Optical Visual Aid Astigmatic Power Depth of Field
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical visual aids do not effectively enhance the natural depth of field of the human eye, particularly for individuals with presbyopia, as they fail to optimize the distribution of astigmatism across different viewing distances, leading to reduced visual acuity and increased image unsharpness.
Innovation Solution
The introduction of an optical visual aid with a dioptric power composed of multiple components, including a first dioptric power component for best possible correction and an additional astigmatic power component with a cylindrical refractive power of −1.0 DC to −0.125 DC and an axis location between 70° to 110°, which is specifically designed to increase the depth of field by modifying the prescription values determined from refraction measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spectacle lenses with single dioptric power components are used, then the prescription is simple and easy to manufacture, but the depth of field is limited and visual acuity is reduced
Solution Approach 1:
The dioptric power is segmented into multiple independent components: a first dioptric power component for best possible correction and a second dioptric power component for additional astigmatic effect. This segmentation allows each component to serve a specific function - the first component corrects the refractive error while the second component increases depth of field, resolving the contradiction between simple prescription and enhanced depth of field
Solution Approach 2:
The patent applies different dioptric power components in specific orientations and magnitudes. The first component is optimized for best possible correction at a specific distance, while the second component is specifically designed with astigmatic power to broaden the near visual field. This local optimization of different power components resolves the contradiction by providing enhanced depth of field without compromising the corrective function
2Reliability
If additional astigmatic power is introduced to increase depth of field, then the near visual field is broadened, but the visual acuity may be reduced
Solution Approach 1:
The second dioptric power component introduces additional astigmatic power that is intentionally not fully corrective but provides a beneficial partial effect. The astigmatic power is optimized to broaden the depth of field while keeping the visual acuity reduction within acceptable limits (not more than 0.2 log MAR), achieving a balance between depth of field enhancement and visual acuity maintenance
Solution Approach 2:
The patent optimizes specific parameters of the second dioptric power component, including the cylindrical refractive power and axis location, to achieve the desired balance. By carefully selecting these parameters, the patent broadens the near visual field while minimizing the impact on visual acuity, resolving the contradiction between depth of field and visual acuity
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
This configuration significantly enhances the depth of field and visual acuity by broadening the near visual field without compromising the accommodation-assisting power, providing a better visual impression across various distances, especially in the near region.
Implementation Method 1
an additional astigmatic power component with a cylindrical refractive power of −1.0 DC to −0.125 DC and an axis location between 70° to 110°, which is specifically designed to increase the depth of field
Implementation Method 2
the dioptric power being composed of a plurality of dioptric power components... a first dioptric power component has a best possible corrective power for the viewing direction
Data Source
AI summary
An optical visual aid is disclosed that assists an observer looking at an object through at least one spectacle lens. The optical visual aid has a dioptric power matched to an eye of the observer for at least one viewing direction. The dioptric power is composed of a plurality of dioptric power components. A first dioptric power component of the plurality of dioptric power components has a best possible corrective power for the eye of the observer at a defined distance of the object from the corneal vertex of the eye for the viewing direction. At the same time, a further dioptric power component of the plurality of dioptric power components has an additional astigmatic, partly corrective power for the viewing direction for the eye of the observer at the defined distance.