WO2005121874A1

WO2005121874A1 - Tear groove hard contact lens

Info

Publication number: WO2005121874A1
Application number: PCT/KR2005/001687
Authority: WO
Inventors: In Ho Choi; Sun Jae Lee
Original assignee: Siris-K Corporation
Priority date: 2004-06-08
Filing date: 2005-06-07
Publication date: 2005-12-22
Also published as: KR100485763B1; KR20040055763A

Abstract

Disclosed herein is a lens comprising an optical portion that corresponds to a part of the cornea covering the pupil of the eye and the iris adjacent to the pupil, a peripheral portion that corresponds to an edge portion of the cornea and the sclera, and a tear storage portion formed between the optical portion and the peripheral portion. The lens is able to gather a large amount of tears from persons suffering from dry eyes due to a limited tear production and to store it between the cornea and the lens, thereby retarding the evaporation of tears and continuously keeping a tear layer. In this way, the lens ensures pleasant wearing and safe use thereof as well as sufficient oxygen supply.

Description

Description TEARGROOVE HARD CONTACT LENS Technical Field

[1] The present invention relates to a lens and, more particularly, to a hard contact lens, which comprises: an optical portion that corresponds to a part of the cornea covering the pupil of the eye and the iris adjacent to the pupil; a peripheral portion that corresponds to an edge portion of the cornea and the sclera; and a tear storage portion, i.e. tear groove, formed between the optical portion and the peripheral portion, whereby tears are stored in the tear storage portion, achieving a rigid gas permeable (RGP) lens, i.e. oxygen permeable lens, available for dry eyes suffering from excessive exposure of the cornea and limited oxygen supply due to tear shortage and rapid tear drying.

[2] Background Art

[3] A conventional oxygen permeable hard contact lens (RGP lens) provides only limited tear circulation between the cornea and the lens, inevitably causing a remarkable deterioration in oxygen supply by tears. For this reason, the conventional RGP lens is unsuitable for use by persons suffering from dry eyes. To solve the problem of the conventional RGP lens, the present invention provides a lens designed to more than double tear circulation to thereby maximize the instantaneous tear storage amount thereof.

[4] Korean Patent Publication No. 2002-49710 (Application No. 10-2000-78953) discloses a tear circulating structure of an oxygen permeable hard contact lens which comprises: a recess formed at a center portion thereof; an inclined circulating portion formed along an outer circumference thereof; and holes formed between the recess and the inclined circulating portion and each having an inclined surface, thereby enabling effective circulation and discharge of tears.

[5] Disclosure of Invention Technical Problem

[6] However, the tear circulating structure of the conventional oxygen permeable hard contact lens has a problem in that it can be used exclusively by persons exhibiting a basal tear production. Thus, it is impossible to use the hard contact lens to persons suffering from dry eyes due to limited tear production and rapid tear drying.

[7] The dried cornea makes it difficult for the contact lens to maintain a good optical plane, resulting in a deterioration of visual acuity. When the cornea cannot get sufficient oxygen from tears, the oxygen shortage must be compensated for by the blood vessels. This causes eye redness and, in severe cases, blindness.

[8] Technical Solution

[9] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an oxygen permeable hard contact lens with a tear groove wherein a tear storage portion is formed between an optical portion and a peripheral portion of the lens, whereby tears are stored in the tear storage portion, providing pleasant wearing to persons suffering from dry eyes due to limited tear production and rapid tear drying. Advantageous Effects

[10] With the present invention, even when being worn by persons with dry eyes, the contact lens can gather a large amount of tears and store it between the cornea and the lens. This has the effect of retarding the evaporation of tears and continuously keeping a tear layer, thereby ensuring pleasant wearing and safe use thereof as well as sufficient oxygen supply. [11] Brief Description of the Drawings [12] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [13] Fig. 1 is a front view of a tear groove hard contact lens in accordance with an embodiment of the present invention; [14] Fig. 2 is a side sectional view of the hard contact lens in accordance with the embodiment of the present invention; and [15] Fig. 3 is a side view showing the hard contact lens of the present invention worn on the eye. [16] Best Mode for Carrying Out the Invention [17] Now, a preferred embodiment of the present invention will be explained in detail with reference to the accompanying drawings. Admittedly, the drawings illustrate only an exemplary embodiment of the present invention, and the present invention is not limited thereto. [18] Fig. 1 is a front view of a tear groove hard contact lens in accordance with an embodiment of the present invention. Here, Fig. 1 shows a front side of the contact lens disposed on the tip of a finger prior to being worn on the eye. [19] Referring to Fig. 1, the lens 10 comprises an optical portion 20, a tear storage portion 30, a peripheral portion 40, and an edge portion 50. It should be understood that all of the portions 20 to 50 are integrally formed with one another although they are classified into the plurality of portions 20 to 50.

[20] In the embodiment of Fig. 1, the optical portion 20 has a diameter of 5mm, and widths of the tear storage portion 30, peripheral portion 40, and edge portion 50 are 0.60mm, 1.25mm, and 0.55mm, respectively.

[21] Although the diameter of the optical portion 20 and the widths of the tear storage portion 30, peripheral portion 40, and edge portion 50 are variable depending on different structures of wearer's eyes, it is preferable to maintain an approximately constant ratio therebetween.

[22] Fig. 2 is a side sectional view of the tear groove hard contact lens in accordance with the embodiment of the present invention.

[23] Referring to Fig. 2, the optical portion 20 corresponds to a part of the cornea covering the pupil of the eye and the iris adjacent to the pupil, thereby serving to correct a visual acuity. The optical portion 20 is variable in the index of refraction and shape depending on the visual acuity of the wearer and the presence of astigmatism, etc.

[24] Located around the optical portion 20 is the tear storage portion 30. The tear storage portion 30 is recessed from a cornea contact surface of the lens 10 by a predetermined depth. A boundary region between the optical portion 20 and the tear storage portion 30 is slightly inclined to eliminate the risk of unpleasant wearing of the lens 10 due to impurities.

[25] The peripheral portion 40 corresponds to a portion of the cornea outside of the iris of the eye, and is adapted to guide the lens 10 to an accurate position. Similarly, a boundary region between the tear storage portion 30 and the peripheral portion 40 is slightly inclined to eliminate the risk of unpleasant wearing of the lens 10 due to impurities.

[26] The edge portion 50 corresponds to a boundary region between the iris and the sclera and a certain limited portion of the sclera. The lens 10 of the present invention has a larger edge lift angle than that of the conventional RGP lens. This is effective to induce the generation of a greater amount of tears. Preferably, the edge portion 50 is designed to have an appropriate curvature to minimize unpleasant feeling upon wearing of the lens 10.

[27] In the embodiment of the present invention, the tear storage portion 30 has a depth of 0.11mm.

[28] Admittedly, the depth of the tear storage portion 30 is variable depending on the thickness, compression degree, material, etc. of the lens 10.

[29] Fig. 3 is a side view showing the hard contact lens worn on the eye. [30] Referring to Fig. 3, the human eye comprises a pupil 70, an iris 80, a not shown transparent cornea that covers the pupil 70 and the iris 80, and a sclera 90. Although not shown, the eye further comprises a crystalline lens, a ciliary body, a vitreous body, a choroids, and a retina.

[31] In use, the lens 10 of the present invention covers the corner, which covers the pupil 70 and the iris 80, and the certain limited portion of the sclera 90.

[32] Between the lens 10 and the center portion of the cornea covering the pupil 70 is defined a slight gap to store tears.

[33] The edge of the lens 10 is located at the juncture of the cornea and the sclera 90.

[34] The tear storage portion 30 is formed at the surface of the lens 10 that comes into contact with the cornea.

[35] With this configuration, tears are stored in the tear storage portion 30 to thereby serve as a lubricant between the cornea and the lens 10, preventing the eye from drying upon wearing of the lens 10.

[36] Mode for the Invention

[37] In accordance with an aspect of the present invention, there is provided a tear groove hard contact lens for use in a human eye, the contact lens being a rigid gas permeable (RGP) lens having a high oxygen permeability, comprising: an optical portion having an inner contact surface corresponding to a cornea of the eye; a tear storage portion formed adjacent to a circumference of the optical portion; a peripheral portion formed adjacent to an outer circumference of the tear storage portion; and an edge portion formed adjacent to an outer circumference of the peripheral portion.

[38] Preferably, the lens may be made of silicon acrylate containing fluorine.

[39] Preferably, when being measured in a plane, a diameter of the optical portion may be 4 to 6.5mm, and widths of the tear storage portion, peripheral portion, and edge portion may be 0.4 to 0.7mm, 1.0 to 1.5mm, and 0.5 to 0.65mm, respectively.

[40] Preferably, a depth of the tear storage portion may be 0.01 to 0.05mm.

[41] Preferably, a cross section of the optical portion may be part of an oval, a cross section of the tear storage portion may be part of a hyperbola, and a cross section of the peripheral portion may be part of a parabola.

[42] Industrial Applicability

[43] As is apparent from the above description, the present invention provides a hard contact lens which can gather the maximum amount of tears even from persons suffering from dry eyes due to a limited tear production, and store it between the cornea and the lens, thereby retarding the evaporation of tears and continuously keeping a tear layer. As a result, the contact lens of the present invention can ensure pleasant wearing and safe use as well as sufficient oxygen supply.

[44] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A tear groove hard contact lens for use in a human eye, the contact lens being a rigid gas permeable (RGP) lens having a high oxygen permeability, comprising: an optical portion having an inner contact surface corresponding to a cornea of the eye; a tear storage portion formed adjacent to a circumference of the optical portion; a peripheral portion formed adjacent to an outer circumference of the tear storage portion; and an edge portion formed adjacent to an outer circumference of the peripheral portion. [2] The contact lens as set forth in claim 1, wherein the lens is made of silicon acrylate containing fluorine. [3] The contact lens as set forth in claim 1 or 2, wherein, when being measured in a plane, a diameter of the optical portion is 4 to 6.5mm, and widths of the tear storage portion, peripheral portion, and edge portion are 0.4 to 0.7mm, 1.0 to 1.5mm, and 0.5 to 0.65mm, respectively. [4] The contact lens as set forth in claim 3, wherein a depth of the tear storage portion is 0.01 to 0.05mm. [5] The contact lens as set forth in claim 4, wherein: a cross section of the optical portion is part of an oval; a cross section of the tear storage portion is part of a hyperbola; and a cross section of the peripheral portion is part of a parabola.