Cornea Posterior Surface Measurement via Ring Imaging and Interferometry
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Solution Overview
Problem
Conventional ophthalmological devices inaccurately estimate the shape of the cornea posterior surface, leading to errors in intraocular lens prescription due to reliance on empirical formulas rather than direct measurement.
Innovation Solution
An ophthalmological device combining a ring image photographic optical system and an interference optical system, with a processor that calculates the anterior surface shape from ring light reflections and the posterior surface shape from measured thicknesses, enabling precise measurement of the cornea posterior surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shape of the cornea posterior surface is estimated using an empirical formula based on the cornea anterior surface shape, then the measurement process is simplified, but the measurement precision deteriorates due to estimation errors
Solution Approach 1:
The cornea measurement is divided into two independent parts: the anterior surface shape measured by the ring image photographic optical system, and the posterior surface shape measured by the interference optical system. This segmentation allows each surface to be measured directly without relying on empirical formulas, thereby improving measurement precision while maintaining operational simplicity through specialized dedicated systems for each measurement task.
Solution Approach 2:
The patent introduces an interference optical system as an intermediary measurement mechanism that directly measures the cornea posterior surface shape. This intermediary system bridges the gap between the inability of conventional direct imaging methods to capture the posterior surface and the need for accurate measurement, enabling direct observation and measurement without empirical estimation.
2Device complexity
If only the cornea anterior surface shape is measured, then the device complexity is reduced, but the reliability of intraocular lens prescription deteriorates due to insufficient data
Solution Approach 1:
The patent merges two distinct optical measurement systems - the ring image photographic optical system for anterior surface measurement and the interference optical system for posterior surface measurement - into a single integrated ophthalmological device. This combination provides comprehensive cornea data (both anterior and posterior surface shapes) necessary for reliable intraocular lens prescription, while sharing common components such as the light source and control unit to manage device complexity.
Solution Approach 2:
The ophthalmological device is designed with multi-functionality, capable of performing both anterior surface imaging and posterior surface interferometry measurements. This universal device eliminates the need for separate measurement instruments, providing all necessary corneal parameters for accurate intraocular lens calculation in a single integrated 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
Accurately measures the shape of the cornea posterior surface, improving the precision of intraocular lens prescription by directly calculating the posterior surface shape from anterior surface data and thickness measurements.
Implementation Method 1
radiate a plurality of concentric ring light around a cornea apex to a cornea surface of an eye to be examined and take reflected images of the plurality of ring light reflected from the cornea surface of the eye
Implementation Method 2
detect interfering light composed of reflected light of the measurement light reflected from the eye and predetermined reference light
Data Source
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AI summary
An ophthalmological device calculates a cornea surface shape of an eye to be examined. The ophthalmological device includes a ring image photographic optical system configured to radiate a plurality of concentric ring light to the cornea surface of the eye and take reflected images of the plurality of ring light reflected from the cornea surface of the eye, an interference optical system configured to radiate measurement light to the eye and detect interfering light composed of reflected light of the measurement light reflected from the eye and predetermined reference light. The shape of the cornea anterior surface of the eye is calculated form the reflected images of the plurality of ring light, the thicknesses of the cornea of the eye at the plurality of incident positions is calculated from the interfering light, and the posterior surface shape of the cornea of the eye is calculated based on these two results.