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At least 19 recordsLinked to original sources
PubMed2006

[Emphasizing the prevention and treatment of immune rejection after corneal transplantation].

Corneal transplantation is a major therapeutic method to recover the sight from corneal blindness, however, the immune rejection is still the major impact factor for graft failure. With the improvement of the medical care in our country, corneal transplantation has been increased continually. Therefore, reducing the complications and increasing the long-term transparency rate of the graft is an important mission for ophthalmologists. The key core of the corneal transplantation is to pay more attention to the follow-up and prevent the immune rejection. Three respects, including the current status and problems of corneal transplantation in China, the update immune rejection theory and the means of reducing the immune rejection of the corneal graft, and the methods to reduce the risk of blindness due to immune rejection, will be focused in this paper.

Corneal Diseases↗
PubMed2005

Outcome of corneal transplantation.

Corneal transplantation is a sight restoring surgery done for corneal blindness. The purpose of this retrospective preliminary study is to analyze the outcome of 54 corneal transplantations (for 32 females and 22 males) done in the Department of Ophthalmology between September 1998 and June 2002. The mean follow-up period was 13 months. Hundred percent (6/6) of the keratoconus (KC) and 85.4% of the nonkeratoconus grafts survived at a mean duration of 7.1 months and 16 months respectively. Seven of the 54 grafts (13%) have failed. The causes of graft failure were graft rejction in 4 and bacterial keratitis in 3 cases. Fifty of the 54 cases (92.6%) had a preoperative visual acuity of < 3/60. As a result of the transplantation, the percentage of blind eyes dropped from 92.6% to 21%. The data in this study confirms that corneal transplantation is a reasonably successful procedure in restoring sight for seleted cases of corneal blindness in Ethiopia.

Blindness↗
PubMed1996

Corneal transplantation.

Corneal transplantation is a highly successful procedure for restoring sight in patients with corneal disease. The most common indication for transplantation is corneal edema following cataract extraction. A common problem following corneal transplantation is astigmatism, which often requires thick lenses for correction. The excimer laser holds promise for correcting postoperative astigmatism but is not yet in wide use. Rejection is a life-long risk and is most likely to occur during the first year. Topical corticosteroids are commonly used to decrease this risk. Frank corneal rejection must be recognized early and treated with intensive topical therapy.

Corneal Diseases↗
PubMed1989

Current status of corneal transplantation.

Corneal transplantation offers the cure for those with blinding corneal disease. Sourcing of a shortage of corneas are important. Graft survival depends on a number of factors, the most important of which is the recipient bed. The management of graft failure by rejection includes tissue matching, local and systemic immunosuppression.

Corneal Transplantation↗
PubMed1991

The Montgomery Lecture. Some factors which affect the visual outcome of corneal transplantation.

Corneal transplantation, which began in Dublin early in the nineteenth century, is now widely practised. Most grafts are done for visual reasons, some to manage corneal destructive disease. The factors associated with allograft rejection are well known, but a clear graft does not mean that the transplantation procedure has been successful. Successful corneal grafts enable patients to improve their life-style. To achieve this, the graft must be transparent and free of optical aberrations, the eye must be capable of achieving good vision, and the patient must have a life-style which would benefit from a successful functioning graft. A study of patients who have had corneal grafts identified the presence of a functioning graft, the lack of need for a contact lens, and the achievement of visual acuity in the operated eye which exceeds that of the contralateral eye, as requirements for patient satisfaction.

Algorithms↗
PubMed1992

Corneal transplantation.

Corneal transplantation is the most widely practiced form of clinical transplantation. This was made possible by the development of donor handling and preservation techniques, such as cooled culture media and organ-culture systems, that guarantee a sufficient supply of donor tissue. Corneal grafting is performed to improve visual function, to preserve the integrity of the eye, or to reduce pain. Patients with visual disability who present with keratoconus or dystrophy have a good prognosis for retaining a thin, transparent graft on a long-term basis. In this patient group the limiting factor for a gratifying visual outcome is high residual postkeratoplasty astigmatism, a still-too-frequent occurrence. Refinement in trephination techniques should help overcome this pitfall. Patients with vascularization or regrafting who are in the high-risk category may benefit from HLA matching or the use of cyclosporine and other immunosuppressive agents that are currently being tested in experimental models for reducing the impact of allograft rejection.

Astigmatism↗
PubMed1988

Corneal transplantation.

Corneal transplantation has become increasingly successful as a result of improved methods of tissue procurement and preservation, refined surgical techniques, better medical care, heightened public awareness and an expanded network of eye banks. Vision improves within a day of surgery and continues to improve for six months to one year. Careful screening of donors and donor corneal tissue is essential. Causes of transplantation failure include rejection, glaucoma and recurrent infections.

Corneal Transplantation↗
PubMed2003

The potential of antibody-based immunosuppressive agents for corneal transplantation.

Corneal transplantation is a sight-restorative procedure but its success is limited by irreversible graft rejection, which accounts for up to 50 per cent of failures. The normal eye is an immune-privileged site. Multiple mechanisms maintain ocular privilege, including the blood-eye barrier, the lack of blood vessels and lymphatics in the normal cornea, the relative paucity of mature antigen-presenting cells in the central cornea, the presence of immunomodulatory factors in ocular fluids, and the constitutive expressive of CD95L (Fas ligand) within the eye. However, privilege can be eroded by the sequelae of inflammation and neovascularization. Corneal graft rejection in humans is currently suppressed with topical glucocorticosteroids, which are moderately effective. Systemically administered immunosuppressive therapy is of limited efficacy and may be accompanied by unacceptable morbidity. Alternative therapies are needed to improve outcomes. Corneal graft rejection is primarily a cell-mediated response controlled by the CD4+ T cell, and thus CD4 and costimulatory molecule blockade are appealing targets for new therapeutic interventions. A number of monoclonal antibodies have shown promise as immunosuppressants to prolong corneal graft survival in experimental animal models, and may eventually prove to be useful adjuncts to corticosteroids.

Antibodies, Monoclonal↗
PubMed1979

Diagnosis and treatment of complications in the follow-up period after corneal transplantation.

Corneal transplantations are usually performed in Eye Clinics. The patient's own ophthalmologist usually performs the follow-up examinations because the patients often live a long way from the Clinic. It is very important that these ophthalmologists can diagnose the complications which may occur in the follow-up period and know how to treat them. The complications considered are: glaucoma, marginal infiltrations, epithelial defects suture infections, wound dehiscence, disturbances of the tear-film and recurrent herpes. Special mention is made of the rejection reaction. This has been recognized for a long time and has received increasing attention in recent years. Both local and general noxae can act as trigger and set off a rejection reaction. Epithelial, endothelial and uveal forms of rejection reaction are recognized. The sooner the immune reaction is recognized and the correct therapy started, the greater the change that graft will become clear again.

Corneal Transplantation↗
PubMed2001

Role of CD4+ and CD8+ T cells in allorecognition: lessons from corneal transplantation.

Corneal transplantation represents an interesting model to investigate the contribution of direct vs indirect Ag recognition pathways to the alloresponse. Corneal allografts are naturally devoid of MHC class II+ APCs. In addition, minor Ag-mismatched corneal grafts are more readily rejected than their MHC-mismatched counterparts. Accordingly, it has been hypothesized that these transplants do not trigger direct T cell alloresponse, but that donor Ags are presented by host APCs, i.e., in an indirect fashion. Here, we have determined the Ag specificity, frequency, and phenotype of T cells activated through direct and indirect pathways in BALB/c mice transplanted orthotopically with fully allogeneic C57BL/6 corneas. In this combination, only 60% of the corneas are rejected, while the remainder enjoy indefinite graft survival. In rejecting mice the T cell response was mediated by two T cell subsets: 1) CD4+ T cells that recognize alloantigens exclusively through indirect pathway and secrete IL-2, and 2) IFN-gamma-producing CD8+ T cells recognizing donor MHC in a direct fashion. Surprisingly, CD8+ T cells activated directly were not required for graft rejection. In nonrejecting mice, no T cell responses were detected. Strikingly, peripheral sensitization to allogeneic MHC molecules in these mice induced acute rejection of corneal grafts. We conclude that only CD4+ T cells activated via indirect allorecognition have the ability to reject allogeneic corneal grafts. Although alloreactive CD8+ T cells are activated via the direct pathway, they are not fully competent and cannot contribute to the rejection unless they receive an additional signal provided by professional APCs in the periphery.

Animals↗
PubMed1988

Report of the organ transplant panel. Corneal transplantation. Council on Scientific Affairs.

Corneal transplantation is the most common form of organ transplantation practiced in the United States. Two procedures for transplantation are utilized. Penetrating keratoplasty is used in about 90% of the cases, with lamellar keratoplasty being utilized in the remaining situations. Demand for corneal transplantation exceeds the available supply of corneas. Advances in procurement and preservation must continue to meet this demand. Finally, these procedures are not without complications, and these are discussed to provide a clear risk-benefit analysis.

Corneal Transplantation↗
PubMed1995

Patient-reported symptoms associated with graft reactions in high-risk patients in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Research Group.

The Collaborative Corneal Transplantation Studies (CCTS) were designed to evaluate the effect of donor-recipient histocompatibility matching and cross-matching on the survival of corneal transplants in high-risk patients. We now report on the role of symptoms in the detection of corneal allograft reactions in the CCTS and on the relationship between symptom reporting and graft survival. The 456 patients transplanted in the CCTS were followed for a minimum of 2 years or until graft failure. The follow-up protocol included 11 scheduled examinations in the first year, four examinations during the second year, and examinations every 6 months thereafter. Interim examinations were performed in response to patient-reported symptoms. At every examination, patients were asked specifically if they had redness, sensitivity to light, loss of vision, or pain (RSVP). Of the 456 patients transplanted, 62% had at least one graft reaction. Patients diagnosed with reactions at scheduled visits in the first postoperative year were 2.5 times more likely to report symptoms than those without reactions. Reports of red eye and vision loss were strongly associated with allograft reaction. However, these symptoms were neither highly sensitive nor specific for reaction (sensitivity = 46%, specificity = 70% at 6 months). The severity of reaction influenced the reporting of symptoms: 69% of patients with severe reactions reported symptoms versus 48% of patients with mild reactions (p < 0.001). The only patient characteristic associated with reliable symptom reporting was age, with younger patients with reactions being more likely to report symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2003

Outcomes of corneal transplantation: a corneal surgeon vs the general ophthalmologist.

AIMS: The aim of this study was to examine the outcomes of corneal transplantation in cases performed by a group of general ophthalmologists and those performed by an ophthalmologist with a subspecialist interest in corneal surgery. METHODS: A retrospective analysis of the outcomes in corneal transplantation was carried out for a 4-year period in three separate units in South Wales. In addition to patient demographic details, the primary diagnosis, type of keratoplasty performed, and outcome of surgery were noted. The data were analysed statistically by the Mann-Whitney U-test (one-tailed). RESULTS: Group A (n=35) was defined as those patients whose surgery was performed by a general ophthalmologist. There were seven surgeons in this group with a mean of five procedures each over the study period. Group B (n=54) were all operated on by the same surgeon. The mean age in both groups was similar with group A comprising of 66% males with 50% males in group B. The commonest indication for surgery in both groups was endothelial cell failure In group A, graft clarity at 1 year was 83% for all aetiologies and 73% at 2 years. In group B, the results were 97 and 92%, respectively. In group A, overall 56% achieved 6/18 or better compared with 68% in group B. In group A 73% had an improvement of one or more lines compared with 84% in group B (P=0.085). Reasons for graft failure in both groups were similar. CONCLUSION: The success rate of corneal transplantation carried out by general ophthalmologists in this study is reduced when compared with cases performed by a corneal surgeon. The explanation for this is not clear, but is undoubtedly multifactorial.

Clinical Competence↗
PubMed1997

Influence of advanced recipient and donor age on the outcome of corneal transplantation. Australian Corneal Graft Registry.

AIMS: The aims of this study were to examine the influence of advanced recipient and donor age on the long term outcome of corneal transplantation. METHODS: Records of 1036 penetrating corneal grafts in recipients aged > or = 80 years at surgery (defined as the elderly subset) and 8092 donor corneas used for transplantation were obtained from the Australian Corneal Graft Register database, Kaplan-Meier graft survival plots were compared using log rank statistics. RESULTS: Elderly recipients constituted 15% of the recipient pool. The major indication for corneal transplantation in the elderly was bullous keratopathy. Graft survival fell with increasing recipient age (p < 0.00001); the major cause of graft failure was rejection (33%). The desired outcome in 51% of cases was to improve vision and in 42% of cases to relieve pain; 23% of elderly recipients achieved a Snellen acuity of 6/18 or better in the grafted eye and 66% recorded improved acuity after transplantation. Elderly recipients suffered more complications and comorbidities in the grafted eye than did younger recipients. Donor age (stratified in 10 year intervals) did not influence corneal graft survival significantly (p = 0.10). CONCLUSIONS: Elderly graft recipients fared less well after corneal transplantation than did younger recipients, but outcomes in terms of long term graft survival and visual rehabilitation were still good. Donor age did not affect graft survival.

Age Factors↗
PubMed1994

Risk factors for corneal graft failure and rejection in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Research Group.

PURPOSE: To evaluate comprehensively the magnitude of suspected risk factors for corneal graft failure from any cause, failure from rejection, and immunologic reaction in patients at high risk for graft failure after corneal transplantation. METHODS: The records of the 457 participants in the Collaborative Corneal Transplantation Studies were reviewed. All participants had at least two quadrants of stromal vascularization and/or a history or previous graft rejection. Patients were followed for 2 to 5 years. Characteristics of the patient, study eye, donor, donor-recipient histocompatibility, and surgical procedure were examined for their association with the graft outcomes of failure from any cause, rejection failure, and immunologic reaction. Multivariate survival analysis techniques were used to estimate rates of graft outcome events and to estimate the magnitude of risk factors. RESULTS: Many apparent risk factors did not maintain their association with graft outcomes after adjustment for other risk factors. Young recipient age, the number of previous grafts, history of previous anterior segment surgery, preoperative glaucoma, quadrants of anterior synechiae, quadrants of stromal vessels, a primary diagnosis of chemical burn, and blood group ABO incompatibility were among the strongest risk factors identified for graft failure. Donor and corneal preservation characteristics had little influence on graft outcome. CONCLUSIONS: Risk of graft failure varies substantially, even within a high-risk population. The number of risk factors present should be considered by the patient and surgeon when contemplating transplantation and planning follow-up.

Adolescent↗
PubMed1992

Reproducibility of HLA-A, B, and DR typing using peripheral blood samples: results of retyping in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Group (corrected)

Recipients enrolled in the Collaborative Corneal Transplantation Studies were retyped as part of a quality assurance program. Because the observed percentage of HLA-DR homozygosity on original typing was more than twice as high as expected from CCTS allele frequencies, the sample selected for retyping was heavily weighted with patients whose original typing identified fewer than two DR antigens. Retyping was performed in a different laboratory from the laboratory performing the original typing. For the 129 patients who were retyped, agreement between the original and retyping laboratories was 88% for HLA-A, 79% for HLA-B, and 55% for HLA-DR. When criteria was relaxed to consider only discrepancies involving readily identifiable antigens, the agreement improved to 95% for HLA-A, 91% for HLA-B, and 59% for HLA-DR. Identification of a second HLA-DR antigen on retyping when only one DR antigen had been identified on original typing was by far the most common form of disagreement. There were no significant differences in the amount of disagreement among the laboratories. Of special interest is that 50% of the discrepancies involved DR3, DR5, and/or DR6, which have structural similarities. Based on the results of the project, we recommend: (1) replicate testing for all DR typing; and (2) retyping using a second source of antiserum for all subjects having DR blanks.

Corneal Transplantation↗
PubMedDate not supplied

[Corneal autograft, an additional alternative in corneal transplantation].

Corneal autotransplantation is a process in practice for various years. This procedure has the advantage of providing corneal tissue which will not be immunologically rejected in the host. This paper reports five cases in which this procedure was undertaken by changing a transparent cornea from a blind eye on the other side.

Adult↗