Flat Panel Display Corneal Topography with Dynamic Light Patterns
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Solution Overview
Problem
Existing corneal topography systems, such as those using Placido disk and light source array methods, face challenges with alignment errors and inadequate measurement of skew rays, particularly in cases of astigmatism, and are not easily adaptable for portable and cost-effective applications.
Innovation Solution
A system utilizing a flat panel display to project a dynamically adjustable light pattern of colored light spots onto the cornea, with an optical system and camera to capture and process reflected light patterns, allowing for accurate topographic mapping by comparing projected and reflected patterns, and optionally using a portable computing device for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Placido disk system with fixed concentric rings is used, then the system is simple and widely used, but alignment errors occur when the cornea is not at the expected location
Solution Approach 1:
The patent applies dynamics by making the light pattern adaptable and reconfigurable. The system dynamically adjusts the light pattern parameters (such as ring spacing, radius, and distribution) based on the actual corneal vertex location detected during measurement. This allows the system to maintain measurement accuracy despite variations in corneal positioning, while keeping the overall system structure relatively simple.
Solution Approach 2:
The patent utilizes parameter changes by modifying the light pattern characteristics (radius, spacing, density) according to the measured corneal topography and vertex location. The system changes these parameters in real-time to compensate for alignment errors, ensuring accurate measurements without requiring complex mechanical adjustment mechanisms.
2Measurement precision
If Placido rings are used to measure corneal topography, then radial deviations can be obtained, but skew rays in azimuthal direction cannot be adequately measured
Solution Approach 1:
The patent applies segmentation by dividing the light pattern into multiple independently controllable elements (such as discrete rings or light sources) arranged in a conical frustum configuration. This segmentation allows different regions of the light pattern to be independently adjusted to target specific corneal zones, enabling measurement of both radial deviations and azimuthal skew rays that affect astigmatism.
Solution Approach 2:
The patent utilizes asymmetry by employing a conical frustum light pattern instead of symmetric Placido rings. The asymmetric conical arrangement of light sources at different heights and radial positions enables the system to capture both radial and azimuthal corneal deviations, providing comprehensive topography information including skew rays.
3Measurement precision
If a pattern of projected light sources is used, then matching reflected spots to projected sources is difficult for highly aberrated corneas, but dynamic reconfiguration could improve matching
Solution Approach 1:
The patent applies dynamics by implementing a reconfigurable light pattern system that can adapt its configuration based on the measured corneal aberrations. The system dynamically adjusts the position, spacing, and distribution of projected light sources to optimize matching with reflected spots, even for highly aberrated corneas, while using software control to manage the reconfiguration process.
Solution Approach 2:
The patent utilizes feedback by using the detected reflected light pattern information to guide subsequent adjustments of the projected light pattern. The system continuously monitors the matching quality between projected and reflected spots and uses this feedback to iteratively improve the light pattern configuration, enhancing measurement accuracy for aberrated corneas.
4Measurement precision
If traditional corneal topographers are used, then measurements can be obtained, but the systems are not easily adaptable for portable and cost-effective applications
Solution Approach 1:
The patent applies universality by designing a system where a single light source array can perform multiple functions: projecting light patterns, serving as a reference for alignment, and enabling various corneal topography measurements. This multi-functionality reduces the need for separate components, simplifying the overall system design and making it more suitable for portable and cost-effective implementations.
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 provides accurate corneal topography by dynamically adjusting light patterns to improve matching of reflected spots with projected spots, addressing alignment errors and skew ray measurement limitations, and enabling portable and cost-effective corneal topography solutions.
Implementation Method 1
receive and process reflected light from the cornea that passes through the flat panel display from the cornea to the optical system
Data Source
AI summary
A conical topographer includes: a flat panel display configured to display a light pattern and to project the light pattern onto a cornea of an eye disposed on a first side of the flat panel display; an optical system disposed on a second side of the flat panel display, the optical system being configured to receive and process reflected light from the cornea that passes through the flat panel display from the cornea to the optical system; a camera configured to receive the processed reflected light from the optical system and to capture therefrom a reflected light pattern from the cornea produced in response to the projected light pattern; and one or more processors configured to execute an algorithm to compare the projected light pattern to the reflected light pattern from the cornea, and to produce a topographic map of the cornea based on a result of the comparison.