Progressive Lens Design Adjusting Corridor Length for Power
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Solution Overview
Problem
Existing progressive-power spectacle lenses often cause discomfort and eye fatigue, especially for first-time users and those with advanced presbyopia, due to abrupt changes in dioptric power along the progressive corridor.
Innovation Solution
The design method adjusts the progressive-power spectacle lens by increasing the distance from the fitting point to the progression start point and varying the length of the progressive corridor based on addition power, providing a gradual change in dioptric power to minimize discomfort and eye fatigue, with the distance from the fitting point to the progression end point fixed to ensure efficient lens design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the progressive corridor length is set to be longer for greater addition power, then the rate of change in dioptric power is reduced, but the field of view for distant vision is compromised and the lens design becomes less efficient
Solution Approach 1:
The patent applies local quality by setting different progressive corridor lengths for different addition power ranges. Specifically, when addition power is 2.00 D or more, the progressive corridor length is set to 10 mm or more, while when addition power is less than 2.00 D, the length is set to less than 10 mm. This localized adjustment optimizes the rate of dioptric power change for each user category without compromising the overall lens design efficiency and distant vision field of view.
2Productivity
If the progressive corridor length is set to be shorter for greater addition power, then the lens design efficiency is improved, but the rate of change in dioptric power increases causing eye fatigue
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the progressive corridor length based on the addition power parameter. The design specifies that when addition power is 2.00 D or more, the progressive corridor length should be 10 mm or more, whereas when addition power is less than 2.00 D, the length should be less than 10 mm. This parameter-based adjustment ensures that users with higher addition power (advanced presbyopia) receive a longer corridor to reduce the rate of dioptric power change and prevent eye fatigue, while maintaining design efficiency for other users.
3Ease of operation
If the progression start point is positioned at the boundary with distance portion, then the transition from distance to near vision is achieved, but first-time users experience discomfort due to abrupt power change
Solution Approach 1:
The patent applies local quality by creating a differentiated design for the progressive corridor based on user experience and addition power. The progressive corridor is positioned and sized differently depending on whether the user is a first-time wearer or has advanced presbyopia. This localized customization allows first-time users to experience a more gradual power transition that reduces discomfort, while still maintaining the necessary vision transition capability from distance to near vision.
Data Source
Figure 1A~1B
Figure 2A~2C
AI summary
A progressive-power spectacle lens design method, the progressive-power spectacle lens including a distance portion, a near portion, and a progressive portion provided between the distance portion and the near portion, the method comprising: decreasing a distance along a principal meridian from a fitting point to a progression start point and increasing a length of a progressive corridor defined by the progression start point and a progression end point when addition power is large, whereas increasing the distance along the principal meridian from the fitting point to the progression start point and decreasing the length of the progressive corridor when the addition power is small, wherein the distance from the fitting point to the progression end point is fixed irrespective of of the addition power.