Low near vision optical typoscope

Abstract

The invention discloses a low near vision optical typoscope. Through clinical verification of the inventor, the correction efficiency of the low near vision optical typoscope is accurately quantified, so that the near vision of a patient can be effectively improved by the'dosage '(namely parameters such as near vision-assisting focal power, total vision-assisting focal power and near vision-assisting distance) of the optical typoscope so as to support long-time near-distance reading of the patient; therefore, the life quality of the patient is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low near - vision correction, and more particularly, to a low near - vision optical aid. Background Art

[0003] When the visual function of both eyes deteriorates to a certain extent, if the patient's vision cannot be improved by surgery, drugs, or conventional refractive correction methods, resulting in partial loss of the patient's living and working abilities, it is defined as low vision. The diagnostic criteria for low vision are: after regular treatment and refractive correction, the decimal visual acuity of the better eye in both eyes is within the range of ≥0.05 to <0.3.

[0004] An optical device that can improve the survival potential of low - vision patients is called an optical aid, and the rehabilitated vision obtained with the help of an optical aid is called aided vision.

[0005] According to the vision requirements of low - vision patients, the categories of optical aids are: an aiding device for quantitatively improving distance vision (also known as locomotion vision), called a distance - specific optical aid (i.e., a low - distance vision optical aid); and an aiding device for quantitatively improving near vision (also known as reading vision), called a near - specific optical aid (i.e., a low near - vision optical aid). Given the increasing popularity of electronic products such as computers and mobile phones, the vast majority of low - vision patients pay more attention to the improvement of near vision. Therefore, the present invention mainly relates to low near - vision optical aids.

[0006] Fitting of low - vision optical aids: It is required that the optometrist master the principles and effects of low - vision optical aids, and select an optical aid with a suitable "dose" for low - vision patients according to the needs of low - vision patients and the conditions of residual vision, so as to maximize the development of the patient's survival potential and improve the patient's quality of life. The "dose" of an optical aid includes, but is not limited to, parameters such as the aiding diopter and aiding distance of the optical aid.

[0007] However, in existing clinical applications, the "dose" of optical aids for low - vision patients is often not strictly accurate. Therefore, it is necessary to select a low near - vision optical aid with a suitable "dose". Summary of the Invention

[0008] The starting point of the present invention is to provide a low near - vision optical aid, thus solving the above - mentioned problems existing in the prior art.

[0009] According to the present invention, there is provided a low near - vision optical aid, wherein the near - aiding diopter Dn of the low near - vision optical aid is: Dn = k / Vn, k≥1.35, where Vn is the patient's best near - vision.

[0010] Optionally, k = 1.35.

[0011] Optionally, the total magnifying power Dt of the low near-vision optical magnifier is: Dt = Dn + Dd + Dp, where Dd is the distance power and Dp is the presbyopia power.

[0012] Optionally, the near magnifying distance of the low near-vision optical magnifier is: dn = 1 / Dt.

[0013] Optionally, the low near-vision optical magnifier includes at least one of the following: near-vision magnifying glasses (e.g., compound near-vision magnifying glasses), hand magnifiers.

[0014] The low near-vision optical magnifier according to the present invention has at least the following advantages:

[0015] Through the clinical verification of the inventor, the correction efficiency of the low near-vision optical magnifier has been accurately quantified, so that the "dose" of the optical magnifier (i.e., parameters such as near magnifying power, total magnifying power, and near magnifying distance) can effectively improve the near vision of patients to support long-term near reading of patients, thereby improving the quality of life of patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other details and advantages of the present invention will become apparent from the detailed description provided below. It should be understood that the following drawings are merely illustrative and not drawn to scale, and thus should not be considered as limiting the present invention. The following will be described in detail with reference to the drawings, where:

[0017] Figure 1 Shows a 30 cm low near-vision chart of a specific embodiment of the present invention.

[0018] Figure 2 Shows the principle of a low vision eye seeing a 0.4 near vision target.

[0019] Figure 3 Shows that the functional viewing angle is negatively correlated with the magnifying distance. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The embodiments of the present invention will be described below with reference to the drawings. In the following description, many specific details are set forth in order 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 some of these specific details may not be required for the implementation of the present invention. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, the present invention can be implemented by 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 regarded as elements or limitations of the claims, unless expressly recited in the claims.

[0021] Through a large number of clinical verifications, the inventor believes that the parameters (i.e., "dose") of the low near-vision optical aids can be set according to the following quantitative principle of low near-vision correction.

[0022] (1) Minimum standard for near reading vision: The elevation size of the small five-point font on books and newspapers is 0.22 mm, which is approximately equivalent to the 0.2 myopia target on a 30-cm near vision chart. Therefore, regardless of the near vision of the affected eye, by using appropriate visual aids, if the affected eye can see the 0.2 myopia target clearly, it should be able to read books and newspapers normally.

[0023] (2) Minimum standard for low near-vision rehabilitation: The near vision chart is a tool for examining the resolution limit of the eye. Figure 1 The 30-cm low near vision chart showing a specific embodiment of the present invention is presented. Although theoretically the affected eye can read normally if it can distinguish the 0.2 myopia target, through the inventor's clinical verification, in fact, using the resolution limit of the eye alone cannot support long-term close reading. Therefore, it is impossible to achieve normal reading only when the low vision eye can only distinguish the 0.2 myopia target. Through clinical verification, the inventor found that by gradually increasing the diopter of the visual aid device and gradually improving the rehabilitation near vision, it was learned that a near vision of 0.4 is necessary to support the low vision eye to continuously read the small five-point font on books and newspapers at a distance of 30 cm. The observation results of the correlation between the aided vision and the duration of continuously reading small five-point font reading materials for 156 low near-vision patients are shown in Table 1.

[0024] Table 1 Association between aided vision and continuous reading time

[0025]

[0026] (3) How to enable the low vision eye to have a near vision of 0.4: Figure 2 The principle of enabling the low vision eye to see the 0.4 myopia target clearly is shown. As Figure 2 shown, the standard fixation distance of the low near vision chart is 30 cm. Let: The minimum target elevation that the low near-vision affected eye can see clearly at 30 cm be h, and the functional visual angle subtended by the myopia target with elevation h to the affected eye be β. Move the 0.4 myopia target gradually from 30 cm towards the affected eye. When the elevation of the 0.4 myopia target exactly intersects with the β visual angle, the affected eye should have a near vision of 0.4 at this position.

[0027] (4) Aided distance and aided diopter: Continuing as Figure 2As shown, when the elevation of the 0.4 near vision target intersects with the functional visual angle β of the eye to be measured, the eye to be measured should theoretically have a near vision of 0.4. Suppose the assisting viewing distance of the 0.4 near vision target from the eye to be measured at this time is dn. The 0.4 near vision target has a large dispersion at the assisting viewing distance dn for the fixation eye, even much greater than the accommodation ability of the eye. Therefore, a positive lens with a focal length equal to the assisting viewing distance dn must be placed in front of the fixation eye. The converging power of the positive lens can exactly offset the dispersion of the 0.4 near vision target for the fixation eye, enabling the affected eye to see the 0.4 target clearly. The reciprocal of the assisting viewing distance dn is the assisting dioptric power Dn required for the affected eye to have a near vision of 0.4.

[0028] (5) Deducing the assisting viewing distance and assisting dioptric power based on the existing low near vision: Summarizing the above analysis, the main steps for correcting low near vision are as follows:

[0029] 1) Determine the functional visual angle from the elevation of the residual vision of the affected eye.

[0030] 2) Determine the assisting viewing distance from the intersection point of the elevation of the 0.4 target and the functional visual angle.

[0031] 3) Quantify the assisting dioptric power that enables the low near vision eye to recover based on the assisting viewing distance.

[0032] The inventor believes that the near assisting dioptric power of the low near vision optical assistor can be deduced in the following way:

[0033] (1) It is known that the decimal target value Vn of low near vision is negatively correlated with the functional visual angle β: Vn = 1 / β (definition of decimal visual acuity).

[0034] (2) With the elevation of the 0.4 target unchanged, the functional visual angle β is negatively correlated with the assisting viewing distance dn: dn = 1 / β. The proof is as follows.

[0035] As Figure 3 shown, suppose the elevation of the 0.4 target on the 30 cm near vision chart is the first right-angled side b. Move the 0.4 target towards the affected eye until b intersects with the functional visual angle (i.e., the hypotenuse). The opposite angle of b is the functional visual angle β of the affected eye, and the assisting viewing distance of b from the eye is the second right-angled side dn. Then tgβ = b / dn, and dn is negatively correlated with β.

[0036] (3) The assisting viewing distance dn is negatively correlated with the assisting dioptric power Dn: dn = 1 / Dn (focal length calculation formula).

[0037] (4) In summary, it can be deduced that the decimal target value Vn of low near vision is negatively correlated with the near assisting dioptric power Dn: Dn = 1 / Vn.

[0038] Empirical formula for seeing clearly with the assisting dioptric power of 0.4

[0039] Through a large number of clinical verifications, the inventor found that the near assistive diopter calculated by the formula Dn = 1 / Vn is not sufficient for the affected eye to clearly see the near visual acuity of 0.4. Through the clinical verification of the inventor, clinical trial and error step by step confirmed that: the ratio of a constant of 1.35 (or above) (which the inventor defines as the near assistive constant k) to the residual visual acuity is the assistive diopter for the affected eye to clearly see the near visual target of 0.4, which can be expressed by the formula:

[0040] Dn = k / Vn, where the near assistive constant k ≥ 1.35, and Vn is the best near visual acuity of the patient.

[0041] The list of the ratio of the assistive diopter calculated by different ratios of the near assistive constant to the residual visual acuity of 84 cases that can clearly see the near visual target of 0.4 by the inventor is as follows (the assistive method uses a precision quantitative hand magnifier).

[0042] Table 2 The ratio of the assistive diopter calculated by different near assistive constants that can clearly see the near visual target of 0.4

[0043]

[0044] As shown in Table 2, the ratio of the assistive visual acuity reaching 0.4 increases with the increase of the value of the near assistive constant k. When the value of the near assistive constant k reaches 1.35, the ratio of the assistive visual acuity reaching 0.4 is 87.4%. Thus, statistically, it can be considered that when the value of the near assistive constant k is greater than or equal to 1.35, the assistive visual acuity of the patient can reach 0.4. Correspondingly, when the near assistive constant k ≥ 1.35, the near assistive diopter Dn of the optical assistive device calculated can enable the assistive visual acuity of the patient to reach 0.4.

[0045] Furthermore, although theoretically the near assistive constant k can take any value greater than or equal to 1.35, through further clinical verification, the inventor found that further increasing the near assistive constant k is not significantly helpful for further increasing the ratio of the assistive visual acuity reaching 0.4. On the contrary, further increasing the near assistive constant k will narrow the field of view of the patient. Therefore, preferably, the value of the near assistive constant k is equal to 1.35, so as to retain a larger field of view for the patient while enabling the assistive visual acuity of the patient to reach 0.4.

[0046] If the influence of refractive factors such as the distance prescription and presbyopia is not considered, the reciprocal of the near assistive diopter is the appropriate near assistive distance: dn = 1 / Dn. In the formula, Dn is the near assistive diopter, with the unit of D; Vn is the best decimal low near visual acuity of the patient; dn is the near assistive distance, with the unit of m.

[0047] The following uses specific examples to illustrate the calculation process of the near assistive diopter and the near assistive distance without considering refractive factors such as the distance prescription and presbyopia.

[0048] Example 1 Suppose: The best near vision of the patient is 0.08, 0.1, and 0.126 respectively, and the value of the near assistive constant k is 1.35.

[0049] Find: The near assistive power and the near assistive distance (without considering refractive factors such as the distance prescription and presbyopia).

[0050] Solution: 1) The best near vision is 0.08

[0051] The near assistive power Dn1 = 1.35 / 0.08 = 17.00 (D)

[0052] The near assistive distance dn1 = 1 / 17 = 6 (cm)

[0053] 2) The best near vision is 0.1

[0054] The near assistive power Dn2 = 1.35 / 0.1 = 13.50 (D)

[0055] The near assistive distance dn2 = 1 / 13.5 = 7.4 (cm)

[0056] 3) The best near vision is 0.126

[0057] The near assistive power Dn3 = 1.35 / 0.126 = 11.00 (D)

[0058] The near assistive distance dn3 = 1 / 11 = 9 (cm)

[0059] The influence of refractive error and presbyopia on the total assistive power of low near vision optical aids

[0060] (1) Quantifying the best near vision Vn: Those skilled in the art can understand that any suitable means can be used to determine the best near vision of the patient. For example, first, by means of conventional methods, the best far vision Vd of the affected eye can be obtained through subjective and objective optometry. Then, wearing a distance optical test lens combination and looking at a low near vision chart at a distance of 30 cm to obtain the near vision of the patient. If the near vision of the patient is not lower than the far vision, it is determined as the best near vision Vn of the patient. If the near vision of the patient is lower than the far vision, an appropriate amount of presbyopic power is added in combination with the patient's age to obtain the best near vision Vn of the patient.

[0061] (2) Calculating the near assistive power Dn based on the best near vision Vn: Dn = k / Vn, k ≥ 1.35.

[0062] (3) Quantifying the total assistive power Dt: The total assistive power Dt = near assistive power Dn + distance power Dd + presbyopic power Dp. Those skilled in the art can understand that any suitable known optometry means can be used to determine the patient's hyperopic power Dd and presbyopic power Dp, which will not be elaborated here.

[0063] (4) Calculate the near aided vision distance: The reciprocal of the total aided vision diopter is the near aided vision distance: dn = 1 / Dt.

[0064] (5) Analysis of the influence of refractive factors on the total near aided vision diopter: If the affected eye has hyperopic refractive error or presbyopia, the positive diopter requirements of hyperopia and / or presbyopia need to be compensated on the basis of the positive near aided vision diopter. If the affected eye has myopic refractive error, the myopic diopter must be subtracted on the basis of the positive near aided vision diopter, and part of the total aided vision diopter is replaced by the inherent positive diopter in the eye.

[0065] Example 2 Assume: distance diopter +3.50, presbyopia diopter +2.00, best near vision 0.16, and the value of the near aided vision constant k is 1.35.

[0066] Find: the total aided vision diopter and the near aided vision distance

[0067] Solution: Near aided vision diopter Dn = 1.35 / 0.16 = 8.50 (D)

[0068] Total aided vision diopter Dt = 8.5 + 3.5 + 2 = 14.00 (D)

[0069] Near aided vision distance dn = 1 / 14 = 7 (cm)

[0070] Example 3 Assume: distance diopter -7.00, presbyopia diopter +3.00, best near vision 0.1

[0071] Find: the total aided vision diopter and the near aided vision distance

[0072] Solution: Near aided vision diopter Dn = 1.35 / 0.1 = 13.50 (D)

[0073] Total aided vision diopter Dt = 13.5 - 7 + 3 = 9.50 (D)

[0074] Near aided vision distance dn = 1 / 9.5 = 11 (cm)

[0075] Those skilled in the art can understand that the technical solution of the present invention can be applied to any suitable type of low near vision optical aids, and these variations do not exceed the protection scope of the present invention. The main types of low near vision optical aids can include: near vision aids glasses (for example, compound near vision aids glasses), hand magnifiers, etc. These optical aids can be fitted and applied based on the near aided vision diopter and near aided vision distance quantified by the present invention, which will not be elaborated here. Preferably, for patients with a best near vision better than 0.1, near vision aids glasses (for example, frame glasses with added prisms) can be used for correction; for patients with a best near vision less than or equal to 0.1, a hand magnifier made of accurately quantified positive diopter spectacle lenses can be used for correction.

[0076] In summary, through the clinical verification of the inventor, the correction efficiency of low near-vision optical aids has been accurately quantified, so that the "dose" of the optical aids (i.e., parameters such as near-vision assist power, total assist power, and near-vision assist distance, etc.) can effectively improve the near vision of patients to support long-term near reading of patients, thereby improving the quality of life of patients.

[0077] Although the present invention has been disclosed above in preferred embodiments, the present invention is not limited thereto. Any changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be incorporated within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A low near vision optical aid, characterized in that: The near vision focal power Dn of the low near vision optical aid is: Dn=k / Vn, k≥1.35, wherein Vn is the patient's best near vision.

2. The low near vision optical aid according to claim 1, wherein: k＝1.35。 3. The low near vision optical aid according to claim 1 or 2, wherein: The total visual aid focal power Dt of the low near vision optical aid is: Dt=Dn+Dd+Dp, wherein Dd is the distance focal power and Dp is the presbyopia focal power.

4. The low near vision optical aid according to claim 3, wherein: The near vision aid distance dn of the low near vision optical aid is: dn=1 / Dt.

5. The low near vision optical aid according to claim 1, wherein: The low myopia optical aid includes at least one of the following: near vision glasses and handheld magnifying glasses.

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