Model Eye Using Vegetable Oil for Corneal Reflectivity
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Solution Overview
Problem
Existing model eyes do not accurately replicate the reflectivity of the anterior and posterior corneas of a human eye, leading to suboptimal corneal signal measurement in ophthalmic equipment.
Innovation Solution
A model eye design featuring a body filled with vegetable oil and a solid glass corneal substitute with a refractive index similar to human corneal glass, minimizing the deviation in reflection coefficients between the model eye and a human eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass with curvature similar to cornea is used as substitute for cornea and water is filled in anterior chamber, then model eye structure is simple and easy to manufacture, but the reflection coefficient at posterior cornea deviates significantly from human eye (0.045 vs 0.015)
Solution Approach 1:
The patent changes the refractive index parameter of the liquid filling material from water (n=1.3332) to vegetable oil (n=1.475). This parameter change adjusts the reflection coefficient at the glass-liquid interface to match human posterior cornea reflectivity (0.006), thereby improving measurement precision while maintaining the simplicity of the model eye structure
Solution Approach 2:
The patent uses a composite material system consisting of specific glass (H-FK95 with n=1.438) combined with vegetable oil (n=1.475). This composite combination creates optimal optical properties where the reflection coefficient at the interface matches human corneal characteristics, resolving the contradiction between manufacturing simplicity and measurement accuracy
2Ease of manufacture
If quartz glass (fused silica) is used for cornea substitute, then material is easy to obtain and process, but reflection coefficient at front surface deviates from human cornea (0.186 vs 0.159)
Solution Approach 1:
The patent changes the glass material parameter from quartz glass (n=1.458) to H-FK95 glass (n=1.438). This parameter adjustment brings the front surface reflection coefficient closer to human cornea values (0.180 vs 0.159) while maintaining ease of manufacturing through standard glass processing techniques
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
The model eye achieves reflection coefficients similar to those of human corneas, enabling higher quality measurement signals for ophthalmic equipment and facilitating the calibration of optometric instruments.
Implementation Method 1
the reflection coefficients of the front and back surfaces of the glass of the model eye are similar to the reflection coefficients of the anterior cornea and the posterior cornea of a human eye
Implementation Method 2
When light passes through different media, the reflection coefficient (ρ) of the light changes depending on the refractive indexes of the media
Data Source
Figure 1~2
AI summary
A model eye having a reflectivity of the posterior cornea similar to that of a human eye is disclosed. The model eye of the present disclosure may include: a body (20) having a space formed therein; solid glass (10) mounted in front of the body (20) to seal the body (20), as a substitute for the cornea of a human eye; and a liquid substance (30) being vegetable oil filled in the space of the body (20). The liquid substance (30) may be sunflower oil. The glass (10) may be H-FK95 glass.