DESC:PORTABLE AND HEAD MOUNT VISUAL FIELD ANALYSER DEVICE AND METHOD OF CONDUCTING VISUAL FIELD TEST
TECHNICAL FIELD
[0001] Embodiments are generally related to visual field testing and analysis devices and methods which help a human operator (subject matter expert) to perform visual field tests faster and more reliable. Embodiments are also related portable and head mount visual field analyser devices. Embodiments are additionally related to an improved portable and head mount visual field analyser for conducting visual field test in a wide range of ophthalmic and neurological screening applications including, but not limited to, glaucoma, brain tumors, lesions in visual pathways and others.
BACKGROUND OF THE INVENTION
[0002] Visual field tests are important tools of the ophthalmologist for detecting numerous diseases and defects of the eye, optic nerve and brain. In simplest form, a visual field test is conducted by sequentially displaying a series of individual light targets on a screen and noting those targets which can be seen by a patient whose eye is fixated on the center of the screen. The targets which the patient can see define the patient's visual field. Targets which the patient cannot see can be used to determine defects within the visual field. Conventionally, in kinetic perimetry tests, a light target is moved along a path from the outside of the patient's visual field until the patient responds to the stimulus. In static perimetry tests, the light targets are fixed points which do not move. Instead, the size and/or intensity may be increased until the patient responds to the stimulus.
[0003] With the advent of new technological introductions in the field of visual field perimetry test, numerous automated devices have been designed to test visual fields in the recent past. Such conventional prior art systems adapt a standard automated perimetry to diagnose visual fields in clinics. Such prior art devices are bulky and are non-portable which thereby limits the applications of such prior art devices in the field of ophthalmic and neurological diseases. Portable devices are introduced to overcome such problems associated with the prior art devices. Majority of portable devices introduced in the field of visual field perimetry are costly and use single field analysis for conducting visual field perimetry tests where such prior arts achieve low test reliability at high cost.
[0004] Based on the foregoing a need therefore exists for an improved visual field testing and analysis devices and methods which help a human operator (subject matter expert) to perform visual field tests faster and more reliable. A need also exists for an improved C3 fields portable and head mount visual field analyser for conducting visual field test in a wide range of ophthalmic and neurological screening applications, as described in greater detail herein.
BRIEF SUMMARY
[0005] The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiment and is not intended to be a full description. A full appreciation of the various aspects of the embodiments disclosed herein can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
[0006] It is, therefore, one aspect of the disclosed embodiments to provide an improved visual field perimeter test device.
[0007] It is another aspect of the disclosed embodiments to provide an improved visual field testing and analysis devices and methods which help a human operator (subject matter expert) to perform visual field tests faster and more reliable.
[0008] It is further aspect of the disclosed embodiments to provide an improved C3 fields portable and head mount visual field analyser for conducting visual field test in a wide range of ophthalmic and neurological screening applications.
[0009] The aforementioned aspects and other objectives and advantages can now be achieved as described herein. An improved portable and head mount visual field analyser using C3 fields for conducting visual field test in a wide range of ophthalmic and neurological screening applications including, but not limited to, glaucoma, brain tumors, lesions in visual pathways and others, is disclosed herein. The system includes a C3 field enabled head mount testing unit that is mounted on a subject’s head wherein the subject receives instructions from the subject matter expert (operator) about the visual field test. The C3 field enabled head mount testing unit comprises at least two infrared illumination units and at least two high power convex lenses to create virtual image. The visual field test shows the stimulus at predefined angles and the proposed C3 field enabled head mount testing unit effectively generates virtual image of the eye using multiple variables.
[0010] A response button (Bluetooth enabled button) which can be accessed by the subject to input the response upon seeing stimuli, while fixating at the centre point. The stimuli can be displayed at a predefined location and may change in intensity. A data processing unit having a user-interface application for receiving and processing the inputs from the head mount testing unit wherein the subject matter expert can track and control the C3 field visual field test and obtain improved visual fields for detection of a wide range of ophthalmic and neurological diseases.
[0011] The system proposed herein can be a portable and head mount perimeter that can be used to conduct visual field test. The C3 field head mount device can be a portable and easy to use visual field analyser which can be used to effectively detect loss in visual fields in various ophthalmic and neurological diseases like glaucoma, brain tumors, lesions in visual pathway and others.
[0012] The subject is instructed to fixate at point shown in the centre location (known as centre fixation), then multiple points are projected in peripheral vision and patient is asked to click button when he perceives any stimuli. Based on the clicks on the response button, the subject’s visual fields are assessed. Since humans have a typical sensitivity pattern of retina, which is max in centre (also known as macula) and decreases gradually to periphery (hill of vision). Therefore intensity of stimuli shown to subject is varied depending upon stimuli location and angle. Also, a standard perimetry normative database is used to generate and refine reports. The database of people with same age group and subject’s fields are evaluated after comparing it with other people’s retinal sensitivity in same age group. Also, screen is backlit with illumination at standard illumination of 10cd/m2.
[0013] A novel method for changing the colour of stimulus from grey to white on a white board for correlation of contrast value into a decibel value. The black is represented by R,G,B values (0,0,0) and white is represented by R,G,B values (255,255,255). The decibel (dB) and contrast (con) can be correlated using:
dB = a * log(1+con) + b.
[0014] Where a and b are variables and values ranges between a = [-1 -20] and b = [-40 -60]. The values of a and b are dependent on various factors like screen quality, contrast levels of screen, screen type, etc.
[0015] Multiple parameters are used to judge fixation of patient while performing the visual field test and the parameters (about how well patient was fixating at centre) are shown adjacent to point locations to ensure quality of test with which each point is tested. Apart from blind spot method and camera based eye tracking, the headset is equipped with electroencephalogram (EEG) bio-sensors that can access if the stimulus is viewed by the user, based on activities in brain, thereby analysing correction required or need to re-test the location.
[0016] The invention proposes a new testing method and algorithm to reduce time duration of test where the user is shown stimulus only once at each location with increasing intensity. Based on the user’s response time, the threshold value is approximated to reduce the overall time for conducting test. Further, it also reduces fatigues for user (that occurs as a result of long period of gazing in the headset) and thus produces more reliable results.
[0017] The VR based visual field analysers are configured for increasing the field of view and enabling the head mount device to even test extreme peripheral vision loss using the curved screen. Use of curved screen provides provision to measure up to 120 degree or more field of view and the curved screen based on ‘e-ink’ requires less mount of energy and used for longer time periods without any interruptions.
[0018] The invention proposes a novel design aspect in device that mirrors the screen as seen by patient onto a tablet phone with operator. Using this tablet operator can see exactly which point is being shown to patient and at what time. Furthermore, this view is transmitted in real time wirelessly. Conventional perimeters give a constant of variable background illumination by using a light source, such as bulb to illuminate the perimetry bowl. However, the invention proposes use of a backlit LED of an LCD to do the same. Finally, the proposed invention uses four-point transformation to capture image from camera and to display it on a screen to the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.
[0020] FIG. 1 illustrates a graphical representation of a C3 field portable and head mount visual field analyser for conducting visual field test in a wide range of ophthalmic and neurological screening applications, in accordance with the disclosed embodiments;
[0021] FIG. 2 illustrates a graphical representation illustrating a high level design illustrating different electronic parts of the C3 field portable and head mount visual field analyser, in accordance with the disclosed embodiments;
[0022] FIG. 3 illustrates a graphical representation of the operator’s screen representing the various options available for the subject matter expert to control and manage the test results of the C3 field portable and head mount visual field analyser, in accordance with the disclosed embodiments; and
[0023] FIG. 4 illustrates a graphical representation of relative positioning and optical modeling of the C3 field portable and head mount visual field analyser, in accordance with the disclosed embodiments.
DETAILED DESCRIPTION
[0024] The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
[0025] The embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. The embodiments disclosed herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0027] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0028] FIG. 1 illustrates a graphical representation of a C3 field portable and head mount visual field analyser device 100 for conducting visual field test in a wide range of ophthalmic and neurological screening applications, in accordance with the disclosed embodiments. The device 100 can be an improved portable and head mount visual field analyser using C3 fields for conducting visual field test in a wide range of ophthalmic and neurological screening applications including, but not limited to, glaucoma, brain tumors, lesions in visual pathways and others.
[0029] The device 100 includes a C3 field enabled head mount testing unit 110 that is mounted on a subject’s head 120 wherein the subject 125 receives instructions from the subject matter expert (operator) about the visual field test. The C3 field enabled head mount testing unit 110 comprises at least two infrared illumination units 220 and at least two high power convex lenses to create virtual image 230.
[0030] FIG. 2 illustrates a graphical representation 200 illustrating a high level design illustrating different electronic parts of the C3 field portable and head mount visual field analyser 100, in accordance with the disclosed embodiments. A response button (Bluetooth enabled button) 130 which can be accessed by the subject 125 to input the response upon seeing stimuli, while fixating at the centre point. The stimuli can be displayed at a predefined location and may change in intensity.
[0031] A data processing unit 140 having an user-interface application 150 for receiving and processing the inputs from the head mount testing unit 110 wherein the subject matter expert can track and control the C3 field visual field test and obtain improved visual fields for detection of a wide range of ophthalmic and neurological diseases.
[0032] The system proposed herein can be a portable and head mount perimeter that can be used to conduct visual field test. The C3 field head mount device can be a portable and easy to use visual field analyser which can be used to effectively detect loss in visual fields in various ophthalmic and neurological diseases like glaucoma, brain tumors, lesions in visual pathway and others.
[0033] FIG. 3 illustrates a graphical representation of the operator’s screen 300 representing the various options available for the subject matter expert to control and manage the test results of the C3 field portable and head mount visual field analyser, in accordance with the disclosed embodiments. The subject 125 is instructed to fixate at point shown in the centre location (known as centre fixation), then multiple points are projected in peripheral vision and patient is asked to click button when he perceives any stimuli.
[0034] FIG. 4 illustrates a graphical representation 400 of relative positioning and optical modeling of the C3 field portable and head mount visual field analyser, in accordance with the disclosed embodiments. Note that all the electrical and imaging system have been excluded to show principle behind creating image. Based on the clicks on the response button, the subject’s visual fields are assessed. Since humans have a typical sensitivity pattern of retina, which is max in centre (also known as macula) and decreases gradually to periphery (hill of vision). Therefore intensity of stimuli shown to subject is varied depending upon stimuli location and angle. Also, a standard perimetry normative database is used to generate and refine reports. The database of people with same age group and subject’s fields are evaluated after comparing it with other people’s retinal sensitivity in same age group. Also, screen is backlit with illumination at standard illumination of 10cd/m2.
[0035] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
,CLAIMS:I/We Claim:
1. An improved portable and head mount visual field analyser device using C3 fields for conducting visual field test in ophthalmic and neurological screening applications, said device comprising:
a C3 field enabled head mount testing unit that is mounted on a subject’s head wherein the subject receives instructions from the subject matter expert (operator) about the visual field test wherein the C3 field enabled head mount testing unit comprises at least two infrared illumination units and at least two high power convex lenses to create virtual image;
a response button (Bluetooth enabled button) which can be accessed by the subject to input the response upon seeing stimuli, while fixating at the centre point wherein the stimuli can be displayed at a predefined location and may change in intensity; and
a data processing unit having a user-interface application for receiving and processing the inputs from the head mount testing unit wherein the subject matter expert can track and control the C3 field visual field test and obtain improved visual fields for detection of a wide range of ophthalmic and neurological diseases.
2. The device as claimed in claim 1 wherein the visual field test shows the stimulus at predefined angles where the C3 field enabled head mount testing unit effectively generates virtual image of the eye using multiple variables.
3. A method for conducting visual field test on a subject using the visual field test analyser device, said method comprising:
instructing a subject to fixate at point shown in a centre location (known as centre fixation), then multiple points are projected in peripheral vision and patient is asked to click button when he perceives any stimuli;
assessing the subject’s visual fields based on the clicks on the response button wherein the intensity of stimuli shown to subject is varied depending upon stimuli location and angle; and
using a standard perimetry normative database to generate and refine reports wherein the database of people with same age group and subject’s fields are evaluated after comparing it with other people’s retinal sensitivity in same age group and the screen is backlit with illumination at standard illumination of 10cd/m2.
4. The device as claimed in claim 1 wherein the visual field test analyser changes the colour of stimulus from grey to white on a white board for correlation of contrast value into a decibel value wherein the decibel (dB) and contrast (con) can be correlated as dB = a * log(1+con) + b.
5. The device as claimed in claim 1 wherein the visual field test analyser uses multiple parameters to judge fixation of patient while performing the visual field test and the parameters are shown adjacent to point locations to ensure quality of test with which each point is tested.
6. The device as claimed in claim 1 wherein the visual field test analyser comprises at least one electroencephalogram (EEG) bio-sensor that can assess if the stimulus is viewed by the subject, based on activities in brain, thereby analysing correction required or need to re-test the location.
7. The device as claimed in claim 1 wherein the visual field test analyser reduce time duration of test by showing the stimulus to subject only once at each location with increasing intensity wherein the threshold value is approximated to reduce the overall time for conducting test based on the subject’s response time.
8. The device as claimed in claim 1 wherein the visual field analyser is configured for increasing the field of view and enabling the device to even test extreme peripheral vision loss using the curved screen wherein the curved screen provides provision to measure up to 120 degree or more field of view.
9. The device as claimed in claim 1 wherein the visual field analyser comprises a novel design aspect in device that mirrors the screen as seen by patient onto a tablet phone with operator wherein the tablet operator can see exactly which point is being shown to patient and at what time and transmitted in real time wirelessly.
10. The device as claimed in claim 1 wherein the visual field analyser uses a backlit LED of an LCD to provide a constant of variable background illumination factor.
11. The device as claimed in claim 1 wherein the visual field analyzer uses four-point transformation to capture image from camera and to display it on a screen to the subject.