JPS6147657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a simple method for manufacturing bifocal, trifocal, or multifocal contact lenses.

Heretofore, two known methods of manufacturing bifocal contact lenses have been implemented.

That is, one method is to scrape off the near vision part of a contact lens, bond another material with a different refractive index to that part, and then polish both the concave and convex surfaces of the contact lens into the same spherical surface. One method is to polish a portion of the concave or convex surface of a contact lens made of one type of material to a different curvature from the remaining portion, thereby forming portions with different refractive powers.

However, the former method involves the trouble of adhering two types of materials, and the manufacturing method also requires advanced technology. On the other hand, in the latter method of forming a spherical surface with two or more different radii of curvature on one lens surface, conventionally, the radius of curvature and the center of cutting rotation are changed during cutting, or
Conventionally, concentric sections with different curvatures are formed around the center of the lens. However, this latter method also had the disadvantage that cutting and polishing had to be carried out twice, once for near use and once for far use, requiring high processing precision and resulting in poor yield.

An object of the present invention is to provide a simple method for manufacturing a multifocal contact lens in order to solve the above-mentioned drawbacks of the prior art.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

First, a spherical lens is manufactured by a normal method. That is, FIG. 1 shows a spherical contact lens 1 having a near vision power necessary for the wearer, and FIG. 2 shows a spherical prism-equipped contact lens 2 having a near vision power necessary for the wearer. In order to prevent rotation of the lens during wear, it is desirable to use a contact lens 2 with a spherical prism. The near vision power of the wearer is measured in advance, the wearer is made to wear a contact lens 2 with a spherical prism of this near vision power, and after confirming the stable position of the contact lens when worn, the near vision part is laid out. That is,
Determine where and what shape and size of the near vision portion will be provided on the contact lens.
Next, the contact lens is removed, a protective film in the shape of the near vision area is prepared according to the layout, and is attached to the convex surface of the contact lens.
As a protective coating, it does not interfere with power correction during the polishing process.
Also, adhesive tape that will not peel or tear,
Adhesive film can be cut into appropriate shapes and sizes. Further, the film may be attached with an adhesive, and in some cases, paint or the like may be applied according to the layout. However, in these cases, it may interfere with the next power correction process, or
It is necessary to choose one that will not peel off or tear. In FIG. 3, the shaded area indicates the area to which the protective coating 3 according to the embodiment of the present invention is attached, and the remaining area indicates the distance viewing area 4 of various shapes. Furthermore, the protective coating 3 must be able to be removed without damaging the contact lens surface after power correction.

FIG. 4 shows a polisher and a special jig 6 used to correct the power by impregnating the sponge 5 with an abrasive, and is an explanatory diagram showing two methods for correcting the power.

Method (A) is a method of polishing a contact lens by pressing it against the sponge 5 so that the tangent of the front curve of the lens is parallel to the contact surface of the rotating barrel of the polisher when you want to increase the power on the negative side. It is.

Method (B) is when you want to increase the power on the plus side, you polish the lens by pressing it against a sponge so that the tangent of the front curve of the contact lens is tilted against the contact surface of the rotating barrel of the polisher. be.

After forming the protective coating 3 on the contact lens, the concave surface of the contact lens is attached to the special jig 6, and the convex surface is polished by the method (A) or (B) above to correct the power until the desired distance power is achieved. Do this. At this time, a hole is made in the center of the special jig 6,
It is convenient to check the power through this hole while polishing. After completing the power correction to the desired power, remove the protective coating 3,
By cleaning, the part to which the protective coating 3 has been pasted retains the power of the original spherical contact lenses 1 and 2, and can be used as a near vision part.

FIG. 5 is an explanatory diagram showing a special jig 6 used for fixing and polishing a contact lens to correct the power. The special feature of this special jig 6 is that a hole is drilled in part A so that the power can be measured without removing the contact lenses 1 and 2 from the special jig 6 during power correction, and the power can be checked through the hole. It's all about what you can do.

Further, the portion other than the protective coating 3 whose power has been corrected can also be used for distance vision. After first determining the resting position of the lens by the prism, the resting position does not substantially change even if the distance power is corrected. Therefore, a bifocal lens adapted to each wearer is thereby completed.

FIG. 6 is a process diagram for manufacturing a trifocal contact lens using the simple manufacturing method of the present invention.

FIG. 6a shows the stage of preparing a spherical contact lens 1 or a contact lens with a spherical prism 2 having the near vision power required by the wearer and laying out the intermediate and near vision parts most suitable for the wearer. , Fig. 6b shows that only the near vision area is covered with the protective coating 3 at first.
2, and the power is corrected using the polishing method described above until a predetermined intermediate power is obtained. In addition, in Figure 6c, the protective coating on the near vision area is left as is,
FIG. 6d is a process diagram showing the step of covering the intermediate portion with a protective coating and correcting the power of the distance vision portion, and the step of removing the protective coating 3 and cleaning after confirming that the desired power has been obtained. .

Note that a multifocal contact lens can be manufactured by further repeating the above method according to the present invention. In addition, in the above explanation, contact lenses with a near vision power were used to correct the power for distance vision, but conversely, after forming a protective coating on contact lenses with a distance vision power, the power was adjusted to the near vision power. You may make corrections. Furthermore, the above-described operation on a convex surface may be applied to a concave surface.

The method for manufacturing multifocal contact lenses according to the present invention is extremely simple compared to conventional methods, and allows for easy production of multifocal contact lenses that are suitable for individual wearers. Useful.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a spherical contact lens with the near vision power required by the wearer, Fig. 2 is an explanatory diagram showing a spherical prism contact lens with the near vision power necessary for the wearer, and Fig. 3 The figure is an explanatory diagram showing the shape and arrangement of the protective coating used in the embodiment of the present invention, FIG. 4 is an explanatory diagram showing the polisher and special jig used in the present invention, and FIG. FIG. 6 is an explanatory view showing a part of the special jig used in the invention, and FIG. 6 is a manufacturing process diagram of a trifocal contact lens according to the invention. Explanation of symbols, 1... Spherical contact lens, 2
...Contact lens with spherical prism, 3...Protective coating, 4...Distance part, 5...Sponge, 6...
…Tools for it.

Claims (1)

[Claims] 1. In a method for manufacturing a multifocal contact lens, a protective coating is adhered to a portion of a spherical contact lens, and the lens surface other than the protective coating is finished to a desired power by polishing the lens, and then the protective coating is A method for manufacturing a multifocal contact lens, comprising repeating the above step at least once.