Intraocular Lens Diffractive Pattern Depth of Focus
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Solution Overview
Problem
Conventional intraocular lenses often require additional corrective optics for both near and far vision, limiting the depth of focus and increasing dependence on spectacles or contact lenses.
Innovation Solution
An intraocular lens with a diffractive pattern imposed on its surfaces, providing both refractive and diffractive power, extends the depth of focus by ensuring the Modulation Transfer Function exceeds 0.17 at a spatial frequency of 50 line pairs per millimeter over a range of at least 1.7 Diopters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional intraocular lenses are corrected for one or more particular object distances, then objects at the particular object distance appear in focus, but objects farther away from the particular object distance appear increasingly blurred with limited depth of focus
Solution Approach 1:
The lens surface is segmented into multiple zones with different optical powers. The diffractive pattern divides the aperture into regions that direct light to different focal points, enabling simultaneous focus at multiple distances while maintaining acceptable visual quality across a broader depth of focus range
Solution Approach 2:
The patent modifies the optical parameters of the lens by superimposing a diffractive pattern on the refractive surface. This changes the way light is focused, creating multiple focal points and extending the depth of focus while maintaining visual clarity through controlled modulation transfer function values
2Reliability
If additional corrective optics are used to improve vision at multiple distances, then visual clarity across distances is improved, but device complexity and patient burden increase
Solution Approach 1:
The patent merges the functions of multiple corrective optics into a single intraocular lens by incorporating a diffractive pattern directly on the lens surface. This integration provides multiple focal points and extended depth of focus within one device, eliminating the need for separate corrective optics for different distances
Solution Approach 2:
The intraocular lens is designed to perform multiple functions simultaneously - providing clear vision at near, intermediate, and far distances through the diffractive pattern. This multi-functional design replaces the need for multiple specialized corrective devices, reducing overall system complexity and patient burden
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 enhances the depth of focus, reducing the need for additional corrective optics and improving visual clarity across a broader range of distances, thereby reducing the burden on patients.
Implementation Method 1
A diffractive pattern is imposed on at least one of the first shape and the second shape so that the intraocular lens has a base power and an add power
Implementation Method 2
The first and second shapes provide a refractive power
Data Source
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AI summary
An intraocular lens is disclosed, which includes a diffractive element with a relatively low add power. The add power may be less than about 2 Diopters, may be less than about 1 Diopter, or may be in the ranges of 0.5 to 2.5 Diopters, or 1.0 lo 2.0 Diopters, or 1.5 to 2.0 Diopters, or 1.0 to 1.5 Diopters. The low-add-power diffractive element increases the depth of the focus of the intraocular lens, for example, compared to a similarly shaped intraocular lens without the diffractive element. In one embodiment, the depth of focus is defined in terms of a threshold MTF value at a particular spaiml frequency. The threshold may be an absolute threshold, such as 0.10, 0.15, 0.17, 0.20, 0.25 or 0.30, or may be a relative threshold, such as a particular percentage of the peak value. The spatial frequency may be 25 line pairs per mm. 50 line pairs per mm. 100 line pairs per mm, or any suitable value.