Scanning Laser Ophthalmoscope Aberration Correction
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Solution Overview
Problem
Ophthalmoscope systems, particularly those with wide field scan relay elements, suffer from aberrations that result in blurring and dimming at peripheral image portions, leading to lower fidelity retinal spatial information and suboptimal image quality.
Innovation Solution
A scanning laser ophthalmoscope with a static aberration correction element having a spatially variant depth along its major and minor axes, positioned to correct aberrations introduced by scan relay elements, which modifies the light beam's phase to maintain collimation and focus, using a transmissive phase mask composed of optical glass with varying depth to address changing aberrations across the scan field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If wide field scan relay elements are used to expand the scan field, then the scan field area is improved, but image quality deteriorates due to aberrations causing blurring and dimming at peripheral portions
Solution Approach 1:
The patent applies local quality by implementing aberration correction specifically for peripheral scan fields where aberrations are most problematic. The freeform optical elements introduce spatially varying phase corrections that are tailored to the local aberration characteristics at different field positions, particularly addressing the blurring and dimming at peripheral portions while maintaining central field quality.
Solution Approach 2:
The patent changes optical parameters by using freeform optical elements with non-symmetric surface profiles that dynamically adjust the phase and wavefront characteristics of light across the scan field. These elements modify the optical path length and ray angles in a position-dependent manner to compensate for aberrations introduced by wide-field scan relay elements.
2Ease of operation
If scan relay elements are used to direct light, then light direction capability is improved, but aberrations are introduced that reduce spatial information fidelity
Solution Approach 1:
The patent introduces freeform optical elements as intermediary components between the light source and the retina. These elements act as mediators that correct the wavefront distortions caused by scan relay elements, restoring spatial information fidelity by compensating for aberrations in the optical path without interfering with the light direction capability.
Solution Approach 2:
The patent employs composite optical systems combining conventional optical elements with freeform optical elements. This composite approach integrates the light direction capability of scan relay elements with the aberration correction capability of freeform elements, achieving both functions simultaneously while maintaining spatial information fidelity.
3Device complexity
If conventional optical elements are used, then system simplicity is maintained, but aberration correction capability is insufficient for wide field scanning
Solution Approach 1:
The patent applies dynamics by using freeform optical elements with continuously varying surface profiles rather than conventional discrete optical zones. This dynamic surface geometry allows a single element to provide position-dependent aberration correction across the entire wide field scan, achieving high correction capability without requiring multiple complex optical components.
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 provides a substantially collimated and aberration-free light beam focused to a sharp spot at the retina, retaining desired spatial information across all retinal image portions, thereby enhancing image quality by reducing blurring and dimming issues.
Implementation Method 1
a static aberration correction element which has a shape defined to provide correction of aberrations of at least some of the scan relay elements and a location within the ophthalmoscope chosen to provide correction of aberrations
Data Source
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AI summary
A scanning laser ophthalmoscope (10) for scanning the retina of an eye (22) is provided comprising a light source (12) emitting a beam of light (13), scan relay elements (14, 16, 18, 20), wherein the light source and the scan relay elements provide a two-dimensional scan of the light beam which is transferred from an apparent point source at a pupillary point of the eye to the retina of the eye, and a static aberration correction element (30) which has a shape defined to provide correction of aberrations of at least some of the scan relay elements and a location within the ophthalmoscope chosen to provide correction of aberrations of at least some of the scan relay elements, which location maintains transfer of the beam of light from the apparent point source at the pupillary point of the eye to the retina of the eye. The invention further provides an aberration correction element (30) and a method of determining a shape of the aberration correction element.