Soft contact lens

Abstract

The utility model discloses a soft contact lens. Through setting the near focus area, far focus area and gradient area with specific parameters, the near reading comfort of the presbyopia crowd is improved, and the wearing time is prolonged; the far vision of the low age presbyopia initial wearer is ensured, the near reading fatigue is reduced, and the development of the presbyopia is delayed; through the design of the far focus area and near focus area of the lens, the combination of the focal power gradient makes the far vision clear and the near vision comfortable and fatigue-free; the binocular fixation difference function and sensory fusion function are used to maintain the clarity of the far vision and the integrity of the far field.

Description

Technical Field

[0001] This utility model relates to the field of vision correction technology, and more specifically, to a soft contact lens for improving the wearing comfort of people with early-onset myopia and young people with myopia. Background Technology

[0002] Regarding presbyopia

[0003] As people age, their near point shifts away, leading to age-related difficulty reading near objects, a condition known as presbyopia.

[0004] Throughout a person's life, the amplitude of accommodation gradually decreases with age, but this is often unnoticed by those who do not engage in close work. After age 40, the amplitude of accommodation decreases further, and the eye's accommodative reserve for near reading is less than half of its original capacity. This leads to the gradual onset of near-reading fatigue in early-aging individuals. Figure 1 ).

[0005] Regarding insufficient regulation

[0006] The physiological response in which the refractive power of the eye's lens changes according to visual needs is called accommodation.

[0007] Near objects, as accommodative stimuli, can quantitatively induce corresponding accommodative responses in the eye. In young myopic individuals, during the initial stage of myopia before wearing glasses, the accommodative far point gradually shifts from infinity to a finite distance in front of the eyes. If this far point is on the near-focused target, accommodation is not required for near vision. Therefore, the amount of accommodative stimulus that a near object can release for an uncorrected myopic eye gradually decreases, and the eye's accommodative response also declines synchronously, though this is not noticeable to the user. As myopia progresses and full-correction glasses are required, the accommodative far point shifts to infinity. When focusing on near objects, the near object releases sufficient accommodative stimulus for the corrected eye. However, the corrected eye remains in a state of habitually insufficient accommodative response for near reading. Because the accommodative amplitude is lower than the normal value for its age, near-reading accommodative fatigue is induced, making it difficult to wear glasses. Figure 1 To avoid customer complaints, optical shops often adopt a lenient approach of prescribing slightly less myopic lenses, allowing the wearer to return to a state of habitual, uncorrected myopia to some extent. This reduces the need for accommodation when reading near objects, alleviating eye strain. However, this leads to blurred distance vision, and the blurred images received by the retina contribute to the further development of myopia. Summary of the Invention

[0008] The starting point of this utility model is to provide a soft contact lens, thereby solving the above-mentioned problems existing in the prior art.

[0009] According to this utility model, a soft contact lens is provided, the soft contact lens including a near-focal zone located at the geometric center of the lens, a far-focal zone located around the periphery of the near-focal zone, and a transition zone located between the near-focal zone and the far-focal zone, wherein,

[0010] The telefocal zone has a fully corrected negative focal power that matches the prescription for myopia in the glasses.

[0011] The near-focal zone power value is reduced by -0.60D to -1.20D compared to the prescription power for myopia with contact lenses.

[0012] The focal length of the gradient zone increases from the near-focus zone to the far-focus zone, with a total increment of -0.60D to -1.20D.

[0013] The sum of the radius of the near-focus zone and the arc width of the transition zone accounts for 1 / 4 to 1 / 3 of the total radius of the lens optical zone, and the arc width of the far-focus zone accounts for 3 / 4 to 2 / 3 of the total radius of the lens optical zone.

[0014] Optionally, the radius of the near-focal zone is 0.3 mm to 0.5 mm.

[0015] Optionally, the arc width of the gradient region is 0.6 mm to 0.9 mm.

[0016] Optionally, the arc width of the telephoto zone is 2.8 mm to 3.2 mm.

[0017] Optionally, the gradient zone includes 3 to 6 rings, each ring having a width of 0.15 mm to 0.2 mm, with the myopia prescription focal power increasing by -0.10D to -0.20D per ring from the near-focal zone to the far-focal zone.

[0018] Optionally, the gradient region is an aspherical negative focal length increasing region with a width of 0.6 mm to 0.9 mm, and the total increase in focal length from the near focal region to the far focal region is -0.60D to -1.20D.

[0019] Optionally, the near-focus area is a hyperbolic quadratic geometric surface designed on the outer curved surface of the lens, with an eccentricity e value greater than 1.0.

[0020] The soft contact lens according to this invention has at least the following advantages:

[0021] This invention relates to a soft contact lens that improves near-vision comfort for people with early-onset myopia by setting up near-focus, far-focus, and variable-power zones with specific parameters, thus helping them extend the lifespan of wearing contact lenses. It also ensures clear, fully corrected distance vision for young first-time wearers of myopia, reducing near-vision fatigue and slowing myopia progression. Through the design of the near-focus and far-focus zones of the lens, combined with a power gradient, it provides clear distance vision and comfortable, fatigue-free near vision. Furthermore, it utilizes binocular fixation difference function and sensory fusion function to maintain the clarity of distance vision and the integrity of the distance field of view. Attached Figure Description

[0022] Other details and advantages of this utility model will become apparent from the detailed description provided below. It should be understood that the following drawings are merely schematic and not drawn to scale, and therefore should not be considered as limitations on this utility model. The following detailed description will refer to the drawings, in which:

[0023] Figure 1 The relationship between the amplitude of adjustment and age is shown.

[0024] Figure 2 This shows how targets at different distances are focused on the retina.

[0025] Figure 3 The field of view of the contact lens when looking at a distant target is shown.

[0026] Figure 4 The field of view of the contact lens when focusing on a near target is shown.

[0027] Figure 5 The contact lens design layout is shown.

[0028] Figure 6 The imaging state of the distant gaze target is shown. Detailed Implementation

[0029] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0030] The design concept of this utility model is as follows: A soft contact lens is fitted with a negative focal power equivalent to full correction for myopia, used to correct distance vision; simultaneously, a low-gradient reduction in myopia focal power is set in specific areas of the lens to reduce accommodative tension in the eye when reading near objects, ensuring clear distance vision and comfortable, fatigue-free near vision. The gradient change in focal power between the distance and near focal areas aims to minimize the impact of minor focal power changes, avoiding alterations in the shape of the object being focused on. Figure 2 ).

[0031] The target audience for this new type of soft contact lens is as follows:

[0032] 1) Contact lens wearers and early-onset presbyopia

[0033] Soft contact lenses have been popular in my country for over thirty years. Those who have been wearing contact lenses since their teens are now entering early aging and cannot adapt to the aberrations caused by switching to eyeglasses. This group has good tear film layering, corneal sensation, and tolerance to low oxygen metabolism, all of which are well adapted to contact lenses. If the lens recommended in this invention can be used to appropriately extend the wearing period, it will significantly increase the target audience.

[0034] 2) Young children who are new to contact lenses for myopia

[0035] The prevalence of myopia among Chinese teenagers is increasing, along with the proportion of time they spend using their eyes for close-up work. Furthermore, the phenomenon of undercorrection due to near-sighted reading fatigue is becoming more common among teenagers with myopia. The blurred retinal image when looking at distance objects caused by insufficient correction is a contributing factor to the progression of myopia. This invention can ensure a clear retinal image when looking at distance objects with full correction without causing near-sighted reading fatigue. It is expected to be widely adopted among young first-time contact lens wearers and hopefully alleviate the progression of myopia.

[0036] Based on theoretical analysis and clinical verification, the inventors believe that, in order to achieve the above-mentioned invention objectives, the parameters of the soft contact lens of this invention can be set according to the following quantitative principles.

[0037] 1. Analysis of the diameter of the far-field optical region of the contact lens

[0038] (1) The visual field angle of the eye when focusing on a distant target

[0039] When the eye is focused on a distant target, the pupil diameter is at its physiological maximum value, such as... Figure 3 As shown, when the eye is focused on a distant target, the light rays incident from the edge of the pupil are refracted by the eye's refractive system and intersect the eye's principal axis at the eye's node N. Let α be the angle between the light rays incident from the edge of the pupil and the eye's principal axis, which is the visual field angle of the eye when focusing on a distant target. α can be calculated as follows.

[0040] Given: When focusing on a distant target, the measured average pupil radius r1 is approximately 2.48 mm, and the measured average distance x from the pupil plane to the node N is approximately 5.13 mm.

[0041] Find: the visual field angle α between the light ray incident from the edge of the pupil and the principal axis of the eye when focusing on a distant target.

[0042] Solution: tanα=r1 / x=2.48 / 5.13=0.48α≈25.7(°)

[0043] (2) Radius of the contact lens's field of view when focusing on a distant target

[0044] Suppose that when focusing on a distant target, the average radius of the field of view projected onto the contact lens is r. d Then r d The following can be calculated.

[0045] Given: When focusing on a distant target, the visual field angle α of the eye is approximately 25.7°, and the measured average distance y between the geometric center of the contact lens and the pupil plane is approximately 3.12 mm.

[0046] Find: the radius r of the field of view at the contact lens plane when focusing on a distant target. d .

[0047] Solution: r d =tan25.7(x+y)=0.48×(5.13+3.12)=3.96(mm)

[0048] Conclusion: When focusing on a distant target, the average diameter of the contact lens's field of view is approximately 8 mm. Figure 3 ).

[0049] 2. Diameter analysis of the near-light zone of the contact lens

[0050] (1) Visual angle of the eye when focusing on a near target

[0051] When focusing on a near object, the pupil diameter constricts moderately, such as Figure 4 As shown, light rays incident from the edge of the pupil are refracted by the eye's refractive system and intersect the eye's principal axis at the eye's node N. Let β be the angle between the light rays incident from the edge of the pupil and the eye's principal axis, representing the visual field angle of the eye when focusing on a near target. β can be calculated as follows.

[0052] Given: When focusing on a target 33cm away, the measured average pupil radius r2 is approximately 1.12mm, and the measured average distance x from the pupil plane to the node N is approximately 5.13mm.

[0053] Find: the near field angle β between the light ray incident from the edge of the pupil and the principal axis of the eye when focusing on a near target.

[0054] Solution: tanβ=r² / x=1.12 / 5.13=0.22β≈12.3(°)

[0055] (2) Radius of the field of view at the contact lens when focusing on a near target

[0056] Assume that when focusing on a near target, the average radius of the field of view angle projected by the contact lens is r. n Then r n The following can be calculated.

[0057] Given: The near field of vision angle β of the eye is approximately 12.3°, and the measured average distance y between the geometric center point of the contact lens and the pupil plane is approximately 3.12 mm.

[0058] Find: the radius rn of the field of view at the contact lens plane when focusing on a near target.

[0059] Solution: r n =tan12.3(x+y)=0.22×(5.13+3.12)=1.81(mm)

[0060] Conclusion: When focusing on a near target, the average diameter of the contact lens's field of view is approximately 3.6 mm. Figure 4 ).

[0061] 3. Design Summary of the Contact Lens of this Utility Model

[0062] Based on the above calculations of the eye's visual field angle and the diameter of the contact lens's visual field when focusing on distant and near targets, the inventors of this invention have designed the optical layout and focal length of the soft contact lens to ensure that the optical layout and focal length of the soft contact lens are precisely matched with the laws of human vision, ultimately achieving the invention goal of "clear vision for distant objects and comfortable, fatigue-free vision for near objects".

[0063] (1) Light area layout

[0064] 1) The near-focus power is located at the geometric center of the lens, while the far-focus power is located around the near-focus power.

[0065] 2) The radius of the near-focal zone is about 0.3mm to 0.5mm, and the arc width of the transition zone is about 0.6mm to 0.9mm. The sum of the two accounts for about 1 / 4 to 1 / 3 of the total radius of the optical zone of the lens.

[0066] 3) The telephoto zone is designed on the outer surface of the lens according to the target focal power of the eye wearing the glasses. The arc width is about 2.8mm to 3.2mm, which accounts for about 3 / 4 to 2 / 3 of the total radius of the optical zone.

[0067] (2) Focal Dimension Design

[0068] 1) The near-focus zone is designed on the outer curved surface of the lens, which is a hyperbolic quadratic geometric surface with an eccentricity e-value > 1.0. The power value is reduced by -0.60D to -1.20D compared to the prescription power of the eye with glasses.

[0069] 2) The gradient zone is designed around the periphery of the near-focus zone, divided into 3 to 6 rings, each ring being 0.15mm to 0.2mm wide. The prescription power for myopia increases by -0.10D to -0.20D with each ring from the near-focus zone to the far-focus zone. Figure 5 Alternatively, an aspherical negative focal length increasing zone with a width of 0.6mm to 0.9mm can be set from the center near-focal area outwards, with a total increase of approximately -0.60D to -1.20D.

[0070] (3) Implementation Principles

[0071] 1) Fixation differences

[0072] In the above design, when looking at distant objects with glasses, if the extended line connecting the nodal points of both eyes to the fovea of ​​the macula is called the physiological visual axis, the physiological visual axis will inevitably pass through the near vision zone in the center of the lens, resulting in undercorrection of myopia and blurred vision when looking at distant objects, no different from undercorrection of myopia during a regular refraction. However, the binocular fixation difference function can cause a slight convergence lag between the two eyes, so that the physiological visual axes of the two eyes are not aligned with the fixation target. The intersection of the actual visual axes is aligned with the fixation target. The actual visual axis can bypass the near vision zone of the lens, so that the distant fixation target is imaged on the temporal side of the macula of both eyes. The micro-scale fusion zone around the macula is called the Panum fusion zone, which allows fusion to be formed even in the non-corresponding areas of the two eyes, without discomfort. Figure 6 ).

[0073] 2) Sensory fusion

[0074] When wearing glasses to see far, the undercorrected image of the near vision zone should theoretically appear in the field of vision of the glasses-wearing eye. However, the glasses-wearing eyes can use sensory fusion to ignore the existence of the near vision zone, thus making the distance vision complete.

[0075] 3) Pupil constriction and dilation

[0076] When wearing glasses for near vision, the above design allows the pupil to constrict and cover most of the peripheral far-focus area, while the lens in the pupil area retains the complete near-focus portion. This effectively compensates for the insufficient accommodative reserve in early-onset myopia or the insufficient accommodative reserve in young myopia, thereby achieving clear near vision.

[0077] In summary, through theoretical analysis and clinical verification by the inventors, a novel soft contact lens was designed. By setting near-focus, far-focus, and variable-power zones with specific parameters, it improves near-reading comfort for people with early-onset myopia and helps them extend the wearing period; it ensures clear and fully corrected distance vision for young myopic beginners, reduces near-reading fatigue, and prevents myopia progression; through the design of the far-focus and near-focus zones of the lens, combined with power variation, it ensures clear distance vision and comfortable, fatigue-free near vision; and it maintains the clarity of distance vision and the integrity of the distance field of view by utilizing binocular fixation difference function and sensory fusion function.

[0078] Although the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any modifications and alterations made by those skilled in the art without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. A soft contact lens, characterized in that, The soft contact lens includes a near-focal zone located at the geometric center of the lens, a far-focal zone located around the periphery of the near-focal zone, and a transition zone located between the near-focal zone and the far-focal zone, wherein, The telefocal zone has a fully corrected negative focal power that matches the prescription for myopia in the glasses. The near-focal zone power value is reduced by -0.60D to -1.20D compared to the prescription power for myopia correction with contact lenses. The focal length of the gradient zone increases from the near-focus zone to the far-focus zone, with a total increment of -0.60D to -1.20D. The sum of the radius of the near-focus zone and the arc width of the transition zone accounts for 1 / 4 to 1 / 3 of the total radius of the lens optical zone, and the arc width of the far-focus zone accounts for 3 / 4 to 2 / 3 of the total radius of the lens optical zone.

2. The soft contact lens according to claim 1, wherein, The radius of the near-focal zone is 0.3 mm to 0.5 mm.

3. The soft contact lens according to claim 1, wherein, The arc width of the gradient zone is 0.6 mm to 0.9 mm.

4. The soft contact lens according to claim 1, wherein, The arc width of the telephoto zone is 2.8 mm to 3.2 mm.

5. The soft contact lens according to claim 1, wherein, The gradient zone comprises 3 to 6 rings, each ring having a width of 0.15 mm to 0.2 mm, with the myopia prescription focal power increasing by -0.10D to -0.20D per ring from the near-focal zone to the far-focal zone.

6. The soft contact lens according to claim 1, wherein, The gradient region is an aspherical negative focal length increasing region with a width of 0.6 mm to 0.9 mm, and the total increase in focal length from the near focal region to the far focal region is -0.60D to -1.20D.

7. The soft contact lens according to claim 1, wherein, The near-focus area is a hyperbolic quadratic geometric surface designed on the outer curved surface of the lens, with an eccentricity e value greater than 1.0.

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