Patent Publication Number: US-2018028834-A1

Title: Ophthalmological device and method for the treatment of corneal diseases

Description:
FIELD OF INVENTION 
     The invention relates to an ophthalmological device and method for the treatment of corneal diseases such as keratoconus and glaucoma. 
     BACKGROUND OF THE INVENTION 
     Various methods for treating corneal diseases such as keratoconus and glaucoma are known. 
     Keratoconus is a bilateral degenerative disorder of the eye that progressively thins and distorts the cornea, changing it to a more conical shape than its normal curvature. The cornea of the eye becomes thinner with a consequent reduction in rigidity and stability. This typically leads to substantial visual impairment and corneal scarring. In most cases, corrective lenses are effective to allow a patient to function normally. Under the influence of the internal pressure of the eye, weakening of the cornea leads to the eye bulging outward which in turn leads to the eye becoming ametropic. There is considerable risk of the ametropia becoming more severe if the disease is not treated effectively. However, further progression of the disease may require treatments such as the insertion of intrastromal corneal ring segments, corneal collagen cross-linking or corneal transplantation. 
     It has been found that a cross-linking of the collagen fibres of the cornea may increase the rigidity of the cornea such that the cornea may better resist the internal pressure on the eye. For this purpose, it is known to use a photo-sensitizer such as riboflavin or a riboflavin solution which is applied onto the eye. Such a photo-sensitizer is able, under the influence of photons, to chemically react with the corneal tissue. After the riboflavin has been absorbed by the eye, the eye is exposed to an irradiation with ultraviolet (UV) radiation. Under the influence of the UV radiation, the photo-sensitizer induces a cross-linking of the collagen fibres, thereby increasing the biomechanical rigidity of the cornea such that the cornea is likely to deform less under the influence of the pressure of the eye. 
     Glaucoma is a disorder of the eye wherein the optic nerve is damaged causing a loss of visual field. Raised intraocular pressure is a risk factor for developing glaucoma. The treatments for glaucoma include the use of medication such as eye drops for reducing intraocular pressure and both laser and conventional surgery. 
     Any reference herein to a “photo-sensitizer” must be interpreted to mean a reference to a substance which under the influence of photons, is able to chemically react with corneal tissue absorbing the photo-sensitizer so as to cross-link corneal collagen and thereby increase the rigidity of the corneal tissue. 
     SUMMARY OF INVENTION 
     According to a first aspect of the invention there is provided an ophthalmological device for the treatment of corneal diseases, which includes: 
     a mould having a curved, transparent moulding surface defining a plurality of apertures therein, which is applied to the cornea of an eye of a patient for shaping the corneal tissue to a desired curvature; 
     a suction body defining a suction chamber in which a partial vacuum is induced so as to form a partial vacuum within the mould which attracts the cornea onto the moulding surface; and 
     a radiation source for irradiating the cornea with a beam of radiation. 
     The mould may include a rigid lens which defines said curved moulding surface, the moulding surface of the lens having a predetermined curvature so as to shape the corneal tissue to said desired curvature. The mould lens may be in the form of a rigid contact lens. The mould may be removably connected to the suction body. In use, this permits the mould to be removed and replaced by another mould with a lens having a different curvature. 
     The suction body may be in the form of an elongate, hollow tube having a connecting formation at a lower end thereof to which the mould is removably connected. 
     One of the suction body and the mould may have a connector to which a conduit connected to a suction device such as a suction pump, can be connected, in use. 
     The radiation source may be in the form of a lamp which is operable to emit a beam of UV light. More specifically, the radiation source may be operable to emit a beam of UV light having a wavelength of 375 nm. 
     According to a second aspect of the present invention there is provided a method of treating corneal diseases, which includes: 
     applying an effective amount of a photo-sensitizer to a cornea of an eye of a patient; 
     applying a mould to the cornea thereby to shape the cornea until a desired corneal shape is achieved; 
     applying a suction to the cornea so as to attract the cornea onto the moulding surface of the mould; and 
     irradiating the cornea with a focused beam of radiation thereby to induce a cross-linking of collagen fibres in the cornea while the cornea is attracted onto the moulding surface of the moulding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features of the invention are described hereinafter by way of a non-limiting example of the invention, with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings: 
         FIG. 1  shows a side view of a device for the treatment of corneal diseases, in accordance with the invention; 
         FIG. 2  shows a sectional side view of the device of  FIG. 1 ; and 
         FIG. 3  shows a bottom plan view of the device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     With reference to the drawings, an ophthalmological device for the treatment of corneal diseases such as keratoconus and glaucoma, is designated generally by the reference numeral  10 . The device  10  has a generally elongate cylindrical configuration and comprises a moulding head  12 , a suction body  14  and a UV lamp  15 . 
     The device  10  is specifically adapted for use in the treatment of corneal diseases wherein the moulding head  12  is used to shape the cornea of an eye of a patient while the UV lamp  15  is used to induce cross-linking of collagen fibres in the cornea by a photo-sensitizer such as riboflavin or a riboflavin solution. 
     The moulding head  12  is of a plastics material and has a generally hollow cylindrical configuration. The moulding head has a first end  16  which is open and a second end  18  in which a rigid glass moulding lens is mounted. The end  16  defines a boss  17 . The moulding lens  20  defines a curved moulding surface  22  having a predetermined curvature. The lens  20  defines a plurality of apertures  21  therein, the purpose of which is explained hereinbelow. The moulding head  12  further includes a connector  24  to which a hose  26  which is connected to a suction pump, is connected. 
     The suction body  14  is aluminium and has a generally hollow cylindrical configuration and has a first end  28  and a second end  30 . The first end  28  is open and is releasably fitted onto the boss  17  at the open end  16  of the moulding head in an airtight arrangement. The UV lamp  15  is fitted to the suction body  16  at its closed end  30  in an airtight manner. The UV lamp  15  is in the form of a light emitting diode (LED) which is operable to emit a beam of UV light having a wavelength of 375 nm. The aluminium of the suction body acts as a heat sink, cooling the suction body when it is heated by the LED, in use. 
     The moulding head  12  and the suction body  14  together define a chamber  32  from which air is evacuated as will be explained in further detail below, in order to induce a partial vacuum within the chamber  32 . 
     In use, the device  10  is used in the treatment of corneal diseases, for example, keratoconus. In the treatment of keratoconus in accordance with the method of the invention, an effective amount of a photo-sensitizer such as riboflavin or a riboflavin solution is applied to an eye  11  of a patient. Thereafter a lens  20  of the moulding head  12  of the ophthalmological device  10  is pressed against the cornea so as to shape the cornea until a desired corneal shape is achieved. A suction is applied to the chamber defined by the moulding head  12  and the suction body  14  until a partial vacuum is created within the chamber  32  which causes a suction to be applied to the cornea of the eye so as to attract the cornea onto the moulding surface of the lens  20 . The suction applied to the eye from within the chamber  32  enhances the moulding of the cornea by attracting the cornea onto the moulding lens while at the same time reducing intraocular pressure within the eye. While the cornea is held against the mould by the suction, the cornea is irradiated with a focused beam of UV light by means of the UV lamp  15  thereby inducing a cross linking of the collagen fibres in the cornea of the eye which in turn increases the biomechanical rigidity of the cornea. 
     By being releasably secured to the suction body, the moulding head  12  can be removed and replaced with another moulding head having a lens which has a different curvature. In this manner, this allows the ophthalmological device  10  to be used with different moulding lenses for use with patient&#39;s having corneas having different curvatures. Furthermore, with the moulding head  12  removed, the ophthalmological device can be used for conventional cross-linking using a photo-sensitizer and beam of UV light only. 
     The method and device described hereinabove have been found to be useful as an adjunct in the treatment of certain types of glaucoma by lowering the intraocular pressure within the eye. The method and device described hereinabove have also been found to be useful in the treatment of keratoconus wherein the device is used to change the curvature of the cornea while simultaneously increasing the biomechanical rigidity of the cornea by inducing cross-linking of collagen fibres within the cornea.