METHOD FOR PREVENTING OR LIMITING PROGRESSION OF MYOPIA

Abstract

A method for preventing or limiting the progression the myopia includes: providing a soft contact lens. The contact lens includes: a solid polymeric component, which is provided for conferring shape and structure on the contact lens and a liquid component which is distributed in the solid component, and which comprises tyrosine, at a concentration between 1 and 200 mg/l. The method further includes putting the soft contact lens on an eye of a patient so as to apply the compound on the eye.

Claims

1. A method for preventing or limiting progression of myopia comprising: providing a soft contact lens comprising: a solid polymeric component, which is provided for conferring shape and structure on the contact lens and a liquid component which is distributed in the solid component, and which comprises tyrosine, at a concentration between 1 and 200 mg/l, putting the soft contact lens on an eye of a patient so as to apply the compound on the eye.

2. The method of claim 1, wherein the liquid component is gradually released into the patient's eye.

3. The method according to claim 1, wherein the concentration of tyrosine in the liquid component of the contact lens is between 10 and 100 mg/l.

4. The method according to claim 1, wherein the liquid component of the contact lens comprises L-tyrosine.

5. The method according to claim 1, wherein the liquid component of the contact lens further comprises an effective quantity of an antioxidant compound.

6. The method according to claim 5, wherein the antioxidant compound comprises vitamin E or vitamin B2 or admixtures thereof.

7. The method according to claim 6, wherein the vitamin E, when present, has a concentration between 1 and 500 mg/l, more preferably between 1 and 100 mg/l, even more preferably between 2 and 20 mg/l, and the vitamin B2, when present, has a concentration between 1 and 1000 μg/l, more preferably between 1 and 100 μg/l, even more preferably between 2 and 50 μg/l.

8. The method according to claim 1, wherein the liquid component of the contact lens further comprises an effective quantity of regulating compounds for the regulating the rheological properties of the liquid component, the regulating compounds comprising hyaluronic acid or a salt thereof or a polysaccharide.

9. The method according to claim 8, wherein the polysaccharide is galacto xyloglucan which is extracted from tamarind seeds (TSP).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The features of the invention will be better appreciated from the following detailed description of a preferred embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

[0073] FIG. 1 is a schematic perspective Figure of a contact lens produced according to the present invention,

[0074] FIG. 2 is a schematic perspective view of a packaging for storing and preserving the contact lens of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] In the appended Figures, a soft contact lens produced according to the present invention is generally designated 4.

[0076] The soft contact lens 4 is preferably a corrective lens but generally may be of any known type.

[0077] The soft contact lens 4 is produced according to the following process.

[0078] In a first step, there is produced according to techniques which are generally conventional per se (by injection-molding or by turning) a dry semi-finished product of polymer material which is capable of conferring on the lens the final structure and formation. The dry semi-finished product may be obtained from a polymer admixture based on HEMA or from any other polymer or copolymer which is suitable for this purpose or which is normally used in the field, for example, a polymer based on silicone.

[0079] In a subsequent processing step, the dry semi-finished product is hydrated by immersion in an aqueous solution which is advantageously agitated so that there is absorbed in the solid component in a substantially uniform manner a liquid component which promotes the comfortable use of the contact lens and therefore the compatibility thereof with the eye of a user.

[0080] At the end of the hydration step, the soft contact lens 4 is then ready for being packaged and subsequently sterilized by means of processing in an autoclave at approximately 120° C. for a time of approximately 20 minutes.

[0081] FIG. 2 illustrates a packaging for storing and preserving the soft contact lens 4, which is generally designated 1. The packaging 1 comprises a support 2 which is produced, for example, from plastics material which is shaped so as to define a container 3, inside which the soft contact lens 4 is immersed in a preservation solution 5.

[0082] The packaging 1 further comprises a membrane 6 which is connected, for example, by means of thermowelding, to a peripheral edge of the support 2 so as to seal the container 3 and to prevent the discharge of the soft contact lens 4 or the preservation solution 5.

[0083] For greater clarity, the membrane 6 is illustrated in FIG. 2 in a partially raised position.

[0084] According to a first aspect of the invention, the aqueous solution in which the dry semi-finished product is immersed for the hydration processing comprises an effective quantity of a compound selected from the group formed by tyrosine, derivatives of tyrosine, precursors of tyrosine and dopamine.

[0085] In the preferred example described here, the aqueous solution comprises an effective quantity of L-tyrosine, for example, at a concentration between 10 and 100 mg/l, a quantity of sodium chloride of approximately 0.9 g/l and a concentration of vitamin E between 1 and 100 mg/l and/or a concentration of vitamin B2 between 1 and 100 μg/l. Optionally, the aqueous solution may comprise lubrication compounds, such as, for example, polyvinyl alcohols, or regulating compounds for the rheological properties, such as, for example, sodium hyaluronate or galacto xyloglucan which is extracted from tamarind seeds at a concentration of approximately 0.2%.

[0086] In addition, the aqueous solution may comprise a surfactant agent, a disinfecting agent, for example, disodium EDTA, at a quantity of approximately 0.1%, a buffering agent, such as, for example, sodium phosphate, so as to maintain an overall pH of approximately from 7.3 to 7.4.

[0087] The soft contact lens 4 which is thereby obtained therefore comprises, at the level of a conventional lens, a solid component which is substantially constituted by the polymer material and a liquid component which is distributed in a substantially uniform manner in the solid component in which the liquid component has substantially the same composition as the aqueous solution in which the dry semi-finished product has been immersed.

[0088] The portion of liquid component present in the soft contact lens is between 25% and 75%.

[0089] In an alternative production process, the contact lens 4 may be hydrated with an aqueous solution which does not have any L-tyrosine and vitamin E and/or B2 while these compounds may instead be present in the above-indicated concentrations in the preservation solution 5 in which the contact lens 4 is immersed, once it has been formed, for the packaging thereof. In this case, the introduction of the L-tyrosine and the vitamins E and/or B2 in the liquid component of the contact lens 4 is carried out during the sterilization step of the packaging 1.

[0090] According to another aspect of the invention, the preservation solution 5 comprises a concentration of L-tyrosine which is at least equal to that present in the liquid component of the soft contact lens 4.

[0091] If the second production process is used, the preservation solution 5 will naturally have a concentration of L-tyrosine and vitamin E and B2 which is substantially identical to the liquid component of the contact lens 4.

[0092] The soft contact lens 4, once it has been removed from the packaging 1 and put in place by the user, releases slowly and gradually into the eye the L-tyrosine which at a suitable time gives rise to dopamine which carries out the action thereof of limiting and preventing the progression of myopia.

[0093] Furthermore, the soft contact lens 4 slowly and gradually releases into the eye of the user the antioxidant compound vitamin E and/or vitamin B2 which prevents the damaging effects of exposure to sunlight which is advantageous in retarding the progression of myopia.

[0094] The contact lenses according to the invention may be produced so as to be replaced at a monthly frequency or at a greater frequency, for example, at a daily rate, weekly rate or bi-weekly rate, in accordance with the polymer material which is preselected and the characteristics thereof for retaining the liquid component.

[0095] Preferably, the contact lens is provided for weekly or daily replacement.

[0096] The present invention thereby solves the problem set out above by providing a soft contact lens which is capable of preventing or at least limiting the progression of myopia.

[0097] Furthermore, at the same time it affords a number of other advantages, including the fact of allowing the production of this soft contact lens by means of a production process which is simple and inexpensive.