Multi-View Corneal Topographer for Apex Detail and Coverage
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Solution Overview
Problem
Existing corneal topographers fail to provide detailed information along specific directions of the pattern or around the apex of the eye and often cannot illuminate a sufficient area of the cornea, limiting corneal coverage.
Innovation Solution
A multi-view corneal topographer system using an illuminator to project a Placido pattern onto the anterior corneal surface, multiple cameras to capture images from different viewpoints, and a computer to calculate curvature values and generate topography by adjusting normal vectors and applying ray-tracing procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single camera is used to capture the reflected Placido pattern, then the device complexity is reduced, but the measurement precision and corneal coverage are insufficient
Solution Approach 1:
The system divides the corneal surface into multiple regions and uses multiple cameras to capture different portions of the reflected Placido pattern from different viewpoints. Each camera captures a specific segment of the corneal surface, allowing comprehensive coverage through segmentation of the measurement task across multiple devices.
Solution Approach 2:
The system transitions from a single-view (2D) measurement approach to a multi-view (3D) measurement approach by positioning cameras at different angles and orientations. This dimensional change enables capture of curvature information from multiple directions simultaneously, improving comprehensive corneal coverage and measurement precision.
2Area of stationary object
If the illumination area is increased to cover more cornea, then the corneal coverage is improved, but the illumination intensity decreases
Solution Approach 1:
The illumination system divides the corneal surface into multiple zones and uses multiple illuminators to provide localized illumination. Each illuminator covers a specific region of the cornea, maintaining sufficient illumination intensity in each segment while collectively covering the entire corneal surface area.
Solution Approach 2:
The system applies different illumination characteristics to different regions of the cornea based on their specific measurement requirements. Each illuminator is optimized for its specific zone, providing appropriate intensity and pattern quality for that local area rather than using uniform illumination across the entire cornea.
3Measurement precision
If detailed information is captured around the apex and in specific directions, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The system positions cameras at specific orientations and angles to capture detailed curvature information in specific directions around the apex. Each camera is optimized for its specific viewing angle, providing enhanced measurement precision in its designated direction while the overall system integrates these localized detailed measurements.
Solution Approach 2:
The system adds the dimension of camera orientation and viewing angle to the measurement setup. By positioning cameras at multiple different angles and orientations, the system captures curvature information from multiple directions simultaneously, enabling detailed measurement of the apex and specific corneal regions without requiring a single complex measurement system.
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
Enhances corneal coverage and provides detailed curvature information across various directions, including the apex, by utilizing multiple camera viewpoints and advanced image analysis techniques.
Implementation Method 1
The illuminator illuminates the anterior corneal surface of the eye with a Placido pattern, which reflects the Placido pattern
Data Source
AI summary
An ophthalmic system for generating a topography of an anterior corneal surface of an eye comprises an illuminator, cameras, and a computer. The illuminator illuminates the anterior corneal surface of the eye with a Placido pattern, which reflects the Placido pattern. Each camera generates an image of the reflected Placido pattern to yield multiple images. At least one camera is oriented off an axis of the eye. For each image, the computer calculates a curvature value for each data point of the image, where a data point corresponds to a surface point of the anterior corneal surface. The calculations yield curvature values for each surface point. The computer determines the curvature at each surface point from one or more curvature values for the surface point. The computer generates the topography of the anterior corneal surface from the curvatures at the surface points of the anterior corneal surface.