FR2740232A1 - LIQUID DIOPTRE CORNEAL LENS - Google Patents

Abstract

This lens comprises an annular edge (1) surrounding a central optical zone shaped as a network structure. This comprises blades, preferably parallel, which can be machined in the lens, for example using a micro-milling machine with parallel discs. When wearing, the tear secretion is introduced by capillary action into the interstices between the blades, thus forming the liquid diopter.

Description

Correction of refractive errors of the eye, or refractive errors,

  Whether they are congenital or acquired, simple or complex is achieved, furthermore by lenses embedded in appropriate frames, known as spectacles, by the application directly to the cornea of appropriate lenses generally known as lenses. contact lenses or contact lenses. Compared to lenses embedded in a frame (glasses), contact lenses offer unmatched optical advantages, especially in refractive errors of particular importance or complexity, such as astigmatism, high myopia, keratoconus and aphakia. A problem still unresolved and related to the use of contact lenses is their tolerance or their insufficient portability, because they behave mechanically like foreign bodies present on the eye and because they interfere, more or less important, the normal oxygenation of the cornea. This second mechanism is considered to be the major factor limiting the use of contact lenses so that, despite the use of gas-permeable plastics, their permanent use is permitted correctly only for relatively short periods of time during the life of the contact lens. day. In fact, the oxygenation of the cornea, which is the essential process at the base of normal trophism, transparency, and turgor of the cornea itself, is carried out essentially by the oxygen of the air which is found dissolved in the tear film that

  permanently moistens the surface of the cornea.

  The interposition of any conventional corneal lens, even with gas-permeable materials, therefore prevents normal corneal wetting and physiological regeneration of the tear film and, in particular

  Consequently, it interferes with the oxygenation of the cornea.

  The subject of the invention is a corneal lens, characterized in that the refraction means in the zone

  optic is constituted by the lacrimal secretion.

  Unlike currently used contact lenses, the lens of the present invention completely solves the problem of oxygenation of the cornea. According to the present invention, the optical part, instead of being made by means of a transparent inert material suitably profiled as in the case of conventional contact lenses, is produced by means of a more or less thick layer of

  tear fluid. In this way, the tear film itself

  even acts as a means of refraction and allows at the same time

  time a perfectly natural oxygenation of the cornea.

  The use as a means of refraction of the tear film, ie the element which under normal conditions transports oxygen to the cornea, completely eliminates the risk of under-oxygenation of the cornea and consequently allows much greater tolerance and portability than other common contact lenses, including those

gas permeable.

  The lens according to the invention allows permanent application without time limit, handling operations can be widely spaced in the

time.

  The lens thus constructed also has the unparalleled advantage of being, at diameter, thickness and

  material used identical, significantly lighter.

  The present invention will now be described in detail by way of examples and drawings in which: - Figure 1 shows an embodiment of the corneal lens; and FIGS. 2 and 3 show examples of blade shapes that can be used in the lens according to

the invention.

  In Figure 1, we see a lens in axonometric view where the reference numeral 1 designates the edge of the lens and numeral 2 designates one of the blades arranged with its axis along the surface of the cornea and with a determined profile. Figures 2 and 3 show two different embodiments of blades having different concavities and convexities. In a first embodiment according to the invention, the corneal lens is constituted by: a) an annular edge shaped and profiled so as to press on the paracornean zone of the eyeball and so as to serve as a support for the optical zone; b) a grating optical zone inserted inside the annular edge; c) a liquid refraction means constituted by the lacrimal secretion which is introduced by capillarity into

the networked area.

  In the structure of the corneal lens, in accordance with the present invention, the ring-shaped edge is suitably patterned and profiled, in a suitable profile, on the limb area of the sclera and on the more peripheral portion of the sclera. this

  according to the need and the diameter of the lens itself

  even. The role of the edge is to stabilize the lens when it is applied to the eye and to support the optical zone. It also allows direct manipulation of the lens during the application and removal phases. The optical zone proper is located concentrically at the edge, is perfectly connected to it and consists essentially of a network structure,

or a "grid".

  The grid must be made in such a way as to allow the tear liquid to enter the open spaces (windows) of the optical zone by capillarity, by

  therefore, to build the support structure.

  In a first preferred embodiment of the present invention, the optical zone consists of blades arranged with their axis along the surface of the cornea, the profile being suitably shaped and curved to have the concave portion directed towards the rear, in order to satisfy the ocular geometry parameters and to adapt to the curvature of the cornea, and the front profile having a variable convexity depending on the power of the lens and the refractive error to be corrected. The blades can be shaped with a variable profile and height depending on the dioptric power that

  we want to give to the optical zone.

  The arrangement of the blades parallel to each other

  others is particularly preferred.

  In a second preferred embodiment of the

  In the present invention, the blades are arranged slatted.

  In a typical embodiment of the present invention, the blades are separated from each other by a gap normally between 0.25 and 1.00 mm and the

  edge may have a range of between 1.00 and 1.50 mm.

  The edge and the grid are made of transparent biocompatible plastic or any other material, organic or mineral, which must be appropriate for the transmission of light, the index

  of refraction, relative hardness and stiffness.

  The tear fluid is introduced into the spaces between the blades of the grid, to constitute an excellent means of refraction with respect to the transparency and the refractive index; since the material used in the construction of the grid is designed to have a transparency and a refractive index equal to or very similar to those of tears, the lens as a whole produces a means of refraction that is perfectly transparent and homogeneous from the point

optical view.

  Preferably the material is methylmetacrylate.

  In addition, as from the point of view of the construction and with a suitable method it is possible to configure the blades individually as needed, it is possible to obtain dioptric powers and variable curvatures in the optical zone, extremely difficult thing

  and complex to get in traditional lenses.

  The lens can also be used for therapeutic use in ophthalmology, in the case where it is impregnated with appropriate drugs that can be released in a progressive and prolonged manner over time. Therefore, the subject of the invention is also a corneal lens as described above having dioptric powers and variable curvatures in the

optical zone.

  The subject of the invention is furthermore a use of a corneal lens described above for constituting a controlled release vehicle of an active ingredient, in particular an active principle for the treatment of

Ophthalmic diseases.

  The corneal lens according to the present invention may be manufactured by a method of: a) defining an edge in a corneal lens having a determined thickness and curvature; b) shaping the network structure in the optical zone

with an appropriate means.

  Alternatively, it is possible to use another method of: a) defining an edge in a rough blank; b) shaping the network structure in the optical zone with appropriate means; c) Shaping the required curvatures of the surfaces

  anterior and posterior of the lens.

  The lens can be shaped by machining conventional contact lenses already available or can be obtained entirely from rough blanks

of contact lenses.

  In both cases, the embodiment is made with rigid materials based on methylmetacrylate; other materials with physical and chemical characteristics

analogs can be used.

  The following examples illustrate the invention.

EXAMPLE 1

  Method of Making from Conventional Lenses Rigid contact lenses having a thickness and curvature already defined based on corneal geometry and type and extent of defect are used

of refraction to correct.

  The lens is stably centered in an enlarging system that projects the image onto a screen

  to control the successive phases of machining.

  The lens being suitably fixed, and being oriented horizontally with the convex portion facing upwards, the extent of the edge

is between 1.0 and 1.50 mm.

  A ring of appropriate diameter and thickness is applied to the lens, which completely covers the edge for the previously chosen extent and leaves the central portion of the lens or optical zone totally uncovered. The ring is firmly attached to the support on

which rests the lens.

  By using a milling cutter with several microdisks arranged side by side, or alternatively a single disk microfraise, the optical zone of the lens is engraved over the whole thickness so as to form a variable number of thin, paired blades which extend at their ends into the edge of the lens and which

  reproduce the exact geometry of the original lens.

  The blades, as needed, are separated from each other by a space between 0.25 and 1.0 mm and their

  thickness depends on their number and the space between them.

  The network-shaping of the lens can also be effected by any other mechanical or physical means for producing a microarray of blades, including devices operating with a lens.

laser light.

  Depending on the need, the space between the blades can also be much larger than

the indicated one.

EXAMPLE 2

  Method of producing raw blanks The lens is made from rough blanks of rigid contact lenses in which the shaping of the blade array is carried out using the same method described for producing from

classic lenses.

  In this case, the blade patterning is followed by a proper finishing which gives the required curvatures to the anterior and posterior surfaces of the lens.

Claims (19)

  1. Corneal lens characterized in that the refractive means in the optical zone is constituted by the lachrymal secretion. 2. Corneal lens consisting of: a) an annular rim (1) shaped and profiled so as to be able to bear against the intercorneal area of the eyeball and so as to serve as a support for the optical zone; b) a grating optical zone inserted inside the annular edge; c) a liquid refractive means (2) consisting of the lacrimal secretion which is introduced by   capillarity in the networked area.   3. Corneal lens according to claim 2, characterized in that said optical zone consists of blades (2) arranged with their axis along the surface of the cornea, the profile being shaped and curved appropriately to have the concave portion to the back, so as to satisfy the ocular geometry parameters and adapt to the curvature of the cornea and the front profile having a variable convexity depending on the power of the lens and the refractive error to correct.   4. Corneal lens according to claim 3, characterized in that said blades (2) are arranged parallel to each other.   5. The corneal lens according to claim 3, characterized in that said blades (2) are arranged louvre.   6. Corneal lens according to claim 3, characterized in that said blades (2) are arranged   according to various geometric designs.   7. Corneal lens according to one of the claims   4, 5 or 6, characterized in that said blades (2) are separated by a gap normally between 0.25 and 1.00 mm or more.   8. Corneal lens according to claims 2 to   7, characterized in that said edge (1) has a width between 1.00 and 1.50 mm.   9. Corneal lens according to claims 2 to   8, characterized in that said edge (1) and said blades (2) of the optical zone consist of a material compatible with ophthalmic use and whose transparency and refractive index are equal or   similar to those of lacrimal secretion.   10. The corneal lens according to claim 9, characterized in that said material is methylmetacrylate.   11. Corneal lens according to claims 2 to   10 having various optical powers.   12. Corneal lens according to any one of   preceding claims containing a medicament.   13. The corneal lens according to claim 11,   wherein said medicament is for ophthalmic use.   14. Method of manufacturing a corneal lens   according to claims 2 to 11:   a) defining an edge in a corneal lens having a determined thickness and curvature; b) shaping a network structure in the area optical with a suitable means.   15. Method of manufacturing a corneal lens   according to claims 2 to 11, consisting of:   a) defining an edge in a rough blank; b) shaping a network structure in the optical zone with appropriate means; c) Shaping the required curvatures of the surfaces   anterior and posterior of the lens.   16. The method of claim 14 or 15, wherein the network structure is obtained with a mill with several microdisks arranged side by side, or, in   variant, with a single disk microfraise.   The method of claim 14 or 15, wherein the network structure is obtained with a device with laser light.   18. Use of a corneal lens according to   Claims 12 to 13 for the preparation of a vehicle   controlled release of an active ingredient.   The use according to claim 18, wherein said active ingredient is for the treatment of Ophthalmic diseases.