Patent Publication Number: US-11045088-B2

Title: Through focus retinal image capturing

Description:
INTRODUCTION 
     People with type 1 or type 2 diabetes can develop eye disease as a result of having diabetes. One of the most common diabetic eye diseases is diabetic retinopathy, which is damage to the blood vessels of the light-sensitive tissue at the back of the eye, known as the retina. Trained medical professionals use cameras during eye examinations for diabetic retinopathy screening. The cameras can produce images of the back of the eye and trained medical professionals use those images to diagnose and treat diabetic retinopathy. 
     These images are produced either with pharmacological pupil dilation, known as mydriatic fundus imaging, or without pharmacological pupil dilation, known as non-mydriatic fundus imaging. Because pupil dilation is inversely related, in part, to the amount of ambient light, non-mydriatic fundus imaging usually occurs in low lighting environments. Medical professionals can also use fundus imaging apparatus to detect or monitor other diseases, such as hypertension, glaucoma, and papilledema. 
     SUMMARY 
     In one aspect, an apparatus for producing a non-mydriatic fundus image is disclosed. The apparatus can include a processor and memory, a light source, and a camera including a variable focus lens. The memory can store instructions that, when executed by the processor, cause the apparatus to adjust the focus of the lens to a plurality of different diopter ranges and capture a plurality of images of the fundus, where the camera captures at least one image at each of the different diopter ranges. 
     In another aspect, a method for capturing a non-mydriatic image of a fundus is disclosed. The method can include dividing a depth of field into a plurality of zones, adjusting a lens of a camera to focus on each of the plurality of zones and capturing at least one image at each of the plurality of zones. 
     In another aspect, a non-mydriatic image capture system is disclosed. The system can include a housing, an image capture device coupled to the housing and configured to capture images of an eye fundus of a subject, and a control module programmed to: instruct the image capture device to capture a plurality of images in a first image capture mode, process at least a portion of the plurality of images to determine a position of a pupil of the subject, and instruct the image capture device to capture an image in a second image capture mode when the position of the pupil is substantially aligned with an optical axis of the image capture device. The second image capture mode includes an illumination of a light source and a plurality of adjustments of a lens of the image capture device such that the image capture device captures an image at each of the plurality of adjustments in a depth of field focus range. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       The following figures, which form a part of this application, are illustrative of described technology and are not meant to limit the scope of the claims in any manner, which scope shall be based on the claims appended hereto. 
         FIG. 1  is an embodiment of an example system for recording and viewing an image of a patient&#39;s fundus; 
         FIG. 2  is an embodiment of an example fundus imaging system; 
         FIG. 3  is an embodiment of an example method for imaging a patient&#39;s fundus using a fundus imaging system; 
         FIG. 4  is an embodiment of an example fundus imaging system; 
         FIG. 5  illustrates an example method of initiating a fundus imaging using passive eye tracking; 
         FIG. 6  is an embodiment of an example use of a fundus imaging system; and 
         FIG. 7  is an example computing device used within the fundus imaging system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic block diagram illustrating an example system  100  for recording and viewing an image of a patient&#39;s fundus. In this example, the system  100  includes a patient P, a fundus imaging system  102 , a computing device  1800  including an image processor  106 , a camera  104  in communication with the computing device  1800 , a display  108  in communication with the computing device  1800  and used by clinician C, and a network  110 . An embodiment of the example fundus imaging system  102  is shown and described in more detail below with reference to  FIG. 4 . 
     The fundus imaging system  102  functions to create a set of digital image of a patient&#39;s P eye fundus. As used herein, “fundus” refers to the eye fundus and includes the retina, optic nerve, macula, vitreous, choroid and posterior pole. 
     In this example, one or more images of the eye are desired. For instance, the patient P is being screened for an eye disease, such as diabetic retinopathy. The fundus imaging system  102  can also be used to provide images of the eye for other purposes, such as to diagnose or monitor the progression of a disease such as diabetic retinopathy. 
     The fundus imaging system  102  includes a handheld housing that supports the system&#39;s components. The housing supports one or two apertures for imaging one or two eyes at a time. In embodiments, the housing supports positional guides for the patient P, such as an optional adjustable chin rest. The positional guide or guides help to align the patient&#39;s P eye or eyes with the one or two apertures. In embodiments, the housing supports means for raising and lowering the one or more apertures to align them with the patient&#39;s P eye or eyes. Once the patient&#39;s P eyes are aligned, the clinician C then initiates the image captures by the fundus imaging system  102 . 
     One technique for fundus imaging requires mydriasis, or the dilation of the patient&#39;s pupil, which can be painful and/or inconvenient to the patient P. Example system  100  does not require a mydriatic drug to be administered to the patient P before imaging, although the system  100  can image the fundus if a mydriatic drug has been administered. 
     The system  100  can be used to assist the clinician C in screening for, monitoring, or diagnosing various eye diseases, such as hypertension, diabetic retinopathy, glaucoma and papilledema. It will be appreciated that the clinician C that operates the fundus imaging system  102  can be different from the clinician C evaluating the resulting image. 
     In the example embodiment  100 , the fundus imaging system  102  includes a camera  104  in communication with an image processor  106 . In this embodiment, the camera  104  is a digital camera including a lens, an aperture, and a sensor array. The camera  104  lens is a variable focus lens, such as a lens moved by a step motor, or a fluid lens, also known as a liquid lens in the art. The camera  104  is configured to record images of the fundus one eye at a time. In other embodiments, the camera  104  is configured to record an image of both eyes substantially simultaneously. In those embodiments, the fundus imaging system  102  can include two separate cameras, one for each eye. 
     In example system  100 , the image processor  106  is operatively coupled to the camera  104  and configured to communicate with the network  110  and display  108 . 
     The image processor  106  regulates the operation of the camera  104 . Components of an example computing device, including an image processor, are shown in more detail in  FIG. 7 , which is described further below. 
     The display  108  is in communication with the image processor  106 . In the example embodiment, the housing supports the display  108 . In other embodiments, the display connects to the image processor, such as a smart phone, tablet computer, or external monitor. The display  108  functions to reproduce the images produced by the fundus imaging system  102  in a size and format readable by the clinician C. For example, the display  108  can be a liquid crystal display (LCD) and active matrix organic light emitting diode (AMOLED) display. The display can be touch sensitive. 
     The example fundus imaging system  102  is connected to a network  110 . The network  110  may include any type of wireless network, a wired network, or any communication network known in the art. For example, wireless connections can include cellular network connections and connections made using protocols such as 802.11a, b, and/or g. In other examples, a wireless connection can be accomplished directly between the fundus imaging system  102  and an external display using one or more wired or wireless protocols, such as Bluetooth, Wi-Fi Direct, radio-frequency identification (RFID), or Zigbee. Other configurations are possible. 
       FIG. 2  illustrates components of an example fundus imaging system  102 . The example fundus imaging system  102  includes a variable focus lens  180 , an illumination LED  182 , an image sensor array  186 , a fixation LED  184 , a computing device  1800 , and a display  108 . Each component is in electrical communication with, at least, the computing device  1800 . Other embodiments can include more or fewer components. 
     In one of the embodiments, the variable focus lens  180  is a liquid lens. A liquid lens is an optical lens whose focal length can be controlled by the application of an external force, such as a voltage. The lens includes a transparent fluid, such as water or water and oil, sealed within a cell and a transparent membrane. By applying a force to the fluid, the curvature of the fluid changes, thereby changing the focal length. This effect is known as electrowetting. 
     Generally, a liquid lens can focus between about −10 diopters to about +30 diopters. The focus of a liquid lens can be made quickly, even with large changes in focus. For instance, some liquid lenses can autofocus in tens of milliseconds or faster. Liquid lenses can focus from about 10 cm to infinity and can have an effective focal length of about 16 mm or shorter. 
     In another embodiment of example fundus imaging system  102 , the variable focus lens  180  is one or more movable lenses that are controlled by a stepping motor, a voice coil, an ultrasonic motor, or a piezoelectric actuator. Additionally, a stepping motor can also move the image sensor array  186 . In those embodiments, the variable focus lens  180  and/or the image sensor array  186  are oriented normal to an optical axis of the fundus imaging system  102  and move along the optical axis. An example stepping motor is shown and described below with reference to  FIG. 4 . 
     The example fundus imaging system  102  also includes an illumination light-emitting diode (LED)  182 . The illumination LED  182  can be single color or multi-color. For example, the illumination LED  182  can be a three-channel RGB LED, where each die is capable of independent and tandem operation. 
     Optionally, the illumination LED  182  is an assembly including one or more visible light LEDs and a near-infrared LED. The optional near-infrared LED can be used in a preview mode, for example, for the clinician C to determine or estimate the patient&#39;s P eye focus without illuminating visible light that could cause the pupil to contract or irritate the patient P. 
     The illumination LED  182  is in electrical communication with the computing device  1800 . Thus, the illumination of illumination LED  182  is coordinated with the adjustment of the variable focus lens  180  and image capture. The illumination LED  182  can be overdriven to draw more than the maximum standard current draw rating. In other embodiments, the illumination LED  182  can also include a near-infrared LED. The near-infrared LED is illuminated during a preview mode. 
     The example fundus imaging system  102  also optionally includes a fixation LED  184 . The fixation LED  184  is in communication with the computing device  1800  and produces a light to guide the patient&#39;s P eye for alignment. The fixation LED  184  can be a single color or multicolor LED. For example, the fixation LED  184  can produce a beam of green light that appears as a green dot when the patient P looks into the fundus imaging system  102 . Other colors and designs, such as a cross, “x” and circle are possible. 
     The example fundus imaging system  102  also includes an image sensor array  186  that receives and processes light reflected by the patient&#39;s fundus. The image sensor array  186  is, for example, a complementary metal-oxide semiconductor (CMOS) sensor array, also known as an active pixel sensor (APS), or a charge coupled device (CCD) sensor. 
     The image sensor array  186  has a plurality of rows of pixels and a plurality of columns of pixels. In some embodiments, the image sensor array has about 1280 by 1024 pixels, about 640 by 480 pixels, about 1500 by 1152 pixels, about 2048 by 1536 pixels, or about 2560 by 1920 pixels. 
     In some embodiments, the pixel size in the image sensor array  186  is from about four micrometers by about four micrometers; from about two micrometers by about two micrometers; from about six micrometers by about six micrometers; or from about one micrometer by about one micrometer. 
     The example image sensor array  186  includes photodiodes that have a light-receiving surface and have substantially uniform length and width. During exposure, the photodiodes convert the incident light to a charge. The image sensor array  186  can be operated as a global reset, that is, substantially all of the photodiodes are exposed simultaneously and for substantially identical lengths of time. 
     The example fundus imaging system  102  also includes a display  108 , discussed in more detail above with reference to  FIG. 1 . Additionally, the example fundus imaging system  102  includes a computing device  1800 , discussed in more detail below with reference to  FIG. 7 . 
       FIG. 3  is an embodiment of a method  200  for imaging a patient&#39;s fundus using a fundus imaging system. In the embodiment shown, the lighting is optimally dimmed prior to execution, although lowering the lighting is optional. The embodiment shown includes a set depth of field operation  204 , a set number of zones operation  206 , an illuminate lighting operation  208 , an adjust lens focus operation  210 , a capture image operation  212 , repeat operation(s)  213 , a show images operation  214  and a determine representative image operation  216 . Other embodiments can include more or fewer steps. 
     The embodiment of method  200  begins with setting a depth of field operation  204 . In embodiments, the variable focus lens  180  is capable of focusing from about −20 diopters to about +20 diopters. Set depth of field operation  204  defines the lower and upper bounds in terms of diopters. For example, the depth of field range could be set to about −10 to +10 diopters; about −5 to about +5 diopters; about −10 to about +20 diopters; about −5 to about +20 diopters; about −20 to about +0 diopters; or about −5 to about +5 diopters. Other settings are possible. The depth of field can be preprogrammed by the manufacturer. Alternatively, the end user, such as the clinician C, can set the depth of field. 
     As shown in  FIG. 3 , the next operation in embodiment of method  200  is setting the number of zones operation  206 . However, zones operation  206  can occur before or concurrent with field operation  204 . In zones operation  206 , the depth of field is divided into equal parts, where each part is called a zone. In other embodiments, the zones are not all equal. The number of zones is equal to the number of images captured in capture image operation  212 . 
     For example, when the depth of field is from −10 to +10 diopters, the focus of the variable focus lens can be changed by 4 diopters before each image capture. Thus, in this example, images would be captured at −10, −6, −2, +2, +6 and +10 diopters. Or, images could be captured at −8, −4, 0, +4 and +8 diopters, thereby capturing an image in zones −10 to −6 diopters, −6 to −2 diopters, −2 to +2 diopters, +2 to +6 diopters and +6 to +10 diopters, respectively. In that instance, the depth of focus is about +/−2 diopters. Of course, the number of zones and the depth of field can vary, resulting in different ranges of depth of field image capture. 
     In embodiments, both depth of field and number of zones are predetermined. For example, −10 D to +10 D and 5 zones. Both can be changed by a user. 
     After the depth of field and number of zones are set, the next operation in embodiment of method  200  is the image capture process, which includes illuminate lighting operation  208 , adjust lens focus operation  210  and capture image operation  212 . As shown in  FIG. 3 , the lighting component is illuminated (lighting operation  208 ) before the lens focus is adjusted (lens focus operation  210 ). However, lens focus operation  210  can occur before or concurrent with lighting operation  208 . 
     The illumination LED  182  is illuminated in lighting operation  208 . The illumination LED  182  can remain illuminated throughout the duration of each image capture. Alternatively, the illumination LED  182  can be turned on and off for each image capture. In embodiments, the illumination LED  182  only turns on for the same period of time as the image sensor array  186  exposure time period. 
     Optionally, lighting operation  208  can additionally include illuminating a near-infrared LED. The clinician C can use the illumination of the near-infrared LED as a way to preview the position of the patient&#39;s P pupil. 
     The focus of variable focus lens  180  is adjusted in lens focus operation  210 . Autofocusing is not used in embodiment of method  200 . That is, the diopter setting is provided to the lens without regard to the quality of the focus of the image. Indeed, traditional autofocusing fails in the low-lighting non-mydriatic image capturing environment. The embodiment of method  200  results in a plurality of images at least one of which, or a combination of which, yields an in-focus view of the patient&#39;s P fundus. 
     Additionally, the lack of autofocusing enables the fundus imaging system  102  to rapidly capture multiple images in capture image operation  212  at different diopter ranges. That is, variable focus lens  180  can be set to a particular diopter range and an image captured without the system verifying that the particular focus level will produce an in-focus image, as is found in autofocusing systems. Because the system does not attempt to autofocus, and the focus of the variable focus lens  180  can be altered in roughly tens of milliseconds, images can be captured throughout the depth of field in well under a second, in embodiments. Thus, in the embodiment of method  200 , the fundus imaging system  102  can capture images of the entire depth of field before the patient&#39;s P eye can react to the illuminated light. Without being bound to a particular theory, depending on the patient P, the eye might react to the light from illumination LED  182  in about 150 milliseconds. 
     The image sensor array  186  captures an image of the fundus in capture image operation  212 . As discussed above, the embodiment of method  200  includes multiple image captures of the same fundus at different diopter foci. The example fundus imaging system  102  uses a global reset or global shutter array, although other types of shutter arrays, such as a rolling shutter, can be used. The entire image capture method  200  can also be triggered by passive eye tracking and automatically capture, for example, 5 frames of images. An embodiment of example method for passive eye tracking is shown and described in more detail with reference to  FIG. 5 , below. 
     After the fundus imaging system  102  captures an image of the fundus, the embodiment of method  200  returns in loop  213  to either the illuminate lighting operation  208  or the adjust lens focus operation  210 . That is, operations  208 ,  210  and  212  are repeated until an image is captured in each of the preset zones from zones operation  206 . It is noted that the image capture does not need to be sequential through the depth of field. Additionally, each of the images does not need to be captured in a single loop; a patient could have one or more fundus images captured and then one or more after a pause or break. 
     After an image is captured in each of the zones (capture image operation  212 ) in embodiment of method  200 , either the images are displayed in show images operation  214  or a representative image is determined in operation  216  and then the image is displayed. Show images operation  214  can include showing all images simultaneously or sequentially on display  108 . A user interface shown on display  108  can then enable the clinician C or other reviewing medical professional to select or identify the best or a representative image of the patient&#39;s P fundus. 
     In addition to, or in place of, show images operation  214 , the computing device can determine a representative fundus image in operation  216 . Operation  216  can also produce a single image by compiling aspects of one or more of the images captured. This can be accomplished by, for example, using a wavelet feature reconstruction method to select, interpolate, and/or synthesize the most representative frequency or location components. 
     The fundus imaging system  102  can also produce a three-dimensional image of the fundus by compiling the multiple captured images. Because the images are taken at different focus ranges of the fundus, the compilation of the pictures can contain three-dimensional information about the fundus. 
     In turn, the image or images from operation  214  or  216  can be sent to a patient&#39;s electronic medical record or to a different medical professional via network  110 . 
       FIG. 4  illustrates an embodiment of example fundus imaging system  400 . The embodiment  400  includes a housing  401  that supports an optional fixation LED  402 , an objective lens  404 , fixation LED mirrors  405 , variable focus lens assembly  406 , display  408 , printed circuit board  410 , step motor  412 , image sensor array  414 , and illumination LED  416 . Also shown in  FIG. 4  are light paths L that include potential light paths from optional fixation LED  402  and incoming light paths from outside the fundus imaging system  400 . The illustrated components have the same or similar functionality to the corresponding components discussed above with reference to  FIGS. 1-3  above. Other embodiments can include more or fewer components. 
     The housing  401  of example fundus imaging system  400  is sized to be hand held. In embodiments, the housing  401  additionally supports one or more user input buttons near display  408 , not shown in  FIG. 4 . The user input button can initiate the image capture sequence, at least a portion of which is shown and discussed with reference to  FIG. 3 , above. Thus, the fundus imaging system  400  is capable of being configured such that the clinician C does not need to adjust the lens focus. 
     Fixation LED  402  is an optional component of the fundus imaging system  400 . The fixation LED  402  is a single or multi-colored LED. Fixation LED  402  can be more than one LED. 
     As shown in  FIG. 4 , pivoting mirrors  405  can be used to direct light from the fixation LED  402  towards the patient&#39;s pupil. Additionally, an overlay or filter can be used to project a particular shape or image, such as an “X”, to direct the patient&#39;s focus. The pivoting mirrors  405  can control where the fixation image appears in the patient&#39;s view. The pivoting mirrors  405  do not affect the light reflected from the patient&#39;s fundus. 
     The embodiment of example fundus imaging system  400  also includes a variable focus lens assembly  406 . As shown in  FIG. 4 , the variable focus lens assembly  406  is substantially aligned with the longitudinal axis of the housing  401 . Additionally, the variable focus lens assembly  406  is positioned between the objective lens  404  and the image sensor array  414  such that it can control the focus of the incident light L onto the image sensor array. 
     The example printed circuit board  410  is shown positioned within one distal end of the housing  401  near the display  408 . However, the printed circuit board  410  can be positioned in a different location. The printed circuit board  410  supports the components of the example computing device  1800 . A power supply can also be positioned near printed circuit board  410  and configured to power the components of the embodiment of example fundus imaging system  400 . 
     Step motor  412  is an optional component in the example embodiment  400 . Step motor  412  can also be, for example, a voice coil, an ultrasonic motor, or a piezoelectric actuator. In the example embodiment  400 , step motor  412  moves the variable focus lens assembly  406  and/or the sensor array  414  to achieve variable focus. The step motor  412  moves the variable focus lens assembly  406  or the sensor array  414  in a direction parallel to a longitudinal axis of the housing  401  (the optical axis). The movement of step motor  412  is actuated by computing device  1800 . 
     The example image sensor array  414  is positioned normal to the longitudinal axis of the housing  401 . As discussed above, the image sensor array  414  is in electrical communication with the computing device. Also, as discussed above, the image sensor array can be a CMOS (APS) or CCD sensor. 
     An illumination LED  416  is positioned near the variable focus lens assembly  406 . However, the illumination LED  416  can be positioned in other locations, such as near or with the fixation LED  402 . 
       FIG. 5  illustrates an alternate embodiment of initiate retinal imaging step  306  using passive eye tracking. The initiate retinal imaging step  306  operates to image the fundus of the patient P using passive eye tracking. In the initiate retinal imaging step  306 , the fundus imaging system  102  monitors the pupil/fovea orientation of the patient P. Although the initiate retinal imaging step  306  is described with respect to fundus imaging system  102 , the initiate retinal imaging step  306  may be performed using a wearable or nonwearable fundus imaging system, such as a handheld digital fundus imaging system. 
     Initially, at step  303 , the pupil or fovea or both of the patient P are monitored. The fundus imaging system  102  captures images in a first image capture mode. In the first image capture mode, the fundus imaging system  102  captures images at a higher frame rate. In some embodiments, in the first image capture mode, the fundus imaging system  102  captures images with infra-red illumination and at lower resolutions. In some embodiments, the infra-red illumination is created by the illumination LED  182  operating to generate and direct light of a lower intensity towards the subject. The first image capture mode may minimize discomfort to the patient P, allow the patient P to relax, and allow for a larger pupil size without dilation (non-mydriatic). 
     Next, at step  305 , the computing system  1800  processes at least a portion of the images captured by the fundus imaging system  102 . The computing system  1800  processes the images to identify the location of the pupil or fovea or both of the patient P. Using the location of the pupil or fovea or both in one of the images, a vector corresponding to the pupil/fovea orientation is calculated. In some embodiments, the pupil/fovea orientation is approximated based on the distance between the pupil and fovea in the image. In other embodiments, the pupil/fovea orientation is calculated by approximating the position of the fovea relative to the pupil in three dimensions using estimates of the distance to the pupil and the distance between the pupil and the fovea. In other embodiments, the pupil/fovea orientation is approximated from the position of the pupil alone. In yet other embodiments, other methods of approximating the pupil/fovea orientation are used. 
     Next, at step  307 , the pupil/fovea orientation is compared to the optical axis of the fundus imaging system  102 . If the pupil/fovea orientation is substantially aligned with the optical axis of the fundus imaging system  102 , the process proceeds to step  309  to capture a fundus image. If not, the process returns to step  303  to continue to monitor the pupil or fovea. In some embodiments, the pupil/fovea orientation is substantially aligned with the optical axis when the angle between them is less than two to fifteen degrees. 
     Next, at step  309 , fundus images are captured by triggering the embodiment of example thru focusing image capturing method  200 . In embodiments, five images are captured at step  309 . In some embodiments, the fundus image is captured in a second image capture mode. In some embodiments, in the second image capture mode, the fundus imaging system  102  captures images with visible illumination and at higher resolutions. In some embodiments, the visible illumination is created by the illumination LED  182  operating to generate and direct light of a higher intensity towards the subject. In other embodiments, the higher illumination is created by an external light source or ambient light. The second image capture mode may facilitate capturing a clear, well-illuminated, and detailed fundus image. 
     In some embodiments, after step  309 , the initiate retinal imaging step  306  returns to step  303  to continue to monitor the pupil/fovea orientation. The initiate retinal imaging step  306  may continue to collect fundus images indefinitely or until a specified number of images have been collected. Further information regarding passive eye tracking can be found in U.S. patent application Ser. No. 14/177,594, titled Ophthalmoscope Device, which is hereby incorporated by reference in its entirety 
       FIG. 6  is an embodiment of example use  500  of fundus imaging system  102 . In the embodiment of example use  500 , a clinician positions the fundus imaging system (operation  502 ), initiates image capture (operation  504 ), positions the fundus imaging system over the other eye (operation  506 ), initiates image capture (operation  508 ), and views images (operation  520 ). Although the example use  500  is conducted without first administering mydriatic pharmaceuticals, the example use  500  can also be performed for a patient who has taken a pupil-dilating compound. The embodiment of example use  500  can also include lowering the lighting. The embodiment of example use  500  is conducted using the same or similar components as those described above with reference to  FIGS. 1-3 . Other embodiments can include more or fewer operations. 
     The embodiment of example use  500  begins by positioning the fundus imaging system (operation  502 ). In embodiments, the clinician first initiates an image capture sequence via a button on the housing or a graphical user interface shown by the display. The graphical user interface can instruct the clinician to position the fundus imaging system over a particular eye of the patient. Alternatively, the clinician can use the graphical user interface to indicate which eye fundus is being imaged first. 
     In operation  502 , the clinician positions the fundus imaging system near the patient&#39;s eye socket. The clinician positions the aperture of the system flush against the patient&#39;s eye socket such that the aperture, or a soft material eye cup extending from the aperture, seals out most of the ambient light. Of course, the example use  500  does not require positioning the aperture flush against the patient&#39;s eye socket. 
     When the fundus imaging system is in position, the system captures more than one image of the fundus in operation  504 . As discussed above, the system does not require the clinician to manually focus the lens. Additionally, the system does not attempt to autofocus on the fundus. Rather, the clinician simply initiates the image capture, via a button or the GUI, and the fundus imaging system controls when to capture the images and the focus of the variable focus lens. Also, as discussed above at least with reference to  FIG. 5 , the system can initiate image capture using passive eye tracking. 
     The patient may require the fundus imaging system to be moved away from the eye socket during image capture operation  504 . The clinician can re-initiate the image capture sequence of the same eye using the button or the GUI on the display. 
     After capturing an image in each of the specified zones, the fundus imaging system notifies the clinician that the housing should be positioned over the other eye (operation  506 ). The notification can be audible, such as a beep, and/or the display can show a notification. In embodiments, the system is configured to capture a set of images of only one eye, wherein the example method  500  proceeds to view images operation  520  after image capture operation  504 . 
     Similar to operation  502 , the clinician then positions the fundus imaging system near or flush with the patient&#39;s other eye socket in operation  506 . Again, when the system is in place, an image is captured in every zone in operation  508 . 
     After images have been captured of the fundus in each pre-set zone, the clinician can view the resulting images in operation  520 . As noted above with reference to  FIG. 3 , the images can be post-processed before the clinician views the images to select or synthesize a representative image. Additionally, the fundus images can be sent to a remote location for viewing by a different medical professional. 
       FIG. 7  is a block diagram illustrating physical components (i.e., hardware) of a computing device  1800  with which embodiments of the disclosure may be practiced. The computing device components described below may be suitable to act as the computing devices described above, such as wireless computing device and/or medical device of  FIG. 1 . In a basic configuration, the computing device  1800  may include at least one processing unit  1802  and a system memory  1804 . Depending on the configuration and type of computing device, the system memory  1804  may comprise, but is not limited to, volatile storage (e.g., random access memory), non-volatile storage (e.g., read-only memory), flash memory, or any combination of such memories. The system memory  1804  may include an operating system  1805  and one or more program modules  1806  suitable for running software applications  1820 . The operating system  1805 , for example, may be suitable for controlling the operation of the computing device  1800 . Furthermore, embodiments of the disclosure may be practiced in conjunction with a graphics library, other operating systems, or any other application program and is not limited to any particular application or system. This basic configuration is illustrated in  FIG. 7  by those components within a dashed line  1808 . The computing device  1800  may have additional features or functionality. For example, the computing device  1800  may also include additional data storage devices (removable and/or non-removable) such as, for example, magnetic disks, optical disks, or tape. Such additional storage is illustrated in  FIG. 7  by a removable storage device  1809  and a non-removable storage device  1810 . 
     As stated above, a number of program modules and data files may be stored in the system memory  1804 . While executing on the processing unit  1802 , the program modules  1806  may perform processes including, but not limited to, generate list of devices, broadcast user-friendly name, broadcast transmitter power, determine proximity of wireless computing device, connect with wireless computing device, transfer vital sign data to a patient&#39;s EMR, sort list of wireless computing devices within range, and other processes described with reference to the figures as described herein. Other program modules that may be used in accordance with embodiments of the present disclosure, and in particular to generate screen content, may include electronic mail and contacts applications, word processing applications, spreadsheet applications, database applications, slide presentation applications, drawing or computer-aided application programs, etc. 
     Furthermore, embodiments of the disclosure may be practiced in an electrical circuit comprising discrete electronic elements, packaged or integrated electronic chips containing logic gates, a circuit utilizing a microprocessor, or on a single chip containing electronic elements or microprocessors. For example, embodiments of the disclosure may be practiced via a system-on-a-chip (SOC) where each or many of the components illustrated in  FIG. 7  may be integrated onto a single integrated circuit. Such an SOC device may include one or more processing units, graphics units, communications units, system virtualization units and various application functionality all of which are integrated (or “burned”) onto the chip substrate as a single integrated circuit. When operating via an SOC, the functionality, described herein, may be operated via application-specific logic integrated with other components of the computing device  1800  on the single integrated circuit (chip). Embodiments of the disclosure may also be practiced using other technologies capable of performing logical operations such as, for example, AND, OR, and NOT, including but not limited to mechanical, optical, fluidic, and quantum technologies. In addition, embodiments of the disclosure may be practiced within a general purpose computer or in any other circuits or systems. 
     The computing device  1800  may also have one or more input device(s)  1812  such as a keyboard, a mouse, a pen, a sound or voice input device, a touch or swipe input device, etc. The output device(s)  1814  such as a display, speakers, a printer, etc. may also be included. The aforementioned devices are examples and others may be used. The computing device  1800  may include one or more communication connections  1816  allowing communications with other computing devices. Examples of suitable communication connections  1816  include, but are not limited to, RF transmitter, receiver, and/or transceiver circuitry; universal serial bus (USB), parallel, and/or serial ports. 
     The term computer readable media as used herein may include non-transitory computer storage media. Computer storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, or program modules. The system memory  1804 , the removable storage device  1809 , and the non-removable storage device  1810  are all computer storage media examples (i.e., memory storage.) Computer storage media may include RAM, ROM, electrically erasable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other article of manufacture which can be used to store information and which can be accessed by the computing device  1800 . Any such computer storage media may be part of the computing device  1800 . Computer storage media does not include a carrier wave or other propagated or modulated data signal. 
     Communication media may be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media. The term “modulated data signal” may describe a signal that has one or more characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), infrared, and other wireless media. 
     Although the example medical devices described herein are devices used to monitor patients, other types of medical devices can also be used. For example, the different components of the CONNEX™ system, such as the intermediary servers that communication with the monitoring devices, can also require maintenance in the form of firmware and software updates. These intermediary servers can be managed by the systems and methods described herein to update the maintenance requirements of the servers. 
     Embodiments of the present invention may be utilized in various distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network in a distributed computing environment. 
     The block diagrams depicted herein are just examples. There may be many variations to these diagrams described therein without departing from the spirit of the disclosure. For instance, components may be added, deleted or modified. 
     While embodiments have been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements can be made. 
     As used herein, “about” refers to a degree of deviation based on experimental error typical for the particular property identified. The latitude provided the term “about” will depend on the specific context and particular property and can be readily discerned by those skilled in the art. The term “about” is not intended to either expand or limit the degree of equivalents which may otherwise be afforded a particular value. Further, unless otherwise stated, the term “about” shall expressly include “exactly,” consistent with the discussions regarding ranges and numerical data. Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 4 percent to about 7 percent” should be interpreted to include not only the explicitly recited values of about 4 percent to about 7 percent, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 4.5, 5.25 and 6 and sub-ranges such as from 4-5, from 5-7, and from 5.5-6.5; etc. This same principle applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. 
     The description and illustration of one or more embodiments provided in this application are not intended to limit or restrict the scope of the invention as claimed in any way. The embodiments, examples, and details provided in this application are considered sufficient to convey possession and enable others to make and use the best mode of claimed invention. The claimed invention should not be construed as being limited to any embodiment, example, or detail provided in this application. Regardless whether shown and described in combination or separately, the various features (both structural and methodological) are intended to be selectively included or omitted to produce an embodiment with a particular set of features. Having been provided with the description and illustration of the present application, one skilled in the art may envision variations, modifications, and alternate embodiments falling within the spirit of the broader aspects of the claimed invention and the general inventive concept embodied in this application that do not depart from the broader scope.