Progressive Lens Design Using Gaze Mapping
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Solution Overview
Problem
Current methods for determining the progression length of progressive ophthalmic lenses do not adequately account for the wearer's visual behavior and frame dimensions, leading to uncertain inclusion of the near vision zone within the lens, and precise positioning is influenced by the frame's geometry and coverage on the head.
Innovation Solution
A method that involves placing the wearer in a visual task scenario to determine their gaze directions, tracking these directions, and calculating the intersection points with the frame's surface to deduce the optimal progression length, taking into account the wearer's visual behavior and frame geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the progression length is determined using conventional methods (single point determination), then the method is simple and quick, but the near vision zone may not be adequately included in the lens
Solution Approach 1:
The patent performs preliminary mapping of multiple gaze directions and their intersection points with the frame surface before finalizing the progression length determination. This advance preparation ensures that the near vision zone is adequately included in the lens design
Solution Approach 2:
The patent transitions from determining a single progression length value to mapping multiple gaze directions and their intersection points across the frame surface. This dimensional expansion from 1D to 2D/3D space enables more accurate positioning of vision zones
2Reliability
If the progression length is adjusted to ensure near vision zone inclusion, then visual comfort is improved, but the positioning precision of vision zones is compromised
Solution Approach 1:
The patent pre-determines multiple gaze directions and calculates their intersection points with the frame surface before finalizing the progression length. This preliminary mapping ensures both adequate near vision zone inclusion and precise positioning
Solution Approach 2:
The patent uses the mapped intersection points as feedback to optimize the progression length determination, ensuring that the near vision zone is properly positioned while maintaining precision in the vision zone placement
3Productivity
If subjective criteria are used for progression length selection, then the process is simple and fast, but the result does not account for frame geometry and wearer's visual behavior
Solution Approach 1:
The system automatically determines gaze directions and calculates intersection points with the frame surface without requiring subjective optician judgment. The method serves itself by using objective measurements of the wearer's actual visual behavior and frame geometry
Solution Approach 2:
The patent changes from using subjective optician judgment to using objective parameters such as gaze direction vectors, frame surface geometry, and intersection point coordinates. This parameter transformation enables adaptation to both frame geometry and wearer's visual behavior
4Measurement precision
If multiple gaze directions are mapped and intersection points calculated, then positioning precision is improved, but the calculation complexity increases
Solution Approach 1:
The patent performs preliminary calculation of gaze direction vectors and their intersection points with the frame surface before determining the final progression length. This advance computation simplifies the final determination step while maintaining high precision
Data Source
Figure 1~4
AI summary
The invention relates to a method for determining at least one optical design parameter for a progressive ophthalmic lens intended to be fitted in a frame chosen by a wearer, depending on the visual behaviour of the latter, comprising the following steps: a) the wearer is placed in a situation in which he carries out a visual task at a first working distance; b) during this visual task, at least two gaze directions of the wearer at this first working distance are determined in a frame of reference of the head of the wearer; c) a relative position of a surface related to said frame or to an ophthalmic lens intended to be fitted in said frame is determined in this frame of reference of the head of the wearer; d) for each gaze direction at the first working distance determined in step b) the intersection between this gaze direction at the first working distance and said surface is determined so as to establish a map of these points of intersection on this surface; and e) said sought-after optical design parameter is deduced from this map.