Ophthalmic Measurement Apparatus Two-Dimensional Corneal Thickness Analysis
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Solution Overview
Problem
Conventional ophthalmic measurement apparatuses fail to accurately measure corneal thickness due to scattered light from corneal abnormalities or extraneous matters, as they are designed to detect light only in one dimension, neglecting the influence of scattered light on the measurement.
Innovation Solution
An ophthalmic measurement apparatus using a two-dimensional light receiving element to detect the positional information of corneal reflection images from both the anterior and posterior surfaces, allowing for two-dimensional analysis and improved accuracy in corneal thickness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-dimensional light receiving element is used to detect corneal reflection images, then the device complexity is reduced, but the measurement precision deteriorates due to inability to account for scattered light
Solution Approach 1:
The patent transitions from a one-dimensional light receiving element to a two-dimensional light receiving element, adding spatial dimensionality to the detection system. This enables the system to capture scattered light information in addition to direct reflection light, allowing for more comprehensive analysis and improved measurement accuracy of corneal thickness.
2Device complexity
If scattered light is ignored in the measurement model, then the measurement process is simplified, but the reliability deteriorates due to corneal abnormalities and extraneous matters
Solution Approach 1:
The patent converts the harmful effect of scattered light (which previously degraded measurement quality) into a useful signal source. By detecting scattered light with the two-dimensional light receiving element and incorporating it into the measurement model, the system uses what was previously considered noise or interference to improve measurement reliability and identify corneal abnormalities.
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 enables more precise measurement of corneal thickness by accounting for scattered light, reducing measurement errors caused by corneal abnormalities and extraneous matters, resulting in more reliable and accurate results.
Implementation Method 1
receiving, by a light receiving element, a first cornea reflection image formed by measurement light reflected by a corneal anterior surface of an examinee's eye and a second cornea reflection image formed by measurement light reflected by a corneal posterior surface
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An ophthalmic measurement apparatus (1) includes a light projecting optical system (80a) for projecting measurement light to an examinee's eye (E) from an oblique direction, and a light receiving optical system (80b) for receiving, through a two-dimensional light receiving element (87), a first reflection image (R1) formed by the measurement light reflected by a corneal anterior surface of the examinee's eye (E) and a second cornea reflection image (R2) formed by the measurement light reflected by a corneal posterior surface. A control unit (100) of the ophthalmic measurement apparatus (1) obtains corneal thickness of the examinee's eye based on the positional information of the first reflection image (R1) and the second reflection image (R2) in a light receiving signal output from the two-dimensional light receiving element (87) (S4). At that time, the control unit (100) two-dimensionally detects the positional information of at least one of the first reflection image (R1) and the second reflection image (R2) and obtains the corneal thickness by use of the two-dimensionally detected positional information.