Ophthalmic device with self-alignment for operatorless operation - Patent Application 20070122997

Abstract

The object is to easily position the device relative to the user's eyes. [Solution] A processor sends a signal to a display to indicate a target. An optical system is positioned in the optical path taken by the target from the display to the user's eye as indicated by the display. The optical system has an adjustable focal length configured to vary accommodation by the eye, allowing the user to view the target with varying visual acuity. The processor then obtains an indication that the user's eye is focused on the target. In response, the processor sends a signal to an alignment mechanism to align a sensor in the device with the user's eye. After signaling the alignment mechanism to align the sensor with the user's eye, the processor obtains sensor data generated by the sensor measuring characteristics of the eye. Other aspects are also described and claimed.

Description

[Technical Field]

[0001] This patent application claims the benefit of the earlier filing date of U.S. Provisional Patent Application No. 63 / 376,187, filed September 19, 2022.

[0002] The subject matter of this disclosure relates to ophthalmic instruments for measuring characteristics of a user's eye. [Background technology]

[0003]

[0003] Several ophthalmic devices exist that measure characteristics of a user's eye, such as intraocular pressure, retinal condition, corneal topography, etc. These devices may require alignment between the device and the user's eye. Traditionally, alignment is achieved based on input from a human (operator), such as a doctor, physician's assistant, or nurse, who views the user's eye while the user's head is resting on a chin / headrest, and the operator manually moves the device to its appropriate position. Summary of the Invention

[0004] It would be desirable to have an ophthalmic device that can be positioned relative to a user's eye while the device performs measurements of the user's eye without requiring any assistance from an operator. This reduces costs and allows measurements to be performed outside of a doctor's office. One aspect of the present disclosure is an ophthalmic device that presents a visual alignment target that a user is instructed to look at. The user can be instructed to move their eye close to the device and then search for the target through the device's viewport. The target can be either a still or moving image presented by a display, for example, a microdisplay within the device. An alignment mechanism within the device automatically aligns the ocular characteristic measurement sensor with the eye to ensure measurement accuracy. The alignment is automatic in that it does not require input from the operator.

[0005] Alignment may require the user to be able to see the target with sufficient visual acuity. However, many eye measurements do not allow users to wear glasses or contact lenses during the measurement, and the wide distribution of myopia and hyperopia in the population makes it difficult for all users to see the target with sufficiently high resolution (required to ensure comfortable and timely alignment). In addition, as users age, there are changes to the accommodation range (the distance between the eye and the target for comfortable viewing), which also reduces the population that can see the target well enough.

[0006] According to one aspect of the disclosure herein, a device for measuring ocular characteristics includes a device housing (e.g., a tabletop or handheld device housing) containing a sensor subsystem (sensor) that measures a user's ocular characteristics. An electronically controlled alignment mechanism to which the sensor is coupled serves to align the sensor with the user's eye. Also within the device housing are a display that presents a target to the user's eye and an optical system positioned in the optical path taken by the target (as shown by the display) from the display to the user's eye. The optical system has an adjustable focal length configured to vary accommodation by the eye, allowing the user to view the target with varying visual acuity. The alignment process performed by the alignment mechanism is triggered (to start or resume) in response to a processor obtaining an indication that the user's eye is focused on the target (or the user can view the target with sufficient visual acuity). In this manner, alignment that prepares the sensor for measurement of ocular characteristics is likely to be faster and more accurate, which makes the eye examination process more efficient.

[0007] The above summary does not include an exhaustive list of all aspects of the present disclosure. The present disclosure is intended to include all systems and methods that may be implemented from any suitable combination of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the Claims section. Such combinations may have advantages not specifically recited in the above summary. [Brief explanation of the drawings]

[0008] Some aspects of the disclosure herein are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. Like references indicate like elements in the figures. It should be noted that references to "an" or "one" aspect in the present disclosure do not necessarily refer to the same aspect, but rather mean at least one. Also, for the sake of brevity and to reduce the total number of figures, a given figure may be used to illustrate features of more than one aspect of the disclosure, and not all elements of a figure may be required for a given aspect.

[0009] [Figure 1] 1 illustrates an exemplary ophthalmic device being handheld by a user against their eye while the device performs ophthalmic measurements on the user's eye. [Figure 2] 2 is a block diagram illustrating certain components of the exemplary ophthalmic device of FIG. 1 that enables intraocular pressure (IOP) measurement. [Figure 3] 2 is a block diagram illustrating certain components of the exemplary ophthalmic device of FIG. 1 that enable retinal imaging or corneal topography mapping. [Figure 4] FIG. 1 is a flow diagram of a method executed by a programmed processor for measuring eye characteristics using an ophthalmic device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Some aspects of the present disclosure will now be described with reference to the accompanying drawings. Wherever the shape, relative position, and other aspects of the described parts are not explicitly defined, the scope of the present invention is not limited to only the parts shown for illustrative purposes only. Also, while many details are set forth, it will be understood that some aspects of the disclosure can be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0011] 1 illustrates an exemplary device 2 being held by a user against their eye while the device performs ophthalmic measurements on the user's eye. While device 2 is shown as a handheld device (the user is holding the device housing in their hand), one alternative is a tabletop instrument into which the device housing (of device 2) is integrated or attached to a stand that can rest on a tabletop while, for example, the user moves their eye closer to device 2. Proximity is the distance between the device housing and the eye at which sensor 3 can be used to measure a characteristic of the eye. The characteristic of the eye measured may be intraocular pressure (IOP) or some aspect of the cornea or retina (e.g., as depicted in the form of a digital image or map).

[0012] Referring now to FIG. 2 , this is a block diagram illustrating some components of an example of device 2, including sensor 3 within the device housing. In one embodiment, sensor 3 can include a receiving element (e.g., a photodetector, a pixel array) and a transmitting element (e.g., a light emitter), as well as any associated optical components (e.g., filters, lenses) that can be used to measure IOP. In that case, sensor 3 can be an optical sensor that is part of an air-puff tonometer, where sensor 3 is directed at a specific area on the corneal surface while an air-puff generator mechanism within device 2 flattens that area. Sensor 3 then takes a measurement of the flattened area of ​​the cornea, which measurement is then digitally processed to provide an IOP value. In another embodiment, sensor 3 is part of an intraocular pressure monitoring subsystem that has a pressure measurement device implanted in the eye. Here, sensor 3 can be an optical receiver or transceiver that needs to be aligned with the implanted measurement device to generate an IOP value.

[0013] The sensor 3 may need to be aligned with the eye to generate measurements of eye properties. To that end, the sensor 3 is coupled to an alignment mechanism 4 (also located within the device housing). The alignment mechanism 4 is electronically controlled by the processor 6 and may include actuators that serve to move the sensor 3, or in other words, actuate any movable components of the sensor 3 (e.g., the emitter, detector, or optical components of the sensor 3), as commanded by the processor 6.

[0014] The processor 6 is configured or programmed to send a signal to the alignment mechanism 4 (e.g., when executing instructions stored in a memory (not shown)) to initiate or resume either an open-loop or closed-loop process to align the sensor 3 with the user's eye. In one aspect of the disclosure herein, the processor 6 may only do so in response to obtaining some indication that the user's eye is focused on the target displayed on the display 7; in other words, the user can see the target with sufficient visual acuity. This helps ensure that the alignment process accurately and quickly positions the sensor 3 to measure eye characteristics. The target may be an image of a graphical or real object shown by the display 7 within the device housing. The display 7 may be a microdisplay, e.g., a small display having a diagonal display size of less than 2 inches. The target may be a static image or an active image displayed by the display 7. Status information may also be presented by the display 7, such as a countdown clock, which eye is being measured, etc. An optical system 8 within the device housing is positioned in the optical path taken by the target (as shown by the display 7). The optical path is as shown in the figure from the display 7 to the user's eye.

[0015] The optical system 8 has an adjustable focal length that is configured to change accommodation by the eye, allowing the user to view the target with varying visual acuity. Varying accommodation allows the user to view the target more easily, especially when the display 7 is positioned 200 millimeters or less from the eye (when the device housing is close to the eye). In one embodiment, the optical system 8 includes a motorized convex solid lens that is electronically controlled by the processor 6 for movement. This is, of course, a general description in that it encompasses cases where the optical system 8 includes a series of two or more lenses (e.g., a convex lens and a concave lens), including one or more lenses whose axial position can be electronically adjusted and controlled by the processor 6. The axial position can be adjusted by making the lens axially movable, or equivalently, by making the display 7 axially movable. In another embodiment, the optical system 8 includes a fluid lens whose shape is electronically controlled by the processor 6 (to change the focal length).

[0016] In one aspect, processor 6 is configured to obtain an indication that the user's eyes are focused on the target by prompting the user to indicate when they can clearly see the target while processor 6 signals optical system 8 to change the focal length. Providing this prompt may be performed by processor 6 sending a signal to an audio subsystem (not shown) instructing the user to "press a button or respond verbally when you can clearly see the target." The audio subsystem may include a microphone within the device housing, and processor 6 processes an audio signal output by the microphone to detect audible input from the user as an indication that the user can clearly see the target.

[0017] Alternatively, the focal length of optical system 8 may be manually adjustable by the user, for example, by turning a knob within the device housing. In that case, processor 6 may be configured to obtain an indication that the user's eyes are focused on the target by receiving manual (e.g., button press) or audible input from the user so that the user can clearly see the target. For example, the user may be instructed to manually adjust optical system 8 using their fingers until the user can clearly see the target, at which point the user presses a button or speaks a phrase that processor 6 interprets as indicating that the user can clearly see the target.

[0018] In another embodiment, device 2 includes an eye-tracking subsystem within the device housing, in which case processor 6 is configured to process eye-tracking data generated by the eye-tracking subsystem to determine whether the eyes are looking at a target shown on display 7, and in response, processor 6 signals alignment mechanism 4 to perform an alignment process.

[0019] In another embodiment, referring now to FIG. 3 , in addition to sensor 3, the device housing includes an imager / scanner 9 that can be used to map the retina or cornea of ​​the eye. Imager / scanner 9 may include an imaging sensor as part of a still or video camera, a laser scanner, or both, along with their associated optics. Imager / scanner 9 is positioned to receive light reflected from the eye from the back surface of a beam splitter. In contrast, the front surface of the beam splitter serves to reflect light generated by display 7 toward the eye so that the user can see the target. The beam splitter enables device 2 to perform different ocular characteristic measurements. The beam splitter enables imager / scanner 9 to capture digital images of the retinal or corneal surface of the eye (the images may then be digitally processed before being displayed to the user as a retinal photograph or corneal topography map) and allows the user to focus on a target in display 7 during automatic alignment of sensor 3 (measuring other ocular characteristics, such as IOP).

[0020] Referring now to FIG. 4, this figure is a flow diagram of a method executed by processor 6 and other components of device 2 to measure characteristics of a user's eye using device 2. The method may begin at operation 11, in which the processor signals display 7 to present a target. The user can then view the target through a viewport in the device housing when the user's eye is positioned near device 2 and looking in the direction of display 7. The coarsest level of alignment may be when the user can view display 7 but is not focused on the target shown on display 7. A finer level of alignment is desirable, which is when the user can clearly view the target (or is said to be "in focus" on the target). Thus, in operation 13, processor 6 obtains an indication that the user's eye is focused on the target. Then, in operation 14, processor 6 responds by signaling alignment mechanism 4 to align sensor 3 with the user's eye. An alignment process then occurs as operation 15 (e.g., alignment mechanism 4 adjusts the position of sensor 3), and then, once sensor 3 and the eye are deemed aligned, processor 6 acquires sensor data generated by sensor 3 measuring some characteristic of the eye (e.g., an IOP measurement) in operation 17. If device 2 is equipped with an imager / scanner 9 as in FIG. 3, other eye characteristic measurements may also be triggered here, such as taking a photograph of the retina or generating a corneal topography map. Processor 6 may then prepare appropriate eye characteristic measurement data from the sensor output data for storage or display to the operator (operation 19).

[0021] In one embodiment of the method of FIG. 4 , operation 13, which involves determining when the user's eyes are focused on the target, includes operation 18. In operation 18, processor 6 prompts the user to indicate when the user can clearly see the target. If optical system 8 is electronically controllable, this may occur while or just before the processor signals optical system 8 to change the focal length, or the user is turning a manual focus knob (operation 19). The prompt may be a voice command output by an audio subsystem of device 2 and heard by the user. The user's response to the prompt is evaluated in operation 20, and the user's response may be in an audible form, such as a phrase spoken by the user. The phrase may be recognized by processor 6 by processing an audio signal output by a microphone of the audio subsystem (e.g., "I can now clearly see the target"). If operation 20 determines that the target is not focused, the method repeats operation 19 by waiting for the user to turn the focus knob or by the processor sending a signal to the optical system to adjust the focal length.

[0022] Instead of processor 6 sending a signal to a motorized actuator or fluid lens of optical system 8 to change the focal length, optical system 8 may have a manually adjustable focal length, for example, a focus knob that can be adjusted by a user's finger. The user's indication that the target is in focus may be a manual input, for example, a button pressed by the user.

[0023] In another embodiment of the method of FIG. 4, processor 6 processes eye tracking data generated by an eye tracking subsystem within device 2 to determine whether the user's eyes are looking at the target, and in response, the processor signals an alignment mechanism to perform an alignment process.

[0024] While certain embodiments are described and illustrated in the accompanying drawings, it will be understood that these are merely illustrative of the invention and not limiting, and that various other modifications may occur to those skilled in the art, and the invention is not limited to the specific structures and arrangements shown and described. For example, processor 6 may be integrated within the device housing (along with sensor 3, display 7, alignment mechanism 4, and optics 8), but in some cases, some of the functions or operations performed by processor 6 may be performed by another processor in wired or wireless communication with the processor within the device housing. The other processor may be the processor of a laptop computer, tablet computer, smartphone, or website server. Therefore, this description should be considered illustrative and not limiting.

Claims

1. 1. A device for measuring eye characteristics, comprising: A device housing; a sensor within the device housing for measuring a characteristic of a user's eye; an electronically controlled alignment mechanism to which the sensor is coupled; a display within the device housing showing a target; an optical system within the device housing and positioned in an optical path taken by the target as shown by the display from the display to the eye of the user, the optical system being configured to vary accommodation by the eye and having an adjustable focal length that allows the user to view the target with varying visual acuity; and a processor configured to, in response to receiving an indication that the eye of the user is focused on the target, send a signal to the electronically controlled alignment mechanism to align the sensor with the eye of the user; A device comprising:

2. 2. The device of claim 1, wherein the device housing is a housing of a handheld device that is held in the user's hand while the user holds the device in close proximity to the user's eye, the proximity being the distance between the device housing and the eye that allows the sensor to measure the eye pressure or take an image while the user's eye can see the target shown by the display.

3. The device of any one of claims 1 to 3, wherein the target is a static image or an active image.

4. The device of any one of claims 2 to 3, wherein the display is positioned no more than 200 millimeters from the eye when the device housing is proximate to the eye.

5. The device of claim 4 , wherein the optical system includes a movable convex solid lens.

6. 6. The device of claim 5, wherein the convex solid lens is motorized so as to be movable under electronic control by the processor.

7. The device of claim 4 , wherein the optical system includes a fluid lens whose shape is electronically controlled by the processor.

8. The processor:

8. The device of claim 6, wherein the device is configured to obtain the indication that the user's eye is focused on the target by prompting the user to indicate when the user can clearly see the target while the processor is signaling the optical system to change the adjustable focal length.

9. 10. The device of claim 8, further comprising a microphone within the device housing, the processor processing an audio signal output by the microphone to detect audible input from the user as the indication that the user has a clear view of the target.

10. The processor:

6. The device of claim 1, wherein the device is configured to obtain the indication that the user's eye is focused on the target by receiving manual or audible input from the user that the user can clearly see the target, and the optical system can be manually adjusted by the user until the user can clearly see the target.

11. 11. The device of claim 1, further comprising an eye-tracking subsystem within the device housing that tracks the eyes of the user, the processor configured to process eye-tracking data generated by the eye-tracking subsystem to determine whether the user is looking at the target, and in response send a signal to the electronically controlled alignment mechanism.

12. 1. A method for measuring ocular characteristics using a device, the method being carried out by a programmed processor, sending a signal to a display within the device to show a target, the device comprising an optical system positioned in an optical path taken by the target from the display to the user's eye as shown by the display, the optical system configured to vary accommodation by the eye and having an adjustable focal length to allow the user to view the target with varying visual acuity; obtaining an indication that the eye of the user is focused on the target, and in response thereto, sending a signal to an alignment mechanism within the device to align a sensor within the device with the eye of the user; acquiring sensor data generated by the sensor measuring a characteristic of the eye after signaling the alignment mechanism to align the sensor with the eye of the user; A method including the action of:

13. Obtaining the indication that the eye of the user is focused on the target comprises:

13. The method of claim 12, including prompting the user to indicate when the user can clearly see the target while signaling the optical system to change the adjustable focal length.

14. Obtaining an indication that the eye of the user is focused on the target includes:

14. The method of claim 13, comprising processing an audio signal output by a microphone in the device to detect an audible input from the user as the indication that the user has clear visibility of the target.

15. Obtaining the indication that the eye of the user is focused on the target comprises:

13. The method of claim 12, comprising receiving manual or audible input from the user that the target is clearly visible to the user after the user manually adjusts the optical system until the target is clearly visible to the user.

16. the programmed processor:

16. The method of claim 12, further comprising processing eye-tracking data generated by an eye-tracking subsystem within the device that tracks the eyes of the user to determine whether the user is looking at the target, and wherein sending a signal to the alignment mechanism within the device to align the sensor is performed in response to determining that the user is looking at the target.

17. The method of claim 12 , wherein the target is a static image or an active image.

18. 18. The method of claim 17, wherein the display is positioned no more than 200 millimeters from the eye when the device housing is proximate to the eye.

19. A memory having instructions stored therein, the instructions comprising a method: sending a signal to a display within a device to show a target, the device comprising an optical system positioned in an optical path taken by the target from the display to the user's eye as shown by the display, the optical system configured to vary accommodation by the eye and having an adjustable focal length to allow the user to view the target with varying visual acuity; obtaining an indication that the eye of the user is focused on the target, and in response thereto, sending a signal to an alignment mechanism within the device to align a sensor within the device with the eye of the user; acquiring sensor data generated by the sensor measuring a characteristic of the eye after signaling the alignment mechanism to align the sensor with the eye of the user; and a memory for configuring a processor to perform the method.

20. 20. The memory of claim 19, further storing therein further instructions configuring the processor to process eye tracking data generated by an eye tracking subsystem within the device that tracks the eyes of the user to determine whether the user is looking at the target, and wherein the processor, in response to determining that the user is looking at the target, signals the alignment mechanism within the device to align the sensor.

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