Ophthalmic devices and ophthalmic device control programs

Abstract

To provide an ophthalmic device that can measure corneal shape without increasing the subject's discomfort due to glare. [Solution] An ophthalmic device for measuring the corneal shape of an eye under examination, comprising: a first projection optical system that projects a first pattern indicator onto the cornea of ​​the eye under examination using invisible light; a second projection optical system that projects a second pattern indicator onto the cornea of ​​the eye under examination using visible light; an anterior segment imaging optical system that receives reflected light from the anterior segment of the eye under examination; and a control unit, wherein the control unit analyzes and processes imaging data obtained by receiving the reflected light of the first pattern indicator projected onto the cornea of ​​the eye under examination by the first projection optical system with the anterior segment imaging optical system to determine whether or not corneal shape measurement of the eye under examination can be performed, and if it is determined that corneal shape measurement is possible, the second projection optical system projects a second pattern indicator onto the cornea of ​​the eye under examination, and analyzes and processes imaging data obtained by receiving the reflected light of the second pattern indicator with the anterior segment imaging optical system to measure the corneal shape.

Description

Technical Field

[0001] The present disclosure relates to an ophthalmic apparatus for measuring the corneal shape of an eye to be examined and an ophthalmic apparatus control program.

Background Art

[0002] An apparatus that projects a pattern index onto an eye to be examined with visible light and measures the corneal shape of the eye to be examined based on imaging data of a corneal reflection image of the pattern index is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Corneal shape measurement may be affected by, for example, the state of the tear fluid in the eye to be examined, in addition to kerare by the eyelids of the subject. When the measurement is affected by kerare or the state of the tear fluid, etc., it may be necessary to repeat the measurement, and the subject may feel a burden due to glare. An object of the present disclosure is to provide an ophthalmic apparatus capable of performing corneal shape measurement without increasing the burden on the subject due to glare.

Means for Solving the Problems

[0005] In order to solve the above problems, the present invention is characterized by having the following configuration.

[0006] (1) An ophthalmic device for measuring the corneal shape of an eye under examination, comprising: a first projection optical system for projecting a first pattern indicator onto the cornea of ​​the eye under examination using invisible light; a second projection optical system for projecting a second pattern indicator onto the cornea of ​​the eye under examination using visible light; an anterior segment imaging optical system for receiving reflected light from the anterior segment of the eye under examination; and a control unit, wherein the control unit analyzes and processes imaging data obtained by receiving the reflected light of the first pattern indicator projected onto the cornea of ​​the eye under examination by the first projection optical system with the anterior segment imaging optical system to determine whether or not corneal shape measurement of the eye under examination can be performed; and if it is determined that corneal shape measurement is possible, the second projection optical system projects the second pattern indicator onto the cornea of ​​the eye under examination, and analyzes and processes imaging data obtained by receiving the reflected light of the second pattern indicator with the anterior segment imaging optical system to measure the corneal shape. (2) An ophthalmic device control program executed in an ophthalmic device for measuring the corneal shape of an eye under examination, comprising: a first pattern indicator projection step in which a first pattern indicator is projected onto the cornea of ​​the eye under examination using a first projection optical system that projects a first pattern indicator onto the cornea of ​​the eye under examination using invisible light; a first imaging data acquisition step in which the reflected light from the anterior segment of the eye under examination by the projection light from the first pattern indicator projection step is received by the anterior segment imaging optical system to acquire imaging data; and a determination step in which the imaging data acquired in the first imaging data acquisition step is analyzed to determine whether or not the corneal shape measurement of the eye under examination can be performed. An ophthalmic device control program that causes the ophthalmic device to execute the following steps: a step, a second pattern indicator projection step in which, if the determination step determines that corneal shape measurement is possible, a second pattern indicator projection step in which a second projection optical system projects a second pattern indicator onto the cornea of ​​the eye under examination using visible light; a second imaging data acquisition step in which the anterior segment imaging optical system receives the reflected light from the anterior segment of the eye under examination using the second pattern indicator projection step to acquire imaging data; and a measurement step in which the imaging data acquired in the imaging data acquisition step is analyzed and processed to measure the corneal shape. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram illustrating the configuration of ophthalmic equipment. [Figure 2]This diagram explains the pattern plate from the front view on the side where the subject is positioned. [Figure 3] This is a diagram of the Placid ring, a pattern index used for corneal topography. [Figure 4] This diagram illustrates the optical system and control system of an ophthalmic device. [Figure 5] This is an example of anterior segment imaging data in which the first pattern index is projected onto the cornea of ​​the examined eye. [Figure 6] This is a flowchart explaining the operation of corneal topography measurement. [Modes for carrying out the invention]

[0008] The ophthalmic device of this embodiment is an ophthalmic device for measuring the corneal shape of the eye under examination. For example, the ophthalmic device 1 may also include means for performing measurements other than the corneal shape of the eye under examination (e.g., refractive power measurement, corneal curvature measurement, intraocular pressure measurement, corneal thickness measurement, accommodation function measurement).

[0009] The ophthalmic apparatus of this embodiment (for example, ophthalmic apparatus 1) comprises a pattern index projection means (for example, a pattern index projection unit 20, a pattern index projection optical system 30) having a first projection optical system and a second projection optical system, an imaging data acquisition means (for example, an anterior segment imaging optical system 50, a control unit 3), an analysis processing means (for example, a control unit 3), and a measurement execution determination means (for example, a control unit 3). For example, the ophthalmic apparatus may also include an anterior segment illumination means (for example, an anterior segment illumination optical system 80). Furthermore, for example, the ophthalmic apparatus may also include a further pattern index projection means (for example, an internal pattern index projection optical system 40).

[0010] The ophthalmic apparatus of this embodiment uses a first projection optical system to project a first pattern index onto the cornea of ​​the eye under examination using invisible light. The imaging data (hereinafter referred to as the first imaging data) of the first pattern index projected onto the cornea of ​​the eye under examination (hereinafter referred to as the first corneal projection image) is analyzed to determine whether or not corneal shape measurement of the eye under examination can be performed. If it is determined that corneal shape measurement is possible, the imaging data (hereinafter referred to as the second imaging data) of the second pattern index projected onto the cornea of ​​the eye under examination (hereinafter referred to as the second corneal projection image) is analyzed using a second projection optical system to measure the corneal shape. Repeated measurements using visible light can be burdensome for the subject. Therefore, it is desirable for the examiner to be able to determine whether or not the eye under examination is in a state where corneal shape measurement can be performed before performing the measurement. However, if the examiner checks whether or not the eye under examination is in a state where corneal shape measurement can be performed using visible light and then performs the corneal shape measurement, the subject may feel glare each time they are illuminated with visible light. Therefore, if visible light is not illuminated to the subject when the first pattern indicator is projected, and visible light is only illuminated to the subject when the second pattern indicator is projected, the subject will not feel glare during the process of determining whether or not to perform corneal shape measurement of the subject's eye, and will only feel glare when performing corneal shape measurement of the subject's eye, as with conventional technology. As a result, the ophthalmic device of this embodiment can determine whether or not to perform corneal shape measurement of the subject's eye before the measurement is performed without increasing the subject's burden due to glare.

[0011] For example, the pattern index projection means is used to project a pattern index (e.g., Placido ring 29) used for measuring the corneal shape of the eye under examination onto the cornea of ​​the eye under examination. For example, the pattern index projection means includes a first projection optical system including a light source (e.g., light source 31) that emits invisible light for projecting a first pattern index. For example, the first pattern index may be formed of multiple Mayer rings (ring-shaped indexes). For example, the first pattern index may have multiple ring-shaped light-shielding portions (e.g., light-shielding portion 22a) and ring-shaped light-transmitting portions (e.g., light-transmitting portion 22b) formed alternately in concentric circles around the measurement optical axis. Also, for example, the pattern index projection means includes a second projection optical system including a light source (e.g., light source 32) that emits visible light for projecting a second pattern index. For example, the second pattern index may be formed of multiple Mayer rings. For example, the second pattern indicator may consist of multiple ring-shaped light-shielding portions (e.g., light-shielding portion 22a) and ring-shaped light-transmitting portions (e.g., light-transmitting portion 22b) formed alternately in concentric circles around the ophthalmic axis. In other words, the pattern indicator projection means may project a Placido ring.

[0012] For example, the ring-shaped pattern may form a continuous, uninterrupted ring, or it may form an intermittent ring pattern. The intermittent ring pattern may be formed by projecting a dashed ring onto the cornea, by projecting multiple dot indicators arranged on the circumference onto the cornea, or by a combination of these. The pattern indicators may be dot-shaped indicators arranged in a ring shape, or they may not be limited to a ring shape; their shape and arrangement are not restricted as long as the corneal shape can be measured. In addition, a cone method may be applied instead of the Placido plate measurement method. In the cone method, the pattern at the third measurement indicator is formed by a cone instead of the pattern plate 21.

[0013] For example, the invisible light of the first projection optical system may be infrared light. Infrared light is considered to have less impact on the human body among invisible light. For example, the wavelength of the infrared light may be near-infrared light with a peak between 800 nm and 900 nm. As an example, it may be near-infrared light with a peak wavelength of 870 nm. Furthermore, the visible light of the second projection optical system may be monochromatic light such as blue light or green light. Moreover, the visible light of the second projection optical system may be white light. For example, white light may include light of various wavelengths from 400 nm to 700 nm. By using white light, which is multichromatic light, as the visible light, the first pattern index projected onto the eye under examination can be made less susceptible to the influence of the various iris patterns and colors of the eye under examination compared to using monochromatic light. As a result, it is possible to analyze and process clearer imaging data of the first pattern index, improving the accuracy of the measurement.

[0014] For example, the first pattern indicator and the second pattern indicator may be identical in size and shape. Because the first and second pattern indicators are identical in size and shape, if there are no abnormalities in the shape of the first pattern indicator in the imaging data, it is less likely that abnormalities will appear in the shape of the second pattern indicator. As a result, the measurement success rate can be increased. Note that "identical" here includes being substantially identical. Furthermore, the first and second pattern indicators may be different in at least one aspect, such as size or shape.

[0015] For example, the imaging data acquisition means includes an anterior segment imaging optical system (e.g., an anterior segment imaging optical system 50) and a control unit (e.g., a control unit 3). The anterior segment imaging optical system receives reflected light from the anterior segment of the eye under examination and transmits the received light data to the control unit. The control unit acquires imaging data of the anterior segment of the eye under examination based on the received light data received from the anterior segment imaging optical system. For example, the imaging data acquisition means may acquire first imaging data. Alternatively, for example, the imaging data acquisition means may acquire second imaging data.

[0016] For example, the imaging data acquisition means may continuously image the anterior segment using the image sensor in order to obtain at least two anterior segment images with different projection states of the pattern index. This makes it possible to suppress the influence of eye movement (positional displacement of the eye) when imaging to obtain at least two anterior segment images. As a result, the pattern index image can be extracted with high accuracy, and the analysis processing of the pattern index image can also be performed well. For example, continuous imaging by the image sensor may simply mean obtaining anterior segment images continuously at the frame rate of the image sensor.

[0017] For example, the analysis processing means may be a control unit (for example, control unit 3). The analysis processing means analyzes the imaging data of the anterior segment acquired by the imaging data acquisition means. For example, the analysis processing may be a process of analyzing whether or not there is distortion in the shape of the first corneal projection image. Vignetting is often caused by the subject's eyelids. Therefore, the examiner can often improve vignetting by having the subject open their eyelids. However, factors other than vignetting caused by the subject's eyelids cannot be avoided by the examiner's actions, so it is desirable to be able to distinguish and judge these factors from vignetting. Therefore, by analyzing whether or not there is distortion in the shape of the first corneal projection image, the measurement execution determination means described later can refer to factors other than vignetting caused by the subject's eyelids to determine whether or not to perform corneal shape measurement of the subject's eye. Furthermore, for example, the analysis processing means may analyze the shape of the second corneal projection image of the anterior segment imaging data. In this disclosure, distortion of the shape of the first corneal projection image may refer, for example, to a state in which the first corneal projection image is more intermittent than the pattern index. Alternatively, for example, it may refer to a state in which the lines of the first corneal projection image are distorted by a predetermined percentage or more compared to the pattern index. Furthermore, vignetting caused by the subject's eyelids may be distinguished and judged from the first corneal projection image based on the detection of a defect of a predetermined percentage or more in the first corneal projection image.

[0018] For example, the measurement execution determination means may be a control unit (for example, control unit 3). For example, the control unit may determine whether corneal shape measurement of the test eye can be performed. For example, the control unit may determine the feasibility based on whether there is distortion in the shape of the first corneal projection image. Kerare is often caused by the eyelids of the subject. Therefore, in many cases, by the examiner opening the eyelids of the subject, kerare can be improved. However, factors other than kerare caused by the eyelids of the subject cannot be avoided by the actions of the examiner, so it is preferable to be able to distinguish and determine them from kerare. Thus, the measurement execution determination means may determine whether corneal shape measurement of the test eye can be performed by referring to factors other than kerare caused by the eyelids of the subject based on the analysis processing means for whether there is distortion in the shape of the first corneal projection image.

[0019] For example, when it is determined that corneal shape measurement is impossible in the determination of whether corneal shape measurement of the test eye can be performed, the control unit may output a notification prompting the subject to blink. For example, the output of the notification may be by the output of voice by voice output means (for example, voice output unit 9). Also, it may be to display the notification on display means (for example, display unit 5). By this notification, the subject blinks, so factors that make corneal shape measurement impossible, such as abnormal tear film conditions, can be eliminated.

[0020] For example, the internal pattern index projection means (for example, internal pattern projection optical system 40) is used to measure the corneal shape. For example, the internal pattern index projection means projects a so-called Meyer ring, which is a ring-shaped index, onto the test cornea. The internal pattern index projection means may be used as part of the pattern index projection means. For example, the internal pattern index may be used as part of the pattern index for obtaining the corneal shape.

[0021] Note that in the present disclosure, it is not limited to the devices described in this embodiment. For example, a processing program (software) that performs the functions of the following embodiments is supplied to a system or device via a network or various storage media, etc. And it is also possible for a control device (for example, a CPU, etc.) of the system or device to read and execute the program.

[0022] The program illustrated in this disclosure is a program executed in an ophthalmic device for measuring the corneal shape of an eye under examination. The program performs a first pattern indicator projection step in which a first projection optical system projects a first pattern indicator onto the cornea of ​​the eye under examination using invisible light; a first imaging data acquisition step in which the reflected light from the anterior segment of the eye under examination by the projection light from the first pattern indicator projection step is received by an anterior segment imaging optical system to acquire imaging data; and a determination step in which the imaging data acquired in the first imaging data acquisition step is analyzed to determine whether or not corneal shape measurement of the eye under examination can be performed. If the determination step determines that corneal shape measurement is possible, the system executes a second pattern indicator projection step in which a second projection optical system projects a second pattern indicator onto the cornea of ​​the eye under examination using visible light, a second imaging data acquisition step in which the reflected light from the anterior segment of the eye under examination by the projection light from the second pattern indicator projection step is received by an anterior segment imaging optical system to acquire imaging data, and a measurement step in which the imaging data acquired in the imaging data acquisition step is analyzed and processed to measure the corneal shape.

[0023] An embodiment of the ophthalmic apparatus relating to this disclosure will be described based on the drawings. The referenced drawings are used to illustrate the technical features that may be adopted in this disclosure, and the configurations etc. described are not intended to be the sole limiting factors, but are merely illustrative examples.

[0024] Figure 1 is a diagram illustrating the components of the ophthalmic device 1, including the measurement optical system and control system. The first measurement optical system 10 of the ophthalmic device 1 comprises a pattern index projection optical system 30 and an anterior segment imaging optical system 50. The pattern index projection optical system 30 is used to project a pattern index onto the cornea of ​​the eye to obtain the corneal shape of the eye under examination. The ophthalmic device 1 also includes an anterior segment illumination optical system 80. The ophthalmic device 1 may also include an internal pattern index projection optical system 40. In addition, the ophthalmic device 1 may include an alignment index projection optical system 90 and a fixation target optical system 100. Furthermore, the ophthalmic device 1 may be a composite device that includes a second measurement optical system 110 for measuring eye characteristics of the eye under examination that are different from corneal shape.

[0025] Figure 2 is a diagram illustrating a part of the first measurement optical system of the ophthalmic device 1 as viewed from the eye side of the eye being examined. Figure 3 is a diagram of a Placido ring, which is an example of a pattern index used for measuring the corneal shape of the eye being examined. The pattern index projection unit 20 includes a pattern plate 21. The pattern plate 21 has a pattern index for obtaining the corneal shape formed on a transparent plate. In this embodiment, the pattern index is a multi-ring platid ring 29, as shown in Figure 2. The Placido ring 29 is formed by providing multiple ring-shaped light-shielding parts 22a painted black and ring-shaped light-transmitting parts 22b that are not painted on the pattern plate 21, arranged alternately in concentric circles around the measurement optical axis L1.

[0026] Figure 4 is a simplified diagram illustrating the optical system of the ophthalmic device 1. The pattern index projection optical system 30 includes a light source 31 and a light source 32. The light sources 31 and 32 are, for example, positioned behind the pattern plate 21. For example, an LED emitting light in the infrared region is used for the light source 31. The light source 31 illuminates the pattern plate 21. The light from the light source 31 passes through the light-transmitting portion 22b of the pattern plate 21 and projects the Placid ring 29 onto the cornea Ec of the eye being examined (i.e., projects the first pattern index onto the cornea Ec of the eye being examined). The optical system that illuminates each light-transmitting portion 22b of the pattern plate 21 from behind may use a light guide plate. For example, an LED emitting white light is used for the light source 32. The light source 32 projects the Placid ring 29. Light from the light source 32 passes through the light-transmitting section 22b and projects the Placido ring 29 onto the cornea Ec of the eye being examined (i.e., projects the second pattern index onto the cornea Ec of the eye being examined). The optical system that illuminates each light-transmitting section 22b of the pattern plate 21 from behind may use a light guide plate. Note that the Placido ring 29 is not limited to a ring index; it may consist of dot-shaped indexes arranged in a ring shape, or any shape and arrangement that allows for the measurement of corneal shape.

[0027] The anterior segment illumination optical system 80 includes, for example, an illumination light source 81 that emits white light. The illumination light source 81 may also be invisible light, such as infrared light. As shown in Figure 2, two illumination light sources 81 are arranged on the upper side and two on the lower side, flanking the ophthalmoscopic axis L1.

[0028] The internal pattern index projection optical system 40 is positioned inside the pattern index projection unit 20 in the housing 2 of the ophthalmic device 1, centered on the measurement optical axis L1. In this embodiment, the internal pattern index projection optical system 40 is configured to project a double Mayer ring index. The internal pattern index projection optical system 40 includes a light source 41. The light source 41 may be, for example, a light source that illuminates with invisible light. The double Mayer rings illuminated on the cornea Ec of the eye under examination by the internal pattern index projection optical system 40 may be used as part of the first and second pattern indexes for obtaining the corneal shape during corneal shape measurement. The internal pattern index projection optical system 40 may also be provided as part of the pattern index projection unit 20. In this case, during corneal curvature radius (kerat) measurement, the double Mayer rings projected by the illumination of the light source 41 are used for measuring the corneal curvature radius. Furthermore, the internal pattern index projection optical system 40 may also be used as an alignment index projection optical system for aligning the first measurement optical system 10 with respect to the eye under examination E.

[0029] The anterior segment imaging optical system 50 is used to image the anterior segment of the eye E under examination, onto which the first and second corneal projection images are projected by the pattern index projection optical system 30. The anterior segment imaging optical system 50 includes an objective lens 51, an imaging lens 52, an image sensor 53, etc. The image sensor 53 of the anterior segment imaging optical system 50 receives reflected light from the anterior segment, including the first and second corneal projection images. The anterior segment imaging optical system 50 also serves as an imaging optical system for alignment indicators illuminated on the cornea Ec of the eye under examination. The image sensor 53 is an image sensor capable of simultaneously acquiring light of various wavelengths. In the anterior segment imaging optical system 50, the image sensor 53 is positioned such that its imaging surface is located on the image plane of the imaging lens 52. The image sensor 53 may be, for example, a CCD (Charge Coupled Device) image sensor. Alternatively, the image sensor 53 may be, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0030] The alignment index projection optical system 90, for example, has an optical system that is symmetrical on both sides of the measurement optical axis L1, and projects an infinity index by irradiating the cornea Ec of the eye under examination with a parallel beam of light via the light source 91 and the lens 92. The reflected light from the projected infinity index on the cornea Ec of the eye under examination is received by the light-receiving element 94 via the lens 93. The internal pattern index projection optical system 40 is also used as an optical system for projecting alignment indexes at a finite distance. When the first measurement optical system 10 is aligned with the eye under examination E, the reflected light from the anterior segment of the eye, including the alignment index image projected onto the cornea Ec of the eye under examination, is received (acquired), and the signal is input to the control unit 3. Then, based on the index image from the alignment index projection optical system 90 and the Mayerring image from the internal pattern index projection optical system 40, the alignment state of the first measurement optical system 10 with respect to the eye under examination E in the X direction (left-right direction), Y direction (up-down direction), and Z direction (front-back direction) is acquired.

[0031] The anterior segment illumination optical system 80 is used, for example, to illuminate the anterior segment of the eye under examination. For example, the anterior segment illumination optical system 80 illuminates the eye under examination E, and the anterior segment imaging optical system 50 receives the reflected illumination light, so that the control unit 3 can obtain anterior segment imaging data of the eye under examination E where the pattern index is not illuminated.

[0032] For example, the fixation target optical system 100 comprises at least a light source 101 and a fixation target plate 102. The fixation target optical system 100 guides the line of sight of the eye E under examination when the fixation target is fixed to the eye E under examination. The fixation beam from the light source 101 passes through the fixation target plate 102, lens 103, half mirror 104, and lens 105, and is reflected by the half mirror 106 to become coaxial with the measurement optical axis L1. Subsequently, the fixation beam reaches the fundus of the eye E under examination via lens 51.

[0033] The second measurement optical system 110 is, for example, an optical system that acquires a cross-sectional image of the eye under examination. The second measurement optical system 110 includes a light projection optical system 111 that projects slit light onto the anterior segment of the eye under examination, and a light receiving optical system 112 that receives reflected light from the anterior segment of the eye under examination, which has been light-cut by the slit light, with a light receiving element 113. The second measurement optical system may also be, for example, a shineproof camera.

[0034] In Figure 1, the control unit 3 is responsible for the overall control of the ophthalmic device 1. The control unit 3 is connected to each electrical element of the first measurement optical system 10, which includes a pattern indicator illumination optical system 30, an internal pattern indicator projection optical system 40, anterior segment illumination optical system 80, anterior segment imaging optical system 50, etc.

[0035] The control unit 3 includes a CPU (processor), ROM, and RAM. The CPU controls various functions of the ophthalmic device 1. The ROM stores various programs, initial values, etc. The RAM temporarily stores various information. ROM and RAM are memory. The control unit 3 is connected to the display unit 5, the operation unit 6, and the storage unit 4. The storage unit 4 (e.g., non-volatile memory) is a non-transient storage medium that can retain its contents even when the power supply is cut off. For example, a hard disk drive, flash ROM, and a removable USB memory may be used as the storage unit 4. In this embodiment, control programs for executing various processes described later are stored in the storage unit 4. Furthermore, the control unit 3 is electrically connected to the drive unit 7, the measurement optical system 10, the anterior segment imaging optical system 50, etc.

[0036] In this disclosure, the term "processor" refers to one or more hardware components configured to execute computer program code (i.e., one or more instructions of a computer program) contained within a computer program. In other words, a "processor" is a hardware device capable of executing one or more programmed processes. For example, a "processor" may be a general-purpose or application-specific processor, and may be at least one of a CPU, microprocessor, GPU, and DFP (data flow processor).

[0037] In this disclosure, the term “memory” refers to one or more hardware memories, which are non-transitional tangible recording media configured to record at least one of computer program code and data in a manner accessible from a processor. “Memory” can be implemented by memory technologies such as SRAM, SDRAM, non-volatile / flash type memory, or other types of memory. The computer program code constituting the computer program is recorded in memory and executed by the processor to enable various functions of the ophthalmic device 1.

[0038] In this disclosure, the term “circuit” refers to one or more logic circuits as hardware, configured to enable the ophthalmic device 1 to perform functions. In other words, “circuit” refers to one or more non-programmable devices. For example, “circuit” could be a custom IC designed to be non-programmable for a specific application.

[0039] In this disclosure, at least one of a circuit and a processor having memory storing computer program code enables the ophthalmic device 1 to function. The expression "at least one of a circuit and a processor" should be interpreted as disjunctive (logical OR) and not as at least one circuit and at least one processor.

[0040] The control unit 3 is connected to a storage unit 4, a display unit 5, and an operation unit 6. The display unit 5 displays various information such as images captured by the image sensor 53, images processed by the control unit 3, and the results of corneal shape analysis. The operation unit 6 may be a touch panel provided on the display unit 5. Alternatively, the operation unit 6 may include a pointing device such as a mouse or a keyboard operated by the examiner. The storage unit 4 stores various information such as images acquired by the control unit 3 and analysis results. The storage unit 4 also stores a control and processing program for obtaining the corneal shape. The control unit 3 analyzes the corneal shape of the eye under examination using the control and processing program.

[0041] Furthermore, the control unit 3 acquires imaging data based on the reflected light from the anterior segment of the eye under examination, which is received by the image sensor 53. In other words, the control unit 3 functions as an image acquisition means that obtains an image by capturing the anterior segment of the eye under examination with the image sensor 53.

[0042] Figure 5 shows an example of imaging data acquired by the control unit 3. The control unit 3 also functions as an analysis processing means for the imaging data. The analysis processing means, for example, analyzes whether or not there is distortion in the shape of the first corneal projection image in the first imaging data. Distortion in the shape of the first corneal projection image in the first imaging data may refer to, for example, a state in which the Placid ring is intermittent, as shown in Figure 5(a). Alternatively, it may refer to a state in which the Placid ring lines are distorted by a predetermined percentage or more. For example, the control unit 3 may perform an analysis process to detect distortion in the first corneal projection image by performing edge detection on the first imaging data. Alternatively, for example, the control unit 3 may perform an analysis process to detect distortion in the first corneal projection image by performing elliptic fitting based on edge detection on the first imaging data and detecting edges that have a difference of a predetermined percentage or more from the elliptic shape. Furthermore, the control unit 3 may detect vignetting (see Figure 5(b)) in the imaging data based on detecting a defect of a predetermined percentage or more from the first corneal projection image by performing edge detection on the first imaging data.

[0043] The control unit 3 also functions as a measurement execution determination means, determining whether or not corneal shape measurement can be performed based on the results of the analysis processing of the imaging data. If the first corneal projection image is distorted as a result of the analysis processing of the first imaging data, the control unit 3 determines that corneal shape measurement cannot be performed. Conversely, if the first corneal projection image is not distorted as a result of the analysis processing of the first imaging data, the control unit 3 determines that corneal shape measurement can be performed.

[0044] The operation of the ophthalmic device 1, which has the configuration described above, will now be explained. Specifically, the operation when using the ophthalmic device 1 for corneal topography will be explained in conjunction with the flowchart of the operation of the ophthalmic device 1 shown in Figure 6.

[0045] First, the control unit 3 aligns the first measurement optical system 10 with respect to the eye E under examination. When the subject's face is supported by the face support unit 7, the control unit 3 illuminates the eye E under examination with the anterior segment illumination optical system 80 and acquires imaging data of the anterior segment of the eye E under examination by receiving the reflected light from the anterior segment illumination optical system at the eye E under examination with the anterior segment imaging optical system 50. The control unit 3 displays the acquired imaging data on the display unit 5. The control unit 3 processes the acquired imaging data and detects the alignment state of the first measurement optical system 10 (i.e., the measurement optical axis L1) in the XY direction relative to the corneal apex, based on the index (corneal reflection spot) projected onto the corneal Ec of the eye under examination by the internal pattern index illumination optical system 40. The control unit 3 also detects the alignment state in the Z direction based on the output of the light-receiving element 94 of the alignment index projection optical system 90. The control unit 3 then controls the drive of the drive unit 8 and moves the housing 2 in the XYZ directions so that the alignment state in the XYZ directions falls within a predetermined tolerance range. This completes the alignment of the ophthalmic device 1.

[0046] Once the alignment of the first measurement optical system 10 with respect to the eye E under examination is complete, the control unit 3 turns on the light source 31 of the first projection optical system of the pattern index projection optical system 30 and projects the first pattern index onto the cornea Ec of the eye under examination using invisible infrared light (step S1). The first corneal projection image is received by the anterior segment imaging optical system 50, and the control unit 3 acquires the first imaging data based on the data received from the anterior segment imaging optical system 50. After acquiring the first imaging data, the control unit 3 turns off the light source 31 of the first projection optical system. The control unit 3 analyzes the acquired imaging data and determines whether or not there is any distortion in the shape of the first corneal projection image of the first imaging data (step S2). The series of operations from the control to project the first pattern index onto the cornea Ec of the eye under examination to the process to determine whether or not there is any distortion in the shape of the first corneal projection image of the first imaging data is called "preliminary measurement". Once the preliminary measurement is complete, the control unit 3 determines whether or not the main measurement described later can be performed based on whether or not there is any distortion in the shape of the first corneal projection image of the first imaging data. If there is no distortion in the shape of the first corneal projection image of the first imaging data, the control unit 3 determines that the main measurement can be performed. If there is distortion in the shape of the first corneal projection image of the first imaging data, the control unit 3 determines that the main measurement cannot be performed.

[0047] If the control unit 3 determines that the main measurement cannot be performed, it refers to the number of notification outputs N (step S3), and if N < 1, it outputs a notification prompting the subject to blink (step S4). At the start of the flow, the number of notification outputs N is assumed to be N = 0. The notification output by the control unit 3 may be, for example, an audio prompting blinking output from the audio output unit 9. After outputting the notification, the control unit 3 adds 1 to the number of notification outputs N. Next, the control unit 3 performs a preliminary measurement again. If the control unit 3 determines again that the main measurement cannot be performed, since the number of notification outputs N = 1, the control unit 3 notifies the examiner that the measurement is impossible (step S5). If the control unit 3 determines that the main measurement can be performed, it proceeds to the next step.

[0048] If the control unit 3 determines that the measurement can be performed, it analyzes the first imaging data and determines whether or not there is vignetting in the first corneal projection image of the first imaging data (step S6). If the control unit 3 determines that there is vignetting as a result of the analysis, it outputs a notification instructing the examiner to open the eyelids of the eye being examined (step S7). When the examiner opens the eyelids of the examiner, vignetting caused by the eyelids no longer occurs. Therefore, the control unit 3 will no longer detect vignetting when it analyzes the first imaging data. If the control unit 3 determines that there is no vignetting, it starts performing the measurement. The control unit 3 turns on the light source 32 of the second projection optical system of the pattern index projection optical system 30 and projects the second pattern index onto the cornea Ec of the eye being examined with white light (step S8). The second corneal projection image is received by the anterior segment imaging optical system 50, and the control unit 3 acquires the second imaging data based on the data received from the anterior segment imaging optical system 50. The control unit 3 turns off the light source 32 of the second projection optical system after acquiring the second imaging data. The control unit 3 analyzes the acquired second imaging data and calculates the corneal shape based on the analysis. The series of operations from the control of projecting the second pattern index onto the cornea Ec of the eye under examination to the process of calculating the corneal shape based on the analysis of the shape of the second corneal projection image of the second imaging data is called the "main measurement". When the main measurement is completed, the control unit 3 outputs, for example, the calculated corneal shape data to the display unit 5 (step S9). The main measurement may also be started, for example, when the examiner opens the eyelids of the subject and the examiner operates the operation unit 6 to start the main measurement. The control unit 3 may also start the main measurement when it receives a signal to start the main measurement input by the examiner operating the operation unit 6.

[0049] In the above embodiment, the first pattern indicator was projected using a light source 31 that emits invisible light, and the second pattern indicator was projected using a light source 32 that emits visible light. However, the embodiment is not limited to this. For example, a light source capable of switching between invisible and visible light may be used. In such a case, for example, the first illumination optical system and the second illumination optical system may be the same optical system.

[0050] In this example, the notification that prompts the subject to blink when the control unit determines that the measurement cannot be performed is output as sound from the sound output unit 9, but this is not limited to this. For example, the control unit may display the notification on the display unit 5. Alternatively, the control unit may combine, for example, the sound output from the sound output unit 9 with the display output from the display unit 5.

[0051] In this embodiment, the control unit outputs a notification if N < 1 in order to limit the number of notifications to one, but this is not the only configuration. The number of notification outputs N can be any number. [Explanation of Symbols]

[0052] 1 Ophthalmology equipment 3. Control Unit 10 First measurement optical system 20 Pattern Indicator Projection Section 29 Placidring 30 Pattern Indicative Projection Optical System 50 Anterior segment imaging optical system

Claims

1. An ophthalmic device for measuring the corneal shape of the eye under examination, A first projection optical system that projects a first pattern indicator onto the cornea of ​​the eye under examination using invisible light, A second projection optical system that projects a second pattern indicator onto the cornea of ​​the eye under examination using visible light, An anterior segment imaging optical system that receives reflected light from the anterior segment of the eye under examination, It comprises a control unit and, The control unit analyzes and processes imaging data obtained by receiving the reflected light of the first pattern index projected onto the cornea of ​​the eye under examination with the first projection optical system using the anterior segment imaging optical system to determine whether or not corneal shape measurement of the eye under examination can be performed. If it is determined that corneal shape measurement is possible, the control unit projects a second pattern index onto the cornea of ​​the eye under examination with the second projection optical system, and analyzes and processes imaging data obtained by receiving the reflected light of the second pattern index with the anterior segment imaging optical system to measure the corneal shape.

2. An ophthalmic device according to claim 1, The control unit is an ophthalmic device that determines whether or not the procedure can be performed based on whether or not there is a disturbance in the shape of the first pattern index.

3. An ophthalmic device according to claim 1 or 2, The control unit is an ophthalmic device that, when it determines that corneal shape measurement is impossible, outputs a notification prompting the subject to blink.

4. An ophthalmic device according to any one of claims 1 to 3, An ophthalmic device in which the first pattern indicator and the second pattern indicator are identical in size and shape.

5. An ophthalmic device according to any one of claims 1 to 4, An ophthalmic device in which the invisible light is infrared light and the visible light is white light.

6. An ophthalmic device control program executed in an ophthalmic device for measuring the corneal shape of an eye under examination, A first pattern indicator projection step in which a first pattern indicator is projected onto the cornea of ​​the eye under examination using a first projection optical system that projects a first pattern indicator onto the cornea of ​​the eye under examination using invisible light, A first imaging data acquisition step involves receiving the reflected light from the anterior segment of the eye under examination, obtained by the anterior segment imaging optical system, from the projected light of the first pattern index projection step, and acquiring imaging data. A determination step involves analyzing the imaging data acquired in the first imaging data acquisition step to determine whether or not to perform corneal shape measurement of the eye under examination, If it is determined that corneal shape measurement is possible based on the determination step, a second pattern indicator projection step is performed, in which a second pattern indicator is projected onto the cornea of ​​the eye under examination using a second projection optical system that projects a second pattern indicator onto the cornea of ​​the eye under examination using visible light, A second imaging data acquisition step involves receiving the reflected light from the anterior segment of the eye under examination, projected by the second pattern index projection step, with the anterior segment imaging optical system to acquire imaging data, and A measurement step which involves analyzing the image data acquired in the image data acquisition step and measuring the corneal shape, An ophthalmic device control program that causes the ophthalmic device to execute the above.

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