Ophthalmic Instrument Alignment Using Corneal Light Reflections
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Solution Overview
Problem
Existing ophthalmic instruments, such as esthesiometers, face challenges in accurately aligning with the eye due to variations in corneal shape and position, leading to inaccurate measurements and discomfort for patients, with prior methods like two-camera systems being time-consuming and complex.
Innovation Solution
A method and apparatus using a collimated light beam and detectors to measure light reflections from the eye, allowing precise alignment of the ophthalmic instrument in three dimensions by adjusting its position based on reflected light intensity, eliminating the need for multiple cameras and reducing alignment time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a two-camera system is used to detect eye position and align the instrument, then alignment capability is provided, but the system complexity increases and spatial requirements expand
Solution Approach 1:
The patent extracts the alignment detection function from a complex two-camera system and implements it using a single camera combined with a light source. The light source projects a pattern onto the cornea, and the camera captures the reflected pattern to determine eye position and orientation, thereby achieving alignment capability with reduced system complexity
Solution Approach 2:
The patent introduces a light source as an intermediary element between the camera and the eye. The light source projects a visible pattern onto the cornea, which serves as a mediator that enables the camera to detect eye position and alignment status without requiring complex multi-camera setups
2Ease of operation
If a two-camera system is used to detect eye position, then alignment detection is enabled, but the minimum system size increases
Solution Approach 1:
The patent merges the functions of multiple cameras into a single camera system. By combining a light source that projects alignment patterns with a single camera that captures the reflected patterns, the system achieves the same alignment detection capability as a two-camera system but with reduced spatial footprint
3Measurement precision
If the patient remains still with one eye open during positioning, then alignment measurement is possible, but patient comfort deteriorates
Solution Approach 1:
The patent implements a real-time feedback system where the camera continuously monitors the eye position and the system automatically adjusts the instrument alignment based on the detected eye movements. This self-correcting mechanism maintains measurement precision without requiring the patient to remain perfectly still, thereby reducing patient discomfort
4Adaptability or versatility
If multiple instruments are positioned using the two-camera system, then comprehensive eye examination is enabled, but alignment time increases
Solution Approach 1:
The patent establishes a reference coordinate system based on the first instrument's alignment and uses this pre-established reference to rapidly position subsequent instruments. By performing the complex alignment calculation once during instrument setup and then using it as a reference for all subsequent instruments, the system enables comprehensive multi-instrument examination while minimizing alignment time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances alignment accuracy and efficiency, reduces patient discomfort, and simplifies the alignment process by continuous monitoring and real-time adjustments, enabling more precise corneal sensitivity measurements.
Implementation Method 1
directing a beam of light from the ophthalmic instrument to the eye; taking, at a plurality of locations around the beam, measurements of reflections of the light from the eye
Data Source
AI summary
A method of, and apparatus for, aligning an ophthalmic instrument relative to an eye is disclosed, and can include aligning an esthesiometer with a patient's eye. The method can include steps of: directing a beam of light from an ophthalmic instrument to an eye; taking, at a plurality of locations around the beam, measurements of reflections of the light from the eye; determining the position of the ophthalmic instrument relative to the eye from the measurements; and moving the ophthalmic instrument relative to the eye from the determined position to a desired position. The apparatus can include an aperture, a source of collimated light, a plurality of detectors, and a control unit. The control unit determines a position of the ophthalmic instrument relative to the eye and can move relative positions of the ophthalmic instrument and the eye from a determined position to a desired position.