Flat Panel Display Corneal Topography Alignment
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Solution Overview
Problem
Existing corneal topography systems, such as those using Placido disks, 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 solutions for remote populations.
Innovation Solution
A system utilizing a flat panel display to project a pattern of colored light spots onto the cornea, with an optical system and camera to capture and process reflected light patterns, allowing for dynamic adjustment of light spot colors, sizes, and densities to facilitate accurate topographic mapping, and incorporating processors to produce a topographic map of the cornea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If Placido disk systems are used for corneal topography, then the system is simple and widely used, but alignment errors occur between the corneal surface vertex and the design corneal vertex plane
Solution Approach 1:
The patent uses a camera to capture an image of the corneal vertex and creates a digital copy of the actual corneal position. This captured image is then overlaid with reference markings to visually indicate misalignment, allowing the system to detect and compensate for vertex errors without requiring complex mechanical alignment mechanisms
Solution Approach 2:
The patent introduces a display device as an intermediary between the cornea and the measurement system. The display shows captured corneal images with overlay markings that mediate the alignment process by visually guiding the operator to achieve proper vertex alignment, thus resolving the contradiction between system simplicity and measurement precision
2Measurement precision
If Placido rings are used to measure corneal topography, then radial deviations can be detected, but skew rays in azimuthal direction cannot be adequately measured
Solution Approach 1:
The patent transitions from static Placido rings to dynamic, adaptively positioned light sources. The light sources can be dynamically repositioned and reconfigured based on detected corneal aberrations, allowing the system to adaptively measure both radial deviations and skew rays with varying patterns depending on the specific corneal conditions
Solution Approach 2:
The patent segments the corneal surface into multiple measurement zones by using individually controllable light sources positioned at different locations. This segmentation allows independent measurement of radial and azimuthal deviations across different corneal regions, enabling comprehensive detection of both radial deviations and skew rays
3Measurement precision
If light sources are positioned on a conical frustrum or hemisphere to project light patterns, then corneal topography can be determined, but it is difficult to match reflected light spots to projected light sources for highly aberrated corneas
Solution Approach 1:
The patent implements a feedback mechanism where the camera captures the actual positions of reflected light spots, and this information is fed back to adjust and identify the corresponding projected light sources. The system uses this feedback loop to automatically match reflected spots to their source even for highly aberrated corneas, eliminating manual matching complexity
Solution Approach 2:
The patent replaces complex mechanical light source positioning systems with electronically controllable light sources on a flat panel display. The positioning and configuration of light sources are controlled software-based rather than mechanically, simplifying the system while maintaining the ability to determine topography and match light spots through digital processing
4Measurement precision
If traditional corneal topographers are used, then corneal topography can be measured, but the devices are not portable or cost-effective for remote populations
Solution Approach 1:
The patent replaces expensive, complex traditional corneal topographer components with inexpensive alternatives: a flat panel display serves as the light source array, and a standard camera captures images. These consumer-grade components significantly reduce system cost while maintaining measurement capability, making the device suitable for deployment in remote areas
Solution Approach 2:
The patent uses a flat panel display that serves multiple functions: it acts as the light source array for projection, provides a user interface for displaying instructions and results, and can be integrated into portable computing devices. This multi-functionality reduces the number of separate components needed, decreasing overall device complexity and cost while enabling portability
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 enhances the accuracy of corneal topography by improving alignment and measuring skew rays, while enabling a portable and cost-effective solution for corneal diagnostics, particularly beneficial for remote populations.
Implementation Method 1
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
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A corneal 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.