Low near vision optical typoscope
By setting the near vision correction power Dn = k / Vn and the near vision distance dn = 1/Dt for low near vision optical aids, the problem of inaccurate near vision correction for low vision patients in existing technologies is solved, and patients' near vision is effectively improved and their ability to read for extended periods of time is enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2026-03-27
AI Technical Summary
The "dosage" settings of existing low vision optical aids are not precise enough, resulting in poor near vision correction for low vision patients and making it difficult to support long-term close-range reading.
By setting the near vision assist power Dn = k / Vn for low near vision optical aids, where k ≥ 1.35, and combining it with the near vision assist distance dn = 1/Dt, the parameters of the optical aids, including the near vision assist power, the total vision assist power, and the near vision assist distance, are precisely quantified to improve the near vision of patients.
It enables precise quantification of the near vision correction efficiency for patients with low near vision, improves their near vision, allows them to engage in near-distance reading for extended periods, and improves their quality of life.
Smart Images
Figure CN224052514U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of low myopia correction, in particular to a low myopia optical visual aid. BACKGROUND
[0002] If the visual function of both eyes is reduced to a certain degree and the vision of the patient cannot be improved by surgery, drugs or conventional refractive correction methods, resulting in partial loss of the patient's life and work ability, it is defined as low vision. The diagnostic criteria for low vision is that the decimal vision of the better eye in both eyes after regular treatment and refractive correction is in the range of 0.05 to 0.3.
[0003] The optical device that can improve the survival potential of low vision patients is called an optical visual aid, and the rehabilitation vision obtained with the aid of the optical visual aid is called aided vision.
[0004] According to the needs of low vision patients for vision, the categories of optical visual aids are divided into: aided vision devices for quantitatively improving distance vision (also known as action vision), which are called distance-specific visual aids (i.e., low distance vision optical visual aids); and aided vision devices for quantitatively improving near vision (also known as reading vision), which are called near-specific visual aids (i.e., low near vision optical visual aids). Due to the increasing popularity of electronic products such as computers and mobile phones, most low vision patients pay more attention to the improvement of near vision, so the utility model mainly relates to low near vision optical visual aids.
[0005] Fitting of low vision optical visual aids: requires optometrists to master the principles and effects of low vision optical visual aids, and to select optical visual aids with appropriate "dosage" for low vision patients according to their needs and residual vision conditions, in order to maximize the survival potential of patients and improve their quality of life. The "dosage" of optical visual aids includes but is not limited to parameters such as the visual aid power and the visual aid distance of the optical visual aid.
[0006] However, in existing clinical applications, the "dosage" of optical visual aids for low vision patients is often not strictly accurate, so it is necessary to select a low near vision optical visual aid with appropriate "dosage". UTILITY MODEL CONTENT
[0007] The utility model discloses a low near vision optical visual aid, thereby solving the above problems existing in the prior art.
[0008] According to the utility model, a low near vision optical visual aid is provided, and the near visual aid power Dn of the low near vision optical visual aid is: Dn = k / Vn, k >= 1.35, wherein Vn is the best near vision of the patient.
[0009] Optionally, k = 1.35.
[0010] Optionally, the total vision-aiding power Dt of the low near-vision optical vision aid is: Dt = Dn + Dd + Dp, wherein Dd is a far-vision power, and Dp is a presbyopia power.
[0011] Optionally, the near-vision-aiding distance dn of the low near-vision optical vision aid is: dn = 1 / Dt.
[0012] Optionally, the low near-vision optical vision aid comprises at least one of: a near-vision aid glasses (for example, a compound near-vision aid glasses), a hand-held magnifying glass.
[0013] The low near-vision optical vision aid according to the present application has at least the following advantages:
[0014] Through the clinical verification of the inventor, the correction efficiency of the low near-vision optical vision aid is accurately quantified, so that the "dose" (i.e., the near-vision-aiding power, the total vision-aiding power, and the near-vision-aiding distance, etc.) of the optical vision aid can effectively improve the near vision of the patient to support the patient to read for a long time at close range, thereby improving the quality of life of the patient. BRIEF DESCRIPTION OF DRAWINGS
[0015] Other details and advantages of the present application 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 limiting of the present application, which will be described in detail below with reference to the accompanying drawings, in which:
[0016] Figure 1 A 30cm low near-vision table showing one specific embodiment of the present application is shown.
[0017] Figure 2 A principle of a low-vision eye reading 0.4 near-vision target is shown.
[0018] Figure 3 A functional visual angle and a vision-aiding distance are shown to be negatively correlated. DETAILED DESCRIPTION
[0019] Embodiments of the present application will be described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application. In addition, it is to be understood that the present application is not limited in its application to the particularly exemplified embodiments herein. Instead, the present application is capable of achieving its objects and providing its advantages with other embodiments, including those not specifically described herein. Accordingly, the following aspects, features, embodiments and advantages are merely illustrative and are not restrictive of the present application, unless otherwise indicated in the claims.
[0020] Through a large number of clinical verifications, the inventor believes that the parameters (i.e., "dosage") of the optical visual aid for low near vision can be set according to the following quantitative principle for low near vision correction.
[0021] (1) Minimum standard of near reading vision: the size of the standard height of the small five-size character on a book or newspaper is 0.22 mm, which is approximately equal to 0.2 near vision target on a 30 cm near vision chart, so as long as the patient's eye can clearly see the 0.2 near vision target by using appropriate visual aid, the patient should be able to normally read a book or newspaper.
[0022] (2) Minimum standard of low near vision rehabilitation: the near vision chart is a tool for investigating the resolution limit of the eye. Figure 1 A 30 cm low near vision chart of one specific embodiment of the utility model is shown. Although theoretically the patient's eye can distinguish 0.2 near vision target to be able to normally read, but through the inventor's clinical verification, in fact, the resolution limit of the eye cannot support long time close reading, so the low vision eye can only distinguish 0.2 near vision target cannot achieve normal reading. Through clinical verification, the inventor found that by gradually increasing the power of the visual aid device, the rehabilitation near vision is gradually improved, and it is found that the 0.4 near vision is necessary to support the low vision eye to read the small five-size character on the book or newspaper at a distance of 30 cm. The observation results of the correlation between the visual aid vision and the time of continuously reading the small five-size character of 156 cases of low near vision patients are shown in Table 1.
[0023] Table 1 Correlation between visual aid vision and continuous reading time
[0024]
[0025] (3) How to make the low vision eye have 0.4 near vision: Figure 2 The principle of the low vision eye clearly seeing 0.4 near vision target is shown. As shown in Figure 2 , the standard fixation distance of the low near vision chart is 30 cm, and it is assumed that the minimum size of the near vision target that the low near vision patient can clearly see at 30 cm is h, and the functional visual angle of the near vision target with a height of h to the patient's eye is β. The 0.4 near vision target is gradually moved from 30 cm to the patient's eye, and when the height of the 0.4 near vision target is just intersected with the β visual angle, the patient's eye should have 0.4 near vision at the position.
[0026] (4) Visual aid distance and visual aid power: continue as Figure 2As shown, when the elevation of the 0.4 myopia target intersects with the functional visual angle β of the tested eye, the tested eye should theoretically have a near visual acuity of 0.4. Let the auxiliary visual distance of the 0.4 myopia target to the tested eye at this time be dn. The 0.4 myopia target has a large dispersion for the fixating eye at the auxiliary visual distance dn, even much greater than the eye's accommodative ability. Therefore, a positive lens with a focal length equal to the auxiliary visual distance dn must be placed in front of the fixating eye. The convergence force of the positive lens can just cancel out the dispersion of the 0.4 myopia target for the fixating eye, allowing the affected eye to see the 0.4 target clearly. The reciprocal of the auxiliary visual distance dn is the auxiliary focal length Dn required for the affected eye to have a near visual acuity of 0.4.
[0027] (5) Based on the existing low myopia, deduce the assistive distance and assistive focal length: Summarizing the above analysis, the main steps of low myopia correction are:
[0028] 1) The functional visual angle is determined by the elevation of the residual visual acuity of the affected eye.
[0029] 2) The visual aid distance is determined by the intersection of the elevation of the 0.4 target and the functional viewing angle.
[0030] 3) Quantitatively determine the assistive focal length for the rehabilitation of low near vision eyes based on assistive visual distance.
[0031] The inventors believe that the near vision assist focal length of a low near vision optical aid can be derived using the following method:
[0032] (1) It is known that the decimal optotype value Vn of low near vision is negatively correlated with the functional visual angle β: Vn = 1 / β (definition of decimal vision).
[0033] (2) When the target elevation remains constant at 0.4, the functional visual angle β is negatively correlated with the visual aid distance dn: dn = 1 / β, as shown below.
[0034] like Figure 3 As shown, let the height of the 0.4 optotype on the 30cm near vision chart be the first right-angled side b. Move the optotype 0.4 towards the affected eye until b intersects with the functional visual angle (i.e., the hypotenuse). The diagonal of b is the functional visual angle β of the affected eye. The visual aid distance of b from the eye is the second right-angled side dn. Then tgβ = b / dn, and dn is negatively correlated with β.
[0035] (3) The visual aid distance dn is negatively correlated with the visual aid focal length Dn: dn = 1 / Dn (focal length calculation formula).
[0036] (4) In summary, it can be inferred that the decimal optotype value Vn of low near vision is negatively correlated with the near vision assist focal length Dn: Dn=1 / Vn.
[0037] See clearly the empirical formula for 0.4 visual aid diopters
[0038] Through a large number of clinical verifications, the inventor found that the near vision addition power calculated by the formula Dn = 1 / Vn is not sufficient for the affected eye to see 0.4 near vision. Through the inventor's clinical verification, the clinical step-by-step trial and error confirmed that the ratio of the constant (the inventor defines it as the near vision addition constant k) of 1.35 (or above) to the residual vision is the near vision addition power of the affected eye to see 0.4 near vision, which can be expressed by the formula:
[0039] Dn = k / Vn, wherein the near vision addition constant k ≥ 1.35, and Vn is the best near vision of the patient.
[0040] The inventor lists the ratio of the near vision addition power calculated by the ratio of the different near vision addition constant to the residual vision that can see 0.4 near vision for 84 cases as follows (the near vision method uses a precise quantitative hand magnifying glass).
[0041] Table 2 Ratio of near vision addition power calculated by different near vision addition constants to see 0.4 near vision
[0042]
[0043] As shown in Table 2, the ratio of the near vision addition power reaching 0.4 increases as the value of the near vision addition constant k increases. When the value of the near vision addition constant k reaches 1.35, the ratio of the near vision addition power reaching 0.4 is 87.4%. Therefore, statistically, when the value of the near vision addition constant k is greater than or equal to 1.35, the near vision addition power of the optical near vision device calculated under the condition of the near vision addition constant k ≥ 1.35 can make the near vision addition power of the patient reach 0.4.
[0044] Further, although theoretically the near vision addition 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 vision addition constant k does not significantly help to further improve the ratio of the near vision addition power reaching 0.4, on the contrary, further increasing the near vision addition constant k will reduce the patient's visual field. Therefore, preferably, the value of the near vision addition constant k is equal to 1.35, so as to enable the patient's near vision addition power to reach 0.4 while preserving a larger visual field for the patient.
[0045] If the effects of the distance prescription and presbyopia and other refractive factors are not considered, the reciprocal of the near vision addition power is the appropriate near vision distance: dn = 1 / Dn. In the formula, Dn is the near vision addition power, with the unit of D; Vn is the best decimal low near vision of the patient; and dn is the near vision distance, with the unit of m.
[0046] The following illustrates the calculation process of the near vision addition power and the near vision distance without considering the effects of the distance prescription and presbyopia and other refractive factors by means of a specific example.
[0047] Example 1: Suppose the best near vision of a patient is 0.08, 0.1, 0.126 respectively, and the value of near vision constant k is 1.35,
[0048] Find: near vision power and near vision distance (without considering far vision prescription and presbyopia refractive factors)
[0049] Solution: 1) The best near vision is 0.08
[0050] Near vision power Dn1 = 1.35 / 0.08 = 17.00 (D)
[0051] Near vision distance dn1 = 1 / 17 = 6 (cm)
[0052] 2) The best near vision is 0.1
[0053] Near vision power Dn2 = 1.35 / 0.1 = 13.50 (D)
[0054] Near vision distance dn2 = 1 / 13.5 = 7.4 (cm)
[0055] 3) The best near vision is 0.126
[0056] Near vision power Dn3 = 1.35 / 0.126 = 11.00 (D)
[0057] Near vision distance dn3 = 1 / 11 = 9 (cm)
[0058] Influence of ametropia and presbyopia on total optical power of low near vision aid
[0059] (1) Quantitative 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, the best distance vision Vd of the affected eye can be obtained by means of conventional means through subjective and objective refraction. Then, the patient's near vision is obtained by wearing a distance optical test piece combination at a near distance of 30 cm to observe the low near vision table, and if the patient's near vision is not lower than the distance vision, it is determined as the best near vision Vn of the patient. If the patient's near vision is lower than the distance vision, the presbyopia power is added appropriately according to the patient's age to obtain the best near vision Vn of the patient.
[0060] (2) Calculation of near vision power Dn according to the best near vision Vn: Dn = k / Vn, k ≥ 1.35.
[0061] (3) Quantification of total vision power Dt: total vision power Dt = near vision power Dn + distance vision power Dd + presbyopia power Dp. Those skilled in the art can understand that any suitable known refraction means can be used to determine the distance vision power Dd and the presbyopia power Dp of the patient, which is not described here.
[0062] (4) Calculate the near vision distance: the reciprocal of the total near vision power is the near vision distance: dn = 1 / Dt.
[0063] (5) Analysis of the influence of refractive factors on the total near vision power: if the eye has hypermetropia or presbyopia, the positive near vision power should be compensated by the positive refractive power of hypermetropia and / or presbyopia. If the eye has myopia, the total near vision power should be reduced by the myopic refractive power, and the inherent positive refractive power in the eye should replace part of the total near vision power.
[0064] Example 2: Suppose that the far vision power is +3.50, the presbyopia power is +2.00, the best near vision is 0.16, and the value of the near vision constant k is 1.35,
[0065] Solve: total near vision power and near vision distance
[0066] Solution: near vision power Dn = 1.35 / 0.16 = 8.50 (D)
[0067] Total near vision power Dt = 8.5 + 3.5 + 2 = 14.00 (D)
[0068] Near vision distance dn = 1 / 14 = 7 (cm)
[0069] Example 3: Suppose that the far vision power is -7.00, the presbyopia power is +3.00, and the best near vision is 0.1
[0070] Solve: total near vision power and near vision distance
[0071] Solution: near vision power Dn = 1.35 / 0.1 = 13.50 (D)
[0072] Total near vision power Dt = 13.5 - 7 + 3 = 9.50 (D)
[0073] Near vision distance dn = 1 / 9.5 = 11 (cm)
[0074] Those skilled in the art can understand that the technical scheme of the present application can be applied to any suitable type of low near vision optical aid, and these modifications do not exceed the protection scope of the present application. The main types of low near vision optical aids can include: near vision aid glasses (for example, compound near vision aid glasses), handheld magnifiers, etc. These optical aids can be fitted and applied based on the quantified near vision power and near vision distance of the present application, and will not be described here. Preferably, for patients with best near vision better than 0.1, near vision aid glasses (for example, frame glasses with additional prisms) can be used for correction; for patients with best near vision lower than or equal to 0.1, handheld magnifiers made of precisely quantified positive power lenses can be used for correction.
[0075] In summary, by the clinical verification of the inventor, the correction efficiency of the low visual acuity optical visual aid is accurately quantified, so that the "dose" (i.e., the near visual aid power, the total visual aid power, and the near visual aid distance, etc.) of the optical visual aid can effectively improve the near visual acuity of the patient to support the patient to read for a long time at a close distance, thereby improving the life quality of the patient.
[0076] Although the utility model has disclosed as above with preferable embodiment, the utility model is not limited to this. Any person skilled in the art, the various changes and modifications made without departing from the spirit and scope of the utility model, should be included in the protection scope of the utility model, therefore the protection scope of the utility model should be limited to the range defined by the claims.
Claims
1. A low-vision optical magnifier, characterized in that, The near vision addition power Dn of the low near vision optical aid is: Dn = k / Vn, k ≥ 1.35, wherein Vn is the best near vision of the patient, the total vision addition power Dt of the low near vision optical aid is: Dt = Dn + Dd + Dp, wherein Dd is the distance vision power, Dp is the presbyopia power, and the near vision addition distance dn of the low near vision optical aid is: dn = 1 / Dt.
2. The low-vision optical aid according to claim 1, wherein, k = 1.35。 3. The low-vision optical aid of claim 1, wherein, The low near vision optical aid comprises at least one of: a near vision addition spectacle, a hand-held magnifier.