Multiple index of refraction lens

Abstract

There is described lens assemblies which comprises at least two lenses having different refraction indices. The lens assemblies may be used for the examination of the eye of a subject. A first lens assembly comprises a converging biconvex lens body having a first index of refraction, a lens spacing body having a second index of refraction, and a contact lens body having a third index of refraction, wherein the first index of refraction and the third index of refraction are each different from the second index of refraction, the third index of refraction is at most equal to the first index of refraction and the third index of refraction is greater than a fourth index of refraction of a cornea of an eye. A second lens assembly comprises a central biconvex lens body, a first positive meniscus lens body and a second positive meniscus lens body.

Description

MULTIPLE INDEX OF REFRACTION LENSCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claim priority on U.S. Provisional Patent Application No. 63 / 669,784 filed on July 11, 2024, the content of which is incorporated herein by reference.FIELD

[0002] The present technology pertains to the field of optical lenses, and more particularly to lenses having multiples indices of refraction.BACKGROUND

[0003] Examination of the eye requires optical instruments to view the fundus and iridocorneal angle for example. These instruments must usually provide a clear view with minimal chromatic and spherical aberrations. Furthermore, these instruments must usually allow for a view of the peripheral retina. In additional, there are only few instruments that provide a direct way to view the ciliary body.

[0004] For example, indirect or direct gonioscopy is usually used to view the iridocorneal angle. Indirect gonioscopy involves a contact lens and mirrors to overcome total internal reflection and view the iridocorneal angle. Furthermore, direct gonioscopy allows for the direct view of the iridocorneal angle through the refraction of light using a contact lens. Both lenses allow for a view of the iridocorneal angle and zonular fibers, and can allow for laser and surgical procedures. However, no indirect or direct gonioscopy lens can provide a view of the peripheral retina.

[0005] In another example, slit lamp aspheric lenses (such as the 90D / 70D / Digital Wide Field) are frequently used to view the retina with the aid of a slit lamp. Such lenses provide a sufficiently detailed view of the retina. However, they provide no view of the angle and a limited view of the peripheral retina.

[0006] Binocular indirect (BIO) aspheric lenses allow to view the peripheral retina and ora serrata when used in conjunction with scleral depression and provide a binocular view of the fundus. However, the wide field of view provided by such lenses comes at the expense of detail. In order to get a clear view of the ora serrata, scleral depression is often required, which some patients cannot tolerate. Furthermore, such lenses provide no view of the iridocorneal angle.[ 00071 Laser lenses (such as the Superquad / H-R Wide Field / Quad aspheric lens) are contact lenses that allow for a view of the fundus up to the peripheral retina and can provide a view of the ora serrata. These lenses provide a more detailed view of the retina compared to binocular indirect lenses and can also be used to preform laser procedures on the peripheral retina. However, these lenses do not provide a view of the iridocorneal angle.

[0008] Three-mirror lenses are contact lenses that use three mirrors to view both the retina and the iridocorneal angle. Such lenses can be used to view the posterior retina, peripheral retina (including the ora serrata) and the iridocorneal angle. However, to do this the lens must be manually rotated and tilted, which results in an increased examination time in comparison to other lenses.

[0009] Therefore, there is a need for an improved lens for eye examination.SUMMARY

[0010] According to a first broad aspect, there is provided a lens assembly for eye examination, the lens assembly comprising: a converging biconvex lens body having a first index of refraction, the converging biconvex lens body extending between a first convex face and a second convex face; a lens spacing body having a second index of refraction, the lens spacing body extending between a concave face and a first planar face opposite to the concave face, the concave face being mounted to and matching the second convex face of the converging biconvex lens; a contact lens body having a third index of refraction, the contact lens body extending between a second planar face and an opposite face, the second planar face being mounted to the first planar face and the opposite face being provided with a cornea receiving recess, wherein the first index of refraction and the third index of refraction are each different from the second index ofrefraction, the third index of refraction is at most equal to the first index of refraction and the third index of refraction is greater than a fourth index of refraction of a cornea of an eye.

[0011] In some embodiments, the first and second convex faces each have one of a convex shape.

[0012] In some embodiments, the convex shape comprises one of a hyperboloid shape, a paraboloidal shape, an ellipsoidal shape, a part spherical and a spherical cap shape.

[0013] In some embodiments, each one of the first planar face and the second planar face has one of a circular shape and a disc shape.

[0014] In some embodiments, the lens spacing body 14 comprises a solid body.

[0015] In some embodiments, the solid body is made of one of: diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, and flit glass.

[0016] In other embodiments, the lens spacing body 14 defines an internal cavity, the internal cavity being filled with a fluid.

[0017] In some embodiments, the internal cavity is provided with a plano-concave shape.

[0018] In some embodiments, the fluid comprises a liquid.

[0019] In some embodiments, the liquid comprises diiodomethane.

[0020] In some embodiments, the liquid further comprises sulfur.

[0021] In some embodiments, the liquid comprises one of: water, silicone oil, acetone, ethanol, carbon tetrachloride, and a benzene and water glucose solution.

[0022] In other embodiments, the fluid comprises a gas.

[0023] In some embodiments, the gas comprises one of helium neon and hydrogen carbon dioxide.

[0024] In some embodiments, the first index of refraction is greater than the second index of refraction.

[0025] In some embodiments, the third index of refraction is greater than the second index of refraction.

[0026] In other embodiments, the third index of refraction is less than the second index of refraction.

[0027] In some embodiments, the first index of refraction is less than the second index of refraction and the third index of refraction is less than the second index of refraction.

[0028] In some embodiments, the converging biconvex lens body is made of one of: cubic zirconia, diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, and flit glass.

[0029] In some embodiments, the contact lens body 16 is made of one of: polycarbonate, diamond, silicon carbide, polymethyl methacrylate, crown glass, and flit glass.

[0030] In some embodiments, the opposite face is provided with one of a hemispherical shape and an ellipsoidal shape.

[0031] According to another broad aspect, there is provided a lens assembly comprising: a central biconvex lens body having a first index of refraction, the central biconvex body extending between a first convex face and a second convex face opposite to the first convex face; a first positive meniscus lens body extending between a third convex face mounted to the first convex face of the central biconvex lens body and a fourth convex face, the first positive meniscus lens body having a second index of refraction; and a second positive meniscus lens body extending between a fifth convex face mounted to the second convex face of the central biconvex lens body and a sixth convex face, the second positive meniscus lens body having a third index of refraction, wherein the first index of refraction is greater than the second index of refraction and the third index of refraction.

[0032] In some embodiments, the second index of refraction and the third index of refraction are identical.

[0033] In some embodiments, the second index of refraction and the third index of refraction are equal to about 1.6.

[0034] In some embodiments, the first index of refraction is about 1.79.

[0035] In some embodiments, the first positive meniscus lens body and the second positive meniscus lens body are each made of flint glass.

[0036] In some embodiments, the central biconvex lens body defines an internal cavity, the internal cavity comprising a fluid.

[0037] In some embodiments, the fluid comprises a liquid.

[0038] In some embodiments, the liquid comprises a methylene iodide solution.

[0039] In some embodiments, the liquid further comprises sulfur.

[0040] In some embodiments, the central biconvex lens body comprises a rigid body.

[0041] In some embodiments, the first and second positive meniscus lens bodies form together a biconvex lens.

[0042] In some embodiments, a diameter of the central biconvex lens body is less than a diameter of the biconvex lens.

[0043] According to a further broad aspect, there is provided a lens assembly, the lens assembly comprising: a converging biconvex lens body having a first index of refraction, the converging biconvex lens body extending between a first convex face and a second convex face; a lens spacing body having a second index of refraction, the lens spacing body extending between a concave face and a first planar face opposite to the concave face, the concave face being mounted to and matching the second convex face of the converging biconvex lens; a further lens body having a third index of refraction, the further lens body extending between a second planar face and an opposite face, the second planar face being mounted to the first planar face, wherein the firstindex of refraction and the third index of refraction are each different from the second index of refraction, and the third index of refraction is at most equal to the first index of refraction.

[0044] Implementations of the present technology each have at least one of the above-mentioned objects and / or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and / or may satisfy other objects not specifically recited herein.

[0045] Additional and / or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0046] For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0001] Fig. 1 illustrates a front view of a lens assembly, in accordance with a first embodiment.

[0002] Fig. 2 illustrates a bottom view of the lens assembly of Fig. 1.

[0003] Fig. 3 illustrates a front view of a lens assembly, in accordance with a second embodiment.

[0004] Fig. 4 illustrates a front view of a lens assembly, in accordance with a third embodiment.

[0005] Fig. 5 illustrates a front view of a lens assembly, in accordance with a fourth embodiment.

[0006] Fig. 6 illustrates a system comprising a camera, an adaptor and the lens assembly of Fig. 1.

[0007] Fig. 7 illustrates a system comprising a camera, an adaptor and the lens assembly of Fig. 3.

[0008] Fig. 8 illustrates a system comprising two biconcave lenses, three biconvex lenses and the lens assembly of Fig. 5.DETAILED DESCRIPTION

[0047] The examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements which, although not explicitly described or shown herein, nonetheless embody the principles of the present technology and are included within its spirit and scope.

[0048] Furthermore, as an aid to understanding, the following description may describe relatively simplified implementations of the present technology. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity.

[0049] In some cases, what are believed to be helpful examples of modifications to the present technology may also be set forth. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while nonetheless remaining within the scope of the present technology. Further, where no examples of modifications have been set forth, it should not be interpreted that no modifications are possible and / or that what is described is the sole manner of implementing that element of the present technology.

[0050] Fig. 1 illustrates one embodiment of a lens or lens assembly 10 configured for examination of an eye of a subject.[0051 The lens 10 comprises three portions, namely a converging or biconvex lens body (or converging or biconvex lens) 12 (hereinafter referred to as the converging body 12), a lens spacing body 14 and a contact lens (or contact lens) body 16. The lens spacing body 14 extends between the body 12 and the contact lens body 16.

[0052] As illustrated in Fig. 1, the lens 10 is symmetrical about the rotational (or radial) symmetry axis 18. As a result, the shape of the lens 10 does not change after any rotation about the axis 18.

[0053] The converging body 12 has a biconvex shape, i.e., it extends between a first or distal convex face 20 and a second or proximal convex face 22 along the rotational symmetry axis 18. The first and second convex faces 20 and 22 are connected together so that the converging body 12 forms a solid body. As known in the art, a biconvex lens is also known as a converging lens since is it focuses divergent, or unfocused, light rays. The first convex face 20 and the second convex face 22 are each centered about the rotational symmetry axis 18 so that the converging body 12 is symmetrical about the rotational symmetry axis 18. As a result, the cross-section of the converging body 12 taken along any point along the rotational symmetry axis 18 has a circular or disc shape.

[0054] The first convex face 20 of the converging body 112 defines a first convex portion of the converging body 12 and the second convex face 22 defines a second convex portion of the converging body 12. The cross-sectional size of the first convex portion of the converging body 12 increases from its apex or end 24 towards the second convex portion of the converging body 12. The cross-sectional dimension or size of the second portion of the converging body 12 decreases from the first convex portion towards its apex or end 26.

[0055] It will be understood that the first and second convex faces 20 and 22 each have a convex shape such as a hyperboloid shape, a paraboloidal shape, an ellipsoidal shape, a part spherical or spherical cap shape, etc.

[0056] In the illustrated embodiment, the first face 20 of the converging body 12 is provided with a paraboloidal shape while the second face 22 is provided with a spherical cap shape. However, it should be understood that other configurations are possible. However, it should be understood that the first face 20 and the second face 22 may be provided with another adequate shape such as a flat shape, an aspherical shape, etc.

[0057] The converging body 12 is a solid body made of a material having a first refractive index or index of refraction.

[0058] Referring back to Fig. 1, the lens spacing body 14 has a substantially planoconcave shape and extends between a concave face 30 and a planar face 32 along the rotational symmetry axis 18 of the lens 10. The concave face 30 and the planar face 32 are connected together by a lateral face 34 which has a substantially frusto-conical shape.

[0059] The concave face 30 is mounted to the second convex face 22 of the converging body 12 and is identical to the second convex face 22, i.e., the shape and dimension of the concave face 30 are identical to those of the second convex face 22 of the converging body 12. In some embodiments, the concave face 30 of the lens spacing body 14 and the second convex face 30 of the converging body 12 are integral.

[0060] The planar face 32 of the lens spacing body 14 is provided with a circular or disc shape and is substantially orthogonal to the rotational symmetry axis 18. The lateral face 34 extends between the concave face 30 and the planar face 32. The cross-sectional dimension of the lateral face 34 decreases from the concave face 30 towards the planar face 32.

[0061] It should be understood that the lens spacing body 14 is symmetrical about the rotational symmetry axis 19.

[0062] The lens spacing body 14 is made a material having a second index of refraction that is different from the index of refraction of the converging body 12. In some embodiments, the second index of refraction that is less than the index of refraction of the converging body 12. In other embodiments, the second index of refraction that is greater than the index of refraction of the converging body 12. The material from which the lens spacing body 14 is made is chosen so as to be transparent and substantially refracting.

[0063] In some embodiments, the lens spacing body 14 defines an internal cavity or chamber (not shown) that is filled with a fluid. In this case, the lens spacing body 14 comprises a frame defining the internal cavity and the frame comprises a concave wall having the concave face 26 and mounted to the converging body 12, a planar wall having the planar face 32 and mounted to the contact lens body 16, and a lateral wall having the lateral face 34 and extending between the concave wall and the planar wall. In another embodiment, the lens spacing body 14 comprises only a lateral wall providedwith the external face 34 and extending between the converging body 12 and the contact lens body 16. In this case, the bottom of the converging body 12 may be seen as also forming the top concave wall of the lens spacing body 14 and the top portion of the contact lens portion 16 may be seen as forming the bottom planar wall of the lens spacing body 14.

[0064] In some embodiments, the cavity is provided with a plano-concave shape.

[0065] The fluid present in the cavity of the lens spacing body 14 is chosen to have an index of refraction that is different from the index of refraction of the converging body 12. In some embodiments, the index of refraction of the fluid is less than the index of refraction of the converging body 12. In other embodiments, the index of refraction of the fluid is greater than the index of refraction of the converging body 12.

[0066] Referring back to Fig. 1, the contact lens body 16 of the lens 10 is configured to be positioned in physical contact with the cornea of the eye of the subject.

[0067] The contact lens body 16 extends between a planar face 40 and an inwardly curved face 42 along the rotational symmetry axis 18 of the lens 10. The planar face 40 and the curved face 42 are connected together by a lateral face 44 which has a substantially frusto-conical shape. The planar face 40, the curved face 42 and the lateral face are connected together so as to form a solid body, i.e., the contact lens body 16.

[0068] The planar face 40 is mounted to the planar face 32 of the lens spacing body 14 and is identical to the planar face 32, i.e., the shape and dimension of the planar face 40 are identical to those of the planar face 32 of the lens spacing body 14. The planar face 40 of the contact lens body 16 is provided with a circular or disc shape and is substantially orthogonal to the rotational symmetry axis 18. The lateral face 44 extends between the planar face 40 and the curved 42. The cross-sectional dimension of the lateral face 44 decreases from the planar face 40. The curved face 42 projects inwardly towards the planar face 40 and its cross-sectional dimension decreases towards the planar face 40. It should be understood that the curved face 42 defines a recess in the lens assembly 10 for receiving therein the eye of the subject. It should therefore be understood that the shape and dimension of the curved face 42 are chosen so that the eye of the subject may be received in the recess defined by the curved face 42. For example, the curvature of the curved face 42 may be chosen so that the recess it definesis provided with the shape of a portion or segment of a sphere, such as a hemispherical shape, an ellipsoidal shape, etc.

[0069] It should be understood that the lens spacing body 14 is symmetrical about the rotational symmetry axis 19.

[0070] The contact lens body 16 is made of a material that is transparent and has a third index of refraction that is:- different from the index of refraction of the lens spacing body 14, i.e., the index of refraction of the contact lens body 16 may be greater than or less than the index of refraction of the lens spacing body 14, but not equal to the index of refraction of the lens spacing body 14;- at most equal to the index of refraction of the converging body 12, i.e., equal to or less than the index of refraction of the converging body 12; and- greater that the index of refraction of the cornea of an eye which is usually about 1.376.

[0071] In some implementations in which the index of refraction of the converging body 12 is greater than the index of refraction of lens spacing body 14, the index of refraction of the contact lens body 16 may be greater than the index of refraction of lens spacing body 14.

[0072] In some implementations in which the index of refraction of the converging body 12 is greater than the index of refraction of lens spacing body 14, the index of refraction of the contact lens body 16 may be less than the index of refraction of lens spacing body 14.

[0073] In some implementations in which the index of refraction of the converging body 12 is less than the index of refraction of lens spacing body 14, the index of refraction of the contact lens body 16 is less than the index of refraction of lens spacing body 14.

[0074] It should be understood that variations of the above-described lens assembly 10 may be possible. For example, while it is substantially in physical contact or in closeproximity to the planar face 40, the apex of the curved face 42 may be spaced apart from the planar face 40 by a given distance along the longitudinal axis 18. In another example, while, in the illustrated embodiment, it is identical to the cross-sectional dimension of the convex face 22, the cross-sectional dimension of the concave face 30 may be greater than that of the convex face 22.

[0075] In some embodiments, the index of refraction of the converging body 12 is about 2.18, the radius of curvature of the first convex face 20 is about 21 mm, the radius of curvature of the second convex face 22 is about 100 mm, and the converging body 12 is provided with a power of about 60. The index of refraction of the lens spacing body 14 is about 1.78 and the radius of curvature of the concave face 30 is about 100 mm. The index of refraction of the contact lens body 16 is about 1.59 and the radius of curvature of the curved face 42 is about 7.2 mm.

[0076] In at least some embodiments, the index of refraction of the converging body 12 is at most equal to about 2.42.

[0077] In some embodiments in which the lens spacing body 14 is provided with an internal cavity filled with a fluid, the fluid has an index of refraction that is less than 1.79, such as 1.78, while being greater than the index of refraction of the contact lens body 16.

[0078] In some embodiments, the converging body 12 is made of cubic zirconia. However, it should be understood that any other adequate material having an index of refraction being different from that of the lens spacing body 14. For example, the converging body 12 may be made of diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, flit glass, or the like.

[0079] In some embodiments in which the lens spacing body 14 is provided with an internal cavity filled with a fluid, the fluid is a liquid that contains diiodomethane. In some embodiments, the liquid may further contain sulfur. However, it should be understood that any other adequate fluid may be used. For example, the fluid may be a liquid such as water, silicone oil, acetone, ethanol, carbon tetrachloride, a benzene and water glucose solution, or the like. In another example, the fluid may be a gas such as helium neon, hydrogen carbon dioxide.

[0080] In some embodiments in which the lens spacing body 14 comprises a solid body, the lens spacing body 14 may be made of diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, flit glass, or the like.

[0081] In some embodiments, the contact lens body 16 is made of polycarbonate. In some embodiments, the contact lens body 16 is made of diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, flit glass, or the like.

[0082] In some embodiments, the maximal cross-sectional diameter of the converging body 12 is about 42 mm, the cross-sectional diameter of the planar face 32 and that of the planar face 40 are equal to about 25 mm, and the maximal cross-sectional diameter of curved face 42 is about 11 mm.

[0083] In some embodiments, the maximal length or thickness of the lens assembly 10 along the longitudinal axis 18 is about 26.8 mm.

[0084] In some embodiments, the minimal distance between the converging body 12 and the contact lens body 16 is about 1.6 mm, i.e., the minimal length or thickness of the lens spacing body along the longitudinal axis 18 is about 1.6 mm.

[0085] As mentioned above, variations of the above-described lens assembly 10 may be possible. For example, Fig. 3 illustrates another embodiment of a lens assembly 50 which comprises a converging lens body identical to the converging body 12 of the lens assembly 10, a lens spacing body identical to the lens spacing body 14 and a contact lens body 52.

[0086] Since the converging body and the lens spacing body of the lens assembly 50 are identical to those of the lens assembly 10, only the contact lens body 52 is described hereinafter.

[0087] The contact lens body 52 extends between a planar face 54 and a recessed face 56 along the longitudinal axis 58, and the planar face 54 and the recessed face 56 are connected together by a lateral face 60.

[0088] The planar face 54 is substantially orthogonal to the longitudinal axis 58 and is identical to the planar face 32 of the lens spacing body 14, i.e., the shape and size of the planar face 54 are identical to these of the planar face 32. Furthermore, the planarface 54 is mounted to the planar face 32 of the lens spacing body 14. In some embodiments, the planar face 54 is integral with the planar face 32.

[0089] The recessed face 56 comprises an annular face 62 and an inwardly curved face 64. The annular face 62 extends substantially orthogonal to the longitudinal axis 58. The external end of the annular face 62 is connected to the lateral face 60 and its inner end is connected to the curved face 64 so that the annular face 62 surrounds the curved face 64. The curved face 64 projects from the annular face 62 inwardly towards the planar face 54. It will be understood that the curved face 64 is shaped and sized so as to receive the eye of a subject therein.

[0090] While in the illustrated embodiment, the apex 66 of the curved face 64 is located way from the planar face 54, it should be understood that the curved face 64 may be designed so that the apex 66 is located adjacent to the planar face 54 or on the planar face 54.

[0091] In some embodiments, the above-described lens assemblies 10 and 50 allow to view both the entire retina and the iridocorneal angle.

[0092] In some embodiments, the above-described lens assemblies 10 and 50 allow to view the posterior cornea, the iridocorneal angle, the zonular fibers, the posterior retina, and the peripheral retina. In some embodiments, the above-described lens assemblies 10 and 50 further allow to view the ciliary body.

[0093] As known in the art, total internal reflection increases as the difference between the index of refraction of an optical material increase. In the periphery of a converging lens that could view the retina, total internal reflection occurs within the lens if the lens has a diameter large enough to view the angle in the periphery. By adding the lens spacing body 14 which refracts light, the converging lens body 12 can be provided with a lower index of refraction while maintaining its advantages and decreasing or minimizing the risk of total internal refraction.

[0094] It should be understood that the converging lens body 12 is designed so as to allow light to focus on the retina of the subject. As known in the art, the power of the converging lens body 12 is determined based on its index of refraction and the radii ofcurvature of its faces 20 and 22, and is chosen so as to at least partially compensate for the index of refraction of the lens spacing body 14.

[0095] It should also be understood that the lens spacing body 14 is designed so as to refract light and minimize or decrease the risk of total internal refraction as the light propagates from the converging lens body 12.

[0096] It should further be understood that the contact lens body 16, 52 is designed so as to decrease or minimize total internal refraction at its interface with the cornea of the subject.

[0097] In some embodiments, the lens 10, 50 may be integrated into a slit lamp.

[0098] While the lenses or lens assemblies 10 and 50 are contact lenses, Fig. 4 illustrates one embodiment of a contact-less lens or lens assembly 100.

[0099] The lens or lens assembly 100 comprises three lenses or lens bodies, i.e., a converging biconvex lens or lens body 102, a first positive meniscus lens or lens body 104 and a second positive meniscus lens or lens body 106.

[0100] The converging lens body 102 has a biconvex shape, i.e., the converging lens body 102 extends between two opposite convex faces 110 and 112 which are connected together to form the converging lens body 102. The converging lens body 102 is provided a first index of refraction.

[0101] The first positive meniscus lens or lens body 104 is mounted to the convex face 110 of the converging body 102 and extends between a first convex face 114 and a second convex face 116. The first convex face 114 of the first positive meniscus lens body 104 is mounted to the convex face 110 of the converging body 102 and is substantially identical to the convex face 110, i.e., the size and shape of the first convex face 114 are substantially identical to those of the convex face 110. In some embodiments, the first convex face 114 and the convex face 114 are integral. The first positive meniscus lens body 104 is made a material having a second index of refraction that is less than the first index of refraction of the converging lens body 102.

[0102] The second positive meniscus lens or lens body 106 is mounted to the convex face 112 of the converging body 102 and extends between a first convex face 120 anda second convex face 122. The first convex face 120 of the second positive meniscus lens body 106 is mounted to the convex face 112 of the converging body 102 and is substantially identical to the convex face 112, i.e., the size and shape of the second convex face 120 are substantially identical to those of the convex face 112. In some embodiments, the first convex face 120 and the convex face 112 are integral. The second positive meniscus lens body 106 is made a material having a third index of refraction that is less than the first index of refraction of the converging lens body 102.

[0103] In some embodiments, the first and second positive meniscus lens bodies 104 and 106 are provided with the same index of refraction, i.e., the second and third indexes of refraction are substantially identical. For example, the first and second positive meniscus lens bodies 104 and 106 may be made of the same material.

[0104] In other embodiments, the first and second positive meniscus lens bodies 104 and 106 are provided with a different index of refraction and / or may be made of a different material.

[0105] As a result, the converging lens body 102 is sandwiched between the first and second positive meniscus lens bodies 104 and 106.

[0106] In some embodiments, the converging body 102 is provided with an internal cavity (not shown) in which a fluid is contained. In this case, the converging body 102 comprises a frame defining the internal cavity and the frame comprises a first convex wall having the convex face 110 mounted to the first positive meniscus lens body 104, and a second convex wall having the convex face 112 mounted to the first positive meniscus lens body 106. In another embodiment, the converging body 102 may only comprise the fluid, i.e., the converging body 102 comprises no frame and the fluid is contained between the first and second positive meniscus lens bodies 104 and 106, between the convex face 114 of the first positive meniscus lens body 104 and the convex face 120 of the second positive meniscus lens body 106.

[0107] In some embodiments, the cavity is provided with a biconvex shape . It should be understood that the lens assembly 100 is symmetrical about the axis 130.

[0108] In embodiments in which the converging body 102 comprises a fluid, it should be understood that the fluid has an index of refraction that is greater than that of the first and second positive meniscus lens bodies 104 and 106.

[0109] In some embodiments, the first and second positive meniscus lens bodies 104 and 106 each have an index of refraction of about 1.6 and the converging lens body 102 has an index of refraction of about 1.79.

[0110] In some embodiments, the first and second positive meniscus lens bodies 104 and 106 are each made of substantially pure flint glass.[01 1 1 ] In some embodiments, the outer convex faces 116 and 122 of the first and second positive meniscus lens bodies 104 and 106, respectively each have a radius of curvature of about 19 mm. The inner convex faces 114 and 120 of the first and second positive meniscus lens bodies 104 and 106, respectively each have a radius of curvature of about 17.1 mm. The maximal diameter for the cross-section of the lens assembly 100 orthogonal to the axis 130 is about 84.7 mm and the height or thickness of the lens assembly 100 along the axis 130 is about 25.5 mm. As a result, the total power of the lens assembly 100 is about 20 D.

[0112] In some embodiments in which the converging lens body 102 comprises a fluid, the fluid comprises a sulphur in methylene iodide solution.

[0113] In some embodiments, the above-described lens assembly or lens 100 allows to view the posterior retina, and the peripheral retina of an eye.

[0114] While in the lens assembly 100, the converging body 102 and the first and second positive meniscus lens bodies 104 and 106 have the same diameter along the axis 132 (which is orthogonal to the symmetry axis 130) and share the same rim or apex 134, it will be understood that other configurations are possible. For example, Fig. 5 illustrates one embodiment of a lens assembly 150 which comprises a converging body 152, a first positive meniscus lens body 154 and a second positive meniscus lens body 156, for which the diameter of the converging body 152 is less that the diameter of the first and second positive meniscus lens bodies 154 and 156. In this embodiment, the apex 158 of the converging body 152 is spaced apart from the apex 160 of the first and second positive meniscus lens bodies 154 and 156 along the axis 162. In the illustratedembodiment, the distance between the two apexes 158 and 160 along the axis 162 is identical on both sides of the lens assembly 150.

[0115] The first and second positive meniscus lens bodies 154 and 156 may be seen as forming a converging lens body provided with an internal chamber in which the converging body 152 is inserted. The internal chamber is then provided with the same shape and same dimensions as the converging body 152.[01 .16] In some embodiments, the lens 100, 150 may be integrated into a binocular indirect or a slit lamp.

[0117] In some embodiments, the lens 10 may be adapted to be integrated into a camera for non ocular imaging. Fig. 6 illustrates such a system comprising an adaptor 200 for mounting the lens 10 to a camera 202. It should be understood that the adaptor is designed and shaped for mounting to the camera 202 at one end and to the lens 10 at an opposite end. In some embodiments the lens 10 may be provided with no recess, i.e., the face 42 may not be inwardly curved. For example, face 42 may be planar or outwardly curved.

[0118] In some embodiments, the lens 100 may be adapted to be integrated into a camera for non ocular imaging. Fig. 7 illustrates such a system comprising an adaptor 210 for mounting the lens 100 to a camera 212. It should be understood that the adaptor is designed and shaped for mounting to the camera 212 at one end and to the lens 100 at an opposite end. Furthermore, the lens 100 could be adapted into a multi lens camera system for ocular and non ocular imaging for example.

[0119] It will be understood that the lens assembly 100, 150 may be integrated into any adequate lens system. For example, Fig. 8 illustrates an exemplary lens system 250 which comprises the lens assembly 150. The lens system 250 comprises a first biconcave lens 252, a first biconvex lens 254, a second biconvex lens 265, the lens assembly 150, a third biconvex lens 258 and a second biconcave lens 260, which are aligned along a longitudinal axis. The first biconvex lens 254 is positioned between the first biconcave lens 252 and the second biconvex lens 256, the second biconvex lens 256 is positioned between the first biconvex lens 254 and the lens assembly 150, the lens assembly 150 is positioned between the second biconvex lens 256 and the thirdbiconvex lens 258, and the third biconvex lens 258 is positioned between the lens assembly 150 and the second biconcave lens 260.

[0120] In some embodiments, the lens system 250 may be used to visualize the anatomy of the eye of a subject. For example, the lens system 250 may be used to visualize the cornea, the retina and / or the optic nerve of the eye of a subject.

[0121] In other embodiments, the lens system 250 can be used for non-ocular imaging applications.

[0122] Modifications and improvements to the above-described implementations of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting.

Claims

CLAIMSWhat is claimed is:

1. A lens assembly for eye examination, the lens assembly comprising: a converging biconvex lens body having a first index of refraction, the converging biconvex lens body extending between a first convex face and a second convex face; a lens spacing body having a second index of refraction, the lens spacing body extending between a concave face and a first planar face opposite to the concave face, the concave face being mounted to and matching the second convex face of the converging biconvex lens; a contact lens body having a third index of refraction, the contact lens body extending between a second planar face and an opposite face, the second planar face being mounted to the first planar face and the opposite face being provided with a cornea receiving recess, wherein the first index of refraction and the third index of refraction are each different from the second index of refraction, the third index of refraction is at most equal to the first index of refraction and the third index of refraction is greater than a fourth index of refraction of a cornea of an eye.

2. The lens assembly of claim 1, wherein the first and second convex faces each have one of a convex shape.

3. The lens assembly of claim 2, wherein the convex shape comprises one of a hyperboloid shape, a paraboloidal shape, an ellipsoidal shape, a part spherical and a spherical cap shape.

4. The lens assembly of any one of claims 1 to 3, wherein each one of the first planar face and the second planar face has one of a circular shape and a disc shape.

5. The lens assembly of any one of claims 1 to 4, wherein the lens spacing body 14 comprises a solid body.

6. The lens assembly of claim 5, wherein the solid body is made of one of: diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, and flit glass.

7. The lens assembly of any one of claims 1 to 4, wherein the lens spacing body 14 defines an internal cavity, the internal cavity being filled with a fluid.

8. The lens assembly of claim 7, wherein the internal cavity is provided with a plano-concave shape.

9. The lens assembly of claim 6 or 7, wherein the fluid comprises a liquid.

10. The lens assembly of claim 9, wherein the liquid comprises diiodomethane.

11. The lens assembly of claim 10, wherein the liquid further comprises sulfur.

12. The lens assembly of claim 9, wherein the liquid comprises one of: water, silicone oil, acetone, ethanol, carbon tetrachloride, and a benzene and water glucose solution.

13. The lens assembly of claim 6 or 7, wherein the fluid comprises a gas.

14. The lens assembly of claim 13, wherein the gas comprises one of helium neon and hydrogen carbon dioxide.

15. The lens assembly of any one of claims 1 to 14, wherein the first index of refraction is greater than the second index of refraction.

16. The lens assembly of claim 15, wherein the third index of refraction is greater than the second index of refraction.

17. The lens assembly of claim 15, wherein the third index of refraction is less than the second index of refraction.

18. The lens assembly of any one of claims 1 to 14, wherein the first index of refraction is less than the second index of refraction and the third index of refraction is less than the second index of refraction.

19. The lens assembly of any one of claims 1 to 18, wherein the converging biconvex lens body is made of one of: cubic zirconia, diamond, silicon carbide, polycarbonate, polymethyl methacrylate, crown glass, and flit glass.

20. The lens assembly of any one of claims 1 to 19, wherein the contact lens body 16 is made of one of: polycarbonate, diamond, silicon carbide, polymethyl methacrylate, crown glass, and flit glass.

21. The lens assembly of any one of claims 1 to 20, wherein the opposite face is provided with one of a hemispherical shape and an ellipsoidal shape.

22. A lens assembly comprising: a central biconvex lens body having a first index of refraction, the central biconvex body extending between a first convex face and a second convex face opposite to the first convex face; a first positive meniscus lens body extending between a third convex face mounted to the first convex face of the central biconvex lens body and a fourth convex face, the first positive meniscus lens body having a second index of refraction; and a second positive meniscus lens body extending between a fifth convex face mounted to the second convex face of the central biconvex lens body and a sixth convex face, the second positive meniscus lens body having a third index of refraction, wherein the first index of refraction is greater than the second index of refraction and the third index of refraction.

23. The lens assembly of claim 22, wherein the second index of refraction and the third index of refraction are identical.

24. The lens assembly of claim 23, wherein the second index of refraction and the third index of refraction are equal to about 1.6.

25. The lens assembly of claim 24, wherein the first index of refraction is about 1.79.

26. The lens assembly of claim 23, wherein the first positive meniscus lens body and the second positive meniscus lens body are each made of flint glass.

27. The lens assembly of any one of claims 22 to 26, the central biconvex lens body defines an internal cavity, the internal cavity comprising a fluid.

28. The lens assembly of claim 27, wherein the fluid comprises a liquid.

29. The lens assembly of claim 28, wherein the liquid comprises a methylene iodide solution.

30. The lens assembly of claim 29, wherein the liquid further comprises sulfur.

31. The lens assembly of any one of claims 22 to 26, wherein the central biconvex lens body comprises a rigid body.

32. The lens assembly of any one of claims 22 to 26, wherein the first and second positive meniscus lens bodies form together a biconvex lens.

33. The lens assembly of claim 32, wherein a diameter of the central biconvex lens body is less than a diameter of the biconvex lens.

34. A lens assembly, the lens assembly comprising: a converging biconvex lens body having a first index of refraction, the converging biconvex lens body extending between a first convex face and a second convex face; a lens spacing body having a second index of refraction, the lens spacing body extending between a concave face and a first planar face opposite to the concave face, the concave face being mounted to and matching the second convex face of the converging biconvex lens; a further lens body having a third index of refraction, the further lens body extending between a second planar face and an opposite face, the second planar face being mounted to the first planar face,wherein the first index of refraction and the third index of refraction are each different from the second index of refraction, and the third index of refraction is at most equal to the first index of refraction.

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