Balanced Progressive Lens Pair for Binocular Vision Comfort
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Solution Overview
Problem
Existing progressive ophthalmic lenses often cause vision discomfort due to mismatched peripheral gaze directions when paired, as they are optimized separately for far and proximate vision without considering binocular vision requirements.
Innovation Solution
A pair of progressive ophthalmic lenses with a common prescribed addition and specific refractive power and astigmatism parameters for each gaze direction, ensuring a minimum threshold difference in vision zones and a controlled refractive power gradient to balance the design between lenses, thereby enhancing binocular vision comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If progressive ophthalmic lenses are optimized separately for far and proximate vision zones, then the sharp vision zone area is improved, but peripheral vision discomfort increases due to mismatched refractive power gradients
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the refractive power distribution parameters across different zones of the progressive lenses. Specifically, it modifies the mean refractive power PPOα,β and astigmatism values ASRα,β as functions of position (α,β) to create optimized lens designs that balance sharp vision zone area with peripheral comfort. The invention uses computer-implemented optimization methods to determine parameter distributions that satisfy multiple constraints simultaneously.
Solution Approach 2:
The patent employs asymmetry by creating lens pairs where the left and right lenses have different optical parameter distributions. The optimization process determines asymmetric refractive power gradients and astigmatism patterns tailored to each lens's position in the spectacle frame, allowing the lenses to work together binocularly while accounting for individual eye characteristics and frame geometry.
2Measurement precision
If lenses are selected with different designs for large far vision zone and large proximate vision zone, then binocular vision sharpness is improved, but vision discomfort arises in peripheral gaze directions
Solution Approach 1:
The patent resolves this contradiction by implementing continuous parameter optimization across the lens surface. It adjusts the refractive power PPOα,β and astigmatism ASRα,β parameters as continuous functions of position, creating smooth transitions between zones. The optimization ensures that while far and proximate vision zones are enlarged for sharp binocular vision, the refractive power gradients in peripheral regions are controlled to prevent discomfort.
Solution Approach 2:
The patent applies equipotentiality by balancing the refractive power gradients between corresponding peripheral regions of the lens pair. The optimization process ensures that lenses with different designs maintain compatible refractive power distributions in their respective peripheral zones, creating a balanced binocular visual experience without discomfort.
3Area of stationary object
If refractive power values are increased to expand vision zones, then the area of sharp vision is improved, but the refractive power gradient becomes too steep causing adaptation difficulties
Solution Approach 1:
The patent uses parameter changes to optimally balance vision zone area with refractive power gradient magnitude. The computer-implemented optimization method adjusts the refractive power distribution parameters to maximize sharp vision zone area while constraining the gradients to remain within comfortable ranges for wearers. This creates lens designs that expand useful vision areas without creating excessively steep power transitions.
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
The solution provides improved binocular vision with reduced discomfort in peripheral vision by ensuring a balanced design between lenses, offering a larger sharp vision zone and a wider perceived field of vision while maintaining a comfortable refractive power gradient.
Implementation Method 1
each progressive ophthalmic lens has a mean refractive power which varies along a meridian line of the lens
Implementation Method 2
a progressive ophthalmic lens has mean refractive power values and resultant astigmatism values which are not equal to those on the meridian line
Data Source
AI summary
A pair of progressive ophthalmic lenses (1, 2) meets special conditions for improving binocular vision of a wearer, while avoiding discomfort for peripheral vision. A first one of the conditions relates to width values of far vision fields and/or proximate vision fields, for indicating that the fields are different enough in width between both lenses. A second one of the conditions sets a maximum value for the relative difference in mean refractive power gradient between both lenses.