JP2590078B2 - Portable scanning digital pupillometer - Google Patents

Description

The present invention is useful for examining holes and measuring gaps up to about 10 mm in diameter, and more particularly to a handheld scanning, measuring and recording device useful for pupillometers. .

Since pupil size is an important indicator of the subject's autonomic nervous system and general physiological condition, it is necessary to measure and record the pupil size of human and experimental animal eyes. Many objective methods have been devised. These methods provide quantitative information to monitor the duration of action of drugs that produce miotic or mydriatic effects and can be used by anesthesiologists and others in operating rooms, intensive care units, and recovery rooms. It was useful for those of us.

However, in many applications, especially in clinical and basic research, it is necessary to measure the dynamic response of the pupil to light stimuli, ie, the light response. Some dynamic pupil measurement systems developed for human research include infrared (IR) cinematography (Lowenstein, U.S. Pat. No. 3,533).
No. 3683), IR spot scanning or IR video pupil recording. All of these methods are complex, expensive and require bulky equipment and are not suitable for use in operating rooms or other confined space locations. In addition, these known methods and devices require considerable installation time, high initial costs, subject training and skilled maintenance.

SUMMARY OF THE INVENTION The present invention solves the above-identified problems and provides two primary components, a container that can be easily used by physicians or personnel engaged in higher animal and clinical research. The need for a lightweight, low-cost digital pupillometer by providing a measurement device using a hand-held optical unit combined with a commercially available microprocessor-based control processing unit Is satisfied.

Broadly, the apparatus of the present invention is for measuring hole diameter, particularly pupil diameter, and the change in pupil diameter in response to an exciting light pulse. The device according to the invention can be used by physicians, in particular by anesthesiologists as an indicator of the level of anesthesia of patients on the operating table, or in bioassays of various pharmacopharmacological compounds, in the evaluation of anesthetic dependence or in the iris It is primarily intended for use by researchers in the analysis of drugs with local effects. The device of the present invention
It can be used for measuring the pupil diameter under various conditions limited only by the ability to center the pupil image of the operator on the image sensor. The device of the present invention has a pore size of 10
If it does not elapse mm, it can also be suitable for measuring the linear dimensions of a suitably illuminated object on which the image can be so positioned.

The device of the invention comprises a hand-held, lightweight optical / image sensor and a microprocessor based control and data processing unit. The main tube of the optical unit projects an image of the eye onto a reticle having concentric circles. It is observed by the operator via the eyepiece, and the operator will be provided with a means for focusing and centering the pupil image. An image sensor is housed in a handle perpendicular to the main tube. The optical beam splitter directs the reflected near-infrared light (given by the infrared light emitting diodes) from the object being observed toward the image sensor. The lenses in the path project an image of the eye on the sensor at approximately one-third the size. A set of infrared light emitting diodes (IRED _s ) are positioned to illuminate the pupil / iris region and provide emission of the image. Lamps for background lighting ("viewing" lamps and pulsed excitation lamps) are arranged along a "trigger" switch to start a series of measurements.

The microprocessor-based unit contains a computer, battery power, 4x4 keypad, and two rows of 16 character displays. The unit controls the viewing lamp, pulses the excitation lamp, and sequences a series of 10 image captures per second. The pupil diameter is calculated for each capture, and the result is displayed. The obtained data is stored. Means for outputting to a printer is provided.

The pupilometer of the present invention comprises a body adapted to be held by hand and attached to the body so that light is guided to the pupil region of the eye during manual alignment of the body in front of the eye. One light source is adapted to emit a beam of light illuminating the eye along a line within a limit of 0 ° to 9 ° from a plane tangent to the center of the pupil, and the other light source Are adapted to emit light rays that are directed into the pupil more directly than the first-mentioned light rays on the eye in the vicinity of the pupil, two light sources from the other light source Means for selectively activating the light source so that the effect of the pupil in response to the irradiation of light is observed and recorded, irradiating the eye with infrared radiation and imaging the radiation from the eye being observed Means for pointing towards the sensor, image sensor, and computer It has a microcomputer-based control and data processing unit with data, battery power, keypad, and display unit.

The present invention further comprises illuminating the iris and pupil region of the eye with infrared radiation, selectively directing light from a (visible) light source to the pupil region to excite the pupil response. Methods for studying the effects of pupils on laboratory animals are also included.

BRIEF DESCRIPTION OF THE DRAWINGS The novel features and operation of the present invention will be better understood from the description and description of the disclosed embodiments, taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an embodiment of a pupilometer constructed according to the present invention, FIG. 2 is a front view of the pupilometer shown in FIG. 1, FIG. FIG. 5 is a rear view, FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 2, FIG. 6 is a view showing a control and display panel, and FIG. FIG. 8, FIG. 8 is another front view of the pupillometer shown in FIG. 1, and FIG. 9 is another side view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, will be described in detail.

In a preferred embodiment, the optical unit (1) shown in FIG.
0) and a handheld pupilometer comprising a microprocessor based control and data processing unit (42) shown in FIG. The main tube (12) of the optical unit projects an image of the patient's eye (14) onto a reticle (20). The screen observed by the operator via the eyepiece (16) is marked by concentric circles. The image sensor (32) and the associated circuit board (34) housed in the handle (15) at right angles to the main tube (18) comprise a 64K dynamic RAM memory chip with a glass lid (IS32 optic RAM) (Available commercially from Micron Technology, Boise, Idaho). An optic RAM is made up of 65,536 independent image sensing elements called pixels. Each of these pixels is 128x2
It is organized into two rectangles with 56 pixels.
They can be used as a single 256x256 pixel array. Pixels can only be used to indicate light and shade. During the scan, the capacitance of each pixel is charged to the supply voltage. Between each scan, the light impinging on each pixel discharges the capacitance. If the voltage at a particular pixel capacitance is discharged below a preset level, the pixel is read out as bright (white) in the next scan. Otherwise, the pixel is dark (black)
Is shown. The contrast between the iris and the pupil is very suitable for distinguishing light and dark between the iris and the edge of the pupil. A complete scan can be performed every tenth of a second.

The IS32 optic RAM has a 256-row × 256-column geometric matrix pixel array in which 512 element positions are extended in the row direction. The high-speed scanner sequentially scans the positions of 256 columns for each row. The data bits are transmitted serially to the microprocessor unit at 3 MHz. These are assembled into 8-bit bytes and 8Kx
Stored in an 8-bit static RAM chip. A complete scan takes about 22ms. Next scan is 78ms
Starts later. The pupil image for each row is ideally just a continuous string of dark bits, the number of which can be easily determined. The row of the darkest bit corresponds to the desired diameter. However, because there is inevitable noise,
The bits of several adjacent rows are examined and the most probable pixel count is selected. With the known optical reduction ratio and pixel spacing, the diameter can be calculated using the count.

High speed hardware scanner system for IS32 optic RAM is packaged with optical unit (15)
Mounted inside the handle. Dynamic RAM
Bit reading is a 4 step process, so 3MHz
A 12 MHz clock is required to obtain a bit rate of. For this reason, it is highly desirable to have a scanner physically close to the sensor. In addition to the data bits, the scanner sends out a synchronization signal via the connecting cable (40) to tell the microprocessor if each bit is there and if there is a bit at the end of each group of 8 data bits.

Illumination for pupil measurement is adjusted for iris-pupil contrast. If the illumination level is too low, some of the pixels in the iris area will remain dark and mottled (mott
led) is understood to produce an effect. If the level is too high, the pixels in the pupil region indicate light. The mottle effect is easy to detect in the image and the radiation level can be increased until it disappears. As the radiation level is increased above a certain point, the observed diameter will be constant or will decrease slightly to a level where the pixels in the pupil region begin to show light. This radiation level is usually preset. However, it may also be adjustable manually or automatically for special applications.

Illuminated by the viewing lamp (38), the operator can properly position and focus the eye image. The position of the viewing lamp is such that any excitation of the pupil reaction is minimized, but it is practical to keep the intensity as low as possible. In some cases, the switch may be turned off to avoid affecting the pupil response.

The microprocessor based control and data processing unit of the present invention is a Motorola 68092E program.
ROM (EPROM-2764, 8K bytes), RAM (two HM6264,
LCD with two 16 character lines (41) (45), 4x4 array keypad (44), 24 hour clock, manual or automatic select switch with half 16% to full Turn on / off the viewing lamp control unit that gives eight levels up to the rated voltage and the exciter lamp
A control unit for turning off is provided. The level of the excimer lamp is usually set to a predetermined intensity measured by a standard radiometer. The power supply for the unit is a 6V, 4.5AH, cell-cell battery, with a 5.0V regulator, built into a current limiting, constant voltage charge regulator.

The keypad (44) shown in FIG. 6 is a means for setting and operating the pupilometer of the present invention by the operator. The keypad is a digital display (45) with a cable 46
It is connected to the. Control is performed by inputting a two-character command, each of which consists of one character followed by one number. When data from the operator is required, a prompt is shown on the display and the required items are displayed. The operations are divided into three main groups: setting, measurement, data reading / printing.

When the power switch is turned on, date / time data is displayed. If correction is required, a time setting command, that is, "C2" is input. Prompts follow for month / day and hour / minute. As new data is entered, the display clears and prompts for the next command. The display time command, ie, "C1", calls up the new date and time data on the display and updates it to the current time.

One of the two 8K byte static RAM units is
Patient data is used from the lower address end of the unit, used to store image data from the sensor, and on the other hand, to store and execute patient data. A relatively small area at the upper address end of the RAM is used for programming. The area is protected from patient data. At the beginning of a series of measurements, the previous data is cleared from the patient data area. Clock and RAM
Are continuously connected to a power source, so that one series of patient data is stored until erased. Otherwise, new patient data is entered following the old data. The memory test command clears both the image and the patient data area.

If not, the Set Patient ID command prompts a memory clear, the date and time are automatically entered into the patient data record, and the patient ID number is requested. Once the number has been entered, a prompt for the level of the viewing lamp will follow. To set the level manually, one number from 1 to 7 is entered. The numbers 1 to 7 provide eight different lamp voltages from half voltage to full voltage rating. The next prompt is for the exciter lamp pulse period in tenths of a second. The selected viewing lamp level and exciter lamp duration are entered in the patient record. In this state, a two character "measure" command must be entered.

The measurement is performed by positioning the optical unit above the patient's eye (14) with the push button switch (36) activated,
Focus the iris / pupil image on the reticle-screen (1
0) by centering on top. When the switch is released, scanning of the sensor (32) begins and the processor extracts the diameter from each scan. However, the result is ignored until the image is focused, centered and the operator releases the switch. If a well focused image appears on the sensor, several identical diameter readings will be obtained. The exciter lamp (24) is pulsed, the diameter of which is entered as the first diameter for each set of readings. The emitted light passes through the aperture (25), is reflected by the beam splitter (22), passes through the focusing lens (26) and the second beam splitter (28) and is focused on the pupil. The dynamic pupil response is obtained every 0.1 seconds and is accumulated from 3.0 to 5.0 seconds, timed from the beginning of the exciter lamp pulse. The infrared light emitting diode (39) supplies light to be reflected from the pupil. The reflected light passes through the focusing lens (30) and reaches the detector (32). The infrared light emitting diodes are arranged at included angles, as indicated by angle A in FIG. The preferred orientation of the infrared light emitting diode is the optical unit 10A for performing measurements from the reflective surface, and is shown in FIGS. 8 and 9. Each diameter entered in the patient record is the number of dark pixels representing each diameter, which number is less than 255 and can be stored in a byte. While a series of 30 scans (every 3 seconds) is being performed, the processor looks for the smallest diameter.
And it may be programmed to stop the series. At the end of the series, the processor performs an operation and displays the initial diameter, the minimum diameter, the diameter after 3 seconds, and the elapsed time from stimulation to the minimum diameter. Those data are displayed last and next to the last series of measurements.

Either back up one series at a time, or start the first series in the set and go one step at a time, and the results of earlier measurements may be displayed. The processor calculates the diameter data from the pixel data and displays it as described above. If desired, the device of the present invention can also include a printer so that all patient records can be printed in the desired format. Pixel data can also be used to plot a response curve. The diameter data can be calculated and printed as described above.

By adopting the above configuration, the present invention determines the diameter of the object based on the maximum number of the continuous signals obtained from a plurality of rows of the two-dimensional array.
That is, the number of consecutive signals obtained from the plurality of rows of the two-dimensional array includes the maximum number corresponding to the diameter of the object. According to the present invention, the diameter of the object can be obtained by detecting the maximum number. As a result, there is a remarkable effect that it is not necessary to precisely position the pupilometer with the pupil. Hereinafter, the operation and effect of the present invention will be described in more detail.

The pupilometer of the present invention does not need to be precisely positioned with respect to the pupil of the subject. This is because the pupilometer of the present invention is “2”.
Due to the use of "dimensional pixel arrays" and "electronic data processing units". That is, in the present invention, the diameter of the pupil is determined based on the run length having the maximum value among the run lengths of the plurality of dark bits. Therefore, when scanning each row, the pupil diameter is 25
The pupil diameter is uniquely determined by finding the maximum of 256 run lengths as long as it corresponds to any of the six dark bit run lengths. Therefore,
The center of the subject's pupil is the reticle of the pupillometer
It is sufficient if the pupil is positioned so that it is covered by the two-dimensional pixel array, so that an unskilled operator can easily handle the pupil meter. Also, there is no need to require the subject not to move the pupil. According to the present invention, as a result, the diameter of the pupil can be measured quickly and accurately.

A preferred embodiment of the pupillometer of the present invention has been described which can be used extensively in anesthesiology as well as in both research and clinical cases. One skilled in the art will readily appreciate that various modifications are possible to optimize the performance of an individual pupillometer for a particular experiment or measurement.

The present invention provides a convenient and accurate means of collecting data indicating various neuropsychological conditions, even at an early stage, if analyzed and properly interpreted.

It will be apparent to those skilled in the art that various additions, changes, modifications, and omissions can be made in the present invention without departing from the scope and spirit of the invention. Therefore, provided that it falls within the scope of the appended claims and their equivalents,
The present invention encompasses such.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-59-174138 (JP, A) JP-A-59-91942 (JP, A) JP-A-59-120128 (JP, A) JP-A-59-120128 91942 (JP, A) JP-A-58-2227 (JP, A) US Patent 3,963,310 (US, A)

Claims (10)

(57) [Claims] 1. A visible image projection assembly (20, 2) comprising a reticle (20) and means (26) for imaging a visually observable image of a pupil (14) on said reticle.
6) an image sensing assembly (32, 34) having an array of individual pixels (photosensitive elements) and electronic means associated with the array, the image sensing assembly comprising a series of a plurality of output signals. And each of the output signals corresponds to a portion of an image incident on a given pixel of the array, and each of the output signals is received by the pixel. An image sensing assembly in which the amount of light taken can only take either a high level or a low level with respect to a predetermined light threshold; means (39) for illuminating the pupil (14) by infrared irradiation;
Means (28, 30) for imaging an infrared image of the pupil (14) onto the array of pixels of the image sensing assembly when a visible image of the pupil is imaged on the reticle. An infrared image projection assembly (28, 30, 39) and an electronic data processing unit (42) for processing image information from the image sensing assembly (32, 34) and providing a digital output signal of the pupil diameter And a portable scanning digital pupillometer comprising: at least the visible and infrared image projection assembly and the array of pixels of the image sensing assembly are integrated into one body (10); The array of pixels is a two-dimensional array; the body (10) is designed to be portable by hand; Illuminating the pupil with visible light to form the visually observable image of the pupil (3)
8), wherein the two-dimensional array of pixels incorporated in the portable body is formed on a chip of a dynamic random access memory and is in a matrix of rows and columns, and The electronic means associated with the two-dimensional array of pixels are also incorporated into the portable body, and the electronic data processing unit (42) comprises two possible levels obtained from each row of the two-dimensional array of pixels. By determining the number of consecutive ones of the high and low levels of the output signal, and corresponding to each row of the two-dimensional array of pixels. The one level is connected to supply the diameter of the pupil by selecting the largest number of the output signals that are continuous. The diameter of the pupil aperture, portable scanning digital pupilometer correspond to said maximum number of said output signals said one level are continuous. 2. The system according to claim 1, wherein said electronic data processing unit selects a row giving a maximum number of dark signals.
A portable scanning digital pupillometer according to claim 1. 3. The pupil diameter of the pupil by examining and comparing the number of dark signals obtained from adjacent rows in an image area containing a row providing a maximum number of dark signals. 3. A portable scanning digital pupillometer according to claim 2, which determines: 4. An exciter mounted on said portable body (10) and positioned such that light is directed into an area of the pupil of the eye during manual alignment of said body in front of said eye. A light source (24), and means for selectively activating the light source so that the effect of the pupil in response to the illumination of light from the light source can be observed and recorded. A portable scanning digital pupilometer according to claim 1, 2 or 3. 5. The illumination means (38) for viewing the eye so as to emit light rays illuminated on the eye along a line within a range of 0 ° to 9 ° from a plane tangent to the center of the pupil. A second light source provided, wherein the excitation light source (2
4. The method according to claim 4, wherein 4) emits light rays that illuminate the pupil more directly on the eye in the vicinity of the pupil than light rays from the second light source (38). Portable scanning digital pupillometer. 6. The apparatus of claim 1, wherein said excitation light source (24) is arranged such that a directional light beam is directed into said eye substantially along an optical and viewing axis of said portable body. A portable scanning digital pupillometer according to claim 4 or 5. 7. The portable body comprises an eyepiece (16) adjacent to a reticle (20) for viewing the eye by a human observer, and beam splitting means (22), so that a common axis is provided. 7. The portable scanning digital pupillometer of claim 6, wherein the eye can be viewed along and illuminated by the first light source. 8. The means for irradiating with infrared radiation provides infrared illumination or illuminance distributed on the surface of the pupil.
A portable scanning digital pupillometer according to any one of claims 1 to 7. 9. The infrared irradiating means includes a plurality of infrared light sources distributed around an optical axis of a portable body.
9. A portable scanning digital pupillometer according to claim 8. 10. The portable device according to claim 1, wherein said two-dimensional array formed on said dynamic random access memory chip includes an array of 256 pixels × 256 pixels. Scanning digital pupil meter.