JPH026421Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a contact lens, and uses a hard, non-hydrous, and transparent resin such as esterified pullulan, CAB, or silicone resin to form a contact lens at least on the convex side of the optical part. The curve of the concave side is the same, that is, at least the thickness of the optical part is the same regardless of the location, and the curve does not match the curve of the corneal surface.By configuring the contact lens in a substantially dome shape, The contact lens can be made thinner, for example, with a thickness of about 0.01 to 0.05 mm, and can be used to correct mild to moderate visual acuity, or can be effective in correcting irregular corneal astigmatism, keratoconus, etc. Another object of the present invention is to provide a contact lens that is ultra-thin and has excellent wearing comfort, and that has good oxygen permeability and even better wearing comfort because of its ultra-thin design. .

Conventionally, contact lenses have been made by cutting and polishing a resin such as PMMA so that the posterior curve is approximately parallel to the curve of the corneal surface, and the anterior curve is different from the posterior curve. It is something. That is, the power of the contact lens is determined based on the radius of curvature of both surfaces of the contact lens and the thickness of the central portion of the lens, thereby correcting vision. Accordingly, contact lenses have to be relatively thick in order to fulfill their role. For this reason, even if a contact lens material with good oxygen permeability is used, the thickness of the contact lens is so thick that oxygen permeation will be that low, making it impossible to wear it continuously for a long time. The disadvantage is that the higher the weight, the greater the feeling of a foreign body when worn, resulting in poor wearing comfort.

The inventor of the present invention aims to correct mild to moderate vision and correct corneal irregular astigmatism by utilizing the tear film that exists between the contact lens and the corneal surface when the contact lens is attached to the eye. We thought that it would be possible to effectively treat keratoconus, etc., and if this could be achieved using the tear film, the thickness of the contact lens could be made extremely thin. Therefore, the present invention was achieved by noting that the amount of oxygen permeation increases accordingly, and the wearer is comfortable to wear with less foreign body sensation.

Examples of contact lenses according to the present invention will be described below.

First of all, it is ultra-thin, about 0.05mm or less, for example about 0.01~
Even with a thickness of 0.05 mm, it is rigid and non-hydrous and does not undergo deformation due to eyelid pressure when worn, and the amount of oxygen permeation necessary for respiratory metabolism (for example,
4.8 μl (STP)/hr.cm ² or more), and because the lens is manufactured, it is soluble in organic solvents (because it is ultra-thin, it cannot be used with conventional lenses). (It is extremely difficult to manufacture using the cutting and polishing method), and transparent physical resins such as esterified pullulan, cellulose esters such as CAB, and silicone resins are dissolved in an organic solvent in a predetermined amount, and this solution is mixed with the front curve. The rear curve is the same,
and inject it into a mold configured such that the curve has a curvature different from the curve of the corneal surface, and leave the mold standing still or give it appropriate rotation to remove the solvent and harden it to form a contact lens, Take out from the mold.

In the contact lenses constructed in this way, the shapes of the front curve and the rear curve of the contact lenses 1 and 2 are the same, as shown in the explanatory diagrams of the − lens in FIG. 1 and the + lens in FIG. , and in the case of the contact lens shown in FIG. 1, the radius of curvature of the posterior surface curve is larger than the radius of curvature of the corneal surface 3, and in the case of the contact lens shown in FIG. 3
The thickness of these contact lenses is approximately constant, approximately 0.05 mm or less, not only in the optical part but also in the peripheral part.
For example, it is formed to have a thickness of approximately 0.01 to 0.05 mm.

When such contact lenses are worn on the eyes, visual acuity is mainly corrected by the lachrymal fluid (n ^D ₂₃ ≒ 1.33) 4 that exists between the cornea and the contact lenses, and Vision correction becomes possible under conditions close to normal physiological conditions. For example, from the relationship between the base curve of the contact lens, the curvature of the corneal surface, and their clearance, +
It was possible to correct visual acuity of about 5.00D to -5.00D. Even though contact lenses are ultra-thin, they can not only correct vision, but because they are ultra-thin, they have lower oxygen permeability, for example.
Even if the material is 0.5 to 10 ^-10 [cm ³ (STP) cm/cm ²・sec・mmHg], the oxygen permeation rate is approximately 5.04.
μl (STP)/hr・cm ² , the amount of oxygen permeation required for corneal respiratory metabolism is ensured, and therefore it is possible to wear it continuously for a long time. Furthermore, non-hydrous hard resins such as CAB and silicone resins do not undergo deformation due to eyelid pressure even if the thickness is 0.05 mm or less, and therefore there is no risk of poor vision correction.

As mentioned above, the contact lens according to the present invention is made of a hard, water-free, transparent resin that does not deform due to pressure when worn on the eye, and is made of a transparent resin that does not deform due to pressure when worn on the eye. Since the contact lens is formed into a substantially dome shape that has the same curve as the side and does not match the curve of the corneal surface, the thickness of the contact lens should be approximately 0.05 mm, for example.
The following items can also be used to correct vision, and since they can be made ultra-thin, they have a large amount of oxygen permeation, ensuring the amount of oxygen permeation required for respiratory metabolism, and are easy to wear with little foreign body sensation. It is an extremely excellent product with little negative impact on the physiological activities of the eye, and has the characteristics of being effective in correcting mild to moderate visual acuity, irregular corneal astigmatism, keratoconus, etc. have

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a contact lens according to the present invention. 1, 2...Contact lens, 3...Cornea surface,
4...Tear fluid.

Claims (1)

[Scope of utility model registration request] Using a hard, water-free, transparent resin that does not deform under pressure when worn on the eye,
A contact lens characterized in that the convex side and the concave side of at least the optical part have the same curve and are formed in a substantially dome shape that does not match the curve of the corneal surface.