DMEK after penetrating keratoplasty: cohort with DMEK grafts and descemetorhexis larger than full-thickness graft.

PURPOSE: The study aims to evaluate visual outcome, central corneal thickness, and rebubbling rate in a cohort with oversized DMEK grafts after failed penetrating keratoplasty (PK). The unique feature of the study is a descemetorhexis diameter larger than the full-thickness graft, i.e., peripheral to the PK interface. METHODS: A monocentric, retrospective evaluation of all patients with endothelial graft failure after PK treated with an oversized DMEK graft and descemetorhexis outside of the PK interface (i.e., in host tissue) between January 2015 and July 2019 at the Department of Ophthalmology at the University of Düsseldorf (Germany) was performed. RESULTS: Eleven eyes of 10 patients were identified. Mean age was 69 years. On average (arithmetic mean ± standard deviation), 1.7 ± 1.0 previous PKs have been performed per eye in this cohort. The mean time between last PK and DMEK was 10.1 ± 7.3 years (range 2 to 23 years). In all cases, the graft diameter exceeded the diameter of the previous PK and descemetorhexis was performed in host tissue, that is, peripheral to the graft-host interface. Rebubbling was performed in 18.2% of the patients (n = 2 eyes) because of central graft detachment. Mean central corneal thickness showed a statistically significant improvement at 5.3 ± 3.5 months after surgery from 688.23 ± 151.01 to 527.75 ± 88 µm (p = 0.002). Visual acuity increased significantly by 5 lines from 1.24 ± 0.5 logMAR (range from 0.5 to 2) to 0.73 ± 0.76 logMAR (range from 0.1 to 2) within 3 months (p = 0.006). Excluding patients without visual potential and transplant failure, visual acuity improved significantly by 8 lines (p < 0.001), and stayed stable until the last follow-up at 15.1 ± 11.4 months (range 6 to 39 months, p < 0.001, n = 8) after surgery. CONCLUSION: DMEK can be successfully used to treat endothelial cell failure after PK, and can provide good postoperative results with regards to visual acuity. This study shows that stripping of Descemet's membrane (DM) peripheral to the PK interface is surgically feasible. Overlapping, larger DMEK grafts with more endothelial cells can be used without increasing rebubbling rates and may potentially improve long-term graft survival.

[Cooperation between the department of ophthalmology at the University of Düsseldorf (Germany) and the Fundación Visión in Asunción (Paraguay) as an example of the German hospital partnerships programm]. / Das deutsche Klinikpartnerschaftsprogramm am Beispiel der Kooperation der Klinik für Augenheilkunde des Universitätsklinikums Düsseldorf mit der Fundación Visión in Asunción (Paraguay).

BACKGROUND: A hospital partnership between the University Eye Hospital Düsseldorf (UAK Düsseldorf) and Fundación Visión in Asunción has existed since 2014 based on a memorandum of understanding. Fundación Visión plays a leading role in ophthalmological treatment and prevention of blindness in Paraguay. Since 2016 a program for the promotion of international hospital partnerships of the German government has been in place. MATERIAL AND METHODS: Following a written application in 2016 the hospital partnership Düsseldorf-Asunción is funded by the Federal Ministry for Economic Cooperation in Germany. The aim of the project was to establish modern minimally invasive corneal transplantation techniques with faster postoperative rehabilitation and less follow-up in Paraguay with the help of several activities within a defined schedule. Secondary aims were to obtain first data on the prevalence of eye diseases in a typical patient cohort of the Fundación Visión and to establish an infrastructure for modern eye banking techniques in Paraguay. RESULTS: First a Paraguayan surgeon was trained to carry out Descemet membrane endothelial keratoplasty (DMEK) transplantations in Germany. At the same time, the surgical instruments required for the DMEK technique were purchased and delivered to the Fundación Visión. In September 2018 the first lamellar corneal transplantations were successfully performed in Paraguay by the team from the Fundación Visión under the supervision of an experienced surgical team from Düsseldorf. Subsequently, the split cornea approach using a donor cornea for a posterior and an anterior lamellar keratoplasty (DMEK and DALK) was also implemented in Asunción. In November 2019 epidemiological data on eye diseases were collected during a field campaign of the Fundación Visión in a rural region of Paraguay. In the course of data collection an employee of the University Eye Hospital Düsseldorf learned small incision cataract surgery. In March 2019, a technician from the Fundación Visión was trained in Düsseldorf in corneal tissue culture techniques and preparation of amniotic membrane transplants in the Lions eye bank North-Rhine/Westfalia. CONCLUSION: With the aid of a supported hospital partnership modern minimally invasive corneal transplantation techniques can be successfully transferred to the eye hospital of a developing country and in return surgical skills can be taught to surgeons from Germany who are in training. Therefore, an efficient hospital partnership is the basis for a mutual exchange and is not purely one-way traffic.

Development and Assessment of a Simulator for in Vivo Confocal Microscopy in Fungal and Acanthamoeba Keratitis.

BACKGROUND AND PURPOSE: In vivo confocal microscopy (IVCM) is a non-invasive imaging technique that allows morphological analysis as a diagnostic approach of the cornea in real time, thus providing a suspected diagnosis of fungal or amoebic keratitis immediately, whereas culture or PCR require several days or even weeks. Since these infections are rare, it is difficult for ophthalmologists to gain the experience necessary to differentiate infection from normal findings or artefacts. The purpose of this project was to establish a simulator, on which physicians could practice as well as acquiring a database of IVCM images of fungal or amoebic keratitis and respective analyses. PATIENTS AND METHODS: An IVCM simulator was set up with cadaver human corneas, infected with either acanthamoeba, candida or aspergillus. Twenty-one ophthalmologists were trained in IVC microscopy first in a Dry Lab, then practically on the simulator. For evaluation, the participants were asked to fill out a standardized questionnaire, with a pre- and post-course self-assessment. RESULTS: The self-assessed theoretical and practical skills in differentiating infectious from non-infectious keratitis in IVCM significantly increased (p = 0.0001, p = 0.0002, respectively). The barrier to use this technique decreased (p = 0.0474). CONCLUSION: A very simple protocol based on a model of ex vivo corneal mycotic and amoebic infections can be used to train novices in the structured approach and diagnostic use of IVCM for corneal infections.