Ophthalmic Scanning Pivot Point Control for Wide-Field OCT
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Solution Overview
Problem
Current ophthalmic imaging systems face challenges in achieving a wide field-of-view without incurring significant costs for optics and mechanics, and they require user intervention to stitch together multiple images, limiting flexibility and image quality.
Innovation Solution
The system moves relative to the eye while maintaining the optical scanning pivot point coincident with the patient's pupil center, allowing for automated scanning and stitching of images to cover large areas of the retina without apodization and refocusing, using a combination of translational and rotational adjustments and an independent pupil imaging device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of optics and opto-mechanical elements is enlarged to expand field-of-view, then field-of-view is increased, but device cost increases considerably
Solution Approach 1:
The patent employs dynamic motion of the imaging device relative to the eye, combining translational and rotational movements to scan wide areas of the retina. The device moves along a curved path with radius of curvature matching the eye's geometry, allowing extensive field coverage without requiring large static optical elements. This dynamic scanning approach replaces bulky fixed optics with a compact moving system.
Solution Approach 2:
The patent transitions from static 2D field-of-view expansion to dynamic 3D spatial scanning. By introducing temporal dimension through sequential imaging and automated stitching of multiple frames, the system achieves wide-field coverage equivalent to large optics but through motion in three-dimensional space rather than increased optical aperture size.
2Area of stationary object
If multiple fundus images are stitched together in post processing to expand field-of-view, then field-of-view is increased, but user intervention is required and image quality may be compromised
Solution Approach 1:
The patent incorporates an independent pupil imaging device (iris camera) that provides real-time feedback on pupil position and orientation. This feedback is used by automated control to dynamically adjust the imaging device's position and orientation, ensuring the optical scanning pivot point remains coincident with the pupil center throughout the scanning sequence. This closed-loop control enables seamless automated stitching without user intervention.
Solution Approach 2:
The system performs automated scanning and image stitching without requiring user operation. The control system automatically coordinates the motion of the imaging device, triggers image capture at appropriate positions, and stitches the sequence of images into a composite wide-field view, making the system self-sufficient and eliminating the need for manual image alignment.
3Area of stationary object
If the imaging device is moved relative to the eye to scan wide areas, then field-of-view is increased, but maintaining pivot point coincidence becomes difficult
Solution Approach 1:
The patent uses an independent pupil imaging device to continuously monitor pupil position and provide feedback to the control system. This real-time feedback enables dynamic adjustment of the imaging device's motion to maintain precise coincidence between the optical scanning pivot point and the pupil center throughout the scanning sequence, ensuring image quality across the entire field-of-view.
Solution Approach 2:
The patent dynamically adjusts motion parameters (position, orientation, speed) of the imaging device during scanning to maintain pivot point coincidence. The control system modifies these parameters in real-time based on feedback from the pupil imaging device, allowing the system to adapt to variations in eye position and pupil location while scanning wide areas.
Data Source
AI summary
Systems and methods for expanding the field-of-view ofophthalmic scanning devices are presented. An ophthalmic scanning device is designed such that the pivot point of the scanning optics is maintained at a fixed location in the pupil while the scanning optics are rotated about the eye to obtain imaging data over an increased field-of-view than can be achieved by the scanning optics alone. The rotation can be achieved using a singular rotational motion of the scanning optics about a rotational axes coincident with the scanning pivot point or can be achieved using a combination of rotational motion with a second motion either rotational or translational to maintain the scanning pivot point at the fixed location. Embodiments related to optical coherence tomography and scanning laser ophthalmoscopy are described.