Adaptive Optics Asymmetric Double-Pass Ocular PSF Measurement
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Solution Overview
Problem
Current methods for measuring the ocular point spread function, such as Shack-Hartmann wavefront sensors and double-pass techniques, are limited in capturing high spatial frequency wavefronts and lose phase information, which is crucial for assessing optical quality, especially in conditions like dry eye and cataracts.
Innovation Solution
An adaptive optics asymmetric double-pass technique is employed to form a tiny point source on the retina, allowing for the measurement of wavefront aberrations with a large pupil, which corrects aberrations in the first pass and captures the entire optical transfer function, including phase information, in the second pass, enabling comprehensive assessment of the ocular point spread function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Shack-Hartmann wavefront sensor is used to measure ocular wavefront aberration, then wavefront measurement is achieved, but lateral resolution is limited by finite sampling and lenslet size, preventing accurate measurement of very high spatial frequency wavefronts
Solution Approach 1:
The patent introduces an adaptive optics system with a deformable mirror as an intermediary between the light source and the ocular media. This deformable mirror acts as a controllable wavefront modulator that can dynamically adjust its surface shape to compensate for ocular aberrations and enable high-resolution wavefront measurement without being limited by lenslet array sampling
Solution Approach 2:
The patent changes the key parameter of wavefront sampling from discrete lenslet-based sampling to continuous deformable mirror surface control. By using a deformable mirror with many more control points than lenslets, the system achieves much finer spatial frequency resolution in wavefront measurement
2Measurement precision
If symmetric double-pass technique is used to measure optical transfer function, then modulation transfer can be estimated, but odd-aberrations and phase information are lost
Solution Approach 1:
The patent employs an asymmetric double-pass configuration where the first pass through the ocular media has different optical conditions than the second pass. This asymmetry prevents the cancellation of odd-aberrations and preserves phase information that would otherwise be lost in symmetric double-pass measurements
Solution Approach 2:
The patent applies preliminary wavefront correction using adaptive optics in the first pass before the light enters the ocular media. This preliminary action ensures that the wavefront is properly conditioned before measurement, allowing accurate capture of both amplitude and phase information in the subsequent passes
3Measurement precision
If asymmetric double-pass technique is used with small pupil, then high spatial frequency features are captured, but the laser beacon on retina is extended and PSF measurement is inadequate
Solution Approach 1:
The patent changes the pupil size parameter from small to large in the asymmetric double-pass configuration. By using a large pupil combined with adaptive optics correction, the system achieves both a tight focal spot on the retina and adequate capture of high spatial frequency features in the PSF measurement
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 method effectively captures high spatial frequency wavefronts and phase information, providing a more accurate optical quality assessment of the eye, improving the measurement of image-forming properties and enabling better design of vision corrective devices.
Implementation Method 1
adaptive optics, which focuses light to form a sharp point source on the retina by compensating for optical defects
Implementation Method 2
The point spread function (PSF) is a comprehensive measure of the eye's ability to form images and is based on the diffraction, aberration, and scatter from the ocular components
Implementation Method 3
The point spread function (PSF) is a comprehensive measure of the eye's ability to form images and is based on the diffraction, aberration, and scatter from the ocular components
Implementation Method 4
The point spread function (PSF) is a comprehensive measure of the eye's ability to form images and is based on the diffraction, aberration, and scatter from the ocular components
Data Source
AI summary
Measurement of the optical point spread function through a double-pass technique is enhanced by using adaptive optics to form a tiny spot of light on the retina.