Non-Contact Tonometer Calibration Tool Direct Mounting
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Solution Overview
Problem
Existing non-contact tonometer calibration tools are costly, complex, difficult to use, and require time-consuming alignment procedures, often relying on expensive and unreliable precision-manufactured rubber eyes or clinical trials involving human subjects, and lack direct alignment with the tonometer's fluid discharge passage.
Innovation Solution
A calibration tool that mounts directly onto the tonometer's nosepiece or measurement head, eliminating the need for alignment steps by incorporating a pressure sensor and emitter to simulate an applanation event, thereby simplifying the calibration process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mirror and lever system is used for calibration, then measurement capability is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the essential calibration function from the complex mirror-and-lever system. Instead of using optical components (mirror) and mechanical amplification (lever), the invention directly places a pressure sensor in the fluid discharge passage to measure the air pulse pressure directly, eliminating unnecessary intermediate components while preserving the core measurement capability.
Solution Approach 2:
The patent replaces the mechanical-optical system (mirror and lever) with a direct pressure sensing system. The pressure sensor electronically detects the air pulse pressure without requiring mechanical movement or optical reflection, substituting complex mechanical components with a simpler electronic sensing approach.
2Measurement precision
If alignment procedures are required for calibration, then measurement accuracy can be achieved, but ease of operation deteriorates
Solution Approach 1:
The patent incorporates the pressure sensor directly into the fluid discharge passage during manufacturing, so that the sensor is pre-positioned in the correct location. This preliminary integration eliminates the need for field alignment procedures, as the sensor is already in its proper position relative to the air pulse generation components.
Solution Approach 2:
The calibration tool is designed to be self-aligning through direct integration. The pressure sensor automatically receives the air pulse through the fluid discharge passage without requiring external alignment actions by the operator. The system serves itself by having the sensor inherently positioned to detect the pressure signal.
3Adaptability or versatility
If rubber eyes are used as calibration standards, then IOP measurement simulation is achieved, but reliability and stability deteriorate
Solution Approach 1:
Instead of using physical rubber eyes that attempt to copy the mechanical properties of a real eye, the patent creates a simplified functional copy of the calibration process. It directly measures the air pulse pressure at the point of corneal contact using a pressure sensor, capturing the essential pressure parameter without requiring a physical replica of the eye structure.
Solution Approach 2:
The patent changes the calibration approach from measuring mechanical deformation of rubber eyes to directly measuring pressure parameters. By focusing on the pressure parameter (air pulse pressure at applanation) rather than mechanical properties of a rubber model, the system achieves greater stability and reliability in calibration measurements.
4Measurement precision
If clinical trials with human eyes are conducted, then calibration accuracy is improved, but loss of time and cost increase
Solution Approach 1:
The patent extracts the essential calibration data (air pulse pressure at applanation) from the complex clinical trial process. Instead of conducting trials with human eyes involving multiple measurements and statistical analysis, the invention directly measures the pressure parameter in a controlled setting, obtaining calibration information without the time and resource expenditure of clinical studies.
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 solution provides a more user-friendly, cost-effective, and accurate calibration method by eliminating the need for complex alignment, using a direct mounting system that enhances calibration efficiency and reduces the risk of calibration errors.
Implementation Method 1
a pressure sensor mounted in the plenum for providing a signal proportional to the plenum pressure
Implementation Method 2
an infra-red emitter connected to the pressure sensor for providing a pseudo-applanation event, such as an infra-red pulse, when the pressure sensor signal reaches a predetermined level
Data Source
AI summary
A tool for calibrating a non-contact tonometer (NCT) comprises a body having a mating feature configured for removably mounting the body on the nosepiece or on the measurement head of the NCT, a pressure sensor carried by the body and arranged to receive an air pulse discharged by the NCT to provide a pressure signal in response to the air pulse, and a radiation emitter carried by the body, wherein the radiation emitter provides a pseudo-applanation event when the pressure signal reaches a predetermined level that is detectable by the NCT as though an actual corneal applanation had taken place. In one embodiment, the mating feature includes a mounting orifice for receiving a portion of the nosepiece. In another embodiment, the mating feature includes a pair of mounting pins sized for receipt by a corresponding pair of mounting holes in the measurement head of the NCT.