Sonja Heinzelmann

Background: This study aims to compare the refractive outcomes of cataract surgery using two different biometry devices, the IOL Master 500 and IOL Master 700, and to investigate the influence of patient-related factors on these outcomes. Methods: In this retrospective study, we analyzed data from 2994 eyes that underwent cataract surgery. Multiple linear regression analyses were performed to examine the impact of the biometry device (IOL Master 500 or IOL Master 700), patient age, time elapsed between biometry and surgery, gender, and insurance status, as well as biometric parameters (anterior chamber depth, axial length, and corneal curvature), on postoperative refractive outcomes, specifically the deviation from target refraction. Results: The choice of the IOL Master device did not result in a statistically significant difference between the two devices (p = 0.205). Age (p = 0.006) and gender (p = 0.001) were identified as significant predictors of refractive outcomes, with older patients and males experiencing slightly more hyperopic outcomes compared to younger patients and females, respectively. The time elapsed between biometry and surgery and insurance status did not significantly influence the refractive outcomes. Conclusions: Our study, supported by a large cohort and a diverse group of patients representing typical anatomical variants seen in cataract surgery, supports the thesis that the IOL Master 500 and IOL Master 700 can be regarded as equivalent and effective for biometry in cataract surgery. The differences between the devices were negligible. Therefore, switching between the devices is safe for bilateral patients.

The microbiome of the ocular surface has been characterised, but only limited information is available on a possible silent intraocular microbial colonisation in normal eyes. Therefore, we performed next-generation sequencing (NGS) of 16S rDNA genes in the aqueous humour. The aqueous humour was sampled from three patients during cataract surgery. Air swabs, conjunctival swabs from patients as well as from healthy donors served as controls. Following DNA extraction, the V3 and V4 hypervariable regions of the 16S rDNA gene were amplified and sequenced followed by denoising. The resulting Amplicon Sequence Variants were matched to a subset of the Ribosomal Database Project 16S database. The deduced bacterial community was then statistically analysed. The DNA content in all samples was low (0–1.49 ng/µL) but sufficient for analysis. The main phyla in the samples were Acinetobacteria (48%), Proteobacteria (26%), Firmicutes (14%), Acidobacteria (8%), and Bacteroidetes (2%). Patients’ conjunctival control samples and anterior chamber fluid showed similar patterns of bacterial species containing many waterborne species. Non-disinfected samples showed a different bacterial spectrum than the air swab samples. The data confirm the existence of an ocular surface microbiome. Meanwhile, a distinct intraocular microbiome was not discernible from the background, suggesting the absence of an intraocular microbiome in normal eyes.

Background: The microbiome of the ocular surface has been characterised, but only limited in-formation is available on a possible silent intraocular microbial colonisation in normal eyes. Therefore, we performed next generation sequencing (NGS) of 16S rDNA genes in aqueous hu-mor. Methods: Aqueous humor was sampled from three patients during cataract surgery. Air swabs, patient’s and healthy donor conjunctival swab served as controls. Following DNA extraction, the V3 and V4 hypervariable regions of the 16S rDNA gene were amplified and sequenced fol-lowed by denoising. The resulting Amplicon Sequence Variants were matched to a subset of the Ribosomal Database Project 16S database. The deduced bacterial community was then statis-tically analysed. Results: DNA content in all samples was low (0-1.49 ng/µl) but sufficient for analysis. Main phyla in all samples were Acinetobacteria (48%), Proteobacteria (26%), Firmicutes (14%), Acidobac-teria (8%) and Bacteroidetes (2%). Patients conjunctival control samples and anterior chamber fluid showed similar patterns of bacterial species containing many waterborne species. Non-disinfected samples showed a different bacterial spectrum than the air swab sample. Conclusions: The data confirm the existence of an ocular surface microbiome. A distinct intraoc-ular microbiome was not discernable from the background, suggesting the absence of an intra-ocular microbiome in normal eyes.

Background Descemet membrane endothelial keratoplasty (DMEK) may be an elegant solution for endothelial failure after penetrating keratoplasty (PK). However, it is currently unclear whether this approach comes with any long-term drawbacks concerning chronic endothelial cell loss, rebubbling rates, graft survival and severity of immune reactions. We therefore herein compare the outcomes of DMEK to repair failed PK to the outcomes of DMEK to repair failed DMEK grafts. Methods This retrospective study included 117 patients with DMEK after keratoplasty (82 following DMEK and 35 following PK). Postoperative visual acuity, endothelial cell count, rebubbling rates, graft survival and rejection rates were recorded. Kaplan-Meier-analysis was used to assess survival rates. Results Visual acuity improved, but stayed at a lower level in PK patients. Endothelial cell loss was more severe in patients with DMEK as an initial procedure, whereas rebubbling rates, graft failure and immune reactions did not differ significantly between both groups. Ratios of graft diameters of the first and second graft did not influence survival or rejection of the graft. Conclusions Repeat DMEK is an appropriate method of treating endothelial graft failure after both DMEK and PK. The higher endothelial cell loss in the DMEK-DMEK group may be due to a different recipient endothelial reservoir and assimilate in the long term follow-up. These data may encourage treating endothelial graft failure with DMEK even in PK eyes.

Corneal transplantation is one of the most common forms of tissue transplantation worldwide. Donor corneal tissue used in transplantation is provided by eye banks, which store the tissue in culture medium after procurement. To date, the effects of cell culture on human corneal tissue have not been fully elucidated. Using the 3′ RNA sequencing method for massive analysis of cDNA ends (MACE), we show that cultivation of corneal tissue leads to significant changes in a variety of molecular processes in human corneal tissue that go well beyond aspects of previously known culture effects. Functionally grouped network analysis revealed nine major groups of biological processes that were affected by corneal organ culture, among them keratinization, hypoxia, and angiogenesis, with genes from each group being affected by culture time. A cell type deconvolution analysis revealed significant modulations of the corneal immune cell profile in a time dependent manner. The results suggest that current culture conditions should be further refined and that prolonged cultivation may be detrimental. Recently, we showed that MACE enables transcriptional profiling of formalin-fixed and paraffin-embedded (FFPE) conjunctival tissue with high accuracy even after more than 10 years of storage. Here we demonstrate that MACE provides comparable results for native and FFPE corneal tissue, confirming that the technology is suitable for transcriptome analysis of a wide range of archived diseased corneal samples stored in histological archives. Finally, our data underscore the feasibility of bioinformatics cell-type enrichment analysis in bulk RNA-seq data to profile immune cell composition in fixed and archived corneal tissue samples, for which RNA-seq analysis of individual cells is often not possible.

Background Penetrating keratoplasty (PK) gets more and more reserved to cases of increasing complexity. In such cases, ocular comorbidities may limit graft survival following PK. A major cause for graft failure is endothelial graft rejection. Suture removal is a known risk factor for graft rejection. Nevertheless, there is no evidence-based regimen for rejection prophylaxis following suture removal. Therefore, a survey of rejection prophylaxis was conducted at 7 German keratoplasty centres.Objective The aim of the study was documentation of the variability of medicinal aftercare following suture removal in Germany.Methods Seven German keratoplasty centres with the highest numbers for PK were selected. The centres were sent a survey consisting of half-open questions. The centres performed a mean of 140 PK in 2018. The return rate was 100%. The findings were tabulated.Results All centres perform a double-running cross-stitch suture for standard PK, as well as a treatment for rejection prophylaxis with topical steroids after suture removal. There are differences in intensity (1 – 5 times daily) and tapering (2 – 20 weeks) of the topical steroids following suture removal. Two centres additionally use systemic steroids for a few days.Discussion Rejection prophylaxis following PK is currently poorly standardised and not evidence-based. All included centres perform medical aftercare following suture removal. It is assumed that different treatment strategies show different cost-benefit ratios. In the face of the diversity, a systematic analysis is required to develop an optimised regimen for all patients.

Hintergrund Ein Hornhauttransplantat aus Organkultur darf i. d. R. nur verwendet werden, wenn präoperativ eine Endothelzelldichte von mindestens 2000 Zellen pro mm² nachgewiesen ist. Die Messung der Endothelzelldichte ist dadurch erschwert, dass in der Phasenkontrastmikroskopie die Zellgrenzen der Endothelzellen nicht immer gut sichtbar sind und die zählbare Fläche durch quellungsbedingte Descemet-Falten limitiert ist. Bislang ist daher keine automatische Methode zur Endothelzelldichtebestimmung in Hornhauttransplantaten verfügbar. Das neuronale Netzwerk U-Net hat sich in der vollautomatischen Analyse von spiegelmikroskopischen Aufnahmen des Hornhautendothels bewährt. Ziel dieser Studie war die Anwendung des U-Net in der Qualitätssicherung von Hornhauttransplantaten. Material und Methoden Das U-Net wurde zunächst anhand von 100 manuell markierten Befundungsbildern von Hornhäuten aus der Lions-Hornhautbank Baden-Württemberg trainiert. Für die Prüfung der Messgenauigkeit des U-Net wurden 100 weitere Befundungsbilder von der o. g. Hornhautbank zur Verfügung gestellt. Diese wurden jeweils von a) einer erfahrenen Befunderin und b) einem weniger erfahrenen Augenarzt manuell gezählt. Die identischen Bilder wurden vollautomatisch über das trainierte U-Net ausgezählt und dieses Ergebnis mit beiden manuellen Analysen mittels Pearson-Korrelation verglichen. Ergebnisse Der Korrelationskoeffizient zwischen dem U-Net und der erfahren Untersucherin als „Goldstandard“ betrug 0,90. Der Korrelationskoeffizient des weniger erfahrenen Augenarztes mit dem Goldstandard betrug nur 0,81. Beide Korrelationen erwiesen sich als statistisch hochsignifikant (p < 0,0001). Schlussfolgerung Die enge Korrelation des U-Net mit dem „Goldstandard“ deutet darauf hin, dass mit dem U-Net, die medizintechnische Zulassung vorausgesetzt, eine effektive Unterstützung in der Qualitätsbeurteilung von Hornhauttransplantaten in der Hornhautbank möglich ist. Dies hätte Vorteile für die Objektivität und die Arbeitseffizienz. Background Human corneal grafts from organ culture need to have more than 2000 endothelial cells/mm² to be suitable for transplantation. Measurement of the endothelial cell density is complicated by invisible cell borders in phase contrast microscopy, as well as by limited areas for counting due to folds in the Descemet membrane of the swollen corneal grafts. To date, no automated counting method for measuring the endothelial cell density exists. The neuronal network U-Net has already proven itself in automated segmentation of specular microscopy images of human corneal endothelium. The aim of this study was the application of the U-Net in the quality control of human corneal grafts. Material and Methods Training of the U-Net was performed using 100 manually tagged endothelial cell images of corneal grafts from the Lions eye bank in Baden-Württemberg. Another 100 images were obtained for testing the precision of measurements of the U-Net. These were adjudged manually by a) an experienced investigator and b) a less experienced ophthalmologist. The endothelial cells in identical images were then counted automatically by the trained U-Net. Comparison with the manually counted results was drawn by Pearson correlation. Results The correlation coefficient between the U-Net and the experienced investigator as gold standard was 0.9. The correlation coefficient between the less experienced ophthalmologist and the gold standard was only 0.81. Both correlations were statistically highly significant (p < 0.0001). Discussion The strong correlation between the U-Net and the gold standard points out that, given medical approval, effective assistance for eye banks is possible in quality control by automated counting. This could improve objectivity and efficiency of work flow.

Purpose: Descemet membrane endothelial keratoplasty (DMEK) seems to be the most promising technique for treating endothelium-related disorders of the cornea. However, graft detachment is a frequent complication. It often can be treated by rebubbling procedures. Unfortunately, this increases the risk of subsequent graft failure. It is therefore essential to define risk factors for graft detachment in DMEK. In this study, postoperative intraocular pressure (IOP) is investigated in this regard. Methods: In total, 1047 DMEK procedures in patients with Fuchs endothelial dystrophy or bullous keratopathy were reviewed. All rebubbling procedures were recorded as well as postoperative IOP values (first measure 2 hours postoperatively and highest and lowest value within 3 days after surgery), donor factors (donor age, organ culture time, and endothelial cell count), and whether DMEK surgery had been combined with cataract surgery (triple-DMEK). Incidence rates were estimated with the Kaplan–Meier method. Cox regression was used to assess statistical significance. Results: The overall rebubbling rate was 24% after 8 weeks. Relative dips in IOP may be associated with a higher risk for graft detachment (hazards ratio = 0.41; P < 0.001). Graft detachment was neither significantly influenced by donor factors, first or maximum IOP, nor by simultaneous cataract surgery (triple-DMEK). Conclusions: Avoiding dips in IOP may reduce the risk for graft detachment after DMEK. To prevent lowering of IOP values in the early postsurgical period, it may be advisable to achieve tight surgical wounds at the end of DMEK surgery and optimal filling of the anterior chamber with air and optionally with gas.

Patients with intermediate uveitis (IU) represent a heterogenous group characterized by a wide spectrum of etiologies and regional differences. Aim of the study was to analyze the characteristics of patients with IU examined in an academic center in Germany. We conducted a retrospective analysis of the clinical records of all patients with intermediate uveitis referred to the Eye Center, University of Freiburg from 2007 to 2014. Diagnosis followed the Standardization in Uveitis Nomenclature (SUN) criteria. Data analysis included: etiology of IU, demographics, complications, treatment and visual acuity. We identified 159 patients with intermediate uveitis during that period. Mean age at diagnosis was 35 years. Most are female (64%), and the mean duration of IU was 6.1 years (range 1 month – 35 years). Etiology of IU was idiopathic in 59%. Multiple sclerosis (MS) (20%) and sarcoidosis (10%) were frequent systemic causes of IU. Other etiologies including infectious diseases (tuberculosis, borreliosis) or immune-mediated conditions (eg, after vaccination) were present in 11%. The pattern of complications included macular edema (CME) (36%), cataract (24%), secondary glaucoma (7%), and epiretinal membrane formation (19%). Periphlebitis and optic neuritis were more frequent in conjunction with MS. Treatment comprised local and systemic steroids, immunosuppressive agents, biologics, and surgery. Best corrected visual acuity was better than 20/25 in 60% of the eyes after more than 10 years of follow-up. In our German academic center, most IU cases were idiopathic or associated with MS or sarcoidosis. In contrast to other countries, infectious cases were rare. Patients’ overall visual prognosis is favorable even when the duration of IU has been long and and despite numerous complications.