Peripheral Defocus Contact Lens for Myopia Progression Control
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Solution Overview
Problem
Existing multi-focal contact lenses for myopia correction introduce visual distortions and are difficult to design and manufacture, and they do not effectively address the peripheral refraction issues that contribute to myopia progression, as they focus on central image quality rather than peripheral refraction.
Innovation Solution
A multi-zone contact lens design with a central optical zone matching the pupil diameter for clear distance vision and a peripheral optical zone outside the pupil diameter to focus peripheral rays anterior to the retina, reducing elongation and myopia progression, using a transition zone to smooth refractive power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-focal contact lenses are used to correct myopia, then central vision is improved, but peripheral refraction remains uncorrected and visual distortion is introduced
Solution Approach 1:
The contact lens is divided into distinct optical zones: a central zone for distance vision correction and a peripheral zone for peripheral refraction correction. This segmentation allows each zone to independently address specific visual requirements, correcting both central and peripheral refraction errors simultaneously without introducing distortion.
Solution Approach 2:
Different optical zones are designed with different refractive powers tailored to their specific functions. The central zone has refractive power for distance vision, while the peripheral zone has refractive power to correct peripheral refraction. This local differentiation of optical properties enables simultaneous correction of central and peripheral vision issues.
2Reliability
If multi-focal contact lenses are designed with multiple refractive zones, then myopia correction is improved, but manufacturing complexity increases
Solution Approach 1:
The lens is segmented into functional zones (central and peripheral) with distinct refractive powers. This segmentation simplifies the manufacturing process by allowing each zone to be optimized independently, reducing the overall design complexity compared to multi-focal lenses that require complex transitions between multiple focal points.
3Reliability
If peripheral focal plane is shifted anterior to the retina, then myopia progression is inhibited, but central image quality may be compromised
Solution Approach 1:
The contact lens separates the functions of central vision correction and peripheral refraction correction into distinct zones. The central zone maintains clear central image quality by providing appropriate refractive power for distance vision, while the peripheral zone shifts the peripheral focal plane anterior to the retina to inhibit myopia progression. This segmentation ensures both functions are achieved simultaneously without compromising central image quality.
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 lens provides clear distance and near vision without central image distortion and effectively inhibits myopia progression by aligning peripheral focal planes anterior to the retina, offering a practical and cost-effective solution.
Implementation Method 1
a peripheral optical zone disposed radially outward from said central zone... said peripheral optical zone having a peripheral optical zone refractive power that is greater than said central optical zone refractive power by an amount sufficient to focus off-axis rays that enter the eye through said peripheral optical zone when the lens is worn onto points on or anterior to a peripheral region of the retina
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A contact lens (10) for use in controlling or retarding the progression of myopia in an eye has a central optical zone (20) approximating the normal diameter of the pupil of the eye (22) that gives clear central vision at distance for the wearer. An annular peripheral optical zone 24 that is substantially outside the diameter of the pupil is formed around the central optical zone (20) with greater refractive power than that of the central zone (22) so that oblique rays entering the eye through the peripheral optical zone (24) will be brought to focus at a focal plane that is substantially on or anterior to the peripheral region of the retina. Preferably, the rear surface (16) of the lens is shaped to conform to the cornea of the eye and the front surface (18) of the lens (10) is shaped to provide - in conjunction with the rear surface (16) - the desired optical properties of the central and peripheral optical zones. The front surface (18) is also preferably contoured to form a smooth transition (30) between the junction of the central optical zone (20) and the peripheral optical zone (24), with or without designed optical properties such as progressive power.