Fiducial-Marked Contact Lenses for Position and Tilt Tracking
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Solution Overview
Problem
Current methods for determining the alignment and tilt of scleral contact lenses on the eye are inaccurate, leading to misalignment of wavefront correction patches, which affects the effectiveness of vision correction for conditions like keratoconus.
Innovation Solution
A combined optical wavefront aberrometer and topographer system with fiducial marks located radially inside the pupil's diameter on the contact lens, using image analysis algorithms to track and correct for misalignments and rotation, and optionally employing retro-illumination for better visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If scleral contact lenses are used to stabilize the lens on the eye, then lens stability is improved, but accurate measurement of lens alignment and tilt becomes more difficult
Solution Approach 1:
Fiducial marks are introduced as intermediary reference features on the contact lens. These marks serve as mediators between the lens positioning system and the measurement system, enabling precise optical measurement of lens alignment and tilt by providing detectable reference points that do not interfere with lens stability or patient vision
Solution Approach 2:
The patent replaces mechanical alignment measurement methods with optical measurement techniques. Instead of using physical markers visible to the naked eye or requiring mechanical measurement tools, the system uses optical imaging through the wavefront aberrometer to detect fiducial marks and calculate lens position, tilt, and rotation non-invasively
2Measurement precision
If fiducial marks are placed on the contact lens for alignment measurement, then measurement capability is improved, but visibility of the transparent lens becomes more difficult
Solution Approach 1:
The fiducial marks utilize optical contrast rather than physical opacity. The marks are designed to reflect or absorb specific wavelengths of light used in wavefront measurement, creating detectable contrast in the optical measurement system without significantly affecting the lens's transparency to visible light or patient vision
Solution Approach 2:
The system creates an optical copy or representation of the fiducial marks through wavefront imaging. Instead of requiring direct visual observation of the marks, the optical measurement system captures images of the marks through the transparent lens material, allowing measurement without compromising lens transparency
3Ease of manufacture
If wavefront correction patch is centered on the contact lens during manufacturing, then manufacturing simplicity is improved, but vision correction accuracy deteriorates due to lens misalignment on the eye
Solution Approach 1:
The wavefront correction patch is pre-centered on the contact lens during manufacturing for simplicity. The misalignment compensation is performed as a preliminary calculation step before lens fabrication, using measured lens positioning parameters to determine the appropriate optical correction pattern that will be applied when the lens is worn
Solution Approach 2:
The system uses feedback from measured lens alignment and tilt (obtained through fiducial mark tracking) to adjust and optimize the wavefront correction. The measured misalignment parameters feed back into the correction algorithm to ensure accurate vision correction despite lens positioning variations
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
Accurately measures and corrects for misalignments and rotation of the contact lens, ensuring precise alignment of the wavefront correction patch with the pupil, thereby improving vision correction accuracy.
Implementation Method 1
A combined optical wavefront aberrometer and topographer system with fiducial marks located radially inside the pupil's diameter on the contact lens, using image analysis algorithms to track and correct for misalignments and rotation
Implementation Method 2
optionally employing retro-illumination for better visibility
Data Source
AI summary
This invention comprises a combined optical wavefront aberrometer and topographer system that is used in conjunction with a contact lens that has a plurality of fiducial marks disposed on the lens. The fiducial marks are located radially inside of the undilated pupil's diameter. The optical imaging capacity of the aberrometer is used to measure and monitor any misalignments of the contact lens's position (XY decentration) and/or rotation. Image analysis algorithms are used to track the positions of the fiducial marks, and, hence, the amount of geometric misalignment of the contact lens can be calculated. The fiducial marks can comprise micro ink spots, or depressions in the surface of the contact lens (e.g., divots, dimples, pits), or other small surface features, including raised bumps, which can help to stabilize motions of the contact lens on the eye.