Scanning type human eye peripheral aberration measuring system and method based on wavefront sensing

Abstract

The invention belongs to the technical field of eye vision optics, and relates to a scanning type human eye peripheral aberration measuring system and method based on wavefront sensing. The system comprises a measuring light path, an off-axis scanning structure, a full meridian scanning structure, an echo light beam restraining and folding lens group, a conjugate adjusting structure, a sighting mark module, an aligning and imaging module and a control and communication system. The off-axis scanning structure comprises a galvanometer and a linear displacement mechanism, and through the linkage of the position and the angle of the galvanometer, the incident main light enters the entrance pupil center of the detected eye at different off-axis angles; in the full meridian scanning structure, a rotating table drives a front structure to rotate around a system main shaft; echo beams enter a rear fixed light path through the center of the rotary table via the reflector. According to the system, full meridian, large off-axis angle and programmable path human eye peripheral aberration measurement can be realized under the condition that the head and eyeballs of a subject do not need to move, and the system has the advantages of compact structure, small additional aberration, high measurement precision and efficiency and the like.

Description

Technical Field

[0001] This invention belongs to the field of ophthalmic optical testing and vision optics technology, and in particular, it is a scanning method and system for measuring peripheral aberrations of the human eye based on wavefront sensing. Background Technology

[0002] Peripheral vision plays a crucial role in daily activities such as motion navigation, environmental monitoring, target search, and driving. For patients with macular degeneration or other foveal region damage, peripheral vision often becomes the primary source of visual information. Therefore, the measurement and correction of peripheral refractive status and aberrations have significant clinical importance and practical value.

[0003] Furthermore, the demand for peripheral aberration measurements is increasing in the fields of myopia development and prevention. Studies have shown that peripheral retinal imaging signals may participate in the process of emmetropization and affect axial growth; by introducing relative myopic or relative hyperopic defocus into the peripheral retina, the development trend of axial growth and refractive status can be altered. Compared with the central field of vision, the peripheral optical characteristics of the human eye are more complex. In addition to defocus, astigmatism and coma, and other non-rotationally symmetric higher-order aberrations, are more significant in the peripheral region. These aberrations not only affect peripheral image quality but also directly relate to the design and evaluation of peripheral optical interventions such as defocus lenses, orthokeratology lenses, and multifocal contact lenses. Therefore, obtaining peripheral aberration distribution data covering a larger field of vision and more meridional directions is of great significance for applications such as myopia prevention and control, refractive correction design evaluation and optimization, and the establishment of precise eye models.

[0004] However, compared to the rapidly growing research and clinical needs, the methods and equipment for measuring peripheral aberrations remain extremely inadequate. Traditional subjective peripheral refraction requires off-axis placement of the target and continuous changes in its position to sample aberrations at different off-axis angles. This method is difficult to perform due to its low peripheral visual resolution, lengthy process, and high sensitivity to fixation stability. While various objective methods (such as retinoscopy, dual-channel imaging, light reflex, and automated refraction) reduce the requirements for subjective cooperation, most still require the subject to change their gaze direction (eye rotation or head turn) to obtain results at different off-axis angles. This makes it difficult to perform rapid sampling of high-density, large-area retinal areas, limiting its application in large sample sizes or high-throughput clinical scenarios.

[0005] Wavefront sensing-based aberration measurements are widely used in central refractive estimation and aberration analysis due to their high accuracy and repeatability. However, existing commercial aberrometers are mainly designed for on-axis measurements. If used for peripheral measurements, the instrument usually needs to be modified, and it mainly relies on changing the angle of the human eye's line of sight to obtain aberration data at different off-axis angles, which limits the measurement efficiency and range.

[0006] Currently, there are also peripheral aberration measurement schemes that maintain the subject's line of sight by changing the direction of the measurement beam. These schemes can be broadly divided into two categories: one uses multiple lens groups combined with scanning galvanometers to achieve beam steering. Although this allows for multi-point measurements within a certain range, the system is complex, costly, and more prone to introducing additional aberrations as the scanning range expands; the other uses mechanical structures such as robotic arms, turntables, or pan-tilt units for scanning, but most are only applicable to a single meridian, have a small scanning range, and are complex and bulky. Some systems also lack optotype and accommodation modules, making it difficult to simultaneously handle fixation and refractive state control. More importantly, most existing peripheral aberration measurement devices are experimental research systems with poor usability, making them unsuitable for clinical environments. Some schemes currently only support testing with model eyes and cannot yet adapt to the dynamic characteristics of accommodation, pupillary changes, and eye movements in living human eyes.

[0007] Therefore, there is an urgent need for a new peripheral aberration measurement system and method that can achieve full meridian, large off-axis angle, and programmable path peripheral aberration measurement of the human eye while keeping the subject's line of sight basically fixed, and also take into account the compact system structure, automated control, and measurement accuracy and efficiency. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing methods and provide a scanning method and system for measuring peripheral aberrations of the human eye based on wavefront sensing. This method achieves large off-axis angle and programmable path scanning across the entire meridian without requiring the subject to rotate their eyes or head. Furthermore, it maintains the echo beam in accordance with predetermined spatial constraints under any meridian and off-axis angle measurement, thus taking into account the advantages of compact system structure, small additional system aberrations, high measurement accuracy, and high measurement efficiency.

[0009] The technical solution adopted by this invention to solve the technical problem is:

[0010] The first aspect of the present invention provides a wavefront sensing-based scanning peripheral aberration measurement system for the human eye, comprising a measurement optical path, an off-axis scanning structure, a full meridional scanning structure, an echo beam constraint and folding lens group, a conjugate adjustment structure, a target module, an alignment and imaging module, and a control and communication system.

[0011] The measurement optical path is used to introduce the measurement beam into the human eye and receive the light reflected from the retina. At least two lenses are provided in the measurement optical path to form a conjugate relationship between the measured pupil plane and the wavefront sensor WFS: a first lens L1 and a second lens L2. As one implementation, the focal lengths of the first lens L1 and the second lens L2 are respectively... , The distance between the two lenses is The pupil surface being measured is located in front of the first lens L1. At this location, the wavefront sensor is positioned behind the second lens L2. Place. and The corresponding conjugate constraint relationship is satisfied. The measurement light emitted by the light source is coupled into the measurement optical path through a beam splitter. The measurement light enters the eye being measured through the center of the entrance pupil, and the reflection from the retina of the eye forming an echo beam reaches the wavefront sensor along the measurement optical path to achieve wavefront measurement.

[0012] The off-axis scanning structure is positioned between the first lens L1 and the pupil plane being measured, and includes a galvanometer G and a first linear displacement mechanism LS1 that carries the galvanometer. When measuring central aberration, the galvanometer G is located at the center of the system, and the incident principal ray is aligned with the visual axis of the eye being measured by adjusting the galvanometer deflection angle. When measuring peripheral aberration, the galvanometer G deviates from the visual axis along the first linear displacement mechanism LS1, and the deflection angle is changed so that the reflected incident principal ray passes through a designated point in the pupil being measured, preferably the entrance pupil center, and forms a set off-axis angle with the visual axis, thereby achieving off-axis measurement. The system pre-establishes a mapping relationship or lookup table between the off-axis angle, the galvanometer angle, and the displacement of the first linear displacement mechanism LS1 to ensure that the optical path meets predetermined spatial constraints during off-axis scanning.

[0013] The full meridional scanning structure includes a rotating stage RS, whose axis of rotation is adjustable and coaxial with the visual axis of the eye being measured, and remains coaxial during measurement. A first linear displacement mechanism LS1, a galvanometer G, and some reflectors are mounted on the RS and rotate with it, thereby expanding the single half-meridian scan into a full meridional scan. The side of the rotating stage RS closest to the human eye is defined as the front section, which rotates synchronously with the rotating stage RS; the side of the rotating stage furthest from the human eye is defined as the rear section, which remains fixed. The front section includes the galvanometer G, the first linear displacement mechanism LS1, a reflector group (including at least a first reflector M1, a second reflector M2, and a third reflector M3), and an auxiliary optical path; the rear section includes a second lens L2, a wavefront sensor WFS, and a reflector group MS for folding the optical path, etc.

[0014] The echo beam constraint and folding mirror assembly includes at least a first reflecting mirror M1, a second reflecting mirror M2, and a third reflecting mirror M3 disposed at the front. The first reflecting mirror M1 is arranged on the extension line of the galvanometer's motion trajectory, and in conjunction with the control of the galvanometer's angle, the optical path direction between the galvanometer G and the first reflecting mirror M1 is always parallel to the galvanometer's displacement trajectory, thereby ensuring that the measurement light incident on the human eye and the echo light returning from the human eye satisfy a predetermined path constraint between the galvanometer G and the first reflecting mirror M1. The second reflecting mirror M2 and the third reflecting mirror M3 guide the beam to the center of the rotary table's rotation axis and into the rear fixed optical path, ensuring that the echo beam can pass through the central region of the rotary table and enter the rear section under different meridional angles and different off-axis angles.

[0015] The conjugate adjustment structure is used to adjust the distance between the wavefront sensor WFS and the second lens L2. Preferably, the wavefront sensor is mounted on the second linear displacement mechanism LS2, or forms an adjustable optical path length with the second lens L2, so that when the effective optical path changes due to different off-axis scanning angles, the optical path between the wavefront sensor and the second lens L2 can be adjusted to the corresponding length to maintain the conjugate relationship between the measured pupil surface and the wavefront sensor WFS.

[0016] The target module is located at the foremost end of the measurement optical path and is coupled to the central measurement optical path via a beam splitter. The target module includes a Badal system and an electronic display screen, capable of displaying any fixation pattern and adjusting diopter for subject fixation and refractive state adjustment. The beam splitter can be a beam splitter or a dichroic beam splitter.

[0017] The alignment and imaging module is used to observe the human eye, assist the alignment device, and the eye being tested. Its main component is camera C. Camera C can be coupled to the measurement optical path or the target module through a beam splitter, or it can be independently placed near the pupil of the eye being tested.

[0018] The control and communication system is jointly controlled by a host computer and a front-end embedded controller. Each motion mechanism is preferably driven by a motor. The host computer runs graphical control software for communicating with each drive / controller, sensor, and front-end embedded controller; setting scan paths and sampling strategies; performing measurements; processing data; and displaying and recording measurement results. The front-end embedded controller controls the front-end galvanometer G, the first linear displacement mechanism LS1, the light source, illumination, and camera, and communicates with the host computer via a slip ring located on the rotary table.

[0019] A second aspect of the present invention provides a scanning method for measuring peripheral aberrations of the human eye based on the above-described system, comprising:

[0020] S1. Establish geometric mapping relationships: Establish the correspondence between the displacement of the first displacement mechanism, the deflection angle of the galvanometer G, the displacement of the second linear displacement mechanism LS2, and the off-axis angle of the incident principal ray; establish the correspondence between the meridional angle and the angle of the rotary table; a lookup table or function model can be formed.

[0021] S2. System alignment: Use the camera to align the center of the human eye's pupil with the system's pupil surface and the system's main axis. Preferably, the intersection of the system's pupil surface and the system's main axis is a fixed scanning point. Move the entire device using a three-axis platform to make the fixed scanning point coincide with the center of the human eye's pupil.

[0022] S3. Fixing the line of sight: Using a single optotype to keep the subject's line of sight fixed and adjust the refractive state of the eye being tested.

[0023] S4. Center measurement: Place the galvanometer at the visual axis position and set the galvanometer angle so that the incident principal ray coincides with the visual axis, collect the retinal echo and obtain the center wavefront by the wavefront sensor.

[0024] S5. Peripheral Measurement: The galvanometer is controlled to move along the first linear displacement mechanism according to the preset scanning path, and the deflection angle is changed synchronously. This ensures that the incident principal ray passes through the center of the entrance pupil and forms a target off-axis angle with the visual axis. Simultaneously, the rotary table is controlled to rotate to the set meridional angle, and the wavefront sensor position is adjusted to maintain a conjugate relationship. After the system reaches the target point, the retinal echo is acquired, and the peripheral wavefront is obtained by the wavefront sensor. By coordinating different off-axis angles and meridions, programmable trajectory scanning (isomeridians, iso-off-axis angles, spirals, etc.) is achieved.

[0025] S6. Wavefront Reconstruction and Output: The acquired wavefront data is reconstructed and output to obtain the aberration distribution of the tested eye at different meridian angles and off-axis angles.

[0026] The present invention adopts the above technical solution and has the following beneficial effects compared with the prior art:

[0027] 1. This invention can complete peripheral aberration measurement without requiring the subject to turn their head or eyes, requiring low cooperation and being user-friendly.

[0028] 2. This invention can achieve measurement of the entire meridian (360°) and large off-axis angle (e.g., ≥45°), with programmable scanning path and high angular resolution.

[0029] 3. The overall optomechanical structure of this invention is compact, low in cost, easy to implement and maintain in engineering, and has fewer additional system aberrations and optical path drift, resulting in high measurement accuracy.

[0030] 4. This invention combines motor drive and embedded control to achieve high-speed scanning and automated measurement, which is highly efficient and fast. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a wavefront sensing-based scanning peripheral aberration measurement system for the human eye, and an optical path diagram for measuring central aberration.

[0032] Figure 2 This is the optical path diagram for measuring peripheral aberrations.

[0033] Figure 3 This is a schematic diagram of the geometric relationship of the system's principal axes.

[0034] Figure 4 This is the optical path diagram for the camera and target module.

[0035] Figure 5 This is a schematic diagram of the electromechanical, control, and interactive system structure.

[0036] Figure 6 This is a flowchart of a scanning method for measuring peripheral aberrations of the human eye based on wavefront sensing. Detailed implementation method:

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0038] Example 1

[0039] like Figures 1 to 5 As shown, a scanning peripheral aberration measurement system for the human eye based on wavefront sensing is provided. Figure 1 The red line segment with arrows represents the path of the measurement light emitted by the system's light source into the system; the orange line segment represents the two-way optical path through which both the light incident on the human eye and the echo beam reflected from the retina pass; and the blue line segment with arrows represents the optical path through which the echo beam enters the wavefront sensor WFS. Figure 1 The measurement light emitted from the system light source NIR passes sequentially through the aperture S and the first beam splitter B1 into the measurement optical path. The system light source NIR is preferably a near-infrared semiconductor laser with a wavelength of 852 nm. The aperture S is used to limit the aperture of the light entering the system, preferably with a diameter of 1 to 2 mm. The first beam splitter B1 couples the measurement light into the measurement optical path. To reduce the influence of stray light and corneal reflection, the first beam splitter B1 is preferably a polarizing beam splitter. After being reflected by the galvanometer G, the incident light passes through the second beam splitter B2 and enters the center of the entrance pupil of the tested eye. After reaching the retina, it is reflected by the retina to form an echo beam. The echo beam exits from the entrance pupil of the tested eye and returns to the measurement optical path, where it is separated from the incident light by the galvanometer G and the first beam splitter B1, and then enters the subsequent wavefront detection optical path.

[0040] In the central aberration measurement state, the position and angle of the galvanometer G ensure that the two-way optical path between the galvanometer G and the tested eye coincides with the visual axis of the tested eye, thereby realizing the central aberration measurement. In this embodiment, the first beam splitter B1 simultaneously realizes the optical path reversal function of the aforementioned first reflector M1. After leaving the first beam splitter B1, the echo beam passes sequentially through the first lens L1, the second reflector M2, and the third reflector M3, and is guided through the central hole of the rotary stage RS, entering the rear part of the system from the front. A reflector group MS can be set in the rear part to fold the optical path and compress the system volume. After passing through the second lens L2, the echo beam reaches the wavefront sensor WFS, which is preferably a Hartmann-Shack type wavefront sensor.

[0041] Preferably, a camera C is set at the front of the eye being tested to observe the state of the human eye and assist in alignment, and a visual target F is set for the subject to fixate and adjust the refractive state.

[0042] The focal lengths of the first lens L1 and the second lens L2 are respectively and The preferred optical path length between the two lenses is Preferably, the first lens L1 is positioned at the front of the system between the first beam splitter B1 and the second reflector M2 to compress the optical path length using a shorter focal length lens; the second lens L2 and the wavefront sensor WFS are positioned at the rear of the system to reduce the complexity of the front section. The length of the optical path between the entrance pupil of the tested eye and the first lens L1 (entrance pupil of the tested eye—second beam splitter B2—galvanometer G—first beam splitter B1—first lens L1) is... The optical path length between the wavefront sensor WFS and the second lens L2 .in and Used to describe the conjugate position offset from the focal plane, the two satisfy a conjugate constraint relationship to keep the entrance pupil plane of the tested eye conjugate with the wavefront sensor WFS:

[0043]

[0044] The galvanometer G and the wavefront sensor WFS are respectively mounted on the first linear displacement mechanism LS1 and the second linear displacement mechanism LS2. Figure 1 Both the galvanometer G and the wavefront sensor WFS are positioned when measuring central aberration. When measuring peripheral aberration, the galvanometer G moves along the first linear displacement mechanism LS1 to the position of galvanometer G', and rotates to the corresponding angle so that the incident principal ray always passes through the center of the entrance pupil of the eye being measured and forms a set off-axis angle with the visual axis. The change in the position of the galvanometer G will cause the optical path from the measured pupil plane to the first lens L1 and the corresponding... The change. To maintain the conjugate relationship, the wavefront sensor WFS moves along the second linear displacement mechanism LS2 to the position of the wavefront sensor WFS', so that... and Maintain conjugate constraints.

[0045] like Figure 2 As shown, when measuring peripheral aberrations, the incident light rays to the eye being tested and the echo beam returning from the retina both form a predetermined angle with the visual axis of the eye being tested, namely the off-axis angle. By controlling the position and angle of the galvanometer G, the light rays incident on the human eye always pass through a single point, which is the entrance pupil center of the system. During measurement, the entrance pupil center of the tested eye coincides with the entrance pupil center of the system. Figure 2The black dashed line represents the straight line containing the incident point trajectory of light rays on the surface of the galvanometer G at different off-axis angles, parallel to the direction of the galvanometer's motion. By arranging the first beam splitter B1 in an appropriate position, the incident point trajectory of the galvanometer coincides with the incident point trajectory of the first beam splitter B1 at different off-axis angles. Thus, when measuring different off-axis angles, most components between the first beam splitter B1 and the rotating stage RS, and between the first beam splitter B1 and the system light source NIR, can remain relatively fixed, reducing system complexity.

[0046] like Figure 3 As shown, to achieve full meridional scanning, the components at the front of the system are mounted on the rotary stage RS and rotate with it, while the rear remains fixed. The axis of rotation of the rotary stage RS is defined as the system's main axis. The plane containing the front two-way optical path and the echo beam constitutes the system's meridional plane, which rotates with the rotary stage RS around the system's main axis. Measuring a certain angle... When dealing with aberrations along a meridian, simply align the meridian plane with the meridian being measured. After aligning the system's main axis with the visual axis of the eye being measured, the position and angle of the galvanometer G can remain constant when scanning different meridians at the same off-axis angle, thus ensuring that the incident light always passes through the center of the entrance pupil of the eye being measured. Through the combined arrangement of the first beam splitter B1, the second reflector M2, and the third reflector M3, the echo beam reflected by the third reflector M3 is ensured to always pass along the system's main axis, through the center of the rotary stage RS, and enter the rear fixed optical path when the rotary stage RS is at different angular positions. Therefore, the system's main axis, the connecting optical path between the front and rear sections, the visual axis of the eye being measured, and the optical path between the galvanometer G and the eye being measured during center measurement can all be on the same straight line.

[0047] like Figure 4 As shown, camera C and target F are coupled to the front optical path via the second beam splitter B2 and the third beam splitter B3. The red arrowed line segment represents the camera module optical path, and the blue arrowed line segment represents the target module optical path. Preferably, camera C operates in the near-infrared band; the second beam splitter B2 is a partial long-pass dichroic beam splitter, and the third beam splitter B3 is a short-pass dichroic beam splitter. Under the illumination of the infrared LED, the light reflected from the human eye and surrounding area enters camera C after being reflected by the second beam splitter B2 and the third beam splitter B3. The control program identifies the center of the entrance pupil of the tested eye based on the iris and pupil images, and determines the distance between the system and the tested eye, thereby controlling the three-axis displacement stage supporting the entire measurement system to achieve alignment. Target F uses the Badal system, transmitted through the third beam splitter B3 and reflected by the second beam splitter B2 into the tested eye, providing a fixation target with adjustable refractive power and a basically fixed visual angle, allowing the subject to maintain stable line of sight and adjust refractive state during measurement.

[0048] like Figure 5As shown, this embodiment employs a distributed control architecture of a host computer and a front-end embedded controller, combined with multi-bus communication and slip rings to achieve power supply and data transmission for the front-end rotating mechanism, thereby completing automated control and interaction for functions such as rotational scanning, off-axis scanning, wavefront acquisition, fixation, refractive adjustment, and alignment. The system uses a host computer (PC) for communication with various drives / controllers and sensors, measurement data processing and recording, scan path planning, control algorithm execution, graphical user interface (GUI) display, and parameter configuration. The operator sets the measurement mode, step parameters, and sampling frequency through the GUI. Simultaneously, the host computer acquires and processes the data collected by the wavefront sensor (WFS), outputting low-order refractive parameters and high-order aberration coefficients, and providing visualization and storage.

[0049] The fixed rear section of the system includes a wavefront sensor (WFS) and its associated motion positioning mechanism. Preferably, the host computer communicates with the corresponding drive / controller of the second linear displacement mechanism (LS2), the rotary table (RS), and the three-axis displacement stage via a Modbus bus to achieve positioning and synchronization control. Specifically, the second linear displacement mechanism (LS2) is used to move the wavefront sensor (WFS) and maintain its conjugate relationship; the rotary table (RS) is used to set the meridional angle or perform rotational scanning; and the three-axis displacement stage is used for overall alignment with the human eye, including adjustments in the forward / backward, up / down, and left / right directions.

[0050] An embedded controller is installed in the front rotating section of the system. This embedded controller is used to realize real-time control, status monitoring, and data exchange with the host computer for the front actuators and electronic components. Preferably, the front embedded controller can be connected to multiple drivers or controllers via a CAN bus to drive the first linear displacement mechanism LS1, the galvanometer G, and the target F. The first linear displacement mechanism LS1 is used to drive the galvanometer G to translate for off-axis scanning; the galvanometer G is used to control the direction of the incident main light beam; the Badal adjustment part in the target F can be focused or adjusted by a motor or other controllable actuator, and the pattern is displayed on the screen.

[0051] To reduce the number of cables during front rotation and improve communication reliability, a miniature switch can be installed at the front to connect camera C and the front embedded controller to an Ethernet network. This Ethernet signal is connected to a fixed host computer at the rear via a slip ring at the RS of the rotary table, ensuring continuous data transmission during rotation. Camera C is used to acquire pupil images to assist in alignment and fixation monitoring, and these images can be displayed in real time in the host computer's GUI. The front embedded controller controls the on / off state of the NIR laser and infrared LED system light sources via semiconductor switches, achieving timing management and safety interlocking of the measurement and illumination lights. Preferably, the measurement light source is only allowed to be turned on when each motion axis reaches the target position and stabilizes, the alignment meets the preset threshold, and the system is in a state where data acquisition is permitted. In the event of data acquisition completion or an emergency stop, communication abnormality, out-of-range position, misalignment, or other abnormalities, the system can immediately shut down the measurement light source.

[0052] In a typical measurement process, the host computer generates a target sequence according to the user-defined scanning strategy and issues control commands to the front and rear control modules: the rotary stage RS reaches or continuously passes through the target meridional angle, the second linear displacement mechanism LS2 performs conjugate compensation displacement, and the first linear displacement mechanism LS1 and the galvanometer G are linked according to a lookup table to ensure that the incident principal ray passes through the fixed scanning point defined by the system at different off-axis angles and forms the target off-axis angle; when the system determines that the conditions of position, stability, and allowable emission are met, the system light source NIR laser is turned on and the wavefront sensor WFS is triggered to acquire data; after acquisition, the laser is turned off and the measurement proceeds to the next measurement point. Thus, automated, rapid, and programmable scanning measurements can be achieved across the entire meridional range and large off-axis angles without requiring the subject to rotate their head or eyes.

[0053] Example 2

[0054] like Figure 6 As shown, a scanning method for measuring peripheral aberrations of the human eye based on wavefront sensing is provided. This method utilizes the system described in Example 1 to measure aberrations of the tested eye at arbitrary meridional and off-axis angles. This method eliminates the need for the subject to rotate their head or eyes. By controlling components such as the rotating stage RS, galvanometer G, first linear displacement mechanism LS1, second linear displacement mechanism LS2, optotype F, and wavefront sensor WFS, it achieves programmable scanning across the entire meridional range and a large off-axis angle, and outputs the peripheral refractive state and higher-order aberration distribution.

[0055] After the system is built and calibrated, two types of mapping relationships are pre-established and stored in the host computer in the form of lookup tables or function models: one type is a mapping of "off-axis angle - galvanometer angle - displacement of the first linear displacement mechanism LS1", used to determine the translation position and deflection angle of the galvanometer G under different off-axis angles; the other type is a mapping of "off-axis angle or galvanometer position - conjugate compensation displacement of the second linear displacement mechanism LS2", used to determine the conjugate compensation position of the wavefront sensor WFS under different off-axis measurement states. Before measurement, system initialization and parameter settings must be completed first, specifically including:

[0056] Before measurement begins, system initialization and parameter settings are performed. The host computer starts the measurement software and establishes communication connections with each controller, embedded controller, and sensor. Zero-homing operations are performed on the rotary table RS, the first linear displacement mechanism LS1, the second linear displacement mechanism LS2, and the three-axis displacement stage, and the current position and limit status of each axis are read. Measurement parameters are set, including scanning mode, off-axis angle range and step, meridian angle range and step, number of single-point acquisitions, and sampling frequency. Pre-stored historical parameters or recommended parameters can also be called. Then, methods such as fixed meridian scanning of the off-axis angle, fixed off-axis angle scanning of the meridian or helix, and custom curve synchronous scanning are selected, and corresponding scanning sequences are generated, where the meridian angle is denoted as... The off-axis angle is denoted as .

[0057] After system initialization, the subject placed their head on the system's forehead support. Camera C and the infrared LED were then activated to acquire eye images for alignment and status monitoring.

[0058] The alignment process consists of two steps: First, based on the camera image, the pupil boundary and entrance pupil center position are identified to obtain the relative deviation between the entrance pupil center of the tested eye and the system's main axis. The three-axis stage is then controlled to move the entire measurement system vertically and horizontally to align the system's main axis with the entrance pupil center of the tested eye. Second, based on the eye image sharpness or other distance evaluation indicators, the three-axis stage is controlled to move the system forward and backward to align the system's entrance pupil surface with the entrance pupil surface of the tested eye.

[0059] After alignment, the visual target F is activated to provide the subject with a fixation target. The formal measurement then begins, preferably with central aberration measurement followed by peripheral aberration measurement. For central aberration measurement, the rotary stage RS is first moved to the reference meridian angle, preferably 0°. Then, the galvanometer G is positioned at the center measurement location, and its angle is set so that the incident principal ray coincides with the visual axis, and the off-axis angle is 0°. Next, the second linear displacement mechanism LS2 is controlled to adjust the wavefront sensor WFS to the corresponding conjugate position. Subsequently, the infrared LED is turned off, and the system light source NIR laser is activated to collect the echo beam formed by the reflected light from the retina. The wavefront sensor WFS then acquires the central wavefront data. After acquisition, the measurement light source is turned off, and the infrared LED is turned back on.

[0060] After completing the central aberration measurement, peripheral aberration measurements are performed on each measurement point according to the preset scanning sequence. For each target point, the rotary stage RS is first controlled to rotate to the target meridian angle. The rotation can be performed in a stepping or continuous rotation manner; then, the first linear displacement mechanism LS1 is controlled to move the galvanometer G to the target off-axis angle. The corresponding position is determined, and the deflection angle of the galvanometer G is set simultaneously so that the incident principal ray passes through the center of the entrance pupil of the tested eye and forms a set off-axis angle with the visual axis of the tested eye. Next, based on the current off-axis angle The conjugate compensation table is invoked at the position of the galvanometer G, driving the second linear displacement mechanism LS2 to move the wavefront sensor WFS to the corresponding position, so as to maintain the conjugate relationship between the measured pupil surface and the wavefront sensor WFS.

[0061] Once the host computer determines that all motion axes are in position and stable, it turns off the infrared LEDs and turns on the system's NIR laser light source. It then collects the echo wavefront data of the corresponding measurement point and records the meridional angle, off-axis angle, and system status information for that point. If multiple sampling is preset, the data is repeatedly collected and saved at the same measurement point. After collection, the system's NIR laser light source is turned off, the infrared LEDs are turned on again, and the process moves to the next measurement point until the preset scanning range is completed.

[0062] In this embodiment, the scanning strategy can be flexibly set according to actual applications, including but not limited to: scanning off-axis angles with fixed different meridian angles; scanning meridian angles with fixed different off-axis angles; and adjusting the meridian angle... off-axis angle Synchronous changes form spirals or arbitrary custom trajectories to improve field-of-view coverage efficiency or meet different application requirements.

[0063] During the measurement process, if any abnormalities occur, such as emergency stop triggering, communication failure, subject exiting the measurement position, fixation loss, or alignment deviation exceeding the threshold, the system can immediately shut down the system light source NIR laser and stop all motion mechanisms, while recording the cause of the abnormality; if the situation is recoverable, the system can continue the measurement after realignment.

[0064] After the measurement is completed, the measurement program in the host computer performs wavefront reconstruction on the wavefront sensor WFS data collected at each measurement point to obtain the corresponding echo wavefront. It then further performs aberration decomposition and parameter calculation, outputting low-order refractive parameters, axis information, and high-order aberration parameters and statistics. Finally, based on the meridian angle... and off-axis angle Establish a dataset of peripheral aberration distributions for the tested eye, and visualize and store it, for example, by generating two-dimensional or three-dimensional distribution maps, tables, and report files. If binocular measurements are required, after completing the measurement of one eye, align the other eye and repeat the above measurement steps.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A scanning peripheral aberration measurement system for the human eye based on wavefront sensing, characterized in that, include: The measurement optical path is used to introduce the measurement beam into the eye under test and receive the retinal reflected echo beam returned by the eye under test. A wavefront sensor (WFS) is provided in the measurement optical path. An off-axis scanning structure is disposed between the eye under test and the rear wavefront detection optical path. It includes a galvanometer G and a first linear displacement mechanism LS1 that carries the galvanometer G. The first linear displacement mechanism LS1 is used to drive the galvanometer G to move along a predetermined direction. The galvanometer G is used to change the direction of the incident principal ray so that when measuring central aberration, the incident principal ray coincides with the visual axis of the eye under test, and when measuring peripheral aberration, the incident principal ray passes through the entrance pupil center of the eye under test and forms a set off-axis angle with the visual axis. The full meridional scanning structure includes a rotating stage RS, the axis of rotation of the rotating stage RS is coaxial with the visual axis of the eye being measured, the first linear displacement mechanism LS1 and the galvanometer G are mounted on the front of the rotating stage RS and rotate with the rotating stage RS to achieve scanning in different meridional directions; The echo beam constraint and folding mirror group is used to guide the echo beam to the central region of the rotary stage RS, and to make the echo beam enter the fixed optical path located at the rear of the rotary stage RS at a fixed position and angle before reaching the wavefront sensor WFS. A conjugate adjustment structure is used to maintain the conjugate relationship between the measured pupil surface and the wavefront sensor WFS under different off-axis angle measurement states; The control and communication system consists of a host computer and a front-end embedded controller, and is used to interact with the operator, plan scanning tasks, control the measurement process and data processing, display and record data.

2. The system according to claim 1, characterized in that: It also includes a target module, which is coupled to the measurement optical path through a beam splitter to provide a fixation target to the eye being tested, so as to keep the subject's line of sight stable and adjust the refractive state of the eye being tested.

3. The system according to claim 1 or 2, characterized in that: It also includes an alignment and imaging module, which is used to acquire eye images and control the movement of the displacement platform carrying the system based on image feedback so that the eye under test is in a set alignment position. The alignment and imaging module includes a camera C, which is either coupled to the measurement optical path or the target module through a beam splitter or is independently set near the pupil of the eye under test to acquire eye images, assist in observing the state of the eye under test and complete the alignment between the system and the eye under test.

4. The system according to claim 1 or 2, characterized in that: The measurement optical path also includes a conjugate optical system for transmitting the wavefront. The conjugate optical system includes at least a first lens L1 and a second lens L2. The first lens L1 is disposed in the rotating structure at the front of the system, and the second lens L2 is disposed in the fixed optical path at the rear of the system. Both the first lens L1 and the second lens L2 are composed of a combination of multiple lenses or a single lens.

5. The system according to claim 1 or 2, characterized in that: The conjugate adjustment structure includes a second linear displacement mechanism LS2, on which the wavefront sensor WFS is mounted. The second linear displacement mechanism LS2 is used to adjust the relative position between the wavefront sensor WFS and the second lens L2 to maintain the conjugate relationship between the measured pupil surface and the wavefront sensor WFS under different off-axis angle measurement states.

6. The system according to claim 1 or 2, characterized in that: The echo beam constraint and folding mirror assembly includes a first reflector M1, a second reflector M2, and a third reflector M3; the first reflector M1 is either a first beam splitter B1 or a separate first reflector M1, and is located at the extension line of the galvanometer's motion trajectory; the second reflector M2 and the third reflector M3 are used to connect the optical path between the first reflector M1 and the rotary stage RS, and to ensure that the echo beam always passes through the center of the rotary stage RS.

7. A wavefront sensing-based scanning method for measuring peripheral aberrations of the human eye according to any one of claims 1-6, characterized in that, Includes the following steps: S1, establish geometric mapping relationships, establish the correspondence between off-axis angle, galvanometer G deflection angle and displacement of first linear displacement mechanism LS1, and the correspondence between meridional angle and rotary table RS angle; S2, System alignment: The alignment and imaging module acquires images of the eye being tested, identifies the spatial position of the entrance pupil center of the eye being tested based on the images, and controls the movement of the displacement platform carrying the system to align the main axis of the system with the entrance pupil center of the eye being tested and align the entrance pupil surface of the system with the entrance pupil surface of the eye being tested. S3, fix the line of sight. The optotype module provides the subject with a fixation target, so that the subject can keep the line of sight fixed during the measurement and adjust the refractive state of the eye being tested. S4, Measure the central aberration. The control and communication system adjusts the measurement system to the central measurement optical path and collects the central wavefront data. S5, Measure peripheral aberrations. The control and communication system adjusts the peripheral measurement optical path of the measurement system to the target according to the preset scanning path, so that the incident main ray passes through the center of the entrance pupil of the eye being measured and forms an off-axis angle with the visual axis at the meridional angle of the target, and collects peripheral wavefront data at the corresponding point. S6, Reconstruct and Output Wavefront: Reconstruct and calculate the wavefront data of each measurement point, and output the aberration distribution of the tested eye under different meridian angles and off-axis angles.

8. The method according to claim 7, characterized in that: In step S1, the geometric mapping relationship also includes the correspondence between the off-axis angle or the position of the galvanometer G and the compensation displacement of the second linear displacement mechanism LS2, and the correspondence is stored in the form of a lookup table or a function model.

9. The method according to claim 7, characterized in that: In step S4, the central measurement optical path is the optical path when the rotary stage RS is at the reference meridian angle position, the galvanometer G is at the central measurement position and the deflection angle makes the incident principal ray coincide with the visual axis of the eye being measured, and the wavefront sensor WFS is adjusted to the corresponding conjugate position by the second linear displacement mechanism LS2.

10. The method according to claim 8 or 9, characterized in that: In step S5, the peripheral measurement optical route is achieved through the combined movement of the first linear displacement mechanism LS1, the galvanometer G, the second linear displacement mechanism LS2, and the rotary stage RS. The first linear displacement mechanism LS1 moves the galvanometer G, which simultaneously changes its deflection angle, so that the incident principal ray passes through the center of the pupil of the tested eye and forms a target off-axis angle with the visual axis of the tested eye. The second linear displacement mechanism LS2 adjusts the position of the wavefront sensor WFS to maintain the conjugate relationship between the tested pupil surface and the wavefront sensor WFS. The rotary stage RS rotates to the set meridional angle. The displacement and rotation angle are determined by calling the geometric mapping relationship described in step S1. In step S5, the preset scanning path can be programmably defined, including any of the following: scanning the off-axis angle with a fixed meridian angle, scanning the meridian angle with a fixed off-axis angle, and a spiral or custom trajectory that makes the meridian angle and the off-axis angle change synchronously.

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