Fiber Optic Needle Probe for Accurate Intraocular Pressure Sensing
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Solution Overview
Problem
Existing applanation tonometers, both contact and non-contact types, rely on corneal shape for intraocular pressure measurement, leading to variability in measurement values due to corneal changes and failing to accurately detect glaucoma in cases with normal intraocular pressure.
Innovation Solution
A probe with a fiber optic pressure sensor and a needle tube, where the pressure receiver is positioned at the needle tip, allowing for low-invasive measurement by puncturing into the eye, specifically designed for higher accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If applanation tonometers measure intraocular pressure through the cornea, then measurement can be performed with low invasiveness, but measurement accuracy deteriorates due to dependence on corneal shape
Solution Approach 1:
The invention extracts the pressure measurement function from the corneal interface and relocates it to the vitreous body. By puncturing the eye and placing the pressure receiver inside the vitreous body, the measurement is decoupled from the corneal shape, eliminating the dependency on corneal characteristics while maintaining low invasiveness through a fine needle tube.
Solution Approach 2:
The needle tube serves as an intermediary element that bridges the external measurement device and the internal vitreous body environment. It allows the pressure receiver to access the intraocular space through a minimally invasive puncture, enabling direct pressure measurement without requiring corneal contact or complex corneal interface management.
2Ease of operation
If conventional tonometers are used, then measurement procedure remains simple, but reliability deteriorates in cases with abnormal corneal shape or normal-tension glaucoma
Solution Approach 1:
The measurement function is extracted from the corneal interface and relocated to the vitreous body, eliminating the influence of corneal abnormalities on measurement reliability. This allows the procedure to remain simple while achieving reliable results in cases of abnormal corneal shape or normal-tension glaucoma where conventional methods fail.
3Object-affected harmful factors
If a fine needle tube is used to reduce invasiveness, then patient comfort improves, but device complexity increases due to precise positioning requirements
Solution Approach 1:
The pressure receiver and needle tube are merged into an integrated assembly where the pressure receiver is positioned at the distal end of the needle tube. This integration simplifies the positioning process, as the entire assembly moves together as a single unit, reducing the complexity associated with precise positioning of separate components while maintaining fine needle tube dimensions for low invasiveness.
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
Enables precise intraocular pressure measurement with reduced invasiveness, addressing the limitations of conventional tonometers by providing accurate readings independent of corneal shape and suitable for detecting glaucoma even with normal pressure.
Implementation Method 1
a fiber optic pressure sensor having a pressure receiver provided at the distal end of an optical fiber
Data Source
AI summary
There is provided an instrument capable of measuring intraocular pressure of a subject with low invasiveness at higher accuracy. The instrument is a probe for intraocular pressure measurement 10 including a fiber optic pressure sensor 30 having a pressure receiver 38 provided at the distal end of an optical fiber 37 and a needle tube 20 that covers the pressure receiver 38 side of the fiber optic pressure sensor 30 and accommodates the pressure receiver 38 inside. The needle tube 20 has a needle tip 21 to be punctured into a subject at the distal end thereof and has a gauge size of 30 to 34 G. The pressure receiver 38 is provided at a position of the needle tip 21 inside the needle tube 20. The fiber optic pressure sensor 30 and the needle tube 20 are fixed on the proximal end 23 side of the needle tube 20 by a joint between the optical fiber 37 and the needle tube 20.