RU2362523C2 - Bidirectional-prism spheroprismatic lenses - Google Patents

Abstract

FIELD: medicine; ophthalmology.

SUBSTANCE: bidirectional-prism spheroprismatic lenses comprise a prism with a horizontally-directed base and a prism with a vertically-directed basis. Strength of the second vertically-directed prism differs upward from that of the first horizontally-directed prism.

EFFECT: unloading of eye muscle at short-distance work related to down-looking.

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Description

The invention relates to medicine, namely to optical devices for primary prevention, treatment and secondary prevention of visual disturbances caused by work at close distances, as well as to create comfortable working conditions of the visual apparatus at close distances in healthy children and adults (reading, writing, work on the computer, small manual work, etc.).

The use of sphere-prismatic optics for the treatment, and subsequently the prevention of myopia and other visual impairments associated with working at short distances, has been in Russia for more than 50 years, thanks to the work of Dashevsky [1], Utekhina and Utekhina [5, 6] and other authors [2, 3, 4].

For the technical implementation of the unloading of the ciliary and internal muscles of the eye, first combined lenses were used, which were inserted separately into the ophthalmic frame [1]. The use of such glasses was possible only in the doctor’s office. Utekhin came up with the idea of sticking an additional sphere-prismatic component on the lens of ordinary glasses [5, 6]. The patient was given the opportunity to use the glasses on their own. As the imperfection of this solution, the specialists described the falling of air bubbles under the glued block and some other inconveniences [4]. Subsequently, the industrial production of solid spherical-prismatic lenses with a different combination of spherical and prismatic characteristics was established, which allowed their wider use in solving the stated problems.

Lyalin and co-authors drew attention to the fact that the latter solution also does not completely remove the problems of unloading the visual apparatus when working at close distances. When reading a text that is usually below the horizon, the eye is forced to direct the axis of view not only from the inside for convergence, but also down with the inclusion of the lower muscles of the eyes and neck muscles. This group of authors proposed the following technical solution: rotation of a sphere-prismatic lens when assembling glasses 45 degrees relative to the horizon with the base of the prism at the bottom of the nose in order to more balanced load compensation [4]. The latter invention is taken as a prototype.

This solution allows optimizing the eye's work in terms of its prismatic unloading, but the prismatic effect, sufficient for the inner muscles of the eye, is clearly not enough for the lower muscles of the eye and neck muscles, since the deviation when looking down is obviously greater than the convergent deviation of the axis of vision. For muscles that deflect downward, lenses with large prismatic diopters may be useful than for muscles that provide convergence.

The aim of the invention is the creation of lenses capable of more harmoniously unloading the eye muscles when working at close range, associated with lowering the gaze, in three directions: 1) unloading the ciliary muscle responsible for the lens accommodation, 2) unloading the internal muscles of the eyes responsible for convergence and 3 ) unloading of the lower muscles of the eyes and muscles of the neck, trunk, responsible for lowering the gaze.

This goal is achieved by the fact that three optical effects are incorporated in the design characteristics of a single lens: 1) spherical, unloading the ciliary muscle, responsible for the lens accommodation to close distances, 2) prismatic, unloading the internal muscles of the eyes, responsible for reducing the axes of vision, i.e. . unloading convergence (a prism oriented horizontally with the base at the nose) and 3) prismatic, unloading muscles that lower the gaze (a prism oriented vertically with the base at the bottom). Moreover, the vertically oriented prismatic effect, "raising the gaze", can extend to the entire field of view, if we are talking about lenses for use in glasses exclusively for reading, or can be turned on only when the gaze drops below the horizon, which is useful in glasses for working on a computer . The strength of the prism, which “raises” the gaze, may differ from the strength of the prism, which unloads convergence, in a larger direction. The spherical effect can change its characteristics in the direction of a shift to the plus side when the gaze is moved in the lower sector of the lens.

Structurally, this can be solved in two versions: simple, when the prisms are in the form of straight wedges superimposed on each other in the perpendicular direction, and the sphere (convex or concave) is extended to one surface (Figure 1-4), and more elegant, when everything effects are achieved due to spherical surfaces of different optical powers, rotated to each other at different angles (Figure 5). The prismatic effect of greater force in the vertical direction (the base of the prism below) and lesser force in the horizontal direction (the base of the prism near the nose), extending to the entire field of the lens, can also be achieved by turning a sphere-prismatic lens of sufficient strength when assembling sphere-prismatic glasses at an angle greater than 45 ° (but not more than 90 °) base.

Figure 1 - a possible combination of the prismatic components of the lenses: one prism is oriented horizontally, the other vertically, and the strength of the prisms may be different. The strength of a prism oriented downward by the base is greater than the strength of a horizontal oriented lens. This lens can cover only the lower part of the field of view, to "turn on" only when the deviation of the gaze downward, assisting the eye (Figure 2).

Figure 3, 4 shows a transverse section of the lens in its middle part if there is a convex spherical component (Figure 3) or a concave spherical component (Figure 4). On the front surface side (left) is a sphere, then a horizontally oriented lens and - a lens oriented downward with its base. Thus, in the total geometry of the lens three effects are summarized.

It is possible to manufacture lenses with a vertical oriented prismatic component in two versions: 1) with a full coverage of the field of view (in glasses exclusively for reading from a horizontal surface below eye level) (Figure 1), 2) with a coating of the field of view only in its lower part (Fig.2-5). In the latter case, the prismatic component, which “raises the gaze”, is turned on only when the axis of vision falls below the horizon.

The spherical component of the lenses in the near glasses is selected according to the principle of comfort. For people without deviations in refraction, these will be plus diopters on average from 0.25 to 1.25. In people with myopia, this will be diopters with a shift by the same values in the plus direction relative to the diopters used in glasses for distance. In hyperopia, it is advisable to complete the "plus" correction of existing hyperopia also on the principle of comfort. Bi-directional aspherical prismatic lenses are also possible.

With the advancement of the prior art, it is assumed that bi-directional prismatic sphere-prismatic lenses can be manufactured with a stepped or smooth transition of spherical characteristics along the vertical axis with a large positive shift in the lower part of the field of view, as is done in progressive lenses.

Technically, the creation of such lenses is possible by grinding lenses from semi-finished products, by molding plastic optical materials under pressure into a mold using a thermoplastic machine, or by injection molding using thermosets, it being assumed that the molds store the necessary integral characteristics. Other technical solutions are possible.

As a result of a combination of optical effects in glasses or other devices made using this type of lenses, harmonious unloading of the muscles responsible for accommodation, convergence and lowering of the gaze is achieved, as well as a smooth change in the installation of the eye when moving the gaze up, which usually requires focusing on more distant objects, and when moving the gaze down, which requires focusing the vision on nearby objects.

Information sources

1. Vatchenko A.A. Spasm of accommodation and myopia. Kiev, "Health", 1977.

2. Ermoshin A.F. A method for the primary prevention of visual impairment. Patent for invention No. 2177282, priority from 11/17/2000.

3. Lyalin A.N. A method for the prevention and treatment of myopia. Patent for invention No. 2145827, date of publication: 2000.02.27.

4. Lyalin A.N., Lyalin A.A., Chauzov V.A. Glasses for the prevention and treatment of visual fatigue syndrome. Patent for invention No. 2199987, publication date 03/10/2003.

5. Utekhin Yu.A., Tsameryan A.P. A method for the prevention and stabilization of myopia using bifocal sphere-prismatic glasses (BSPO). International Symposium "Myopia". Pathogenesis, prevention of progression and complications. - M .: 1990. P.109, 110.

6. Utekhin Yu.A. "Active rehabilitation optometry." Scientific Newsletter. Corporation "Sobko and K ⁰ ". - M .: 2000. S.7.

Claims (1)

Spherically prismatic lenses with bi-directional prismatic action, characterized in that they contain a prism with a base oriented in the horizontal direction and a prism with a base oriented in the vertical direction, the strength of the second prism oriented vertically differs from the strength of the first prism oriented horizontally in a larger direction.

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