Punctiform Light Source Night Vision Testing
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Solution Overview
Problem
Current methods for testing night vision are inadequate in precisely determining visual acuity and correcting refraction issues under low lighting conditions, leading to reduced visibility at dusk and night, particularly for motorists, due to the limitations of conventional optotypes and devices that do not accurately simulate nighttime pupil dilation and ambient light conditions.
Innovation Solution
A method and device utilizing a punctiform light source as optotypes, which the subject perceives with an enlarged circular or elliptical outline and laterally sloping flanks, allowing precise determination of visual acuity by adjusting trial lenses to minimize flank visibility, and employing a darkened room to mimic nighttime conditions, with a presentation device positioned several meters away and adjustable lighting to simulate glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional optotypes are used in darkened rooms, then the subject's pupil dilates to simulate nighttime conditions, but the visual acuity measurement becomes imprecise due to the enlarged pupil diameter changing refraction properties
Solution Approach 1:
The patent changes the physical parameters of the optotype from conventional large characters to punctiform light sources (point-like). This parameter change allows the optotype to be viewed through the dilated nighttime pupil while maintaining measurement precision, as the point source creates a diffraction pattern that is sensitive to refraction changes regardless of pupil size.
Solution Approach 2:
The patent uses punctiform light sources that replicate the visual characteristics of nighttime vision through diffraction patterns rather than relying on conventional optotypes. The diffraction pattern of a point source through a circular aperture creates a characteristic Airy pattern that can be measured objectively, copying the essential visual phenomenon of nighttime vision without requiring the subject to actually see conventional optotypes in the dark.
2Ease of manufacture
If conventional optotypes are used, then the test can be performed with standard equipment, but the device cannot accurately simulate nighttime glare conditions and peripheral light sources
Solution Approach 1:
The patent makes the testing device multi-functional by enabling it to simulate various nighttime conditions including glare from oncoming vehicles and peripheral light sources. The punctiform light sources can be positioned at different locations and brightness levels, allowing the same device to test for multiple types of nighttime visual impairments (glare sensitivity, peripheral vision, contrast sensitivity) rather than requiring separate specialized equipment for each condition.
3Loss of information
If subjective testing methods are used, then the subject's visual impression is captured, but the objective refraction measurement does not always correspond to the subjective visual acuity
Solution Approach 1:
The patent introduces the diffraction pattern of the punctiform light source as an intermediary element that bridges subjective and objective measurements. The diffraction pattern provides an objective physical representation of the light distribution that the subject perceives, allowing for precise measurement of visual acuity and refraction without relying solely on subjective reporting. The pattern's characteristics (sharpness, contrast, spatial distribution) can be measured objectively while corresponding to the subject's visual experience.
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 testing of night vision acuity and optimal lens correction, significantly improving visibility at dusk and night, enhancing safety for motorists by accurately measuring and correcting visual impairments under low-light conditions.
Implementation Method 1
The subject perceives the punctiform light source with an enlarged circular or elliptical outline and laterally sloping flanks
Implementation Method 2
The refractive properties of an eye depend, among other things, on the diameter of the pupil
Implementation Method 3
a subject with an open pupil, preferably in a darkened room
Data Source
Figure 1
Figure 2~7
AI summary
The invention relates to a method for testing scotopic vision. To this end, a test person (16) with a dilated pupil, preferably inside a darkened room (12), is presented at least one optotype at a distance (a) of several meters. The optotype is provided in the form of a point of light. The associated device has an examination position (14), which is located inside the room (12), for the test person (16) and has a presentation device (30) for optotypes, which is placed inside the room at a distance (a) of several meters from the examination position (14). The presentation device (30) contains at least one point source of light whose light beam (42) is oriented toward the examination position (14). The visual impression, particularly the visual acuity of the test person is determined with the aid of the optotypes.