Long-term follow-up of intraocular pressure and pressure-lowering medication in patients following Excimer laser trabeculotomy.

BACKGROUND: Excimer laser trabeculotomy (ELT) is a minimally invasive procedure to lower the intraocular pressure (IOP) via a photo-ablative laser that is applied to the trabecular meshwork. With this procedure, it is possible to improve the outflow of the aqueous humor. Until now, a limited number of studies examining mostly relatively small sample sizes with midterm follow-up exist. We therefore present the analysis of a large ELT cohort in a long-term follow-up. METHODS: We recorded data from 580 patients who underwent ELT or combined ELT with cataract surgery at our institution from November 2000 until March 2011. A total of 512 patients with primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and ocular hypertension (OHT) were included in the analysis. At every follow-up examination, the usage of IOP-lowering medication and the IOP were recorded. Failure criteria were defined as the need for another surgical glaucoma procedure, when the IOP was not 21 mmHg or less and a reduction of 20% from the baseline was not achieved with (qualified success) or without (absolute success) additional medication. Statistical analysis was done using Kaplan-Meier analysis and Cox regression. RESULTS: Four hundred twenty-eight patients underwent combined cataract and ELT surgery, and 84 underwent solitary ELT surgery. After a median follow-up time of 656 days, 87% (combined surgery) and 66% (ELT) of the patients did not have to undergo another IOP-lowering intervention; 47/31% were classified as a qualified success and 31/11% as a complete success. The IOP-lowering medication, however, could not be significantly reduced within that time period. CONCLUSION: Especially when combined with cataract surgery, ELT is a feasible minimally invasive procedure to lower the IOP on a mid- to long-term basis. Over the long term, however, IOP-lowering medication could not be reduced.

Toric IOL positioning with a no-touch head-up display axis alignment.

PURPOSE: To compare a new no-touch alignment technique for toric intraocular lenses (IOL) with the conventional technique that uses a manual pendulum. METHODS: In this retrospective case-control study, patients who underwent toric IOL implantation using two different alignment techniques (digital Callisto® system vs. manual-pendulum-based marking) were compared in a vector analysis using the Alpins method and an analysis of variance regarding corrected and uncorrected visual acuity and the deviation of the achieved IOL axis from the targeted axis. RESULTS: Sixty-one eyes were included into analysis. Thirty-six of these surgeries were performed via the Callisto® system and 25 eyes via pendulum-based corneal markings. Median IOL axis misalignment was 3° in both groups. Median uncorrected distance visual acuity was 0.097 logMAR versus 0.200. Median best-corrected visual acuity was 0.000 logMAR versus 0.097. All these data were below the range of statistical significance (p > 0.05). Vector analysis showed no significant difference for TIA [median of 3.14 diopters (D) vs. 2.73 D], SIA (median of 3.82 D vs. 3.79 D), DV (1.18 D vs. 1.08 D), and CI (1.23 vs. 1.29). Median angle of error was 1.96° versus - 0.44° (p > 0.05). CONCLUSIONS: We found no significant difference in the refractive results, the IOL positioning, and the best-corrected and uncorrected distance visual acuity between the two compared methods. Nevertheless, the Callisto® IOL alignment system delivers a standardized and easy-to-use technology. In particular, less-experienced surgeons might benefit from this marking technique.

Intraocular pressure measurement with Corvis ST in comparison with applanation tonometry and Tomey non-contact tonometry.

PURPOSE: Intraocular pressure (IOP) measurement can be performed with different methods. Newer methods have to be compared to the standard method, the Goldmann applanation tonometry (GAT). We herein compare two air-puff tonometers, the non-contact tonometer (Tomey NCT) and the Corvis ST (CST) with GAT in eyes with a broad spectrum of IOP. METHODS: Two hundred and forty-nine eyes of 249 patients (with diagnosis of either glaucoma or ocular hypertension) were included in this monocenter prospective cohort study. Each eye underwent IOP measurements via GAT, NCT and CST. Bland-Altman plots were calculated to compare the different methods in the three groups. Paired t tests were used for statistical comparison between the three measurement methods. The difference between the different methods was tested on correlation against central corneal thickness (CCT). RESULTS: Mean IOP in GAT was 17.6 mmHg (standard deviation (SD) 5.9), 16.3 mmHg (SD 5.6) in NCT and 18.0 mmHg (SD 5.5) in CST. Comparisons between GAT and CST vs. NCT showed significant differences (p < 0.001), while GAT vs. CST showed no significant difference (p = 0.1162). Mean CCT was 538.7 µm (SD 35.1). CONCLUSIONS: Mean values of GAT and CST show comparable results. However, both GAT and CST differ significantly from NCT. NCT shows lower IOP values compared to both other methods.

Bleb-related infections and long-term follow-up after trabeculectomy.

PURPOSE: Bleb-related infections are serious complications after trabeculectomy. They can be limited to the bleb or disseminate and lead to endophthalmitis. We herein report on all bleb-related infections that have been diagnosed at the Eye Center of the University of Freiburg, Germany, since 1999. METHODS: We reviewed a total of 1816 consecutive trabeculectomies that were performed at our hospital between the years 1999 and 2014 (353 without and 1463 with intraoperative application of mitomycin C). All bleb-related infections that were diagnosed at our clinic during the same period were included in the analysis. We fitted a Cox proportional hazards model to characterize risk factors for bleb-related infections. RESULTS: We diagnosed a total of 19 bleb-related infections in this period. Three patients with bleb-related infections that came to our clinic had their trabeculectomy performed elsewhere. The overall percentage of bleb-related infections was 0.1% after 2 years (Kaplan-Meier estimate at median follow-up). Nine eyes suffered from only localized infection of the bleb. Seven eyes developed endophthalmitis. Four infections occurred during the first postoperative month. The median age on the day of diagnosis was 71 years; the median age at surgery was 69 years. In the Cox model, intraoperative application of mitomycin C and a fornix-based conjunctival flap were identified as significant risk factors (hazard ratio: 79.02, 4.69; p < 0.01, p < 0.01). The whole group showed a reduction of visual acuity in the median from logMAR 0.12 to 0.2. Eyes that suffered from endophthalmitis showed a loss from 0.3 to 0.96, while the localized infections had a reduction from 0.04 to 0.07. CONCLUSION: Bleb-related infections are a rare complication following trabeculectomy and can be localized on the bleb or can lead to endophthalmitis, thereby threatening visual acuity. The risks and benefits of mitomycin C-augmented trabeculectomies should be taken into consideration.

[Keratoplasty in Children and Adolescents]. / Keratoplastiken im Kindes- und Jugendalter.

BACKGROUND: The conditions for long-term graft survival in infants and children are unfavorable, due to the different immunological features, the impaired clinical examination and the reduced compliance and treatment adherence. However, penetrating keratoplasty is often the only option to prevent amblyopia and there may be no alternative. We examined the different indications, graft survival and complications in two specialised centres. MATERIAL AND METHODS: We identified all patients who were under the age of 18 years at the time of their penetrating keratoplasty. We then assessed the electronic file on indications, graft failure, visual acuity, enucleation and further complications. RESULTS: A total of 104 eyes of 95 patients (54 % female) were identified. Median age at the time of surgery was 14 years (quartiles 8 and 16 years). Median follow-up was 2.7 years. The following indications were identified: keratoconus (39 %), penetrating injury (18 %), non-herpetic corneal scars (12 %), herpetic corneal scars (6 %), sclerocornea (3 %), chemical burn (3 %) and miscellaneous indications (19 %). Clear graft survival according to the Kaplan-Meier method ranged from 100 % (keratoconus) to 35 % (sclerocornea). Enucleation was only necessary in patients with penetrating injuries (n = 2). Kaplan-Meier analysis estimated the failure of all grafts after one year in infants. In older patients, 90 % of grafts were still clear at that time. CONCLUSION: Prognosis of penetrating keratoplasty in children is related to the indication, and therefore the underlying disease, as well as the patients' age. In particular, infants exhibited poor prognosis, with only a very short period of clear graft survival. In indications, keratoconus showed the best prognosis, whereas sclerocornea and penetrating injuries had the worst prognosis.

[Bruch's Membrane Opening in OCT in Correlation with Corneal Correction - a Pilot Study]. / Abhängigkeit der Größe der OCT-Bruch-Membran-Öffnung von Hornhautkorrekturfaktoren ­ eine Pilotstudie.

Background: The measurement by optical coherence tomography (OCT) of the Bruch membrane opening (BMO) and the thinnest retinal fiber nerve layer in relation to it (BMO-MRW) has been performed in clinical routine since 2014. To compensate for astigmatism, or increased or decreased corneal power, a correction is performed through the mean K-value of the measured eye. The aim of this study was to measure the value of this correction and its influence on the measurement results. Methods: The sectors of BMO-MRW and BMO values of the five right eyes of five healthy patients were measured five times each with Heidelberg Spectralis OCT. Corneal compensation was systematically raised with each single measurement (7.1, 7.4, 7.7, 8.0, 8.3 mm). RESULTS: The data showed almost linear dependence on the given corneal compensation values, with intraindividual variability. For the BMO-MRW, only small effects of compensation were found (0.85 up to 1.97 % per K-value difference of 0.3 mm). For BMO, the effect was greater, with a mean change of 7.71 % for every 0.3 mm change in compensation. Conclusion: For BMO-MRW, corneal compensation is of low clinical relevance. BMO is more dependent on this correction. In follow-up measurements, the compensation might not account for significant changes, although we recommend using correct corneal compensation values when obtaining single or first-time measurements.

Outcomes of Descemet membrane endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and penetrating keratoplasty from a single centre study.

PURPOSE: According to some pioneer surgeons, lamellar endothelial keratoplasty techniques (EK), including Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), yield excellent clinical results. However, there is a lack of studies with high levels of evidence and results of large national keratoplasty registers are contradictory. Therefore, two large cohorts of DMEK and DSAEK procedures are compared to a cohort of penetrating keratoplasty (PK). METHODS: The study reports 868 keratoplasty procedures at a single centre (694 eyes with Fuchs endothelial dystrophy (FED) and 174 with bullous keratopathy (BK)). Patients underwent DMEK (450 eyes), DSAEK (89 eyes), or PK (329 eyes). Postoperative visual acuity, endothelial cell density (ECD), rate of regrafting, and rejections were recorded. RESULTS: Visual acuity recovers faster and to a greater extent in EK compared to PK. DMEK performs better than DSAEK. ECD drops faster initially for EK compared to PK. In EK the rate of regrafting is higher than in PK (7 % in DMEK, 20 % in DSAEK and 2 % in PK in FED). The rejection rate is lowest following DMEK (7 % after DMEK, 21 % after DSAEK and 18 % after PK in FED). CONCLUSIONS: In contrast to recent reports from national keratoplasty registers, the overall clinical outcome of EK in FED and BK is superior to PK. Including ocular comorbidities and learning curves, these data reflect a realistic setting for comparing the different keratoplasty techniques. Corneal surgeons may be encouraged to preferentially use DMEK in FED and BK.

[Crosslinking in Keratoconus]. / Crosslinking bei Keratokonus.

Keratoconus leads to progressive thinning and protrusion of the cornea. Young patients exhibit the highest risk for progression. Corneal crosslinking was introduced in 1998 and is intended to prevent progression of keratoconus. Only a few prospective controlled trials have been published. Six randomised controlled trials have been published. All these trials confirmed the efficacy of crosslinking through keratometric data. In two trials, progression was reported in some patients of the treatment group. This indicates that not all patients benefit from corneal crosslinking. The risks of the procedure include corneal scarring, haze, endothelial cell damage and infections of the cornea. In order to avoid these risks, patients without progression should not be treated with crosslinking.

Refractive and visual outcomes after combined cataract and trabectome surgery: a report on the possible influences of combining cataract and trabectome surgery on refractive and visual outcomes.

PURPOSE: To compare combined trabectome-cataract surgery with cataract-alone surgery regarding their refractive and visual outcomes and complications. METHODS: In 137 eyes that underwent combined trabectome-cataract surgery, the postoperative refraction error and best visual acuity after at least 2 months postoperatively were compared to those of an in-house control group of 1,704 eyes that underwent outpatient cataract surgery. RESULTS: Combined trabectome-cataract surgery showed no significant differences regarding the biometry prediction error (BPE, mean 0.53 D vs. 0.48 D, p = 0.24) or visual outcome (BCVA, 0.81 vs. 0.78, p = 0.06). The rate of postoperative cystoid macular edema was slightly higher in the combined surgery group (2.2 % vs. 1.9 %). CONCLUSIONS: Refractive and visual outcomes were similar in both groups. Despite the slightly higher rate of postoperative macula edema, we were able to observe that the combination of these two procedures is a feasible method in glaucoma and cataract surgeries.

[Intraocular Lens Opacification Following Posterior Lamellar Keratoplasty]. / Kunstlinsentrübungen nach hinterer lamellärer Keratoplastik.

BACKGROUND: The opacification of an artificial intraocular lens is a rare but serious complication following cataract surgery as an exchange of the intraocular lens can become necessary. At our eye center we observed single cases of IOL opacifications following complicated posterior lamellar keratoplasty (Descemet stripping automated endothelial keratoplasty = DSAEK or Descemet membrane endothelial keratoplasty = DMEK). Therefore, we performed a retrospective analysis of all our digital charts regarding the incidence of this serious complication with respect to posterior lamellar keratoplasty, penetrating keratoplasty or sole cataract extraction. METHODS: We searched our digital patient database from 2003 to 2015 using the following headings: intraocular lens, artificial lens or IOL and opacification or calcification and selected only those patients who had undergone either DSAEK, DMEK, penetrating keratoplasty or sole cataract surgery (n = 19,565). RESULTS: In total we found five IOL opacifications out of 153 DSAEK and two out of 450 DMEK cases, respectively. Five of these seven cases had a complicated clinical course with repeated rebubbling or additional intraocular surgery (i.e., repeat DSAEK or DMEK or secondary penetrating keratoplasty). There were no documented IOL opacifications following penetrating keratoplasty or sole cataract extraction. In two cases intraocular lens exchange became necessary. All opacifications showed similar clinical appearance in form of small granular deposits on the surface of the intraocular lens. Almost all implanted lenses were made from hydrophilic acrylate. DISCUSSION: In total we found seven cases of intraocular lens opacification that have only been observed following DSAEK or DMEK. According to reports from the literature these opacifications are superficial calicifications of the hydrophilic lenses. As five of the seven cases had a complicated clinical course, the repeated air contact of the lens could be one major factor in inducing the calcification. Besides the air contact a breakdown of the blood-aqueous barrier could also play a role in the induction of calcium phosphate crystallisation on the intraocular lens. The risk of this serious complication in mainly hydrophilic intraocular lenses with respect to posterior lamellar keratoplasty should be kept in mind for the selection of the type of intraocular lens in patients with endothelial diseases or in patients undergoing combined cataract extraction and DSAEK/DMEK.

[The Influence of Intravitreal Injections on Outpatient Cataract Operations in Germany]. / Der Einfluss der intravitrealen Injektionen auf die ambulante Intraokularchirurgie in Deutschland.

PURPOSE: The number of outpatient operations in Germany is not registered in a centralised manner. To estimate the development of the outpatient intraocular surgery especially since the implementation of the intravitreal injections, surveys among ophthalmic surgeons were analysed. METHODS: Between 2006 and 2013 surveys were done among ophthalmic surgeons in Germany using questionnaires. An average of 318 completed questionnaires were sent back. The mean participation ratio was 37 %. RESULTS: Between 2006 and 2013 an extrapolated mean of 347 564 cataract operations and 139 946 intravitreal injections were reported. Whereas the number of cataract operations was constant in the observation period, the number of injections increased considerably from 35 135 in 2006 to 274 714 in 2013. CONCLUSION: A saturation in the development of the numbers of the intravitreal injections could not yet be observed. Other outpatient operations, especially cataract procedures were not replaced by the increase of the injections in the recent years.

Attitudes toward postmortem cornea donation in Germany: a multicenter survey.

PURPOSE: To analyse the willingness for postmortem cornea donation in Germany. METHODS: Employees in two cities (UKM, UKS), and university hospitals (STM, STE), members of the German Ophthalmological Society (DOG), and employees of an automobile company (BO) participated in a questionnaire about postmortem cornea donation attitudes. The questionnaire consisted of demographic items, motives concerning postmortem cornea donation, general attitudes toward donation, and questions concerning the perceived needs for information about donation. The statistical analyses included logistic regression with the target parameter of 'willingness to donate cornea postmortem'. RESULTS: Of the participants, 67.7 % (UKM, UKS), 70.9 % (STM, STE), 70.8 % (BO), and 79.4 % (DOG) declared their intention to donate their corneas postmortem. Younger age (p < 0.001), poorer general health (p < 0.05), faith in an eternal life (p < 0.05), disagreement with brain death diagnostics (p < 0.001), fear of receiving worse medical treatment (p < 0.001), and fear of the commercialization of organs (p < 0.001) were found to be risk factors for a negative attitude toward postmortem cornea. The majority of participants (57.4 %) indicated that additional information about donation would be appreciated, and the internet (69.9 %) was considered the most appropriate means for conveying this information. CONCLUSIONS: Emotional items were revealed to be the most relevant factors influencing the willingness to donate cornea postmortem, which may be counteracted by means of public education. The relatively low willingness among the medical staff contrasts with previous observations in a professional ophthalmologic society.

[Systematic analysis of the annual quality reports of the Federal Joint Committee with regard to cataract surgery]. / Systematische Analyse der Krankenhausqualitätsberichte im Hinblick auf die Versorgung der Bevölkerung mit Kataraktoperationen.

BACKGROUND: Cataract is one of the most common diseases in ophthalmology. Up to now the only way to estimate the total number of carried out surgeries in Germany were the surveys done by DOG, BVA, DGII and BDOC or reports of the federal statistical office. OBJECTIVES: Objective of this paper is to evaluate the annual quality reports of the Federal Joint Committee with a view to how the hospitals are participating in the nationwide comprehensive coverage concerning cataract surgery and if there is a continuing trend to more outpatient cataract surgeries in German eye hospitals. MATERIAL AND METHODS: The number of outpatient and inpatient cataract surgeries included in the annual quality reports of 2006, 2008 and 2010 were put into relation with population density for every provincial state. RESULTS: In 2006, 2008 and 2010 a total of 765,179 cataract surgeries were recorded. Median number of cataract surgeries per 1000 inhabitants showed an only slight increase (2006: 2.8; 2008 and 2010: 3.0; p = 0.82). The ratio of outpatient to inpatient surgeries showed only a slight increase from 0.84 (2006) to 0.86 (2010). CONCLUSIONS: Lack of spatial and temporal variations imply that hospitals take a part in supplying the population with cataract surgery. There is no trend to more outpatient cataract surgeries at the moment. This implies that there might be a stable patient population that is not suitable for outpatient care.

[Update on corneal dystrophies: new insights following first publication of the IC3D classification]. / Update Hornhautdystrophien: Neues nach der Erstveröffentlichung der IC3D-Klassifikation.

In this review we summarise the new insights into corneal dystrophies following publication of the IC3D classification in 2008. Topics covered are new mutations, new clinical/histological phenotypes, first descriptions of known mutations in previously not mentioned ethnic groups, new dystrophic entities after modern corneal surgery and potentially new types of conservative therapy.

[Morphological analysis of corneal refractive lenticules--is there a correlation with refractive results?]. / Ultrastrukturelle Analyse von Hornhautlentikeln nach fs-Lentikelextraktion gibt es einen Zusammenhang mit den refraktiven Ergebnissen?

BACKGROUND: ReLEx®flex is a corneal refractive procedure performed by removing corneal lenticules with a femtosecond (fs) laser system. Using electron microscopy, tissue parameters of extracted lenticules were analysed for potential correlations to the refractive results. Furthermore, the effect of previous contact lens (CL) wear on refractive stability (regression) was tested. PATIENTS AND METHODS: 19 lenticules from 11 patients (age 24-56 years, 8 f, 3 m) were prepared for EM. The central areas of the samples were photographed and the distance between the collagen fibres and their diameters were digitally measured. ANOVA analysis was used to correlate postoperative refractional stability with time of preoperative CL use, fibre diameter and the coefficient of variation (CV) of fibre distance. RESULTS: 14 of 19 lenticules were from patients who had worn CL preoperatively. The cumulative duration of CL wear averaged around 31.2 ± 35.5 thousand hours. Preoperative CL use significantly influenced the postoperative regression: the longer time patients had worn CL, the greater was the regression towards myopia (p = 0.01). Additionally, the morphological parameters collagen fibre diameter (p = 0.09) and CV of fibre distance (p = 0.07) had an impact on regression. CONCLUSIONS: Prolonged CL use and alterations in ultrastructural patterns affected the refractive stability after ReLExflex. Although the pathophysiological relationships between CL use, corneal morphological parameters, and refractive stability are still poorly understood, these findings could potentially be used as prognostic markers for postoperative refraction after ReLExflex.

[Incidence of delirium in ophthalmology]. / Delir-Inzidenz in der Augenheilkunde.

BACKGROUND: Due to the short duration of inpatient stays and increasing outpatient treatment it is assumed that the incidence of delirium in ophthalmology is underestimated. The overall aim of this study was to record the incidence of delirium in ophthalmology through long-term follow-up. METHOD: The study was divided into 2 groups. In group A delirium events were recorded retrospectively based on the discharge reports of all inpatients at the University Clinic Freiburg, Clinic for Ophthalmology from 1 January 2020 to 31 December 2022. In group B delirium events were recorded prospectively by the Augennetz Südbaden (Eye Network South Baden, ANSB) in the period 60-120 days after ophthalmological surgery. RESULTS: During the study period of the retrospective analysis a total of 16,384 patients were treated as inpatients. There was evidence of a total of 7 new delirium events. This corresponds to a proportion of 0.04%. A total of 12,381 patients were assessed by the ANSB, including 11,530 outpatient cataract operations. There were indications of 31 delirium events, which corresponds to a proportion of 0.25%. CONCLUSION: The long-term prospectively recorded delirium events suggest that the incidence of delirium in the inpatient setting is underdiagnosed; however, postoperative delirium appears to be rare in ophthalmology in relation to the high number of procedures.

Automatic inference of ICD-10 codes from German ophthalmologic physicians' letters using natural language processing.

Physicians' letters are the optimal source of diagnoses for registries. However, most registries demand for diagnosis codes such as ICD-10. We herein describe an algorithm that infers ICD-10 codes from German ophthalmologic physicians' letters. We assess the method in three German eye hospitals. Our algorithm is based on the nearest-neighbor method as well as on a large thesaurus for ICD-10 codes. This thesaurus was embedded into a Word2Vec space created from anonymized physicians' reports of the first hospital. For evaluation, each of the three hospitals sent all diagnoses taken from 100 letters. The inferred ICD-10 codes were evaluated for correctness by the senders. A total of 3332 natural language terms had been sent in (812 hospital one, 1473 hospital two, 1047 hospital three). A total of 526 non-diagnoses were excluded upfront. 2806 ICD-10 codes were inferred (771 hospital one, 1226 hospital two, 809 hospital three). In the first hospital, 98% were fully correct and 99% correct at the level of the superordinate disease concept. The percentages in hospital two were 69% and 86%. The respective numbers for hospital three were 69% and 91%. Our simple method is capable of inferring ICD-10 codes for German natural language diagnoses, especially when the embedding space has been built with physicians' letters from the same hospital. The method may yield sufficient accuracy for many tasks in the multi-centric setting and can easily be adapted to other languages/specialities.

Visual outcome and histological findings following femtosecond laser-assisted versus microkeratome-assisted DSAEK.

BACKGROUND: The aim of this study was to compare the visual outcome of femtosecond laser-assisted Descemet stripping automated endothelial keratoplasty (DSAEK) to microkeratome-assisted DSAEK as well as to contrast precut versus surgeon-cut grafts. Histologic characterization of failed DSAEK grafts was performed in order to correlate ultrastructural changes with graft failures. METHODS: In this case control study, 47 cases of DSAEK were investigated in terms of visual acuity, keratometric astigmatism, spherical equivalent, endothelial cell count, and postoperative complications. We formed three groups: the femtosecondlaser-assisted DSAEK with precut grafts, the microkeratome-assisted DSAEK with precut and with surgeon-cut grafts. Mean follow-up was 6 months. In the case of graft failure, penetrating keratoplasty was performed, and the excised corneal buttons were investigated by light and electron microscopy. RESULTS: Microkeratome-assisted DSAEK lead to better visual outcome than femtosecond laser-assisted DSAEK. Keratometric astigmatism, spherical equivalent and endothelial cell count did not differ significantly between both methods. Precut and surgeon-cut grafts in microkeratome-assisted DSAEK did not show any significant difference regarding all upraised parameters. No definite histological correlate for graft failure following femtosecond laser-assisted DSAEK was found. CONCLUSIONS: Femtosecond laser-assisted DSAEK is not the method of choice, and needs further technical improvement. However, failed femtosecondlaser-assisted DSAEK grafts did not show significant histological changes related to the technique to explain reduced visual acuity. In microkeratome-assisted DSAEK, the preparation time point of the graft does not seem to influence the visual and optical outcome.

[HLA matching in keratoplasty: lessons learned from lamellar techniques]. / Immunologie der Keratoplastik: Macht HLA-Matching bei lamellären Verfahren Sinn?

BACKGROUND: The immunological mechanisms of graft rejections after penetrating keratoplasty are largely investigated in rodent models. Here, antigens are predominantly processed by host antigen presenting cells (APCs). For this reason, graft rejections are not primarily triggered by mismatches in the major histocompatibility complex (MHC). Consequently, MHC matching (equivalent of HLA matching) does not robustly prevent immunological graft rejections in mice. This, however, may not apply to humans because anatomy and the clinical picture of immune reactions differ vastly. METHODS: Immunological experiments are not feasible in humans for ethical reasons. However, the recent surgical modifications in keratoplasty inadvertently gave rise to several interesting immunological field experiments. We herein discuss the potential insight into human graft rejections from selected clinical observations. On this basis, we have evaluated HLA matching for keratoplasty techniques. RESULTS: Several clinical observations hint towards an active role of donor-derived APCs in graft rejections after human keratoplasty. Additionally, donor-specific anti-HLA antibodies may play a significant role. On this basis we suggest that HLA matching is potentially beneficial in human keratoplasty in contrast to the situation in mice. CONCLUSIONS: Graft rejections are rarely observed after Descemet membrane keratoplasty (DMEK). For this reason, we do not recommend HLA matching here. The same is true for deep anterior lamellar keratoplasty, where graft rejections can usually be treated well. However, HLA matching is a viable option in penetrating keratoplasty. This is especially true for high-risk eyes.

[Current and future therapeutic options in limbal stem cell insufficiency]. / Aktuelle und zukünftige therapieoptionen bei erkrankungen der limbusstammzellen.

Therapy for limbal stem cell insufficiency (LSCI) is one of the most challenging tasks in ocular surface surgery. Partial and unilateral LSCI can be treated by fractionated abrasion or autologous limbal stem cell transplantation from the fellow eye. In cases of advanced bilateral and partial LSCI, transplantation of ex vivo expanded sheets of limbal stem cells on amniotic membrane or fibrin may be performed. All patients with complete bilateral LSCI must rely on allogenic limbal stem cell transplantation comprising higher immunological risks. Progress using this technique has been achieved by the application of mitomycin C and amniotic membrane. Alternatively, transplantation of ex vivo expanded oral mucosal sheets may be used in bilateral LSCI, but only few long-term data are available on this technique as yet. While experimental attempts to use transdifferentiated bone marrow stem cells as a substitute for corneal epithelial cells have been without success, transdifferentiation of hair follicle stem cells to corneal epithelial cells may be more promising due to the identical lineage. But these experiments have not gone beyond the in vitro stage yet.