[The 2021 Activity Report of the Tissue Transplantation and Biotechnology Section of the German Ophthalmological Society]. / Aktivitäten der Sektion Gewebetransplantation und Biotechnologie der Deutschen Ophthalmologischen Gesellschaft: Leistungsbericht 2021.

The Section on Tissue Transplantation and Biotechnology of the German Ophthalmologic Society presented its 11th annual report for the year 2021. The number of corneal samples has still risen in comparison to former years. Nevertheless, there is still a need for import of transplants from abroad. Therefore, the transplant bottleneck has not yet been eliminated.

Comparison of Total Immunoglobulin G in Ante- and Postmortem Blood Samples from Tissue Donors.

BACKGROUND: A serology testing for infectious diseases (HIV, hepatitis B and C, syphilis) is mandatory in tissue donors. In many donors postmortem blood is the only sample available. Even though serological tests and nucleic acid amplification tests (NAT) used are validated for postmortem blood, a characterization of those blood samples is not yet established. We therefore investigated the total immunoglobulin G (IgG) content in postmortem blood of tissue donors and compared it to a corresponding antemortem blood sample. METHODS: Ante- and postmortem blood samples were obtained from 100 consecutive tissue donors. The total IgG of all samples was measured using an immune-turbidometric test on the AU 480 Chemistry Analyzer (Beckman Coulter). RESULTS: The mean total IgG concentration of antemortem blood samples from all 100 donors was 8.9 g/L ± 3.7 g/L (median 8.9 g/L, range 1.5 to 23.8 g/L). In 80 donors the IgG concentration in the antemortem blood sample was within the normal range with values ≥6 g/L (mean 10.0 g/L ± 3.3 g/L, median 9.3 g/L,). The total IgG concentration of the postmortem blood samples was lower with 7.2 g/L ± 3.2 g/L (median 6.7 g/L, range 0.6 to 18.2 g/L). The difference between the values of the antemortem and postmortem blood samples was 1.7 g/L ± 2.6 g/L (16.3%) (median 1.6 g/L, range -7.7 to 10.1 g/L). In 36 donors this difference was less than 10%, in 23 it was between 10 and 25%, in 33 between 26 and 50%, and in 8 over 50%. In 57 donors the total IgG in the postmortem blood sample was within the normal range with ≥6 g/L, in 53 of them also the value of the antemortem blood sample was within the normal range. No correlation for total IgG was found regarding the donor characteristics (age, sex, disease) and the sample characteristics (hemolysis, postmortem time). CONCLUSION: Total IgG values in antemortem samples were below the lower limit of 6 g/L in 20% of the cases. Total IgG was significantly lower in the postmortem samples compared to the antemortem samples, while 57% were still above the lower limit. No correlation with the postmortem time could be found. This lowered IgG levels should be payed attention to when using postmortem blood for infectious serology testing. Additional NAT testing should be considered.

Investigation of Visual System Involvement in Spinocerebellar Ataxia Type 14.

Spinocerebellar ataxia type 14 (SCA-PRKCG, formerly SCA14) is a rare, slowly progressive disorder caused by conventional mutations in protein kinase Cγ (PKCγ). The disease usually manifests with ataxia, but previous reports suggested PRKCG variants in retinal pathology. To systematically investigate for the first time visual function and retinal morphology in patients with SCA-PRKCG. Seventeen patients with PRKCG variants and 17 healthy controls were prospectively recruited, of which 12 genetically confirmed SCA-PRKCG patients and 14 matched controls were analyzed. We enquired a structured history for visual symptoms. Vision-related quality of life was obtained with the National Eye Institute Visual Function Questionnaire (NEI-VFQ) including the Neuro-Ophthalmic Supplement (NOS). Participants underwent testing of visual acuity, contrast sensitivity, visual fields, and retinal morphology with optical coherence tomography (OCT). Measurements of the SCA-PRKCG group were analyzed for their association with clinical parameters (ataxia rating and disease duration). SCA-PRKCG patients rate their vision-related quality of life in NEI-VFQ significantly worse than controls. Furthermore, binocular visual acuity and contrast sensitivity were worse in SCA-PRKCG patients compared with controls. Despite this, none of the OCT measurements differed between groups. NEI-VFQ and NOS composite scores were related to ataxia severity. Additionally, we describe one patient with a genetic variant of uncertain significance in the catalytic domain of PKCγ who, unlike all confirmed SCA-PRKCG, presented with a clinically silent epitheliopathy. SCA-PRKCG patients had reduced binocular vision and vision-related quality of life. Since no structural retinal damage was found, the pathomechanism of these findings remains unclear.

Implementation of the Single European Code in a Multi-Tissue Bank.

INTRODUCTION: The traceability of tissue and cells transplants is important to ensure a high level of safety for the recipients. With the final introduction of the Single European Code (SEC) in April 2017 in the EU a consistent system among all member states became mandatory. METHODS: The regulations for the SEC on EU and national level were evaluated. An overview on the different parts of the SEC with detailed explanations is given. Our own experiences with the implementation of the SEC in our multi-tissue bank are reported in addition. RESULTS: The implementation of the SEC in our multi-tissue bank could be successfully realized. However, it revealed a number of difficulties, especially the sterile labeling of certain tissue transplants and the complex update of the existing database. CONCLUSION: The introduction of the SEC has made a contribution to the safety of recipients of tissue and cells transplants through a system of comprehensive and transparent traceability.

Influence of chloroquine intake on the multifocal electroretinogram in patients with and without maculopathy.

PURPOSE: To evaluate the effect of long-term chloroquine intake on the multifocal electroretinogram (mfERG) in female patients with and without maculopathy. METHODS: Retrospective analysis of the mfERGs recorded in three different groups: (1) patients with bilateral maculopathy having taken chloroquine, (2) patients without maculopathy having taken chloroquine, and (3) healthy control subjects (age-matched to group 2) who never took chloroquine. MfERGs of each group were averaged, and the data of each patient group were compared to the control group. The main outcome measures were N1 and P1 characteristics and the ring ratio analysis. RESULTS: In group 1, 11 female subjects (22 eyes) were included, group 2 consisted of nine patients (18 eyes) and group 3 of seven healthy female subjects (14 eyes). Compared with healthy controls, patients in group 1 showed significantly reduced response densities of both N1 and P1 across all ring eccentricities except ring 5. Implicit times were significantly delayed only concerning N1 (ring 4 and the sum response of the left eye of group 1). P1 implicit times showed no significant alterations in either group. Ring ratios of the response densities were significantly higher mainly concerning group 1 (N1: ring 5/ring 2 and ring 5/ring 4 of the right eye; P1: all ring ratios of the right eye and all ratios except ring 5/ring 1 and ring 5/ring 4 of the left eye). The only ring ratio being significantly higher in group 2 was P1 ring 5/ring 1 ratio of the right eye. CONCLUSIONS: In the absence of clinically apparent maculopathy, chloroquine intake was not associated with major alterations of the mfERG.

Impact of temporary hyperthermia on corneal endothelial cell survival during organ culture preservation.

To evaluate temporary exposure to hyperthermia for its impact on endothelial cell density of porcine corneas in organ culture medium containing dextran with regards to possible negative influences of high temperatures during the storage and transport of corneal grafts. Four groups of central discs (diameter 8 mm) from the corneas of both eyes in 40 pigs were first organ-cultured (MEM with 6% dextran 500) for 24 h at 32°C. Ten corneas were then exposed to 40°C in group 1, to 42°C in group 2, to 44°C in group 3, and to 50°C in group 4 for 12 h each. The paired corneal discs for all groups were not treated, stored at 32°C and served as controls. After further organ culture of all corneas for 48 h at 32°C to allow regenerative processes, corneal endothelium was stained with Alizarin Red S and examined by light microscopy. The endothelial cell densities were determined on three central images using a system for the automatic estimation of morphometric parameters of corneal endothelium. Exposure for 12 h to 40°C as well as to 42°C induced no endothelial cell loss. Statistical analysis showed no significant difference of the endothelial cell density between corneas exposed to 40°C and 42°C and the control corneas (40°C treatment: 4736 ± 426 cells/mm(2) and control: 4762 ± 344 cells/mm(2), p = 0.74; 42°C treatment: 4240 ± 363 cells/mm(2) and control: 4176 ± 448 cells/mm(2), p = 0.40). Exposure to 44°C and 50°C lead to total necrosis of the endothelial cell layer. Exposure of organ cultured porcine corneas in dextran containing medium up to 42°C for 12 h does not compromise the endothelial cell density in a clinically relevant manner. Temperatures above 42°C, as it might be the case during transports from the cornea bank to the ophthalmic surgeon, must be strictly avoided as they damage the endothelial cell layer.

Influence of the difficulty of graft unfolding and attachment on the outcome in Descemet membrane endothelial keratoplasty.

PURPOSE: Descemet membrane endothelial keratoplasty (DMEK) is a standard procedure in patients with endothelial corneal disorders. We investigated the difficulty of unfolding and attaching the graft lamella and its correlation to characteristics of the graft lamella donor, preoperative patient characteristics, and the postoperative outcome. METHODS: After preparation of the graft lamella, we prospectively graded the unfolding of the graft lamella in 169 consecutive DMEK procedures between September 2012 and August 2013 at the Charité-Universitätsmedizin Berlin with four different grades. Various donor characteristics and preoperative patient characteristics were analyzed and correlated to the grading. Additionally, visual acuity, corneal thickness and endothelial cell density were measured and correlated. RESULTS: Donor characteristics (age [range, 49 - 79 years], gender, endothelial cell density, total storage time, storage de-swelling time, postmortem time) did not correlate to the grading. Preoperative visual acuity significantly influenced the grade of unfolding and attaching of the graft lamella (p = 0.023), while all other preoperative parameters (age, gender, indication for DMEK, preoperative endothelial cell density and preoperative central corneal thickness) showed no correlation. Visual acuity improved significantly after surgery (p < 0.001, preoperative 0.73 ± 0.43 LogMAR versus 0.31 ±0.28 LogMAR after one month, 0.25 ± 0.29 LogMAR after three months, and 0.21 ± 0.25 LogMAR after six months). Visual acuity did not differ significantly between the grading groups at any time point postoperatively. After 6 months, the mean loss rate of endothelial cell density was 24.7 %. Grading group IV developed significantly higher endothelial loss after one month, after three months and after six months compared to the other groups (p = 0.039, p = 0.008, p = 0.048). Graft detachment requiring an additional intracameral air injection to fix the graft detachment (re-bubbling) occurred in 61 eyes (38.1 %). In eyes graded IV, more re-bubblings were necessary than in all other groups (grade I: 37.0 %; grade II: 44.7 %; grade III: 43.8 %; grade IV: 50.0 %; p = 0.128; df = 3; χ (2) = 5.676). CONCLUSION: There is no correlation between corneal donor tissue characteristics and the degree of difficulty of unfolding using graft lamella older than 49 years. Therefore, it is not possible to select grafts best suited for DMEK surgery on the basis of donor characteristics when the donor age is above 50 years. Preoperative visual acuity influences the grade of difficulty. The rate of graft detachments and endothelial cell loss increases significantly with a more difficult graft unfolding. The proposed grading system may therefore be relevant for postoperative management.

Intraocular pressure elevation and post-DSEK glaucoma after Descemet`s stripping endothelial keratoplasty.

BACKGROUND: Intraocular pressure (IOP) elevation is a common problem in penetrating keratoplasty (PK), and possibly leads to graft failure. IOP elevation and secondary glaucoma may also be present after Descemet`s stripping endothelial keratoplasty (DSEK). This retrospective study analyzes the risk factors for IOP elevation and the functional outcome in those patients with post-DSEK glaucoma. METHODS: A retrospective analysis of case records of 72 DSEKs between 2007 and 2010 was performed. A total of 59 operated eyes were included. The assessment included the pre-operative history of corneal disease and glaucoma. Furthermore, the response to antiglaucoma treatment, the graft failure, the IOP, and visual acuity development were evaluated. RESULTS: The incidence of IOP elevation was 28.8 % and of post-DSEK glaucoma 11.9 %. Steroid-induced IOP elevation was the most frequent cause, with an incidence of 18.6 %. Patients with pre-existing glaucoma showed a significantly higher risk of developing IOP elevation, steroid-induced glaucoma and post-DSEK glaucoma (p = 0.006, p = 0.023, p = 0.009). In all cases, IOP elevation was treated effectively by tapering down steroid medication and initiating or increasing antiglaucoma medication. Visual acuity after 6 and 12 months improved significantly in cases with and without pre-existing glaucoma (p < 0.0001). After 24 months, clear grafts were achieved in 53 eyes (89.9 %). There was no significant difference in graft failure rates between cases with or without pre-existing glaucoma (p = 0.581) and with or without post-DSEK glaucoma (p = 0.306). CONCLUSIONS: IOP elevation after DSEK shows a high incidence. Pre-existing glaucoma increased the risk of developing IOP elevation and post-DSEK glaucoma. Although steroid-induced IOP elevation was the most frequent cause and could be treated effectively by tapering down steroid medication; there are other reasons why post-DSEK glaucoma developed. Management by medical treatment results in good visual acuity and graft survival.

Comparison of in situ Corneoscleral Disc Excision versus Whole Globe Enucleation in Cornea Donors Regarding Microbial Contamination in Organ Culture Medium - a Prospective Monocentric Study over 9 Years.

BACKGROUND: CORNEAS NEEDED FOR KERATOPLASTY CAN BE HARVESTED USING TWO TECHNIQUES: whole globe enucleation and in situ excision of the corneoscleral disc. This study evaluates the rate of microbial contamination of the donor cornea organ culture medium according to the method of retrieval. METHODS: All donor corneas of our cornea bank received between January 1, 2001 and December 31, 2009 put into organ culture and microbio-logically tested were prospectively analyzed for microbial contamination of the organ culture medium. RESULTS: 2,805 donor corneas could be included in this study in total. 975 of them were retrieved by whole globe enucleation (group 1) and 1,830 by in situ corneoscleral disc excision (group 2). 15 corneas of group 1 (1.5%) and 46 corneas of group 2 (2.5%) showed a contamination of the organ culture medium. The difference was shown not to be statistically significant (p = 0.082). CONCLUSION: The rate of microbial contamination in organ-cultured donor corneas does not seem to be dependent on the method of their retrieval.

Validation of the Microbiological Testing of Tissue Preparations Using the BACTEC™ Blood Culture System.

BACKGROUND: Since blood culture bottles are validated by the manufacturer for blood only, an additional validation for the use with fluids of tissue preparations is necessary. METHODS: Two 10-ml samples of cornea culture medium, histidine-tryptophan-ketoglutarate (HTK) solution, or Ringer solution at the end of femur head thermo-disinfection were given into blood culture bottles (BD BACTEC™ Plus Aerobic/F, Anaerobic/F for cornea culture medium and BD BACTEC™ Standard Aerobic/Anaerobic for HTK and Ringer solution) and subsequently spiked with 10-100 colony forming units (CFU) of bacteria or fungi (aerobic bacteria: Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa; anaerobic bacteria: Clostridium sporogenes; fungi: Candida albicans, Aspergillus brasiliensis) according to the European Pharmacopoeia Chapter 2.6.1. RESULTS: All tested bacteria and fungi could be detected in all solutions. All positive and negative controls were tested correctly. Compared to the positive controls, the microbial growth was delayed in the antibiotic-containing cornea culture medium, and negative in two cases of B. subtilis spiking. CONCLUSION: The use of BACTEC™ blood culture bottles seems to be a suitable method for microbiological testing of HTK solution, Ringer solution, and, with limitations, also for testing of the antibiotic-containing cornea culture medium.

Plasma viscosity in giant cell arteritis.

BACKGROUND: Diagnosis of giant cell arteritis (GCA) is based on criteria of the American College of Rheumatology. However, not all GCA patients meet these criteria and treatment may be delayed in individual patients, leading to an increased risk of complications. METHODS: In an observational study, we investigated acute phase response markers in GCA and non-GCA patients matched for erythrocyte sedimentation rate and CRP levels. RESULTS: Plasma viscosity (PV) was significantly elevated in all GCA patients, but normal in non-GCA patients. CONCLUSIONS: Our data suggest that PV may reflect a more specific component of the acute inflammatory response in patients with GCA. Analysis of PV may significantly contribute to a reliable diagnosis early in the course of the disease, particularly in patients with suspected GCA that do not meet current diagnostic criteria.

Validation of the Serological Testing for Anti-HIV-1/2, Anti-HCV, HBsAg, and Anti-HBc from Post-mortem Blood on the Siemens-BEP-III Automatic System.

BACKGROUND: Some properties of blood are modified post mortem. These modifications might give false-negative or false-positive results in infectious disease testing. Most CE-marked test equipment for infectious serology testing is not validated for testing post-mortal blood. Validation, however, is obligatory, if the results are used for the release of tissues for transplantation. MATHODS: Samples of pre- and post-mortem sera were obtained from 20 cornea donors, and the results were compared for anti-HIV-1/2, anti-HCV, HBsAg, and anti-HBc on the Siemens-BEP-III Automatic System. Negative post-mortem sera were spiked with standard sera (PEI anti-HCV IgG, PEI HBsAg ad 1000 standard, anti-HBc IgG (WHO) NIBSC 95/522, PEI anti-HIV-IV) in concentrations which give low- and high-positive results for the respective marker. RESULTS: All pre-mortem sera were negative for all markers. None of the post-mortem samples was false-positive. None of the spiked postmortem samples was false-negative. Technical errors occurred during the validation process but could be detected and eliminated. Serum samples should be centrifuged immediately after collection, and it must be taken into account that post-mortem serum could rarely lead to blockage of pipetting systems due to clotting phenomena. CONCLUSION: There is no indication that post-mortem samples give false-negative or false-positve results with the test system and test kits used. The procedure described might serve as a model for validating other test kits on post-mortem samples.

SARS-CoV-2: Impact on, Risk Assessment and Countermeasures in German Eye Banks.

INTRODUCTION: Since the beginning of the COVID-19 pandemic there has been some debate regarding the risk of transmission through tissue transplantation and tissue banking processes. AIM OF THE STUDY: To analyze the changes that SARS-CoV-2 has caused regarding the harvesting of corneal donor tissue and eye bank activities in Germany. METHODS: A questionnaire was provided to 26 eye banks in Germany, consisting of questions about adaptations made in the screening of potential donors and the harvesting of corneal tissue following the pandemic spread of SARS-CoV-2. RESULTS: Eighteen eye banks actively reduced recruitment of donors and two banks ceased all activity. Additional diagnostic screening was performed in eight banks, using conjunctival swabs and/or nasopharyngeal swabs. In six eye banks, additional protective measures, such as FFP2 masks and/or facial shields, were implemented. Overall, a mean reduction in the number of obtained donor tissues of 17% was observed. DISCUSSION: Conjunctival and/or nasopharyngeal swabs of donors have been implemented by a minority. Reasons for not performing additional tests may be moderate sensitivity and lack of validation for postmortem use of RT-PCR testing. Also, the hazard of SARS-CoV-2 entering the corneal donor pool with subsequent transmission might be perceived as theoretical. Face shields provide a sufficient barrier against splash and splatter contamination but may be insufficient against aerosols. Additional face masks would provide support against aerosols, but it remains debatable if corneal harvesting can be considered an aerosol-producing procedure. In the future we expect to see changes in current guidelines because of a surge in scientific activities to improve our understanding of the risks involved with cornea donation in the COVID-19 pandemic, and because current practice may reduce the availability of donor corneas due to new exclusion criteria while the demand remains unchanged.

Pseudophakic corneal donor tissue in Descemet membrane endothelial keratoplasty (DMEK): implications for cornea banks and surgeons.

OBJECTIVE: Increasingly, cornea banks are recovering donor tissue from pseudophakic donors. Little is known about their suitability for Descemet membrane endothelial keratoplasty (DMEK) surgery in terms of endothelial cell density (ECD) and preparation failure. METHODS AND ANALYSIS: We explored ECD during donor tissue preparation in 2076 grafts. Preparation failure was analysed in 1028 grafts used in DMEK surgery at our clinic. To monitor ECD and functional results, we matched 86 DMEK patients who received pseudophakic donor grafts with similar recipients of phakic donor grafts and followed them up for 36 months. RESULTS: At recovery, mean ECD in pseudophakic donor grafts was 2193 cells/mm2 (SD 28.7) and 2364 cells/mm2 (SD 15.7) in phakic donor grafts (p<0.001). After cultivation, the difference increased as pseudophakic donor grafts lost 14% of ECD while phakic lost only 6% (p<0.001). At transplantation, mean ECD in pseudophakic donor grafts was 2272 cells/mm2 (SD 250) and 2370 cells/mm2 (SD 204) in phakic donor grafts (p<0.001). After transplantation, the difference in ECD increased as pseudophakic donor grafts lost 27.7% of ECD while phakic donor grafts lost only 13.3% (p<0.001). The risk of preparation failure in pseudophakic donor grafts was higher than in phakic donor grafts (OR 4.75, 95% CI 1.78 to 12.67, p=0.02). Visual acuity increased in both groups similarly. CONCLUSIONS: Pseudophakic donor grafts have a lower ECD, are more prone to endothelial cell loss during recovery and surgery and are associated with a higher risk of preparation failure. Cornea banks and surgeons should consider this in the planning of graft preparation and transplantation.

Endothelial evaluation in the cornea bank.

The light microscope is the first-choice technique for the evaluation of organ-cultured donor corneas. For the microscopic visualization of the endothelial cells, the corneas have to be immersed in ahypotonic solution. The number of cells, their vitality and morphology are analyzed. The cell densityis easily estimated with the fixed frame/L method. Use of an image analysis system enables computer processing and counting of digitalized endothelial cell images. An adequately high endothelial cell density after the culture period is a decisive criterion that must be met before releasing adonor cornea for grafting. An endothelial cell density of 2,000-2,200 cells/mm2 is generally recognized as the lower limit for the longest possible graft survival. While an evaluation of the endothelium does not necessarily have to be performed at the beginning or middle of organ culture, it isobligatory at the end. Morphology assessment should routinely involve estimating the pleomorphism (deviation from hexagonality), polymegathism (variation in cell area) and granulation/vacuolization of the endothelial cells. Recognition of devitalized cells is easily facilitated by vital stainingwith trypan blue.

FUNDUS AUTOFLUORESCENCE FINDINGS IN EARLY CHLOROQUINE MACULOPATHY.

BACKGROUND/PURPOSE: Toxic maculopathy is a rare but severe complication of chloroquine intake. Although the phenotype of established maculopathy was analyzed in detail, few data exist on the ophthalmologic findings in the early stage. METHODS: The authors present 4 female patients with unequivocal signs of chloroquine maculopathy (bilateral [peri-]central scotoma in the visual fields, structural alterations of the macula in the optical coherence tomography) but normal or atypical findings as to fundus autofluorescence imaging. RESULTS: In all patients, optical coherence tomography showed perifoveal thinning and subtle alterations of the outer retinal layers. In one patient, the latter was limited to the pericentral region, whereas it showed a more diffuse distribution in two other patients. One patient showed a combination of pericentral and diffuse damage. Multifocal electroretinography was recorded in three patients and revealed the typical (peri-)central amplitude reductions. CONCLUSION: A normal fundus autofluorescence does not rule out toxic maculopathy. Optical coherence tomography and multifocal electroretinography seem to be more sensitive in the early stage of the disease. In case of typical complaints and visual fields, the optical coherence tomography has to be evaluated for subtle alterations of the outer retina. Their presence justifies the cessation of the drug. Multifocal electroretinography may be of special value in these problematic cases.

Increased sensitivity of microbiological testing of cornea organ culture medium by additional resin treatment.

OBJECTIVE: This validation study investigates the treatment of cornea organ culture medium (Modified Eagle Medium, Biochrom GmbH, Berlin, Germany) with RESEP, a new medical device for antibiotics removal, before microbiological testing with BACTEC TM blood culture bottles. METHODS AND ANALYSIS: 10-100 colony forming units of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtillis, Aspergillus brasiliensis, Clostridium sporogenes, Enterobacter cloacae and Staphylococcus epidermidis were inoculated in 9mL of cornea organ culture medium. In group A, the medium was withdrawn with RESEP and treated for 20 min at room temperature, and then inoculated in BACTEC Plus Aerobic/F/Anaerobic/F blood culture bottles. In group B, the medium, spiked by the inoculation of microorganism, was injected directly. For each strain, a growth control was performed, by direct inoculation of the microorganisms in BACTECTMvials (positive control). All samples were incubated in the automated BACTECTMblood culture system at 36°C ±1°C for maximum of 14 days or until a positive reading. The elimination of antibiotics from the medium by RESEP was determined by high-performance liqiud chromatography. RESULTS: After 20 min of RESEP treatment, 100% (n=9) of streptomycin, 100% (n=9) of amphotericin B and 99.7% (n=9) of penicillin G were eliminated. In group A, all microorganisms were detected within 3 days of incubation with a sensitivity of 100% (n=99) and showed no significant delay compared with the positive controls. In group B, the overall sensitivity was 67.9% (n=96) with a significant delay until detection of microbial growth for all tested microorganisms except for A. brasiliensis. CONLCLUSION: The use of RESEP to eliminate the antibiotics from cornea organ culture medium increases the sensitivity of the microbiological testing with BACTECTMPlus blood culture bottles significantly and fulfils the requirements of the European Pharmacopoeia method suitability test.

Primary Descemet's Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy versus Bullous Keratopathy: Histopathology and Clinical Results.

PURPOSE: To investigate functional and anatomical results up to 12 months after Descemet's membrane endothelial keratoplasty (DMEK) for Fuchs' endothelial dystrophy (FED) versus bullous keratopathy (BK) in consideration of morphologic characteristics on host's endothelium-Descemet's membranes (EDM). METHODS: In a prospective consecutive case series, 119 eyes underwent a primary DMEK for FED or BK. Intraoperatively obtained EDM were investigated immunohistologically. Clinical and morphological parameters were compared between FED and BK. RESULTS: Overall, the 12-months best-corrected visual acuity (BCVA) was 0.14 logMAR, and 0.10 logMAR in eyes without vision-limiting comorbidities; thereby no differences were revealed between eyes with FED and BK up to 12 months postoperative (p = 0.186 and p = 0.095, respectively). Correspondingly, the mean central corneal thickness (CCT) measured 520 vs. 529 µm and the mean endothelial cell density (ECD) was 1743 vs. 1457 cells/mm2 for FED and BK, 12 months postoperative. Regarding CCT and ECD, no differences were observed between the groups (p = 0.181 and p = 0.112, respectively). The overall detachment rate was 40% (48/119). Comparing FED and BK the detachment rates did not differ, which were 41% vs. 39% and 43% vs. 35%, in pseudophakic eyes (p = 0.554 and p = 0.601, respectively). Yet, the distribution of recurring graft detachments differed between FED and BK; secondary re-detachments were more frequent in the FED group (7 cases). Regarding histologic investigations, a lower ECD was found in specimens with BK, no differences were revealed for EDM and anterior banded layer thicknesses. Immunohistologically, differences in the distribution of fibronectin and cytokeratin were observed. A rarification of matrix proteins was found in EDM complexes with FED. CONCLUSIONS: DMEK produces similar results for FED and BK. However, the postoperative course may differ with regard to the recurrence of secondary graft detachments that may be associated by histopathologic particularities.