JPH07159737A - Spectacle lens - Google Patents

Abstract

PURPOSE:To obtain a wide visual field from an intermediate distance to the extreme vicinity by specifying a relation between the refracting power of spectacle lenses at a fitting point and the far sight refracting power of the spectacle lenses. CONSTITUTION:This spectacle lens has a fitting point O between a starting point P and end point Q of a progressing zone. The average gradient of the admission diopter from the start point P of the progressive zone near to the fitting point O and the average gradient of the admission diopter from near the fitting point O to the end point Q of the progressive zone are different. In addition, the refracting power of the spectacle lens is so determined that the relation 0.3<FP-DP<1.0 (unit; diopter) holds when the refracting power of the spectacle lens at the fitting point O is defined as FP diopter and the far sight refracting power of the spectacle as DP diopter. Then, the gradient from P to O and the position of FP are kept constant regardless of the admission diopter. The refracting power changes progressively to the near sight prescription of a user by the admission diopter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presbyopia-correcting spectacle lens, and more particularly to a progressive multifocal lens for making clear vision from an intermediate distance to a short distance.

[0002]

2. Description of the Related Art A monofocal lens, a bifocal lens, a progressive multifocal lens and the like are used to correct presbyopia.
Of these, progressive multifocal lenses in particular do not require the glasses to be changed or removed during distance vision and near vision, and there is no boundary like bifocal lenses in appearance, and the demand for them is increasing considerably. It was

However, the progressive power multifocal lens has problems such as fluctuation and distortion of the visual field. Further, due to its structure, the visual field of far and near is narrow, and especially the visual field from the hand to the intermediate distance is required. Since the visible area is very small, it was not suitable for indoor use.

Under such a background, JP-A-62-106
The progressive bifocal lens for bifocals, which is designed to emphasize near vision from an intermediate distance, has been attracting attention. Compared with a general bifocal progressive multifocal lens, the bifocal progressive multifocal lens has less shaking and distortion, and has a wide field of view from the hand to the intermediate distance, and is said to be particularly easy to use indoors.

[0005]

However, in the progressive power multifocal lens disclosed in Japanese Unexamined Patent Publication No. 62-10617, the visible distance in the vicinity of the fitting point (eye point) changes depending on the addition power of the spectacle wearer. There is a point.

For example, it is assumed that the progressive multifocal lens coordinate system is defined as shown in FIG. 1, the fitting point is represented by O, and the distance prescription of the spectacle wearer is S0.00 diopter (orthotopic). At this time, the change in the refractive power on the main meridian of the progressive power multifocal lens of Japanese Patent Laid-Open No. 62-10617 is shown by A in FIG. 2 when the addition diopter is 1.0 diopter.
When the diopter is 2.0 diopters, it is represented by B in the same figure, and when the diopter is 3.0 diopters, it is represented by C. The refracting power at the fitting point is when Y = O in the same figure, 0.4 diopter if the wearer's addition power is A, 0.8 diopter if B, 1.2 diopter if C, respectively. It is added to the refracting power. Therefore, a person with add power A is 2.5 m near the fitting point, a person with B is 1.25 m, and a person with C is 0.
Only 83 meters can be seen clearly. Since the line of sight of a human being when gazing at an intermediate distance is generally slightly downward from the horizontal, in particular for indoor progressive multifocal lenses or middle-near bifocal progressive multifocal lenses, what kind of addition power a spectacle user uses is However, it is preferable that about 2 m ahead can be clearly seen in the vicinity of the fitting point. Japanese Patent Laid-Open No. 62-1061
With the progressive power multifocal lens No. 7, when the power of addition of the spectacles user becomes strong, only a few tens of centimeters ahead can be seen in the vicinity of the fitting point.

An object of the present invention is to provide a spectacle lens which can solve these problems and which is designed with emphasis on the short distance.

[0008]

The spectacle lens of the present invention comprises:
At least one of the two refracting surfaces forming the lens has a progressive band along the main meridian passing through substantially the center of the lens, and has a predetermined distance between the distance center and the near center on the main meridian. In the spectacle lens to which the addition power is added, having a fitting point between the start point and the end point of the progressive band, and the average gradient of the addition power from the start point of the progressive band to the vicinity of the fitting point,
The average gradient of the addition power from the vicinity of the fitting point to the end point of the progressive zone is different, and the refractive power of the spectacle lens at the fitting point is F
P diopter, DP for the distance refractive power of the spectacle lens
When the diopter is used, the relationship of 0.3 <FP-DP <1.0 (unit: diopter) is established.

The spectacle lens of the present invention does not depend on the addition power,
A predetermined refractive power is added to the distance power DP at the fitting point. Although it is a predetermined refractive power to be added, 0.5 diopter is preferable for the distance power of the spectacle lens. This is because if you can see clearly about 2 m ahead of the fitting point, you can use it without any discomfort in your daily life. However, depending on the use environment, the distance that can be clearly seen in the vicinity of the fitting point has the same effect up to ± 1 m with respect to the above value, so the above relational expression is used.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows the coordinate system of an eyeglass lens of the present invention. The main meridian is placed on the Y axis, the fitting point is O, and the progressive zone start point. , P is the coordinate of the progressive zone end point, Q is the coordinate of the top end of the spectacle lens, and S is the coordinate of the bottom end. FIG. 4 shows several examples of changes in the refracting power on the main meridian of the spectacle lens of the present invention. When DP is the distance refracting power of the spectacle lens of the present invention, the addition power of the user is 1. If it is 0 diopter, it is represented by the line A in the figure, and if the addition diopters are 2.0 and 3.0 diopter, it is represented by the lines B and C, respectively. FP represents the refractive power at the fitting point O of the spectacle lens of the present invention. In FIG. 4, the spectacle lens user of the present invention performs distance vision through the R to P region, near vision through the Q to S region, and an intermediate distance in the progressive zone between P and Q. is there.

At the fitting point O, if the refractive power added to the distance power of the spectacle lens is made constant irrespective of the addition power, P to O in FIG.
The slope of and the position of FP are constant regardless of the addition power,
In the section from O to Q, the refractive power progressively changes to the user's near prescription depending on the addition power. Therefore, as a general rule, the refractive power gradient between PO and OQ between the progressive zones P to Q changes.

Even if the gradient of the refractive power is not a straight line as shown in FIG. 4 but a curved line as shown in FIG. 5, the same effect can be expected.

FIG. 6 shows, as an example, the distance power S0.00.
The values are shown as specific values such as the change in the refractive power on the main meridian of the spectacle lens of the present invention with a diopter and an addition diopter of 3.0 diopters, and the length of the progressive zone. The progressive zone starts 10 mm above the fitting point O and extends 25 mm down to 15 mm below the fitting point O. This is because the gradient of the refractive power is made as gentle as possible to suppress the fluctuation and distortion and to secure the distance portion area and the near portion area. At the fitting point O, 0.5 diopters are added to the distance refractive power, so the user can see clearly at a distance of 2 m, and if the distance is further than that, the line of sight is slightly above and the near is below. Therefore, it is very suitable for indoor living environment.

[0014]

As described above, according to the spectacle lens of the present invention, it is possible to clearly see about 2 m ahead in the vicinity of the fitting point regardless of the distance prescription and the addition dioptric power of the spectacle user, which is extremely effective from the intermediate distance to the hand. You can get a wide field of view.

[Brief description of drawings]

FIG. 1 is a plan view showing a coordinate system of a progressive multifocal lens.

FIG. 2 is a diagram showing a change in refracting power on the main meridian of JP-A-62-10617.

FIG. 3 is a plan view showing the coordinate system of the spectacle lens of the present invention.

FIG. 4 is a diagram showing a change in refracting power on the main meridian of the spectacle lens of the present invention.

FIG. 5 is a diagram showing a change in refracting power on the main meridian of the spectacle lens of the present invention.

FIG. 6 is a diagram showing a change in refracting power on the main meridian of the spectacle lens of the present invention.

[Explanation of symbols]

O ・ ・ ・ Fitting point (eye point) P ・ ・ ・ Progressive zone start point Q ・ ・ ・ Progressive zone end point R ・ ・ ・ Eyeglass lens top end S ・ ・ ・ Eyeglass Bottom end of lens DP: distance power FP: power at fitting point A: refractive power change along the main meridian at addition diopter of 1.0 diopter B ..・ ・ ・ Change in refractive power on the main meridian at add power of 2.0 diopters C ・ ・ ・ Change in refractive power on main meridian at add power of 3.0 diopters

Claims (1)

[Claims] 1. A region where at least one of the two refracting faces constituting the lens has a progressively changing radius of curvature along a main meridian passing through substantially the center of the lens (hereinafter referred to as a progressive zone). ), And a fitting point between the start point and the end point of the progressive band, in a spectacle lens to which a predetermined addition power is added between the distance vision center and the near vision center on the main meridian, and The average gradient of the addition power from the start point of the progressive zone to the vicinity of the fitting point and the average gradient of the addition power from the neighborhood of the fitting point to the end point of the progressive zone are different, and of the spectacle lens at the fitting point. When the refractive power is FP diopter and the distance refractive power of the spectacle lens is DP diopter, 0.3 <FP-DP <1.0 (unit Spectacle lens characterized by dioptre) the relationship is established.