Progressive Lens Power Profile for Expanded Clear Vision
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Solution Overview
Problem
Existing progressive power lenses often fail to provide a comfortable wearing experience due to limitations in the clear vision area, particularly for individuals requiring expansion in the depth or horizontal directions.
Innovation Solution
A method for determining a progressive power lens design that expands the clear vision area by reducing addition power in the intermediate portion or smoothing power distribution in the horizontal direction, based on factors such as third-order aberration, line of sight movement, and object movement analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If addition power is reduced in the intermediate portion of the progressive zone, then the clear vision area is expanded in the depth direction, but the refractive power distribution becomes less effective for intermediate distance correction
Solution Approach 1:
The invention changes the addition power parameter in the intermediate portion of the progressive zone to expand the clear vision area. Specifically, the addition power in the intermediate portion is set to be smaller than in the near portion, creating a non-uniform power distribution that extends the clear vision area toward the distance portion while maintaining effective correction for intermediate distances.
2Ease of operation
If the clear vision area is expanded in the depth direction, then comfort for subjects requiring depth expansion is improved, but the lens design complexity increases
Solution Approach 1:
The invention applies local quality by creating different refractive power characteristics in different zones of the lens. The intermediate portion has reduced addition power compared to the near portion, while the distance portion maintains standard power distribution. This localized modification expands the clear vision area in the depth direction without redesigning the entire lens, thereby improving wearing comfort for specific subjects while controlling design complexity.
3Area of stationary object
If power distribution is smoothed in the horizontal direction, then the clear vision area is expanded horizontally, but the astigmatism correction capability may be reduced
Solution Approach 1:
The invention smooths the power distribution in the horizontal direction by reducing abrupt changes in refractive power across the lens surface. This is achieved by carefully controlling the addition power gradient in the intermediate portion, creating a more gradual transition that expands the horizontal clear vision area while maintaining sufficient astigmatism correction capability through optimized power distribution.
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
There is provided a method for determining a progressive power lens, the method including: determining a necessity for expanding a clear vision area for a subject wearing a progressive power lens; and when it is determined that the subject requires expansion of the clear vision area in a depth direction, selecting a design of the progressive power lens in which the clear vision area is expanded in the depth direction by reducing an addition power in an intermediate portion of a progressive zone of the progressive power lens.