FIELD OF THE INVENTION:
[001] The present invention generally relates to transplantation used for corneal transplants.
[002] More particularly, the present invention relates to corneal transplants surgical method.
BACKGROUND FOR THE INVENTION:
[003] By reference to US application no. US2012282318A1 by Sheet for corneal transplants dated 2010-08-16, titled” Tohoku University NUC, KOYOTO Univ” discloses a sheet for corneal transplants comprising corneal endothelial cells on a gelatin hydrogel, which is obtainable by seeding and culturing corneal endothelial cells on a gelatin hydrogel coated with collagen. The sheet of the present invention is extremely useful as a sheet for corneal transplants not only for its biocompatibility and biodegradability, but also for its high transparency.
[004] By reference to IT application no. IT1144695B by Ufim Nii Glaznykh Bolez dated 1981-04-06, titled” Homo:transplant for lamellar corneal surgery” discloses homotransplant for lamellar keratoplasty consists of slices, 50-300 microns thick, of tendon tissue. Pref. it is stored in a glass or polyethylene container and bathed in an alcoholic medium, e.g. 70% ethanol. The transplants are used in ophthalmology e.g. for treating keratitis, ulcers, abcesses, burns, tumours, etc. These transplants are easily prepd. in large no., have almost unlimited storage life at 0 to 30 deg. C and are easily transported. They give better results than corneal transplants, do not cause secondary reaction (so postoperative recovery is quicker) and the use of immunosuppressants is obviated.
[005] By reference to FR application no. FR2502943A1 by UFIM I GLAZNYKH BOLEZN dated 1981-04-07, titled” Homo:transplant for lamellar corneal surgery - comprises slices of tendon tissue” discloses Homotransplant for lamellar keratoplasty consists of slices, 50-300 microns thick, of tendon tissue. Pref. it is stored in a glass or polyethylene container and bathed in an alcoholic medium, e.g. 70% ethanol. The transplants are used in ophthalmology e.g. for treating keratitis, ulcers, abcesses, burns, tumours, etc. These transplants are easily prepd. in large no., have almost unlimited storage life at 0 to 30 deg. C and are easily transported. They give better results than corneal transplants, do not cause secondary reaction (so postoperative recovery is quicker) and the use of immunosuppressants is obviated.
[006] By reference to CN application no. CN201676074U by Sichuan Peoples Hospital of Sichuan Academy of Medical Sciences dated 2010-02-04, titled” Corneal endothelial nail” discloses a corneal endothelial nail, which belongs to the technical field of corneal transplantation and comprises a nail cap, a nail core and a barb. An included angle between the nail core and the nail cap is larger than 0 degree, and smaller than or equal to 90 degrees, and an included angle between the barb and the nail core is larger than 0 degree and smaller than 90 degrees. The corneal endothelial nail can effectively prevent dropping and displacement of corneal endothelial sample transplants, guarantees success ratio of corneal endothelial transplantation, and is used for fixing a transplanted rear elastic layer or other diaphragms attached to a corneal endothelium during corneal endothelial transplantation, such as amnions and the like.
[007] By reference to PCT application no. PCT/IB2007/001238 by Universita' Degli Studi Di Parma dated 2007-05-14, titled” Surgical instrument for corneal transplants” discloses surgical instrument (20) for manipulating and inserting into an eye a lamina of cells (7), such as a thin stroma support with Descemet membrane and endothelial cells for corneal transplants, or other types of laminas, comprises a hollow tubular body (1) able to contain the lamina of cells (7) immersed in a maintenance solution. The hollow tubular body (1) comprises a distal part (5), tapered and open at the end, and the section of the distal part (5) diminishes towards the end of the hollow tubular body (1) so that, during use, the lamina of cells (7), emerging from the distal part (5), is able to be configured tubularly, adapting to the section of the end of the distal part (5).
[008] By reference to PCT application no. PCT/KZ2009/000011 by Republican State Treasury Enterprise "Kazakh Order "Zhak Honor" Scientific Research Institute of Eye Diseases" of the Ministry of Health of the Republic of Kazakhstan dated 2009-06-05, titled” Method for surgically treating corneal diseases” discloses medicine, in particular to ophthalmic transplantology, and can be used for surgically treating corneal diseases. The method involves applying a biocoating and subsequently securing said coating in the conjunctival cavity. The biocoating is in the form of a collagen base containing cultured porcine limbal growth cells. Said biocoating is secured to the episclera in the fornix area under the conjunctiva with the aid of an amniotic membrane. Tests show that the biocoating begins to be absorbed within a period of 10 to 14 days, which is two times more rapid than with the prototype. No side effects have been observed during the postoperative period. Complete corneal epithelialization and improved visual acuity have been noted in all patients.
[009] By reference to GB application no. GR1008725B by Modified intrastromal suport ring for corneal transplants dated Anastasios Konstantinou Charonis, titled” Modified intrastromal suport ring for corneal transplants” discloses a modified intrastromal ring meant to support transplants in the cornea is disclosed. Technical features: the cornea transplant-supporting ring described herein is immersed in the right position first inside the donor?s cornea and then inside the receiver?s one with none extra surface section but with creation of peripheral oblong cuts (1-2 mm wide) on the peripheral layer of the transplant and the peripheral part of the patient?s cornea. Purpose: to allow the complete or partial deterrence of sutures on the eye surface throughout penetrating keratoplasty or front partial keratoplasty. Advantages: unique easy surgical technique, minimization of postoperative complications due to sutures existing for a lot of months and/or years on the surface of the grafted eye.
[010] By reference to US application no. US10898383B2 by CorneaGen Inc dated 2018-08-03, titled” Systems and methods for tissue dissection in corneal transplants” discloses dissection system for corneal transplants includes a housing including a contact side to be positioned against a cornea. The housing includes an interior passageway with an opening at the contact side. The dissection system includes a blade assembly disposed in the interior passageway. The blade assembly includes a first blade and a second blade. The first blade includes a first cutting edge and the second blade includes a second cutting edge. The first blade and the second blade are movable relative to the housing such that the first cutting edge and the second cutting edge extend through the opening of the housing and out of the interior passageway. The first cutting edge produces a first cut in the cornea. The second cutting edge produces a second cut in the cornea.The first cut and the second cut define a volume of tissue for removal from the cornea.
[011] However, none of the above-discussed inventions provides such a corneal transplants surgical method. The method comprising a plurality of steps.
OBJECTS OF THE INVENTION:
[012] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
[013] The main object of the present invention is to provide a transplantation used for corneal transplants.
[014] Another object of the invention is to provide Donor corneal preparation steps.
[015] Another object of the invention is to provide a commonest indication for transplant is infectious keratitis [n = 49, 81.6%].
[016] Another object of the invention is to provide fresh corneas used in this group are non-optical grade [66.7%].
[017] Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY OF THE INVENTION:
[018] According to one aspect of our invention, corneal transplants surgical method comprising the steps of: a) The TPK (therapeutic keratoplasty) is performed under general anaesthesia and Trephination of donor cornea is done with a disposable hand-held trephine as per the requirement; b) The recipient cornea is trephined gently to cover the edge of the infiltration completely and a 15° side port is used to enter the anterior chamber (AC) from the trephined area; and the AC is formed using a viscoelastic device; c) Corneal scissors are used to cut the rest of the recipient cornea and the excised recipient cornea is sent for microbiological and histopathological examination; d) AC is washed with sterile BSS Solution to remove the debris and infiltrates; and anterior and posterior synechiae are released with the viscoelastic device; e) The donor button is oversized by 0.5-1.0 mm; and the graft is sutured by interrupted suturing using 10-0 nylon suture in all cases; f) At least 2 iridectomies are performed before suturing of the graft and AC is carefully washed with BSS and reformed with air; g) Crystalline lens is not removed in any of the cases, except one, where there is a corneal perforation with lens extrusion.
[019] In another aspect of the invention, the primary indication of TPK is infectious keratitis in both the groups (FCT-81.6%; GPC - 91.2%).
[020] In another aspect of the invention, there is no significant difference in the therapeutic success in both the groups (P = 0.741, Odds ratio- 1.59 with 95% CI- 0.39-6.44).
BRIEF DESCRIPTION OF DRAWINGS:
[021] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
[022] Figure 1: illustrates a cause of infectious keratitis in both the group, as per an embodiment of the present invention.

[023] Figure 2: illustrates a grade of fresh corneal tissue used in FCT group, as per an embodiment of the present invention.
[024] The referral numerals in the figures refer to: 2, 3, 4, 5, 6, 7, 8, 9, 10 - method steps.

BRIEF DESCRIPTION OF INVENTION:
[025] The present invention will now be described hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. While the following description details the preferred embodiments of the present invention is not limited in its application to the details of construction and arrangement of the parts illustrated in the accompanying drawings. With reference to the figures, the enclosed description and drawings are merely illustrative of preferred embodiments and represent several different ways of configuring the present invention. Although specific components, materials, configurations and uses of the present invention are illustrated and set forth in this disclosure, it should be understood that a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein.
[026] The present invention proposes a corneal transplants surgical method comprising the steps of: a) The TPK (therapeutic keratoplasty) is performed under general anaesthesia and Trephination of donor cornea is done with a disposable hand-held trephine as per the requirement; b) The recipient cornea is trephined gently to cover the edge of the infiltration completely and a 15° side port is used to enter the anterior chamber (AC) from the trephined area; and the AC is formed using a viscoelastic device; c) Corneal scissors are used to cut the rest of the recipient cornea and the excised recipient cornea is sent for microbiological and histopathological examination; d) AC is washed with sterile BSS Solution to remove the debris and infiltrates; and anterior and posterior synechiae are released with the viscoelastic device; e) The donor button is oversized by 0.5-1.0 mm; and the graft is sutured by interrupted suturing using 10-0 nylon suture in all cases. f) At least 2 iridectomies are performed before suturing of the graft and AC is carefully washed with BSS and reformed with air; g) Crystalline lens is not removed in any of the cases, except one, where there is a corneal perforation with lens extrusion.
[027] The present invention as illustrated in Figure 1 provides another embodiment of the invention which includes a cause of infectious keratitis in both the group.
[028] The present invention as illustrated in Figure 2 provides another embodiment of the invention which includes a grade of fresh corneal tissue used in the FCT group.
[029] In another embodiment, medical records of the patients who underwent therapeutic penetrating keratoplasty (TPK) are reviewed. The FCT group included patients who underwent TPK with fresh corneal tissue and the GPC group included patients who underwent TPK with glycerol preserved cornea. The indications and outcomes of TPK in the terms of therapeutic success are analysed and compared between both the groups.
[030] In another embodiment, a total of 94 eyes of 91 patients underwent TPK from October 2011 to August 2017. FCT group included 60 eyes of 57 patients and GPC group included 34 eyes of 34 patients. The primary indication of TPK is infectious keratitis in both the groups (FCT-81.6%; GPC - 91.2%) There is no significant difference in the therapeutic success in both the groups (P = 0.741, Odds ratio- 1.59 with 95% CI- 0.39-6.44). Complications included glaucoma (FCT-21.7%; GPC- 35.2%) graft infection (FCT- 18.33% GPC- 2.9%); graft rejection (FCT-11.66%, GPC- 0%); and graft failure (FCT-88.33%, GPC-100%).
[031] In another embodiment, the GPC is comparable to FCTs in therapeutic transplant and can be a useful interim procedure in saving the eyes in cases of infective keratitis in the time of crisis.
[032] In another embodiment, this is the only comparative study between fresh corneal tissue and glycerol preserved tissue in emergency corneal transplants.
[033] In another embodiment, the demographic details, indications of TPK, microbiological investigations, size of the donor cornea, recipient graft size, outcomes of surgery and complications are compiled from the hospital records. The patients are categorized as FCT group, who underwent TPK with Fresh corneal tissue preserved in McCarey–Kaufman (MK) medium and GPC group, who underwent TPK with Glycerol Preserved cornea.TheGPC is used only in emergency situation when the eye bank did not have fresh donor corneal tissue for transplant.
[034] In another embodiment, donor corneal preparation All donor corneas are evaluated by the cornea specialist in the eye bank. The corneas are graded as per NEI criteria.
[035] In another embodiment, all the non-optical grade tissues are first preserved in MK medium for 4 days at 4°C for therapeutic/tectonic transplants. If these tissues are not used for therapeutic use within 4 days, they are transferred to a sterile glass bottle having sterile glycerol solution and preserved at 4°C. The MK medium is evaluated microbiologically to exclude any infection after transferring the tissues to glycerol. The duration of storage of GPC ranged from 1-3 months. Prior to surgery, the donor corneal button is soaked for 10 minutes in sterile balanced salt solution (BSS) to wash away the residual glycerol. Surgical technique The TPK is performed under general anaesthesia. Trephination of donor cornea is done with a disposable hand-held trephine as per the requirement. The recipient cornea is trephined gently to cover the edge of the infiltration completely. A 15° side port is used to enter the anterior chamber (AC) from the trephined area.
[036] In another embodiment, the AC is formed using a viscoelastic device. Corneal scissors are used to cut the rest of the recipient cornea. The excised recipient cornea is sent for microbiological and histo-pathological examination. AC is washed with sterile BSS solution to remove the debris and infiltrates. Anterior and posterior synechiae are released with the viscoelastic device. The donor button is oversized by 0.5-1.0 mm. The graft is sutured by interrupted suturing using 10-0 nylon suture in all cases. At least 2 iridectomies are performed before suturing of the graft. AC is carefully washed with BSS and reformed with air. Crystalline lens is not removed in any of the cases, except one, where there is a corneal perforation with lens extrusion.
[037] In another embodiment, postoperative medication, patients are prescribed topical and oral antibiotics, based on the clinical picture and microbiological reports. Topical steroids are started in only proven cases of bacterial keratitis where sensitivity is known after 48 hours of TPK. In cases of fungal infections, steroids are started after 2 weeks when recurrence of infection is clinically ruled out.
[038] In another embodiment, therapeutic success is defined as anatomical restoration and removal of infectious process while Therapeutic failure is considered if the integrity of the eyeball could not be maintained (e.g. phthisis bulbi or evisceration/ enucleation).
[039] In another embodiment, functional success is defined as a clear graft with best corrected visual acuity of more than 6/60 on Snellen visual acuity chart. Graft failure is defined as a graft that did not retain optical clarity or if there is high astigmatism that could not be optically corrected, resulting in recommendation of re-grafting. A minimal follow-up of 1 year is included to define therapeutic or functional success or failure.
[040] In another embodiment, SPSS software version 22.0 (SPSS Inc, Chicago, IL) is used for statistical analysis. For description, quantitative variables have been expressed as mean+/- SD and qualitative variables have been expressed as a percentage. Mann-Whitney U-test is applied for non-normally distributed continuous variables. Differences between FCT and GPC are analysed using unpaired t-test for continuous variables and Chi-square test for nominal variables. P value =0.05 is considered significant.

[041] In another embodiment, TPK is performed in 94 eyes of 91 patients from October 2011 toAugust 2017. The minimum follow up period is 1 year in all the cases. All the patients hailed from the rural areas and time of presentation ranged from 4 to 270 days (median-30 days, IQR = 14.7-74.2 days). FCT group comprised of 60 eyes of 57 patients with mean age of 51.3 ± 15.7 (14-76 years) and male to female ratio of 2:1 [Table 1]. The commonest indication for transplant is infectious keratitis [n = 49, 81.6%; Table 2]; bacterial keratitis is the most common infection [n = 18, 30%; Fig. 1]. Most of the fresh corneas used in this group are non-optical grade [66.7%; Fig. 2]. Graft failure is seen in 88.33% (n = 53) of patients and only 11.66% (n = 7) grafts survived which are optical grade tissues with a best corrected visual aquity (BCVA) of 6/60 or better on Snellen acuity chart after the therapeutic transplant [Table 3]All non-optical grafts failed aftertransplant within one year. Complications in this group included graft infection (18.33%%, n = 11), graft rejection (11.66%, n = 7) and secondary glaucoma (21.7%, n = 13). At the final outcome, therapeutic success is achieved in 86.7% (n = 52) of eyes [Table 4].
[042] In another embodiment, GPC group comprised 34 eyes of 34 patients with a mean age of 49.05 ± 16.8 years (Age 74 years) with a male preponderance of 94.1% [Table 1]. The duration of preservation of donor GPC ranged from 1-3 months. The commonest indication of transplant in this group is also microbial keratitis seen in 91.2% (n = 31) of cases [Table 2]. The most common infection in this group is bacterial infection [n = 23, 67.6%; Fig. 1]. Graft failure is seen in all cases (100%). Complications include graft infection (2.9%, n = 1), secondary glaucoma (35.2%, n = 12) and delayed epithelialization in all cases. Amniotic membrane transplant is done in five cases for non-healing epithelial defect. There is no episode of graft rejection in this group. At the final outcome, therapeutic success is seen in 91.17% (n = 31) of eyes [Table 4].
[043] In another embodiment, the age in both the groups are comparable (P = 0.5) however, there is male preponderance in GPC group (94.1% vs. 66.7%). There is no significant difference in the size of the trephines used in both the groups [donor P = 0.82, recipient P = 0.9; Table 1]. Incidence of glaucoma post-surgery is clinically higher in GPC group but is statistically not significant (P = 0.34). Therapeutic success is better in GPC group as compared with that in FCT group; however, the difference is not statistically significant (P = 0.741, Odds ratio- 1.59 with 95% CI- 0.39-6.44). Rates of reinfection and rejection is more in FCT group and only one case of reinfection, and no case of rejection is noticed in GPC group [Table 3].
Re-transplant with optical grade tissue is done in 11 eyes in FCT group and 5 eyes in GPC group. Six out of these 11 grafts in FCT group had graft failure at the end of one year, whereas all the grafts survived for more than one year in GPC group.
[044] In another embodiment, the authors recommend GPC as a good and an inexpensive alternative to a FCT for emergency corneal transplant in resource-limited settings or crisis situation as evident from our study. It can be effectively used for saving the eyes when fresh corneal tissues are not available and gives a good anatomical outcome instead of subjecting the patient to evisceration/ enucleation.
[045] The present disclosure described herein above has several technical advantages including, but not limited to,
? Incidence of glaucoma post-surgery is clinically higher in GPC group but is statistically not significant (P = 0.34).
? Therapeutic success is better in GPC group as compared with that in FCT group.
? Graft re-infection seen in the FCT group is 18.33% and is higher than the GPC group 2.9%.
[046] The disclosure has been described with reference to the accompanying embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.
[047] The foregoing description of the specific embodiments so fully revealed the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.

We Claims

1. A corneal transplants surgical method comprising the steps of: a) The TPK (therapeutic keratoplasty) is performed under general anaesthesia and Trephination of donor cornea is done with a disposable hand-held trephine as per the requirement; b) The recipient cornea is trephined gently to cover the edge of the infiltration completely and a 15° side port is used to enter the anterior chamber (AC) from the trephined area; and the AC is formed using a viscoelastic device; c) Corneal scissors are used to cut the rest of the recipient cornea and the excised recipient cornea is sent for microbiological and histopathological examination; d) AC is washed with sterile BSS Solution to remove the debris and infiltrates; and anterior and posterior synechiae are released with the viscoelastic device; e) The donor button is oversized by 0.5-1.0 mm; and the graft is sutured by interrupted suturing using 10-0 nylon suture in all cases; f) At least 2 iridectomies are performed before suturing of the graft and AC is carefully washed with BSS and reformed with air; g) Crystalline lens is not removed in any of the cases, except one, where there is a corneal perforation with lens extrusion.

2. The corneal transplants surgical method as claimed in claim 1, wherein the primary indication of TPK is infectious keratitis in both the groups (FCT-81.6%; GPC - 91.2%).
3. The corneal transplants surgical method as claimed in claim 1, wherein there is no significant difference in the therapeutic success in both the groups (P = 0.741, Odds ratio- 1.59 with 95% CI- 0.39-6.44).
4. The corneal transplants surgical method as claimed in claim 1, wherein complications included glaucoma (FCT-21.7%; GPC- 35.2%) graft infection (FCT- 18.33% GPC- 2.9%); graft rejection (FCT-11.66%, GPC- 0%); and graft failure (FCT-88.33%, GPC-100%).
5. The corneal transplants surgical method as claimed in claim 1, wherein the GPC is comparable to FCTs in therapeutic transplant and can be a useful interim procedure in saving the eyes in cases of infective keratitis in the time of crisis.