Keratoprosthesis

The invention relates to medicine, a precisely to ophthalmology, and is intended for prosthetic cornea with severe cataracts eye.

Known keratoprosthesis comprising a base plate with a central and lateral holes, and coupled with her mushroom-optic rod, while the base plate is provided with radial cut (see para. 562 277 AS N, M. Cl. 2 A 61 F 1/16, BI , 1977, N 23).

The disadvantages of the above-described technical solutions are single and stiffness of the front support member, which cause sores in the cornea and form a "pocket" 'for foreign matter and microflora that contribute to the development of complications, leading to the rejection of the prosthesis.

The closest in technical essence to the claimed keratoprostheses a technical solution (see. Patent of Russian Federation N 1804809, Mkl.5 A 61 F 2/14, BI, 1993, N 12), in which keratoprosthesis consists of two support plates sequentially implanted into the corneal tissue and the space between the eyeball and the eyelids, and a removable optical cylinders screwed into the central hole of the support plates. Thus one plate provided with pins and mounted on the optical cylinder movably.

The disadvantages described above can be attributed integrally keratoprosthesis internal reference element that its implantation requires extensive cuts and bundles of the cornea. Another disadvantage of this prosthesis is the fulfillment of the internal reference element, limited to a diameter of the cornea, which does not increase the size of the optical cylinder while maintaining sufficient fixing it, which prevents rejection of the prosthesis.

The technical problem solved by the claimed invention, - avoiding rejection of the prosthesis with increasing diameter of the optical cylinder.

Said technical result of the invention, which is a keratoprosthesis comprising an inner support member formed as a sleeve provided with an internal thread and the retaining plates and optical cylinder with external thread for screwing into the inner support member and an outer support member with a central coaxial threaded bore for screwing in the optical cylinder is achieved in that the sleeve is split and provided with a locking ring, the ends of the hub items bushings, and related ends adjacent parts are made parallel relative to the axial diameter of the sleeve, and the ends of the opposing parts, and related ends adjacent parts formed radially relative the central longitudinal axis of the sleeve. Fixation plates are formed as rectangular perforated strips arranged crosswise and perpendicular to each other, a length that goes beyond the diameter of the cornea. In addition, the outer support member made of two interconnected plates, the front plate is a monolithic rigid with an outer diameter corresponding to the parameters of the operated cornea and the back plate is made of porous elastic with a diameter greater than the diameter of the front plate, wherein an inner radius of curvature of the front supporter item is selected in accordance with the outer radius of curvature of the operated cornea.

FIG. 1 shows a top view of keratoprosthesis FIG. 2 shows a sectional keratoprosthesis FIG. 3 shows the decoupling of the inner support member, a top view, FIG. 4 illustrates the internal support element in cross-sectional FIG. 5 shows a fragmented frontal support element in cross section.

Figures numbers: 1 - optical cylinder, 2 - sleeve, 3 - fixation plate 4 - Front monolithic plate, 5 - rear porous plate, 6 - a lock ring, 7 - the cornea, 8 - the sclera, 9 - direct oculomotor muscles, 10 - Conjunctivitis.

To produce the claimed keratoprosthesis known use permitted for use biologically inert materials.

Dimensions and details keratoprosthesis cylinder optical power is selected in accordance with the parameters of the patient's eye.

Keratoprosthesis implanted claimed as follows: the first step otseparovyvayut conjunctiva (10) in a circle from the limbus to the width corresponding to the projection of the back plate (5) of the outer support member (Fig. 2 and 5); mark a zone of the second stage burr hole, corneal bundle (7), and sclera (8), the scleral incisions, with their projecting diagonally toward right eye muscles (9); third stage the total removal of the corneal epithelium (7), coaxial to the central cornea trephine shirts (7) by 2/3 of the thickness, diameter 0.3-0.5 mm less than the outer diameter of the sleeve (2) and parallel to the limbus scleral incisions ( 8) 2/3 thickness; fourth stage of counter corneal bundle (7), and sclera (8) forming channels in them by burr hole paving fixation plate (3) and outputting them to the surface through the ends of the scleral incisions; fifth stage of mating parts sleeve (2) inside the retaining ring (6), the part with parallel end faces is placed last; The sixth stage perform pass-through trepanation of the cornea (7) with a diameter corresponding to the inner diameter of the threaded sleeve (2) and is screwed optical cylinder (1) so that the rear end it does not protrude into the anterior chamber; seventh stage the peripheral corneal puncture (7) outside the zone of placement of the fixation plates (3) are introduced into the anterior chamber of the eye with saline and oxygen to the extent necessary, the optical screw down cylinder (1) to a predetermined depth; Eighth step is screwed onto an outer support member (FIGS. 2 and 5) on the optical cylinder (1), the projecting ends of the fixation plates (3) are placed in various embodiments, fix them and the back plate (5) stitches to the sclera (8); ninth stage cover the protruding part of the rear plate (5) the conjunctiva (10) impose temporary sutures operation terminates.

The positive effects of the claimed keratoprosthesis are: the implementation of the internal reference element releasably with a certain configuration and position of the fixation plates allows to implant it through a burr hole of the cornea, dissecting tissue only to the extent necessary, the relevant area and the position of the fixation plates to keep around burr hole unfibered portions of the cornea, which reduces trauma surgery; Distribution of support elements in the region of the sclera and mix them together strengthens hold and creates opportunities to increase the diameter of an optical cylinder, which increases the functional quality of the prosthesis; performing outer support member in the form of two plates with different diameters and physical properties is provided due to the rigidity and solidity of the front plate mechanical protection and cosmetic effects, due to the elasticity, porosity, and larger diameter rear plate to overlay the fixing to the sclera stitches cover the protruding portion of the plate conjunctiva allows to grow tissues of the plate, and also lets you create depots needed drugs to preliminary impregnation plate with gel defined composition, all these enhanced fixation, increased integrity, obstructed the formation of "pockets" for foreign matter and microflora under the outer support element, which reduces the chance of developing complications, leading to rejection of the prosthesis.

Thus, as a result of the collection of all the above partial positive effects which are ensured by the claimed structural nodes keratoprosthesis, a common technical result achieved, ie. E. Warning possibility of rejection of the prosthesis with increasing diameter of the optical cylinder.

Also, performing keratoprosthesis collapsible retains the possibility of implanting it in one or two steps, when necessary to replace the cylinder and optical access into the eye.