distance. Either monocular or binocular measurements of the pupil location may be made with respect to a spectacle frame.
It is an object of the present invention to provide an apparatus and a method for carrying out ophthalmic measurements so as to obtain correct measurements indicating the position of an individual's pupils and to indicate correct positioning of lenses in proper relationship to the individual's line of vision with respect to a particular eyeglass of the individual.
According to the present invention there is provided a method for measuring an individual's pupil position (PP) in relation to a particular eyeglasses frame, wherein a display module (DM) is attached to the eyeglass's frame and a graphic image displayed on the DM is displaced until it extends in alignment with the individual's pupils, whereby the coordinates of the alignment location are registered to obtain the PP.
The above method comprises many embodiments, for example:
The present invention is also concerned with a system for measuring an individual's pupil position (PP) in relation to a particular eyeglasses frame, the system comprising a fixture member for attaching to the eyeglasses frame at a recognizable relation, at least one display module (DM) suited for displaying a graphic image on the DM, a control unit for controlling and displacing the graphic image, and a register for picking up the coordinates of the graphic image location at selected positions.
Once the coordinates of the PP are registered they may be used for different purposes and in various ways. When the information is needed for shaping lenses so as to fit within the particular eyeglass of the individual, e.g. when fitting bi-focal or multi-focal lenses, the information may be directly applied to raw lenses fitted on the frame. Alternatively, the coordinates of the frame are obtained and the coordinates of the PP are superimposed (during or after the process) so the raw lenses may then be machined according to this information.
In order to understand the invention and to see how it may be carried out in practice, some embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:
FIGS. 1 schematically illustrates a system in accordance with the present invention, wherein:
Attention is first directed to
The system 12 comprises a fixture member generally designated 20 which will be discussed in further detail with reference to
The system further comprises a control assembly 28 (
In general, the fixture member 20 is of lightweight and does not interfere with wearing the eyeglass 12 whereby the individual 14 is comfortable during the measurement process.
With further reference being made to
Display modules 24 are fixed to the frame 46, symmetrically positioned. The display modules (DM) may be a variety of display screens, e.g. an LCD screen or any other suitable graphic display module capable of displaying various patterns and images as well as changing its transparency through the range of transparent to opaque, as will be explained hereinafter in more detail with reference to
According to some particular embodiments, the graphic image may be part of a pattern or scheme which when blended with another graphic image (i.e. displayed for another second eye) is perceived as a virtual image. For example, the graphic image may be a first colored pattern (for example a blue circle) displayed in front of one eye and a second colored pattern (for example a yellow circle) displayed in front of the other eye, where only when both graphic images are in alignment with the respective pupils, a third color is perceived (a green circle in the particular example). The same result may be achieved by using other figures, e.g. geometric shapes. For example, if inverted half circles are displayed in front of each eye, the resultant perceived image, when both half circles are in alignment with the respective pupils, when both graphic images are in alignment with the respective pupils will be a complete circle.
A person versed in the art will appreciate that the image may be a reality image or a virtual image.
Similarly, if the target image constitutes part of the virtual image and the displayed graphic image (displayed on the DM) constitutes the other part of said virtual image, the resultant virtual image upon intersection of the graphic image with the line of vision, while staring at the target image, will be perceives as said virtual combined image. Accordingly, each eye may be presented with different images.
As already mentioned hereinabove, the process of locating and measuring the PP may be carried out by locating the point of intersection of the graphic image with the individual's line of vision while staring at a target mark (typically distant, from the individual) and also by displaying an image on a display monitor giving rise to a virtual image mimicking a distant image, and then locating the position of the individual's pupils when they are aligned and staring at the virtual image.
As an example, a display module (DM) according to an embodiment of the invention, is of the type known as a personal monitor (PM), where a high resolution color image is created in the individual's eyesight. The personal monitor is a monoscopic biocular display with a relatively narrow field of view, which can receive video signals from any video source. The signals are converted in the controller unit into signals driving the electronics of the LCD displays. The PM takes standard signals and displays them on a small TFT LCD display module that can be connected to any standard signal source e.g. video, computer, etc. The device comprises lenses and mirrors that project the displayed image into the retina of the eyes. The PM has a mounting slot that fits onto the nose piece of the eyeglasses.
However, other display modules are suitable for use with the present invention, e.g. so called reflective displays, etc.
The display module is typically a thin and lightweight surface which, in accordance with some particular embodiments, may have changing optical parameters to comply with near sighted or far sighted individuals (myopia/hyperopia) and further to adjust the brightness of the graphic image displayed on the module, depending on lightening conditions, etc. furthermore, it may be possible to adjust different optical parameters according to correcting tables, etc. in addition, some other optical elements may be used in conjunction with the apparatus of the invention. For example, power correcting lenses may be applied to correct sight deficiencies of the patient, filtering elements (e.g. to overcome glare, etc), prisms, etc.
The graphic image displayed on the display modules 24 is displaceable about the display module and is controllable by means of a controlling assembly (e.g. in
In practical use, the device 20 in accordance with the present embodiment is securely fixed over the spectacle frame 12 and the eyeglass are then comfortably worn by the individual, as if the device 20 is absent. At this position, the coordinates of the spectacle frame 12 with respect to the frame 46 of device 20 are measured and registered by processor 30. Then, the individual is requested to stare at a target mark (68 in
The process may repeat several times (using the same graphic images or different ones at each time and optionally changing the size and distance of the target mark) and each time the graphic image intercepts with the individual's line of vision a point of interception is registered into the processor 30, e.g. by use of the control unit 32.
It is appreciated that the test may be carried out by the individual or by the professional. It is further appreciated that the measurements may be carried for one eye at a time while the other eye may be comfortably kept open and the display module in front of that eye may be darkened or made opaque to prevent sight interference. Alternatively, the measurement may be carried out for both eyes simultaneously.
At the end of the measurement process, processor 30 generates the coordinates of the pupils 76 with respect to the true position of the eyeglass frame 12, based on the processed data registered by the processor 30. The information may be processed by different statistic analysis as known per se with or without using correction factors to compensate and adjust for different parameters.
The arrangement may be such that during a measuring process the graphic image is constantly displayed and displaced, or, the graphic image may be displayed each time at a different position in a non-continues fashion.
The data concerning the position of the pupils 76 may be used in different ways and for different purposes such as, for example, for machining spectacle lenses according to optic prescriptions, research and study, etc.
It is appreciated that measurements of the pupils' position may be carried out for far distance and for near distance (i.e. reading position) which is advantageous in particular for manufacturing of multi focal lenses whereby indications are provided for determining the position of the individual's eyes during such positions.
With further reference now to
In the embodiment of
In the embodiment of
With further reference being made to
It is appreciated that a variety of attaching mechanisms are available for securely attaching the frame of the device in accordance with the present invention to a variety of different eyeglass frames. Such a device may be attached to both raw lenses or to one lens at a time. It is further to be clear that the DM may by itself attachable to the eyeglass without the need for additional support frame. For example, the device may be attached to the spectacle frame by vacuum-suction cups attached to raw lenses of the eyeglass. Other attachment means may be, for example, magnet arrangements, clips or snap-on arrangements, etc.
Whilst some embodiments have been, described and illustrated with reference to some drawings, the artisan will appreciate that many variations are possible which do not depart from the general scope of the invention, mutatis, mutandis.
