The Rapid Transformation of Transplantation for Corneal Endothelial Diseases: An Evolution From Penetrating to Lamellar to Cellular Transplants.

The cornea is the major focusing structure of the human eye and the corneal endothelium maintains the relatively dehydrated state of the cornea required for clarity. The endothelial cells respond to disease or injury by migration and cellular enlargement. Our current understanding is that there is a very limited degree of proliferative or regenerative capacity in the human corneal endothelium. Thus, corneal endothelial diseases may result in corneal edema, significantly impact vision and quality of life. Contemporary surgical transplantation options for treating moderate to advanced endothelial dysfunction include penetrating keratoplasty (PK), Descemet stripping endothelial keratoplasty (DSEK), and Descemet membrane endothelial keratoplasty. Advances in surgical techniques aim to bring faster visual recovery and improve visual outcomes; however, there is still a significant donor cornea shortage worldwide and alternative methods for treatment for corneal endothelial disease are rapidly evolving. Indeed, we are at a pivotal point in corneal transplantation for endothelial disease and novel surgical strategies include using 1 donor for multiple recipients, a minimally attached endothelial graft, and Descemet membrane stripping only. Crucially, forthcoming approaches include the use of Rho-Kinase (ROCK) inhibitors, endothelial cell therapy, tissue engineered grafts, and consideration of stem cell techniques. Ultimately, the choice of technique will be dependent on recipient factors such as age, type of endothelial disease, extent of the disease, and associated ocular disorders. The safety and efficacy of these rapidly developing treatments warrant further investigations. In time, some or all of these alternatives for corneal transplantation will alleviate the reliance on limited corneal donor tissue.

Awareness and attitudes toward corneal donation among applicants and staff of a driver, vehicle and licensing authority (DVLA) in Ghana.

BACKGROUND: Corneal transplantations are surgeries performed for irreparable corneal diseases and damage. However, there is a gap between the number of potential recipients and the number of donor corneas available. The main aim of the study was to determine the awareness and attitudes toward corneal donation among applicants and staff of DVLA, Kumasi-Ghana. METHODS: A descriptive cross-sectional study was conducted. One hundred participants were selected using convenient sampling method. A structured questionnaire was used to elicit responses from participants concerning awareness and attitudes toward corneal transplant. RESULTS: The mean ± SD age of the participants was 32.05 ± 11.48 years and age range, 18-67 years. Males were 66% whilst females constituted 34%. 32.7% of the participants were aware of corneal donation. Majority of the participants were Christians (83.1%) and Singles (63%). Television was the source of information with the highest preponderance (49.4%). 67.3% were willing to donate their corneas after death. 63.9% were willing to indicate their donor statuses on drivers' license form which had a significant association with willingness to donate cornea after death (p < 0.05, x2 = 12.187). CONCLUSION: There is a poor level of awareness (32.7%) of transplant and donation amongst the study population but a good level of willingness to donate organs (67%). Consent via driving license would seem to be a good potential mode of obtaining consent to supplement the harvesting of adequate tissues for transplant if adequate awareness is created.

Stromal Rejection After SMILE for the Correction of Astigmatism After Graft.

PURPOSE: To describe a case of stromal rejection in a 46-year-old man after small incision lenticule extraction (SMILE) for the correction of residual astigmatism following deep anterior lamellar keratoplasty (DALK). METHODS: Case report. RESULTS: Nine years after an uneventful DALK in the left eye, the patient (uncorrected distance visual acuity [UDVA] = 20/200, corrected distance visual acuity [CDVA] = 20/32, and refraction = -3.25 -4.25 × 165°) underwent SMILE using the VisuMax femtosecond laser platform (Carl Zeiss Meditec, Jena, Germany). The next day, the UDVA, CDVA, and refraction were 20/40, 20/32, and -1.25 -0.50 × 15°, respectively. One week later, the patient presented complaining of pain, photophobia, and blurred vision; at this time, there was a reduction in UDVA to 20/400 and CDVA to 20/63. With a diagnosis of stromal rejection, the patient was treated with corticosteroids (sub-Tenon injection and oral). Five months later, UDVA was 20/40, CDVA was 20/25, and refraction was -1.25 -0.75 × 90°. The graft had completely cleared. CONCLUSIONS: SMILE can be an effective alternative for the correction of astigmatism after DALK, but the risks of inflammatory responses and graft rejection call for caution. [J Refract Surg. 2019;35(11):737-739.].

Clinical efficacy of therapeutic keratoplasty using corneal xenografts in patients with corneal ulcers.

Objective. to assess the clinical efficacy of keratoplasty using a corneal xenograft in patients with corneal ulcers of various etiologies. Methods. A total of 46 patients (49 eyes) with complicated corneal ulcers (perforated or with impending perforation) have been operated. Freeze-dried corneal xenografts have been used for keratoplasty. Results. Our results showed that postoperative period after xenogeneic keratoplasty in patients with corneal ulcers was uneventful and the transplant underwent gradual resorption. In all patients with non-infected corneal erosions, ulcers healed completely and corneal fistulas were fully closed. The implanted corneal xenograft undergoes complete resorption between 2 to 3 months. Conclusions. Given the shortages of donor material, the demonstrated efficacy of using corneal xenografts in patients with complicated corneal ulcers requiring therapeutic keratoplasty allows recommending corneal xenografts for wide use to relieve inflammation and to preserve the eye.

High-risk Corneal Transplantation: Recent Developments and Future Possibilities.

Human corneal transplantation (keratoplasty) is typically considered to have superior short- and long-term outcomes and lower requirement for immunosuppression compared to solid organ transplants because of the inherent immune privilege and tolerogenic mechanisms associated with the anterior segment of the eye. However, in a substantial proportion of corneal transplants, the rates of acute rejection and/or graft failure are comparable to or greater than those of the commonly transplanted solid organs. Critically, while registry data and observational studies have helped to identify factors that are associated with increased risk of corneal transplant failure, the extent to which these risk factors operate through enhancing immune-mediated rejection is less clear. In this overview, we summarize a range of important recent clinical and basic insights related to high-risk corneal transplantation, the factors associated with graft failure, and the immunological basis of corneal allograft rejection. We highlight critical research areas from which continued progress is likely to drive improvements in the long-term survival of high-risk corneal transplants. These include further development and clinical testing of predictive risk scores and assays; greater use of multicenter clinical trials to optimize immunosuppressive therapy in high-risk recipients and robust clinical translation of novel, mechanistically-targeted immunomodulatory and regenerative therapies that are emerging from basic science laboratories. We also emphasize the relative lack of knowledge regarding transplant outcomes for infection-related corneal diseases that are common in the developing world and the potential for greater cross-pollination and synergy between corneal and solid organ transplant research communities.

Corneal transplantation in the modern era.

Corneal blindness is one of the major causes of reversible blindness, which can be managed with transplantation of a healthy donor cornea. It is the most successful organ transplantation in the human body as cornea is devoid of vasculature, minimizing the risk of graft rejection. The first successful transplant was performed by Zirm, and since then, corneal transplantation has seen significant evolution. It has been possible because of the relentless efforts by researchers and the increase in knowledge about corneal anatomy, improvement in instruments and advancements in technology. Keratoplasty has come a long way since the initial surgeries wherein the whole cornea was replaced to the present day where only the selective diseased layer can be replaced. These newer procedures maintain structural integrity and avoid catastrophic complications associated with open globe surgery. Corneal transplantation procedures are broadly classified as full-thickness penetrating keratoplasty and partial lamellar corneal surgeries which include anterior lamellar keratoplasty [sperficial anterior lamellar keratoplasty (SALK), automated lamellar therapeutic keratoplasty (ALTK) and deep anterior lamellar keratoplasty (DALK)] and posterior lamellar keratoplasty [Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK)] broadly.

Femtosecond Laser-Assisted Small Incision Sutureless Intrastromal Lamellar Keratoplasty (SILK) for Corneal Transplantation in Keratoconus.

PURPOSE: To describe a femtosecond laser-assisted small incision sutureless intrastromal lamellar keratoplasty in an eye with severe keratoconus and report on the outcome with a 1-year follow-up. METHODS: A 20-year-old man with a history of keratoconus presented for evaluation at the Tilganga Institute of Ophthalmology, Kathmandu, Nepal. The patient had previously undergone a deep anterior lamellar keratoplasty in the left eye. Examination of the right eye revealed an uncorrected distance visual acuity (UDVA) of counting fingers with a manifest refraction of -5.00 -3.50 × 170, giving a corrected distance visual acuity (CDVA) of 20/80. Thinnest pachymetry was 425 µm and progression of both anterior and posterior corneal elevation tomography and maximum keratometry was noted compared to examination 2 years prior. The VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) was used to prepare the donor and recipient cornea. The donor graft was inserted into the recipient through the 3-mm small incision. No sutures were applied. RESULTS: At 2 weeks postoperatively, UDVA was 20/50 with a manifest refraction of -1.00 -5.00 × 145 (20/32). One year postoperatively, UDVA was 20/80 with a manifest refraction of -2.50 -3.50 × 125 (20/40-2), with the maximum keratometry decreasing from 64.08 to 56.74 diopters. CONCLUSIONS: This femtosecond laser-assisted sutureless intrastromal corneal transplantation technique may provide an option to improve the quality of vision for some patients with keratoconus, affording a simpler postoperative follow-up course compared to traditional anterior lamellar or full-thickness corneal transplantation. [J Refract Surg. 2019;35(10):663-671.].

Ocular tissue distribution in the State of São Paulo: analysis on corneal discarding reasons. / Distribuição do tecido ocular no Estado de São Paulo: análise por razões de descarte de córneas.

OBJECTIVE: to identify the reasons for refusal of corneas. METHOD: this was a cross-sectional, retrospective, descriptive and correlational study composed of 5,560 optical corneas. The information was taken from the notification, organ procurement and distribution centers database as well as donor records. Descriptive statistics were used for the analysis of categorical variables and specific tests with a significance level of 5% for assessing the associations between variables. This study met the ethical aspects of scientific research. RESULTS: 60% of the donors were male and 40% died by circulatory problems. The main reason for refusal as informed by transplant teams is the donor's age and the endothelial cell count. For each year added to the donor's age, there is a 1% decrease in the chance that this cornea will be used for transplantation, and the increase of 100 cells per mm2 increases the chances that this cornea will be used by 9%. CONCLUSION: the main cause of refusal in the acceptance of corneal tissue is related to the age and the endothelial cell count.

Glaucoma Patch Graft Surgery Utilizing Corneas Augmented with Collagen Cross-linking.

PURPOSE: Glaucoma drainage device surgery (GDDS) has gained popularity, with outcomes equivalent to trabeculectomy. Erosion of the tube through the overlying conjunctiva may occur in 5%-10% of eyes. Donor corneal tissue has been used as a patch graft for GDDS. MATERIALS AND METHODS: This was a prospective proof of concept study in 10 patients undergoing GDDS. From patients undergoing endothelial keratoplasty, the donor tissue (approximately 300 µ in thickness) was placed epithelial side down in a well and was allowed to soak in riboflavin solution (VibeX, Avedro, Waltham, MA, USA) for 15 min. This anterior corneal lenticule received 8 mW/cm2 ultraviolet (UV) irradiation applied for 15 min (total energy of 7.2 J/cm2). Each lenticule was then bisected and utilized for the two study participants. The tissue was sutured over the tube during the GDDS and then was covered with recipient conjunctiva as per the usual technique. Representative graft tissues were fixed and examined to determine the depth of cross-linking effect. The patients were followed for 1 year. RESULTS: Histology revealed no apparent demarcation line in the cross-linked grafts; this supported a full-thickness cross-linking treatment effect. There were no intra- or postoperative complications attributed to the graft tissue. No patient developed erosion or exposure of the tube during the 1-year follow-up. CONCLUSIONS: UV-riboflavin cross-linking of the corneal tissue patch graft material appears to be a safe modification when used in GDDS and warrants ongoing study. This method of patch graft can replace other costy methods used with GDD.

Use of Fibrin Glue in the Management of Descemet Membrane Perforation during Deep Anterior Lamellar Keratoplasty.

PURPOSE: To describe the use of fibrin glue to seal Descemet membrane (DM) microperforation and macroperforation during deep anterior lamellar keratoplasty (DALK). METHODS: A retrospective chart review was performed on patients who had DM perforation managed by fibrin glue during DALK at King Khaled Eye Specialist Hospital (KKESH) between June 2014 and February 2019. RESULTS: One thousand two hundred and eighty-eight DALK surgeries were performed at KKESH during the study period. Fibrin glue was used to seal DM perforations in four cases of DALK for keratoconus. CONCLUSION: Fibrin glue is an effective method to seal DM microperforations and macroperforations during DALK, which reduces the rate of conversion to penetrating keratoplasty (PK), preserving the advantage of DALK over PK.

Postoperative detection of unusual pathology in donor corneal tissue.

We present a series of three patients with previously undetected corneal pathology in grafted corneal tissue following keratoplasty for keratoconus. Postoperatively, a faint layer of anterior stromal haze involving the graft was observed in each patient upon slit lamp examination. Anterior segment optical coherence tomography (AS-OCT) confirmed the presence of anterior stromal scarring across the transplanted cornea. However, the ocular and systemic medical histories of the donors were unremarkable. As the suboptimal donor corneal tissue may escape the standard screening protocols, eye banks should consider adding AS-OCT imaging for screening donor corneal tissue before transplantation.

Simultaneous Implantation of Refractive Lenticule and Intracorneal Ring Segment in the Management of Pellucid Marginal Degeneration.

PURPOSE: To describe a patient with pellucid macular degeneration suffering from visual deterioration due to high irregular astigmatism and intolerant to contact lenses, who underwent a new surgical procedure that combined intrastromal lamellar keratoplasty and a 359° intracorneal ring segment implantation, enabling both ametropia and corneal thinning correction. METHODS: Case report. RESULTS: Refractive lenticule obtained during a myopic small incision lenticule extraction procedure was used as the donor lamellar graft. The technique described allowed for partial cylinder reduction and reinforcement of the thinned cornea. Uncorrected distance visual acuity improved from 0.02 to 0.5 (decimal) and corrected distance visual acuity improved from 0.4 to 0.7 with a decrease of 4.50 diopters in corneal astigmatism. CONCLUSIONS: Despite the lack of long-term observation, the new technique described in this case report was successful for this specific patient and therefore might be effective and safe in severe stages of disease. [J Refract Surg. 2019;35(9):606-609.].

Multi-drug resistant Enterococcus faecium in late-onset keratitis after deep anterior lamellar keratoplasty: A case report and review of the literature.

RATIONALE: Interface keratitis after lamellar keratoplasty is one of the causes of graft failure. We report the first case of microbiologically proven Enterococcus faecium infection following deep anterior lamellar keratoplasty (DALK) and review the available literature. PATIENT CONCERNS: A 37-years-old Caucasian man presented with pain, redness and severe vision loss in his right eye. Five weeks before, he underwent DALK using the FEMTO LDV Z8 in the same eye for the surgical correction of keratoconus. DIAGNOSES: Upon presentation, slit-lamp biomiscroscopy revealed corneal graft edema with multiple infiltrates located in the graft-host interface. INTERVENTIONS: Therapeutic penetrating keratoplasty (PKP) was carried out in addition with cultures of the donor lenticule removal. Laboratory results isolated a multi-resistant Enterococcus faecium interface infection. According to the antibiogram, the patient was treated with systemic Tigecycline and Linezolid for 7 days. OUTCOMES: During the following weeks, clinical features improved over time and no signs of active infection were visible seven months postoperatively. LESSONS: Early PKP showed to be a good therapeutic option with great anatomic and functional outcomes.