Method of quantifying light exposure to prevent phototoxicity during ophthalmic procedures

Abstract

To provide a system and method for quantifying light exposure of a patient's retina during an ophthalmic procedure.SOLUTION: The light source illuminates the patient's retina with directional light during the procedure to produce an illuminated retinal surface. The camera collects image data of the illuminated retinal surface. An electronic control unit, ECU, in communication with the camera and the indicating device, receives the image data, calculates a cumulative energy spectral density of the directed light incident on the retina, and in response to the cumulative energy spectral density exceeding a phototoxicity threshold, performs a control action indicative of potential phototoxicity, including activating the indicating device. The illuminated retinal surfaces may be divided into imaginary zones (Z1, Z2) by the ECU mapping the accumulated energy spectral densities onto the illuminated retinal surfaces. Each of the optional zones (Z1, Z2) has corresponding cumulative energy spectral densities.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an automated method for quantifying retinal exposure to light energy during ophthalmic procedures. Certain ophthalmic surgical procedures require high magnification and imaging of the retina and surrounding tissue within the vitreous cavity of a patient's eye. During such procedures, the retina is illuminated by bright light, typically emitted by a hand-operated light pipe / intraluminator or other suitable directional light source. Vitrectomy is a typical procedure in which such directional light is used to illuminate the vitreous cavity. As understood in the art, vitrectomy involves the precise removal of vitreous humor gel to facilitate access and repair of a torn or detached retina, a macular hole, or diseased / damaged ocular tissue. Cataract surgery and other ophthalmic procedures similarly use internal and external directional light for illumination and imaging purposes. [Background technology]

[0002] The retina is a thin, highly delicate lining located at the posterior inner surface of the eyeball and serves as an appendage of the brain. The retinal sensory neurons, complex neural circuits, and synaptic connections respond to incident light by generating corresponding nerve impulses, which are ultimately transmitted via the optic nerve to the brainstem. Due to the photosensitivity of delicate retinal tissue, directed light energy incident on the retinal surface poses a risk of phototoxicity, which is highly variable and factor-dependent.

[0003] Currently, light output during ophthalmic procedures is characterized against models that use worst-case assumptions. Due to the wide variability in individual surgeon's surgical lighting techniques, differences in lighting techniques, and length of surgery, predictions using worst-case models rarely match actual phototoxicity risk or exposure. As a result, surgeons may be distracted during surgery by excessive phototoxicity notifications and false alarms. Summary of the Invention [Means for solving the problem]

[0004] Disclosed herein are automated phototoxicity prevention methods and systems for accurately quantifying a patient's retinal exposure to directed light energy during an ophthalmic procedure. The toxic potential of light energy during such a procedure varies widely based on several factors, including the linear distance between the retina and the light source, the exposed surface area of ​​the retina, the length of time that area is exposed to the light energy, and the spectral content and intensity of the light energy. Measuring working images of the retina during the procedure and quantifying the light energy distribution in terms of cumulative energy spectral density provides the surgeon with true light energy exposure and associated toxicity risk. This allows the surgeon or other attending clinician to make more informed decisions regarding retinal illumination. Advantages of the present teachings include the possibility of using higher intensity light and / or applying light of different spectral content, possibly for a longer duration before a phototoxicity risk warning appears. Once a phototoxicity risk is indicated, in some embodiments, an appropriate warning or notification is issued, along with the possibility of adjusting the light source control settings.

[0005] In an exemplary embodiment, a system for quantifying light exposure of a patient's retina during an ophthalmic procedure includes a light source, a camera, a pointing device, and an electronic control unit (ECU). The light source is configured to illuminate the patient's retina with directional light during the ophthalmic procedure, thereby generating an illuminated retinal surface. As this occurs, the camera collects digital or analog image data of the illuminated retinal surface. The ECU, in communication with the camera, receives the image data and then calculates the cumulative spectral energy density of the directional light energy incident on the retina. The ECU then displays the incident light energy information via the pointing device, which itself has multiple possible configurations as described herein. In another embodiment, the ECU can communicate with the light source and proceed to execute control actions on the light source based on an assessment of potential phototoxicity.

[0006] As used herein, the term "cumulative energy spectral density" refers to the energy density of incident light integrated over time and spread across different wavelengths, i.e., the cumulative exposure of the retina to light energy in a particular bandwidth of the electromagnetic spectrum, and exposure to associated frequencies and intensities of such light. A control action is taken in response to the cumulative energy spectral density of the delivered / incident light exceeding a phototoxicity threshold, which may be a preset value determined by the user / surgeon or may be based on calibration, and includes activating an indicating device.

[0007] The ECU described herein integrates the energy level of the directional light over the course of an ophthalmic procedure, starting from the onset of illumination of the retina, i.e., integration is not triggered when the light source is turned on, but rather begins when active illumination of the retina begins, i.e., when light energy is incident on the retina.

[0008] The ECU can optionally determine the cumulative energy spectral density as multiple different cumulative densities to provide a higher level of accuracy. As one example, the ECU can calculate the cumulative light energy based on multiple light sources, such as a light pipe / probe and a chandelier. In another example, the ECU can calculate the cumulative density for multiple different regions or zones of the illuminated retinal surface. In such an embodiment, the ECU can take control action in response to the cumulative energy spectral density of any one of the zones exceeding a phototoxicity threshold, which itself may be several zone-specific thresholds to account for potential differences in light sensitivity across exposed areas of the retina.

[0009] In certain embodiments, the instruction device contemplated herein includes a display screen. The ECU automatically presents the surgeon with a light energy distribution pattern, or "heat map," of the illuminated retinal surface via the display screen. The heat map is thus representative of the distribution of cumulative energy spectral density, thereby pinpointing locations of relatively high or low energy concentrations delivered to the retina. A fundus image can be used as an optional background for such a heat map, i.e., the heat map can be presented as an overlay or displayed on top of the fundus image to pinpoint zones corresponding to local "hot spots," such as areas exposed to disproportionately high amounts of incident light energy. An optional approach includes changing the color of the overlay in a manner similar to adding a yellow highlight to portions of the displayed image that exceed a threshold.

[0010] In some aspects of the present disclosure, the ECU may be configured to automatically adjust control settings of the light source in response to exceeding a phototoxicity threshold. For example, the wavelength and / or intensity of the directional light may be modified as needed without manual intervention by the surgeon. The control action in such an embodiment may include automatically adjusting the wavelength and / or intensity in real time via the ECU.

[0011] Also disclosed is a method for quantifying light energy exposure of a patient's retina during an ophthalmic procedure. An embodiment of the method includes illuminating the patient's retina with directional light from a light source during the ophthalmic procedure, thereby generating an illuminated retinal surface, and collecting image data of the illuminated retinal surface using a camera. The method also includes receiving image data from the camera via an ECU, and then calculating, via the ECU, a cumulative energy spectral density of the directional light energy incident on the retina during the ophthalmic procedure. In response to the cumulative energy spectral density exceeding a phototoxicity threshold, the method includes executing a control action via the ECU, the control action indicating possible phototoxicity, and the control action including activating an indicating device.

[0012] In one possible embodiment, the ECU includes a processor, input / output (I / O) circuitry in communication with the processor and the light source, a indicating device, a camera, and a memory. The memory has computer-readable instructions stored therein, and execution of the instructions by the processor causes the ECU to receive image data collected from the camera during an ophthalmic procedure. The collected image data is indicative of an illuminated retinal surface. Execution of the instructions also causes the ECU to calculate a cumulative energy spectral density of directional light energy incident on the retina during the ophthalmic procedure and, in response to the cumulative energy spectral density exceeding a phototoxicity threshold, perform a control action indicative of potential phototoxicity, including activating an indicating device. The threshold may be a value arbitrarily set by the surgeon based on previous surgical experience and the surgeon's medical judgment. Alternatively, the threshold may be based on a calibration process that quantifies an appropriate safety threshold.

[0013] The above-mentioned features and advantages of the present disclosure, as well as other possible features and advantages, will become readily apparent from the following detailed description of the best mode for carrying out the disclosure, when read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] Figure 1 is a schematic diagram of an operating room setup that uses an automated system to quantify light exposure to prevent potential phototoxicity or exposure conditions during a typical ophthalmic procedure. [Figure 2] FIG. 2 is a schematic diagram of one embodiment of the automated system shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of an exemplary fundus image-based heat map according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a flow chart illustrating an exemplary method for quantifying light energy exposure using the automated system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, when considered in conjunction with the accompanying drawings.

[0016] Embodiments of the present disclosure are described herein. However, it will be understood that the disclosed embodiments are merely exemplary and that other embodiments may take various alternative forms. The figures are not necessarily drawn to scale. Some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art how to employ the present disclosure in various ways. As will be understood by those skilled in the art, various features shown and described with reference to any one figure can be combined with features shown in one or more other figures to create embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of the present disclosure may be desired for particular applications or implementations.

[0017] In the following description, certain terms may be used for reference purposes only and, therefore, are not intended to be limiting. For example, terms such as "upper" and "lower" refer to directions within the referenced drawings. Terms such as "front," "rear," "forward," "rearward," "left," "right," "rear," and "side" describe the orientation and / or location of a component or portion of an element within a consistent but arbitrary frame of reference that becomes clear by reference to the text and associated drawings that describe the component or element being discussed. Furthermore, terms such as "first," "second," and "third" may be used to describe separate components. Such terms may include those specifically mentioned above, derivatives thereof, and words of similar import.

[0018] Referring to the drawings, wherein like reference numerals refer to like components, a typical ophthalmic operating room 10 is shown generally in FIG. 1. As will be appreciated by those skilled in the art, such an operating room 10 may include a multi-axis surgical robot 12 and an operating table 14. When the operating room 10 is used to perform a typical vitreoretinal surgery or other surgical or diagnostic procedure, the surgical robot 12 is connected to an ophthalmic microscope 16, through which a surgeon (not shown) can view the patient's ocular anatomy at high magnification. Using associated hardware and software, the surgeon can view high-magnification images 18 and 118, e.g., of the retina 25, which may be achieved via corresponding high-resolution medical display screens 20 and 200.

[0019] Also present within the exemplary operating room 10 of Figure 1 is a cabinet 22 containing an electronic control unit (ECU) 50, an exemplary embodiment of which is shown in Figure 2 and described in detail below. The cabinet 22 shown in conjunction with the display screen 20 may, in other embodiments, be located elsewhere within the operating room 10. Such a cabinet 22 may be constructed of a lightweight, easily sanitizable construction, such as painted aluminum or stainless steel, which is used to house the ECU 50 and protect its component hardware from the potential intrusion of dust, debris, and moisture.

[0020] Within the scope of the present disclosure, vitreoretinal surgical procedures performed within the operating room 10 involve the use of directional task lighting for illumination of the retina 25. Such light is primarily emitted by a light source 32, as shown in FIG. 2, with additional illumination provided by an external lamp 17 attached to the ophthalmic microscope 16. Over time, based on numerous variables, the use of such light can pose a risk of phototoxicity, affecting the light-sensitive function of the retina 25. To mitigate such risks, the ECU 50 of the present disclosure is configured to automatically quantify the light energy exposure of the retina 25, with the ultimate goal of delivering accurately derived alarms or warnings to the attending surgeon. The ECU 50 can also perform optional exposure-reducing active control actions, as described below.

[0021] Referring to FIG. 2 , a representative patient's eye 30 is shown undergoing an ophthalmic procedure 13, in this example, invasive vitreoretinal surgery. During this type of ophthalmic procedure 13, the light source 32 described above is inserted into the vitreous cavity 15 of the patient's eye 30. The light LL emitted from the light source 32 falls within a predetermined wavelength range depending on the illumination task, similar to some light from the microscope lamp 17 in FIG. 1 . The light source 32 may, in some embodiments, be embodied as a light pipe or internal illuminator, possibly with controllable intensity and / or spectral content, i.e., specific wavelengths and associated colors of light within the electromagnetic spectrum. An exemplary application may involve a surgeon desiring a blue-light shift to improve visibility, with the source light 32 possibly configured to adjust its output spectrum in response to commands from the surgeon. Various illumination technologies may be used to emit the light LL, including, but not limited to, red / green / blue (RGB) lasers, light-emitting diodes (LEDs), and halogen bulbs.

[0022] During the ophthalmic procedure 13, the surgeon may also insert a surgical tool 34 into the vitreous cavity 15 to perform a given surgical task on or proximate to the retina 25. Non-limiting exemplary embodiments of the surgical tool 34 include devices such as forceps, an extrusion handpiece, a bladed vitreous surgical probe, scissors, an illuminated or non-illuminated laser probe, and / or an injection tool. With regard to the light source 32, directional light LL is emitted from its distal end E1, and the directional light LL is incident on the exposed surface of the retina 25 to generate an illuminated retinal surface 25I. The light source 32 is coupled to an associated filtered power source (PS) 37, such as a filtered wall outlet or a battery pack and power inverter suitable to ensure reliable generation and transmission of the directional light (arrow LL).

[0023] During the course of the ophthalmic procedure 13, a digital or analog camera 36 or another high-resolution medical imaging device collects image data 38 of the illuminated retinal surface 25I, and then transmits the collected image data 38 to the ECU 50 for processing according to a phototoxicity algorithm (L-TOX ALGO) 70. The method enabled by the algorithm 70 is shown in FIG. 4 and described in detail below. An indicating device (IND) 40 is also in communication with the ECU 50 and receives indicating control signals (arrow CC) from the ECU 50. 40 ) and is configured to operate / turn on in response to the instruction control signal (arrow CC 40 ), and depending on the particular configuration of indicating device 40, indicating device 40 may provide appropriate audible, visual, and / or tactile alarms or warnings.

[0024] For example, the pointing device 40 may be embodied as a speaker, in which case the pointing control signal (arrow CC 40 ) can cause pointing device 40 to sound an audible tone. Alternatively, pointing device 40 can use a pointing control signal (arrow CC 40) may include color-coded lamps such that receipt of the signal causes indicating device 40 to illuminate in an easily identifiable manner, for example using a red light. In either embodiment, ECU 50 may also use display screen 20 and / or 200 as part of indicating device 40 to present an intuitive graphical depiction of the light energy concentration or distribution pattern on illuminated retinal surface 25I.

[0025] Within the scope of the present disclosure, the incidence of phototoxicity alarms is reduced relative to conventional approaches that operate on modeled worst-case scenarios of the type described above. Instead, ECU 50 in some embodiments receives light output data (arrow F) as electronic feedback signals from light source 32 indicative of intensity, wavelength, temperature, and / or other relevant output parameters. BL ) The ECU 50 in such an embodiment then quantifies the actual distribution and energy spectral density of the directional light LL from the light source 32 across the illuminated retinal surface 25I.

[0026] 2, the ECU 50 is configured to receive collected image data 38 from the camera 36 in real time during the ophthalmic procedure 13, the received collected image data 38 depicting the illuminated retinal surface 25I and describing the corresponding light intensity level for each constituent image pixel. The ECU 50 estimates or calculates the cumulative energy spectral density of the directional light LL incident on the retina 25 during the course of the ophthalmic procedure 13, and in different embodiments, the ECU 50 calculates the digital image data 38 and possibly the light output data (indicated by arrows F BL ) to do so. As noted above, the term "cumulative energy spectral density" as used herein considers the light energy density across different wavelengths of the electromagnetic spectrum, i.e., the light energy density in a particular wavelength range associated with phototoxicity risk. ECU 50 then executes appropriate control action that indicates potential phototoxicity against one or more corresponding phototoxicity thresholds.

[0027] Although ECU 50 is shown generally as a unitary box for illustrative clarity and simplicity, ECU 50 may include one or more networked devices having a central processing unit (CPU) or other processor 52 and a sufficient amount of memory 54, each including a non-transitory (e.g., tangible) medium that participates in providing data / instructions that can be read by CPU 52. Instructions embodying algorithm 70 may be stored in memory 54 and executed by CPU 52 to perform the various functions described herein, thus enabling the present methods. Memory 54 may take many forms, including, but not limited to, non-volatile and volatile media.

[0028] As will be appreciated, non-volatile media may include optical and / or magnetic disks or other persistent memory, while volatile media may include dynamic random access memory (DRAM), static RAM (SRAM), etc. Any or all of these may constitute the main memory of ECU 50. Input / output (I / O) circuitry 56 may be used to facilitate connection to and communication with various peripheral devices used during ophthalmic procedure 13, including camera 36, ​​light source 32, pointing device 40, and display screen 20 and / or 200. Other hardware not shown but common in the art may be included as part of ECU 50, including, but not limited to, local oscillators or high-speed clocks, signal buffers, filters, etc.

[0029] Within the scope of the present disclosure, the ECU 50 is programmed with software and equipped with hardware, and thus configured to integrate the power level over time of the directional light LL incident on the retina 25 over the duration of the ophthalmic procedure 13. In this manner, the ECU 50 derives the cumulative energy spectral density described above. In other words, rather than considering the entire duration that the light source 32 is turned on, i.e., whether the directional light LL from the light source 32 actually illuminates any portion of the retina 25, the ECU 50 instead evaluates the distribution and concentration of spectral energy from the distributed light LL on the retina 25 over a more meaningful time period, e.g., watts per minute, watts per hour, etc., and potentially distinguish between different zones of the retina 25.

[0030] Referring briefly to FIG. 3, the retina 25 of FIG. 2 is shown as a representative fundus image 42. As understood in the art, a fundus image is a color, black-and-white, or grayscale image of various major structures of the retina 25, primarily the optic lamina 44, the retinal arteries 46 and peripheral veins stemming therefrom, and the macula 48. The fundus image 42 is familiar due to its ubiquity in ophthalmic care and may be used as a background for the displayed heat map 45. In such an arrangement, the ECU 50 may be configured to digitally divide or otherwise separate the illuminated retinal surface 25I into a plurality of virtual zones and map a cumulative energy spectral density onto the illuminated retinal surface 25I, such that each one of the plurality of zones has a corresponding cumulative energy spectral density.

[0031] In such a configuration, the ECU 50 can optionally overlay a heat map 45 onto the fundus image 42 during the ophthalmic procedure 13 of Figure 2 and present this information in real time via the display screens 20 and / or 200 of Figure 1. In this way, the heat map 45 intuitively provides information that, at a glance, indicates the distribution or concentration of cumulative energy spectral density across the illuminated retinal surface 25I shown in Figure 2. Such an approach provides a greater level of granularity or local precision relative to treating the entire retina 25 as having equal light sensitivity or receiving equal exposure to the directional light LL of Figure 2.

[0032] In the course of performing the exemplary ophthalmic procedure 13 of FIG. 2 , the surgeon may be expected to move the distal end E1 around the vitreous cavity 15. As a result, the entire exposed surface area of ​​the retina 25 may be illuminated unevenly, and to a degree that is highly dependent on the position / distance and orientation of the distal end E1 relative to the retina 25, as well as the intensity and other toxicity-related spectral content of the directional light LL. As a result, zones of the illuminated retinal surface 25I of FIG. 2 may receive a greater density or concentration of directional light LL relative to other zones, such as when the surgeon agonizes over a particular region of the retina 25 while performing a complex surgical repair. Thus, from a qualitative perspective, zones receiving a greater cumulative light energy density may be considered by the ECU 50 to be localized “hot spots.” Two such zones are represented schematically in FIG. 3 as zones Z1 and Z2, which are shown to sandwich the macula 48 solely for illustrative purposes.

[0033] The ECU 50 of the present disclosure is equipped to address such imbalances by integrating power both spatially, i.e., across the surface area of ​​the retina 25, and temporally, i.e., with respect to exposure time. The ECU 50 then executes appropriate control action in response to the cumulative energy spectral density of at least one of a plurality of different zones Z1 and / or Z2, or the entire illuminated retinal surface 25I, exceeding a corresponding phototoxicity threshold. Such thresholds may be the same or zone-specific in different embodiments, as described above; for example, the ECU 50 may use a higher threshold in zones where the tissue of the retina 25 is more resilient to light than others.

[0034] In yet another embodiment, the total integrated energy spectral density of the directional light LL incident on the retina 25 is, for example, in watts per square millimeter (W / mm 2 ) units, again, in some cases, different phototoxicity thresholds are applied to different zones of the retina 25, as described above. For example, zones of the retina 25 with a denser concentration of photoreceptors may have corresponding phototoxicity thresholds that are lower relative to other zones, with effective "watts per rod" or "watts per cone" levels of precision being achievable within the scope of the present disclosure. Such phototoxicity thresholds may be adjusted over time based on postoperative history or other factors to provide improved long-term results.

[0035] 4, a method is enabled by the execution of computer-readable instructions embodying an algorithm 70. That is, execution of instructions stored or recorded in the memory (M) of the ECU 50 shown in FIG. 2 causes the processor 52 and other hardware of the ECU 50 to perform the method. Accordingly, for clarity, such a method will hereinafter be referred to as method 70.

[0036] An exemplary embodiment of method 70 begins at logic block B72, which includes illuminating a patient's retina 25, FIG. 2, with directional light LL from light source 32, along with some additional light from microscope lamp 17, FIG. 1, during ophthalmic procedure 13, the aggregate directional light LL generating illuminated retinal surface 25I. Accordingly, the surgical steps preceding performance of logic block B72 may include making an incision in eye 30, inserting a cannula (not shown), and inserting light source 32 into vitreous cavity 15. Once distal end E1 of light source 32 is present in vitreous cavity 15 and energized by power supply 37, in some embodiments, light source 32 transmits light output data (indicated by arrow FB L ) starts transmitting such optical output data (arrow FB L ) is again primarily the contribution of light source 32, but in some embodiments may also describe the light emitted by microscope lamp 17. Method 70 then proceeds to logic block B74.

[0037] Logic block B74 in FIG. 4 receives optical output data (arrows F L ), where the light output data describes the intensity and spectral content of the directional light emitted by the light source as it illuminates the patient's retina. Logic block B74 also includes collecting image data 38 of FIG. 2 using camera 36, ​​where image data 38 optionally includes a two-dimensional or three-dimensional image of the illuminated retinal surface 25I. Camera 36 may, in some embodiments, be integrated with ophthalmic microscope 16 of FIG. 1, or camera 36 may be a separate device. Because the collected image data 38 is formed from image pixels in digital embodiments, logic block B74 may include accompanying quantitative information describing the corresponding illumination level of each of the constituent image pixels, including, for example, its intensity.

[0038] As part of logic block B74, image data 38 is transmitted to ECU 50 via appropriate transfer conductors (not shown). Thus, logic block B74 also includes receiving image data 38 collected from camera 36 via ECU 50. The light output data (arrow FB) provided in logic block B72 is then transmitted to ECU 50 via appropriate transfer conductors (not shown). L ), the image data 38 enables the ECU 50 to estimate the power, intensity, wavelength, and other relevant energy spectral content of the directional light (LL) from the light source 32 and its distribution across the retina 25. The method 70 then proceeds to logic block B76.

[0039] In logic block B76, the ECU 50 then calculates the optical output data (arrow FB L ) and image data 38 in logic block B74 to estimate or calculate the cumulative energy spectral density of the directional light LL incident on the retina 25. In embodiments based solely on the collected image data 38, the estimation may be performed using a model based, for example, on brightness, color, distribution, and other factors present in the image comprising the collected image data 38. L In embodiments using LL, for example, more accurate results can be achieved using knowledge of the power of the light source 32, the spread function of the light source 32, the distance of the light source 32 from the retina 25, and the length of time the retinal tissue is exposed to the light LL.

[0040] Logic block B76 may involve calculating an average or normalized energy spectral density across the illuminated retinal surface 25I, or ECU 50 may calculate multiple discrete energy spectral densities in a zone-specific manner. Using the latter approach, the surgeon may be made aware of disparities in light energy concentration across the surface of retina 25, as shown, for example, in FIG. 3. Once ECU 50 has calculated the cumulative energy spectral density or the zone-specific energy spectral densities, the method proceeds to logic block B78.

[0041] 2 then compares the cumulative energy spectral density to each phototoxicity threshold in block B78. Method 70 repeats block B72 if none of the phototoxicity thresholds have been exceeded. Method 70 alternatively proceeds to block B80 if ECU 50 determines that one or more phototoxicity thresholds have been exceeded.

[0042] Logic block B80 involves executing a control action via ECU 50 in response to the cumulative energy spectral density exceeding a phototoxicity threshold. As described above, the control action is indicative of possible phototoxicity and includes activating indicating device 40. As part of logic block B80, ECU 50 may consider the magnitude by which a given phototoxicity threshold was exceeded in logic block B78 when determining which of many possible control actions ECU 50 should take in a given situation. That is, the control action may be proportional to the magnitude of the difference between the exceedance of the phototoxicity threshold and the cumulative energy spectral density, with ECU 50 potentially escalating a corresponding alarm as the magnitude increases.

[0043] An exemplary embodiment includes establishing phototoxicity threshold levels for representative zones Z1 and Z2 of FIG. 3 . Over the course of the ophthalmic procedure 13, the ECU 50 automatically integrates the power of the directional light LL delivered over time at different regions or zones of the illuminated retinal surface 25I, including zones Z1 and Z2. The ECU 50 can display a color-coded version of the heat map 45 of FIG. 3 via the display screens 20 and / or 200 of FIG. 1 , allowing the surgeon to discern at a glance whether a particular zone is over-irradiated relative to other zones. In an embodiment, the ECU 50 can modify the color of a “hotter” zone as its cumulative energy spectral density increases, such as by gradually coloring the zone from yellow to red. When a given phototoxicity threshold for a given zone is crossed, the ECU 50 can activate the indicating device 40 of FIG. 2 , such as a lamp or an audible alarm.

[0044] Additionally, an ECU 50 within the scope of the present disclosure can respond to exceeding a given phototoxicity threshold level by automatically adjusting the settings of the light source 32. Such an option may be selectable by the surgeon or selectively bypassed or overridden in other embodiments. Exemplary control actions in such an event may include adjusting the power level from the power supply 37 of FIG. 2 to reduce the power of the light source 32 and / or modifying the wavelength and / or intensity of the directional light LL emitted by the light source 32 during the course of the ophthalmic procedure 13. The latter control action may involve modifying the spectral content to reduce ultraviolet / violet / blue light content, thereby creating energy that is safer for the eye, at the potential cost of less detail.

[0045] By using the ECU 50 of Figures 1 and 2, the intuitive heat map 45 of Figure 3, and the algorithm 70 shown in Figure 4, a surgeon performing the ophthalmic procedure 13 shown in Figure 2 is made aware in a more realistic and localized manner of the phototoxicity risks associated with directing incident light LL from the described light source 32 onto the retina 25. Because a phototoxicity alarm is not triggered unless and until a given energy spectral density-specific threshold is exceeded, this approach should help reduce the number of false alarms relative to traditional worst-case modeling scenarios.

[0046] Furthermore, reducing the rate of false alarms provides an increased level of confidence to the surgeon. Alarms sounded in the course of performing the ophthalmic procedure 13, in other words, are much more likely to be true alarms and, as a result, are less likely to be silenced or ignored without action. Embodiments may be standalone, i.e., the ECU 50 and its associated logic may be used in conjunction with an existing ophthalmic microscope 16, camera 36, ​​and light source 32. Alternatively, any or all of the described hardware may be integrated such that the programmed function of the ECU 50 in performing the method 70 of FIG. 4 is seamless.

[0047] While the detailed description and drawings support and explain the present disclosure, the scope of the present disclosure is defined solely by the claims. While the best mode and some other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for carrying out the disclosure defined in the appended claims. Furthermore, the features of the various embodiments shown in the drawings or described herein should not necessarily be understood as independent embodiments of one another. Rather, each of the characteristics described in one of the example embodiments can be combined with one or more other desirable characteristics from other embodiments, resulting in other embodiments not described in words or with reference to drawings. Accordingly, such other embodiments are encompassed within the scope of the appended claims.

Claims

1. 1. A system for quantifying retinal light exposure of a patient during an ophthalmic procedure, comprising: a light source configured to illuminate the patient's retina with directional light during the ophthalmic procedure, thereby generating an illuminated retinal surface; a camera configured to collect image data of the illuminated retinal surface as collected image data; an indicating device; an electronic control unit (ECU) in communication with the pointing device and the camera, receiving the collected image data from the camera indicative of the illuminated retinal surface; using the collected image data to estimate a cumulative energy spectral density of the directional light incident on the retina during the ophthalmic procedure; dividing the illuminated retinal surface into a plurality of virtual zones, each of the plurality of virtual zones having a corresponding zone-specific phototoxicity threshold; mapping the accumulated energy spectral density onto the illuminated retinal surface such that each one of the plurality of virtual zones has a corresponding accumulated energy spectral density; determining a corresponding accumulated energy spectral density for each of the plurality of virtual zones from the accumulated energy spectral densities; performing a control action indicating possible phototoxicity, including activating the indicating device, in response to the corresponding cumulative energy spectral density of one of the plurality of virtual zones exceeding the corresponding zone-specific phototoxicity threshold. an electronic control unit (ECU) configured as follows: A system comprising:

2. 10. The system of claim 1, wherein the ECU is in communication with the light source and is configured to receive light output data therefrom, the light output data describing the intensity and spectral content of the light illuminating the patient's retina.

3. The system of claim 1 , wherein the indicating device includes a speaker and the control action includes sounding an audible alarm via the speaker.

4. The system of claim 1 , wherein the indicating device comprises a color-coded lamp and the control action comprises illuminating the color-coded lamp.

5. The system of claim 1 , wherein the pointing device includes a display screen, and the control action includes displaying information indicative of the cumulative energy spectral density via the display screen.

6. 6. The system of claim 5, wherein the ECU is configured to display a heat map of the illuminated retinal surface via the display screen, the heat map showing the distribution of the cumulative energy spectral density across the illuminated retinal surface.

7. The system of claim 6 , wherein the image data includes a fundus image of the patient's retina, and the heat map is displayed over the fundus image such that the fundus image forms a background for the heat map.

8. 2. The system of claim 1, wherein the ECU is configured to selectively adjust control settings of the light source, the control actions including adjusting the wavelength and / or intensity level of the directional light in real time during the ophthalmic procedure as the control settings.

9. The system of claim 8 , wherein the light source is a light pipe or internal illuminator with variable intensity and / or spectral content.

10. an electronic control unit (ECU) for quantifying light exposure of a patient's retina during an ophthalmic procedure, the ECU communicating with a light source during the ophthalmic procedure to thereby generate an illuminated retinal surface; a processor; input / output (I / O) circuitry in communication with the processor, the light source, the pointing device, and the camera; a memory having computer-readable instructions recorded therein, the execution of the computer-readable instructions by the processor causing the ECU to: receiving image data collected from the camera during the ophthalmic procedure, the collected image data representing an illuminated retinal surface of the patient's retina; receiving light output data from the light source, the light output data describing the intensity and spectral content of directional light emitted by the light source when illuminating the patient's retina; calculating a cumulative energy spectral density of the directional light from the light source that provides the illuminated retinal surface during the ophthalmic procedure; dividing the illuminated retinal surface into a plurality of virtual zones, each of the plurality of virtual zones having a corresponding zone-specific phototoxicity threshold; mapping the accumulated energy spectral density onto the illuminated retinal surface such that each one of the plurality of virtual zones has a corresponding accumulated energy spectral density; performing a control action indicative of possible phototoxicity, including activating the indicating device, in response to the corresponding cumulative energy spectral density of one of the plurality of virtual zones exceeding the corresponding zone-specific phototoxicity threshold. Memory and An electronic control unit (ECU) comprising:

Images