Dual-Plate Michelson Interferometer for Fast Ocular Axial Length
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Solution Overview
Problem
Existing Michelson interferometer systems for measuring ocular axial length face challenges in accurately measuring eyes with varying sizes without manual adjustments and high-frequency oscillations, leading to potential errors due to patient movement and complex setup requirements.
Innovation Solution
A Michelson interferometer with a reflecting arrangement featuring two fixed, parallel reflecting surfaces that maintain a constant distance during translation, utilizing a motorized guide system to achieve precise measurement in a single translation run, reducing scanning time and minimizing the risk of patient movement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reflecting plate is used in the Michelson interferometer, then the device structure is simple, but the scanning time is too long and patient movement causes measurement errors
Solution Approach 1:
The single reflecting plate is segmented into two parallel reflecting plates (first and second reflecting surfaces) separated by a fixed distance. This segmentation allows the interferometer to complete the axial length measurement in a single translation run, as the two surfaces generate interference peaks at different positions along the translation path, thereby reducing scanning time and minimizing patient movement effects.
2Adaptability or versatility
If the distance between reflecting surfaces is adjustable, then the device can adapt to different eye sizes, but the device complexity and manual adjustment requirements increase
Solution Approach 1:
The distance between the two reflecting surfaces is set to a fixed parameter value that corresponds to the typical axial length range of human eyes. This fixed parameter eliminates the need for manual adjustment mechanisms while maintaining adaptability to different eye sizes through the optical interference measurement principle, which can accurately measure various axial lengths within the designed range.
3Productivity
If high-frequency oscillations are applied during measurement, then measurement speed increases, but measurement precision decreases due to patient movement
Solution Approach 1:
The interferometer is positioned and focused on the patient's eye before the translation measurement begins. This preliminary positioning ensures that the measurement can be completed in a single continuous translation run without requiring high-frequency oscillations or repeated adjustments, thereby maintaining both measurement speed and precision by minimizing the total measurement time and patient movement effects.
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
The solution allows for rapid, precise measurement of ocular axial length with reduced scanning time and minimized errors, eliminating the need for high-frequency oscillations and manual adjustments, while maintaining accuracy across varying eye sizes.
Implementation Method 1
the two waves reflected (the one of the external surface of the cornea and the one of the plate) overlap in constructive interference, generating a maximum of signal
Implementation Method 2
Both the ocular surfaces and the plate reflect back certain quantities of radiation that, through the two collimators, re-enter the optical fibers
Data Source
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AI summary
The present invention concerns a Michelson-type interferometer (1) for measuring the intraocular axial length (AL) comprising: an arrangement (7) able to move apart and come near with respect to an emitting light source (5), said arrangement (7) comprising at least a first (8) and second (9) at least partially reflecting surface arranged at a pre-determined mutual distance (d); a motorized driving system (500) to command the movement of the reflecting arrangement (7); wherein said motorized driving system (500) is controlled in such a way that the scanning is completed in a single translation stroke in a direction starting from an initial position in which the first surface (8) generates the first interference peak at the beginning of the translation and with such a fixed distance (d) between the plates that afterwards during said translation the second plate (9) generates the second interference peak.