Portable Pupillometer Using Chromatic Stimuli for Objective Visual Field Testing
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Solution Overview
Problem
Current visual field testing methods are subjective and unreliable, especially for ill, elderly, or mentally challenged patients, due to their dependence on patient cooperation, leading to inaccurate and non-repeatable results.
Innovation Solution
A portable pupillometer system that uses chromatic perimetry to objectively assess the visual field by measuring pupillary responses to specific chromatic stimuli, providing individualized and repeatable health indicators without requiring patient input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard visual field testing methods are used, then the test can cover the entire visual field, but the results are subjective and unreliable due to patient cooperation requirements
Solution Approach 1:
The patent replaces the mechanical/subjective button-pressing system with an optical measurement system that objectively records pupillary responses. The pupillometer measures pupil constriction automatically, eliminating the need for patient cooperation and subjective reporting, thereby resolving the contradiction between measurement coverage and result reliability.
Solution Approach 2:
The patent introduces the pupillary response as an intermediary measurement that indirectly reflects visual field status. Instead of directly measuring patient awareness of stimuli, the system measures the physiological pupillary response to light stimuli, which provides objective data about visual field function without requiring patient subjective input.
2Measurement precision
If small-area light stimuli are used in pupil perimetry, then the test targets specific retinal areas, but the stimuli may fail to stimulate PLR if the retinal area is damaged
Solution Approach 1:
The patent employs dynamic stimulus presentation, alternating between small-area stimuli for localization and full-field stimuli for reliable PLR activation. The system adaptively adjusts stimulus area and intensity based on test progress and patient response, ensuring both precise retinal area targeting and sufficient PLR stimulation even when damage is present.
Solution Approach 2:
The patent uses excessive action by presenting full-field light stimuli in addition to small-area stimuli. This ensures that even if small-area stimuli fail to elicit PLR due to retinal damage, the full-field stimuli will still stimulate the pupil, allowing the test to continue and providing complementary information about overall visual function.
3Ease of operation
If achromatic beam stimuli are used, then the testing procedure is simplified, but the results are susceptible to time variations and individual differences in ocular system behavior
Solution Approach 1:
The patent changes the wavelength parameter of the light stimuli from achromatic (broad spectrum) to chromatic (specific wavelengths). By using specific wavelengths that preferentially stimulate rods (e.g., 480nm blue) and cones (e.g., 640nm red), the system achieves more consistent and reproducible pupillary responses that are less susceptible to time variations and individual differences, while maintaining procedural simplicity.
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 system provides reliable and repeatable visual field testing, capable of identifying eye damage and retinal issues, such as glaucoma and retinitis pigmentosa, with improved accuracy and reduced variability.
Implementation Method 1
at least one camera configured to capture images of a pupil of the subject via infrared detection
Implementation Method 2
two or more light sources disposed in the testing compartment and forming a plurality of visual stimuli
Data Source
AI summary
In one embodiment, a portable pupillometer including a testing compartment, at least one ocular disposed on the testing compartment, two or more light sources disposed in the testing compartment and forming a plurality of visual stimuli for a subject looking through the at least one ocular, at least one camera configured to capture images of a pupil of the subject via infrared detection, the images indicating pupillary responses to the two or more light sources, and an interface for connection with a computing device external to the pupillometer, the interface adapted to (i) provide, to the computing device, images from the at least one camera, and (ii) receive, from the computing device, control signals for controlling the plurality of light sources.