Peripheral Ulcerative Keratitis: Clinical Characteristics, Differential Diagnoses and Therapeutic Concepts. / Periphere ulzerative Keratitis: Klinik, Differenzialdiagnosen und Therapiekonzepte.

Peripheral ulcerative keratitis (PUK) is an inflammatory disease of the peripheral cornea, which may frequently be associated with several rare, but potentially life-threatening systemic diseases. The inflammatory pathogenesis of PUK results from humoral and cell-mediated inflammation. The diagnosis is usually based on the typical clinical findings and always requires detailed diagnostic testing to identify a potential systemic underlying disease. Treatment includes topical and systemic immunosuppressive and immunomodulatory therapeutic strategies and, in the event of impending or existing perforation, also various surgical interventions. PUK is a potentially blinding disease that initially affects the periphery, but, if left untreated, can lead to destruction of the entire cornea. Interdisciplinary diagnostic testing and therapy are crucial to preserve vision in the affected patients and reduce morbidity and mortality. The following article provides an overview of the pathophysiology, clinical findings, possible underlying systemic diseases, relevant differential diagnoses and therapeutic strategies.

Atopic Keratoconjunctivitis: Pathophysiology, Clinic, and Potential New Therapeutic Concepts. / Atopische Keratokonjunktivitis: Pathophysiologie, Klinik und potenzielle neue Therapiekonzepte.

Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease with a bipolar age distribution in childhood, adolescence and middle adulthood. Up to 50% of AD patients show ocular involvement, which can be potentially sight threatening. Clinically, the majority of cases present with atopic blepharo(kerato)conjunctivitis or atopic keratoconjunctivitis (AKC); other clinical variants from this group of inflammatory ocular surface diseases are keratoconjunctivitis vernalis in childhood and adolescence and allergic conjunctivitis. In addition to the aforementioned blepharitis, keratitis and conjunctivitis, AD is also associated with eyelid involvement with subsequent eyelid malposition, limbal insufficiency with the development of pseudopterygia, (chronic) cicatrizing conjunctivitis with symblephara formation and fornix shortening, as well as ocular surface malignancies such as conjunctival intraepithelial neoplasia (CIN) and squamous cell carcinoma. In addition, an association with AD or AKC has been described for keratoconus. Whereas the therapy of AD in dermatology has made revolutionary advances in recent years through the use of biologicals, the primary use of these biologicals in ophthalmological complications is still very hesitant. Treatment here is often provided using topical steroids and calcineurin inhibitors. The following article summarises recent developments in basic and clinical dermatological research and discusses them in the context of current concepts for ophthalmological therapy.

Supine Positioning for Graft Attachment After Descemet Membrane Endothelial Keratoplasty: A Randomized Controlled Trial.

PURPOSE: The Supine Positioning for Descemet Membrane Endothelial Keratoplasty Attachment (SUPER-DMEK) trial assessed the efficacy of prolonged supine head positioning on graft attachment. DESIGN: Randomized controlled trial. METHODS: Participants with Fuchs' dystrophy were randomized to 5 days of supine head positioning (intervention) or to 1 day (control). Participants, surgeons, and investigators were masked until the day after surgery. Adherence to the allocated intervention was monitored using a head sensor. Main outcome measures were area and volume of graft detachment (coprimary end points) 2 weeks after surgery quantified using a validated neural network for image segmentation on anterior segment optical coherence tomography images, and repeat air injection (rebubbling), subjective visual function, and adverse events (secondary end points). RESULTS: A total of 86 participants received the allocated intervention (35 eyes intervention and 51 eyes control). In the intention-to-treat analysis, the mean area of graft detachment was 28.6% in the intervention arm and 27.5% in the control arm (adjusted between-arm difference, 1.3; 95% CI, -8.7 to 11.4; P = .80). Results for volume of detachment and as-treated analyses based on head position sensor data indicated no potentially clinically relevant effect of prolonged supine positioning on graft attachment. Results were not compatible with a relevant treatment effect on rebubbling or subjective visual function. Adverse events, most commonly back pain, were more common and more severe with the intervention. CONCLUSIONS: In this randomized controlled trial, graft attachment was not improved with prolonged supine head positioning. Prolonged supine positioning frequently caused back pain. Prolonged supine positioning after Descemet membrane endothelial keratoplasty for Fuchs' dystrophy may not be needed in routine practice.

Indications, techniques, and graft survival of mini and corneo-scleral tectonic keratoplasties: A retrospective single-center case series.

PURPOSE: Tectonic keratoplasties (TK) are used to treat corneal and scleral perforations and to prevent the loss of the eye. In this study, we retrospectively analyzed indications, surgical procedures, and outcomes of eccentric mini and corneo-scleral tectonic keratoplasties with respect to anatomical survival and clear graft survival rates to identify risk factors for graft failure. METHODS: This retrospective study includes 33 eccentric mini (graft diameter <6 mm) and/or corneo-scleral TK of 32 consecutive patients of a total of 41 TK carried out between 2005 and 2020 in the Eye Center, University of Freiburg, Germany, making up 0.7% of all keratoplasties performed during this period (n = 5557). Patient and graft specific data were extracted from medical files. Anatomical survival-defined as achieving integrity of the globe without further surgical interventions-and clear graft survival-defined as persisting graft clarity-were estimated using the Kaplan-Meier method. We also fitted Cox proportional hazard models to account for factors influencing anatomical and clear graft survival. RESULTS: Median duration of anatomical success was 72.5 months (95% confidence interval (CI) 18.1-infinite (inf.)) and median duration of clear graft survival was 29.6 months (95% CI 12.5-Inf.). The 1-year survival rate for anatomical survival was 67.6% (95% CI 52.2% - 87.6%) and for clear graft survival 66.4% (95% CI 50.5%- 87.1%). No enucleation was necessary during this time-period. Non-inflammatory primary causes (n = 14) presented a trend towards better anatomical survival rates (median remained above 0.75 during follow-up) compared to inflammatory primary causes (n = 19, median 18.1 months (95% CI 2.8 - inf.)) and longer clear graft survival (median 29.6 months (95% CI 12.5 - inf.) versus 13.1 months (95% CI 3.2 - inf.)). Corneo-scleral grafts (n = 18) compared to corneal grafts (n = 15) showed a trend towards better anatomical survival (more than 50% of eyes did not fail during follow-up period (95% CI 21.9-Inf. months) versus 18.1 months (95% CI 2.4-Inf.)) and clear graft survival (median 29.6 months (95% CI 12.6-Inf.) versus 6.2 months (95% CI 2.8-Inf.)). Old age (n = 11, 75.2 - 90.1 years) compared to young age (n = 11, 6.2 - 60.2 years) was the only hazard ratio (hazard ratio 0.04 (95% CI 0.002-0.8)) that reached the level of significance (p = 0.03). CONCLUSION: Eccentric TK is helpful in the successful treatment of a variety of severe eye diseases. Patients at young age, with pre-existing inflammatory conditions or corneal TK are at higher risk for anatomical failure as well as clear graft failure and therefore need to be monitored closely.

Cataract Surgery-Indications, Techniques, and Intraocular Lens Selection.

BACKGROUND: Opacification of the lens of the eye (cataract) is usually due to aging. It is a painless, progressive condition that affects contrast and color perception and alters refraction, leading to visual loss that may be total. In cataract surgery, the turbid lens is replaced by an artificial lens. An estimated 600 000 to 800 000 such procedures are performed in Germany each year. METHODS: This review is based on pertinent publications retrieved by a selective search in PubMed, including meta-analyses, Cochrane reviews, and randomized controlled clinical trials (RCTs). RESULTS: Cataract is the most common reversible cause of blindness around the world (approximately 95 million people). The surgical replacement of a turbid lens with an artificial lens is usually carried out under local anesthesia. The standard technique for fragmentation of the nucleus of the lens is ultrasonic phacoemulsification. RCTs have not shown the superiority of the femtosecond laser over phacoemulsification for this purpose so far. The spectrum of artificial intraocular lenses, aside from the conventional type with a single focus, include lenses with multiple foci, extended-depth-of-focus (EDOF) lenses, and astigmatism-correcting lenses. CONCLUSION: In Germany, cataract surgery is usually performed on an outpatient basis under local anesthesia. Artificial lenses with various additional functions are available nowadays; the choice of lens depends on the needs of the individual patient. Patients must be adequately informed about the advantages and disadvantages of the different lens systems.

Clinical Course of Different Types of Immune Reactions following Keratoplasty.

BACKGROUND: Immune-mediated corneal graft rejection (IR) is a leading cause of corneal graft failure. The endothelium, stroma, epithelium, or a combination can be affected. Little is known about the long-term outcomes of different types of IR. METHODS: We reviewed the medical records of all keratoplasties that had been performed at our eye centre between 2003 and 2016 (n = 3934) for any kind of IR that occurred between the surgery and 2019. All patients with a definite diagnosis of IR and sufficient clinical data were included in the analysis. IRs were grouped according to the affected part of the graft (endothelial, stromal, epithelial, and mixed). We analysed the dynamics of recovery and the clinical outcomes. RESULTS: We identified a total of 319 patients with IR. Twenty-seven of those were lost to follow-up and were excluded from further analysis. Of the IRs, 89% affected the endothelium. Endothelial IR resulted more frequently in a considerable loss of endothelial cell density than other forms of IR. Stromal IR showed a lower relapse rate and a better visual recovery than other types of IR and resulted less often in a failure of the graft. CONCLUSIONS: We herein report comprehensive data about the prognosis regarding functional recovery after different types of IR following keratoplasty. Our data underline that timely recognition and correct classification of IR are important because they determine the clinical course and prognosis.

Long-Term Outcomes of Excimer Laser-Assisted Penetrating Keratoplasty Using a Commercially Available Laser System - A Retrospective Case Series.

BACKGROUND: Favorable functional outcomes have been reported after excimer laser-assisted penetrating keratoplasty (EXL PKP). But this technique has not been widely adopted, and there are reports on EXL PKP from only a very limited number of institutions. Some of these results refer to operations carried out with laser systems that are not commercially available. In this retrospective case series, we report the long-term outcome of EXL PKP using the Schwind Amaris 500E laser system. MATERIAL AND METHODS: This retrospective consecutive case series included 30 eyes of 29 patients who had undergone EXL PKP between 2010 and 2013. Primary outcome measures were topographic astigmatism and visual acuity. Secondary outcome measures were the rates of graft rejection and graft failure, and the rate of grafts with an endothelial cell density below 500 cells/mm2. Survival analyses were carried out for the following endpoints: visual acuity, rate of graft rejection, and rate of grafts with endothelial cell densities higher than 500 cells/mm2. RESULTS: The median interquartile range (IQR) duration of follow-up was 45 (36) months. The indications for PKP were keratoconus (n = 21), corneal scarring (n = 6), Fuchs endothelial dystrophy (n = 1), and corneal dystrophy other than Fuchs endothelial dystrophy (n = 2). The median (IQR) topographic astigmatism at the end of the follow-up period was 5.3 (2.9) D. Forty-five months after surgery, 73% of all eyes had a visual acuity better than 0.3 LogMAR. The rate of graft rejection after 45 months of follow-up was 32%. All eyes maintained endothelial cell densities higher than 500 cells/mm2. There was no graft failure. CONCLUSIONS: EXL PKP is a safe and effective surgical procedure. No general conclusions can be drawn on the refractive outcome of EXL PKP. Potential advantages, such as a higher degree of graft-host congruity, that could possibly improve the refractive outcome should be weighed against the higher costs of EXL PKP.

Web-based gene expression analysis-paving the way to decode healthy and diseased ocular tissue.

BACKGROUND: Gene expression analysis using RNA sequencing has helped to improve the understanding of many diseases. Databases, such as the Gene Expression Omnibus database of the National Center for Biotechnology Information provide RNA sequencing raw data from various diseased tissue types but their analysis requires advanced bioinformatics skills. Therefore, specific ocular databases provide the transcriptional profiles of different ocular tissues and in addition enable intuitive web-based data analysis. OBJECTIVE: The aim of this narrative review is to provide an overview of ocular transcriptome databases and to compare them with the Human Eye Transcriptome Atlas newly established in Freiburg. METHODS: PubMed literature search. RESULTS: A total of nine ocular transcriptome databases focusing on different aspects were identified. The iSyTE and Express platforms specialize in gene expression during lens and retinal development in mice, whereas retina.tigem.it, Eye in a Disk, and Spectacle focus on selected ocular tissues such as the retina. Spectacle, UCSC Cell Browser and Single Cell Portal allow intuitive exploration of single cell RNA sequencing data derived from retinal, choroid, cornea, iris, trabecular meshwork and sclera specimens. The microarray profiles of a variety of healthy ocular tissues are included in the Ocular Tissue Database. The Human Eye Transcriptome Atlas provides the largest collection of different ocular tissue types, contains the highest number of ocular diseases and is characterized by a high level of quality achieved by methodological consistency. CONCLUSION: Ocular transcriptome databases provide comprehensive and intuitive insights into the transcriptional profiles of a variety of healthy and diseased ocular tissues. Thus, they improve our understanding of the underlying molecular mediators, support hypothesis generation and help in the search for new diagnostic and therapeutic targets for various ocular diseases.

Transcriptional profiling specifies the pathogen-specific human host response to infectious keratitis.

Purpose: Corneal infections are a leading cause of visual impairment and blindness worldwide. Here we applied high-resolution transcriptomic profiling to assess the general and pathogen-specific molecular and cellular mechanisms during human corneal infection. Methods: Clinical diagnoses of herpes simplex virus (HSV) (n=5) and bacterial/fungal (n=5) keratitis were confirmed by histology. Healthy corneas (n=7) and keratoconus (n=4) samples served as controls. Formalin-fixed, paraffin-embedded (FFPE) human corneal specimens were analyzed using the 3' RNA sequencing method Massive Analysis of cDNA Ends (MACE RNA-seq). The cellular host response was investigated using comprehensive bioinformatic deconvolution (xCell and CYBERSORTx) analyses and by integration with published single cell RNA-seq data of the human cornea. Results: Our analysis identified 216 and 561 genes, that were specifically overexpressed in viral or bacterial/fungal keratitis, respectively, and allowed to distinguish the two etiologies. The virus-specific host response was driven by adaptive immunity and associated molecular signaling pathways, whereas the bacterial/fungal-specific host response mainly involved innate immunity signaling pathways and cell types. We identified several genes and pathways involved in the host response to infectious keratitis, including CXCL9, CXCR3, and MMP9 for viral, and S100A8/A9, MMP9, and the IL17 pathway for bacterial/fungal keratitis. Conclusions: High-resolution molecular profiling provides new insights into the human corneal host response to viral and bacterial/fungal infection. Pathogen-specific molecular profiles may provide the foundation for novel diagnostic biomarker and therapeutic approaches that target inflammation-induced damage to corneal host cells with the goal to improve the outcome of infectious keratitis.

Transcriptional Profiling Provides New Insights into Organ Culture-Induced Changes in Human Donor Corneas.

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.

The Human Eye Transcriptome Atlas: A searchable comparative transcriptome database for healthy and diseased human eye tissue.

The applications of deep sequencing technologies in life science research and clinical diagnostics have increased rapidly over the last decade. Although fast algorithms for data processing exist, intuitive, portable solutions for data analysis are still rare. For this purpose, we developed a web-based transcriptome database, which provides a platform-independent, intuitive solution to easily explore and compare ocular gene expression of 100 diseased and healthy human tissue samples from 15 different tissue types collected at the Eye Center of the University of Freiburg. To ensure comparability of expression between different tissues, reads were normalized across all 100 samples. Differentially expressed genes were calculated between each tissue type to determine tissue-specific genes. Unsupervised analysis of all 100 samples revealed an accurate clustering according to different tissue types and a high tissue specificity by analyzing known tissue-specific marker genes. Bioinformatic cell type deconvolution using xCell provided detailed insights into the cellular profiles of each tissue type. Several new tissue-specific marker genes were identified. These genes were involved in tissue- or disease-specific processes, such as myelination for the optic nerve, visual perception for retina, keratinocyte differentiation for conjunctival carcinoma, as well as endothelial cell migration for choroidal neovascularization membranes. The results are accessible at the Human Eye Transcriptome Atlas website at https://www.eye-transcriptome.com. In summary, this searchable transcriptome database enables easy exploration of ocular gene expression in healthy and diseased human ocular tissues without bioinformatics expertise. Thus, it provides rapid access to detailed insights into the molecular mechanisms of various ocular tissues and diseases, as well as the rapid retrieval of potential new diagnostic and therapeutic targets.

[Web-based gene expression analysis-paving the way to decode healthy and diseased ocular tissue]. / Webbasierte Genexpressionsanalysen ­ auf dem Weg zur molekularen Entschlüsselung gesunder und erkrankter Augengewebe.

BACKGROUND: Gene expression analysis using RNA sequencing has helped to improve the understanding of many diseases. Databases, such as the Gene Expression Omnibus database of the National Center for Biotechnology Information provide RNA sequencing raw data from various diseased tissue types but their analysis requires advanced bioinformatics skills. Therefore, specific ocular databases provide the transcriptional profiles of different ocular tissues and in addition enable intuitive web-based data analysis. OBJECTIVE: The aim of this narrative review is to provide an overview of ocular transcriptome databases and to compare them with the Human Eye Transcriptome Atlas newly established in Freiburg. METHODS: PubMed literature search. RESULTS: A total of nine ocular transcriptome databases focusing on different aspects were identified. The iSyTE and Express platforms specialize in gene expression during lens and retinal development in mice, whereas retina.tigem.it, Eye in a Disk, and Spectacle focus on selected ocular tissues such as the retina. Spectacle, UCSC Cell Browser and Single Cell Portal allow intuitive exploration of single cell RNA sequencing data derived from retinal, choroid, cornea, iris, trabecular meshwork and sclera specimens. The microarray profiles of a variety of healthy ocular tissues are included in the Ocular Tissue Database. The Human Eye Transcriptome Atlas provides the largest collection of different ocular tissue types, contains the highest number of ocular diseases and is characterized by a high level of quality achieved by methodological consistency. CONCLUSION: Ocular transcriptome databases provide comprehensive and intuitive insights into the transcriptional profiles of a variety of healthy and diseased ocular tissues. Thus, they improve our understanding of the underlying molecular mediators, support hypothesis generation and help in the search for new diagnostic and therapeutic targets for various ocular diseases.

Time- and Stimulus-Dependent Characteristics of Innate Immune Cells in Organ-Cultured Human Corneal Tissue.

PURPOSE: The pattern of immune cells infiltrating the corneal stroma has been extensively studied in mice, but data on human tissue have been far less elaborate. To further characterize the number and differentiation state of resident immune cells in organ-cultured human corneal tissue, we employed a comprehensive bioinformatic deconvolution (xCell) of bulk RNA-sequencing (RNA-seq) data, immunohistochemistry (IHC), and flow cytometry (FC). METHODS: A transcriptome-based analysis of immune cell types in human corneal samples was performed. The results were validated by IHC, focusing on the identification of pro-inflammatory (M1) and regulatory (M2) macrophages. A protocol was established to identify these 2 different macrophage populations in human corneal tissue by means of FC. Subsequently, corneal samples in organ culture were differentially stimulated by IL-10, IL-4 & IL-13, or LPS and macrophage populations were evaluated regarding their response to these stimuli. Furthermore, cell survival was analyzed in correlation with time in organ culture. RESULTS: xCell-based mathematical deconvolution of bulk RNA-seq data revealed the presence of CD8 T cells, Th17 cells, dendritic cells, and macrophages as the predominant immune cell types in organ-cultured human corneal tissue. Furthermore, RNA-seq allowed the detection of different macrophage marker genes in corneal samples, including PTPRC (CD45), ITGAM (CD11b), CD14, and CD74. Our RNA-seq data showed no evidence of a relevant presence of monocytes in human corneal tissue. The presence of different macrophage subtypes was confirmed by IHC. The disintegration and subsequent FC analysis of human corneal samples showed the presence of both M1 (HLA-DR+, CD282+, CD86+, and CD284+) and M2 (CD163+ and CD206+) macrophage subtypes. Furthermore, we found that the total number of macrophages in corneal samples decreased more than the total cell count with increasing tissue culture time. Treatment with IL-10 led to higher total cell counts per cornea and to an increased expression of the M2 marker CD163 (p < 0.05) while expression levels of various M1 macrophage markers were not significantly reduced by interleukin treatment. CONCLUSIONS: Regarding different macrophage populations, untreated human corneas showed more M1 than M2 macrophages. With increasing organ culture time, these macrophages decreased. In terms of cell dynamics, adding interleukins to the organ culture medium influenced the phenotype of macrophages within the cornea as detected by FC. Modifying the immunomodulatory properties of human grafts appears a promising approach to further reduce the risk of graft rejection in patients. In this context, treatment with interleukins was more effective in upregulating M2 macrophages than in suppressing M1 macrophages in corneal tissue.

Viral S protein histochemistry reveals few potential SARS-CoV-2 entry sites in human ocular tissues.

Despite the reported low expression of the primary SARS-CoV-2 receptor ACE2 in distinct ocular tissues, some clinical evidence suggests that SARS-CoV-2 can infect the eye. In this study, we explored potential entry sites for SARS-CoV-2 by viral S protein histochemistry on various ocular tissues and compared the staining patterns with RNA and protein expression of TMPRSS2 and ACE2. Potential viral entry sites were investigated by histochemistry using tagged recombinant viral S protein on 52 ocular tissue samples including specimens of the cornea, conjunctiva, lid margin, lacrimal gland tissue, retina, choroid, and RPE. In addition, ACE2 and TMPRSS2 immunohistochemistry were performed on the same ocular tissue, each with distinct antibodies binding to different epitopes. Lung tissue samples were used as positive controls. Finally, bulk RNA sequencing (RNA-Seq) was used to determine the expression of ACE2 and its auxiliary factors in the tissues mentioned above. S protein histochemistry revealed a positive staining in lung tissue but absent staining in the cornea, the conjunctiva, eye lid samples, the lacrimal glands, the retina and the optic nerve which was supported by hardly any immunoreactivity for ACE2 and TMPRSS2 and scarce ACE2 and TMPRSS2 RNA expression. Negligible staining with antibodies targeting ACE2 or TMPRSS2 was seen in the main and accessory lacrimal glands. In contrast, ocular staining (S protein, ACE2, TMPRSS2) was distinctly present in pigmented cells of the RPE and choroid, as well as in the ciliary body and the iris stroma. S protein histochemistry revealed hardly any SARS-CoV-2 entry sites in all ocular tissues examined. Similarly, no significant ACE2 or TMPRSS2 expression was found in extra- and intraocular tissue. While this study suggest a rather low risk of ocular infection with SARS-CoV-2, it should be noted, that potential viral entry sites may increase in response to inflammation or in certain disease states.

Hyperosmolar Eye Drops for Diurnal Corneal Edema in Fuchs' Endothelial Dystrophy: A Double-Masked, Randomized Controlled Trial.

PURPOSE: The Eye Drops for Early Morning-Associated Swelling (EDEMAS) trial assessed the efficacy of hyperosmolar eye drops on corneal edema resolution. DESIGN: Double-masked, randomized controlled trial of hyperosmolar eye drops. PARTICIPANTS: Participants with Fuchs' dystrophy scheduled for Descemet membrane endothelial keratoplasty. METHODS: One eye was randomized to hyperosmolar eye drops (treatment); the fellow eye was randomized to artificial tears (placebo). After baseline examination in the afternoon, corneas were examined using Scheimpflug tomography after eye opening in the morning. Participants received eye drops twice. Imaging was repeated every 30 minutes up to 4 hours. MAIN OUTCOME MEASURES: Decrease in central corneal thickness 1 hour after eye opening (primary end point), corneal thickness, subjective visual function, glare, visual acuity, and adverse events (AEs) (secondary end points). RESULTS: A total of 68 participants received the allocated intervention (59 eyes received treatment; 55 eyes received placebo). All eyes had stromal edema; none had epithelial edema. Corneal thickness was 626 µm in the treatment arm and 622 µm in the placebo arm after eye opening, indicating an early morning edema compared with baseline of +21 µm and +24 µm, respectively. Decrease in corneal thickness after 1 hour was -10.5 µm in the treatment arm (95% confidence interval [CI], -12.8 to -8.2) and -11.2 µm (95% CI, -13.6 to -8.9) in the placebo arm (between-arm difference, 0.7 µm, 95% CI, -2.0 to 3.5; P = 0.59), indicating no clinically relevant effect of hyperosmolar eye drops on early morning corneal edema. Results were not compatible with a relevant treatment effect on corneal thickness, visual acuity, and glare over the entire course of the study. Increase in subjective visual function was less rapid in the treatment arm than in the placebo arm. Adverse events, most commonly burning after eye drop application, were more common with treatment (30 eyes) than placebo (1 eye; risk difference, 49 percentage points; 95% CI, 36-62). CONCLUSIONS: In this double-masked, randomized controlled trial, resolution of early morning stromal edema was not accelerated by hyperosmolar eye drops, which more frequently caused AEs. These results are not compatible with a clinically relevant effect of hyperosmolar eye drops and do not support their routine use.

Rotational alignment of corneal endothelial grafts and risk of graft detachment after Descemet membrane endothelial keratoplasty: a double-masked pseudo-randomized study.

PURPOSE: The posterior cornea is rotationally asymmetric, and Descemet membrane endothelial keratoplasty (DMEK) grafts preferentially scroll vertically. This prospective study assessed whether graft attachment after DMEK differed depending on the rotational alignment of the donor graft in the recipient eye. METHODS: Pseudo-randomization and blinding of the graft orientation in the recipient's eye were possible by procedural separation: (1) The eye bank recorded the position of an orientation marker in the donor cornea; (2) the surgeon preparing the DMEK graft recorded an upside-down marker relative to the eye bank marker; and (3) the surgeon assessed the position of the upside-down marker in the recipient after DMEK. Surgeons were masked towards the eye bank marker. Using mixed-effects models, we assessed graft attachment relative to the rotational alignment of the donor graft. RESULTS: Postoperatively, the graft was not fully attached in 59 of 179 eyes (33%). A second air fill (rebubbling) was performed in 11%. The graft axis was in line with the recipient cornea axis in 40%, oblique in 28% and orthogonal in 32%. We did not detect an elevated risk of incomplete attachment (odds ratio [OR], 1.16; 95% CI, 0.61-2.20), risk of rebubbling (OR, 1.25; 95% CI, 0.47-3.31) or larger areas of graft detachment in non-aligned grafts compared to aligned grafts. CONCLUSION: Rotational alignment was not strongly associated with the risk of incomplete graft attachment, although modestly elevated risks cannot be ruled out. Efforts are needed to reduce the need for rebubbling after DMEK and to identify modifiable risk factors for graft detachment.

Predicting Edema Resolution After Descemet Membrane Endothelial Keratoplasty for Fuchs Dystrophy Using Scheimpflug Tomography.

IMPORTANCE: Predicting the extent of corneal edema resolution after Descemet membrane endothelial keratoplasty (DMEK) may help in preoperative decision-making by identifying patients who may benefit from restoring endothelial function. OBJECTIVE: To develop and validate a predictive model for edema resolution after DMEK using Scheimpflug tomographic imaging. DESIGN, SETTING, AND PARTICIPANTS: Two prospective studies recruited participants with advanced Fuchs dystrophy at a university-based tertiary referral center between July 1, 2017, and August 31, 2019. Analyses were designed in November 2019 and completed on June 30, 2020. Development of a predictive model using linear least absolute shrinkage and selection operator regression was conducted in a derivation cohort (100 eyes). Overall performance, discrimination, and calibration were tested in the separate validation cohort (32 eyes). EXPOSURES: Preoperative Scheimpflug parameters and patient-reported visual disability were considered as potential predictors of edema resolution: (1) tomographic features (irregularity of lines of equal corneal thickness, displacement of the thinnest point of corneal thickness from the inferior-temporal quadrant, and absolute amount of focal posterior corneal depression), (2) standardized anterior and posterior corneal backscatter, (3) preoperative central corneal thickness, and (4) Fuchs dystrophy-specific visual disability. MAIN OUTCOMES AND MEASURES: Decrease in central corneal thickness after DMEK indicative of edema resolution. RESULTS: Of the 88 patients included in the analysis, 54 were women (61%); median age was 68 years (interquartile range [IQR], 59-76 years). A median of 13 months after DMEK (IQR, 9-16 months), median corneal thickness was 77 µm lower (IQR, 51-94 µm) in the derivation cohort and 75 µm lower in the validation cohort (IQR, 54-96 µm) than before surgery. Per 10-µm edema resolution, eyes gained 0.66 Early Treatment Diabetic Retinopathy Study letters (95% CI, 0.09-1.23) in best-corrected visual acuity. Three tomographic features were present in 68 of 100 eyes (68%) in the derivation cohort and in 18 of 32 eyes (56%) in the validation cohort before DMEK and in only 1 of 132 eyes (1%) after DMEK. To predict edema resolution after DMEK based on preoperative assessment, 5 variables were selected by the statistical learning algorithm: nonparallel isopachs, focal posterior depression, anterior and posterior corneal backscatter, and central corneal thickness. In the separate validation cohort, the model showed high overall performance, discrimination, and calibration. CONCLUSIONS AND RELEVANCE: These post hoc analyses of prospective cohorts support a model for use in the prediction of edema resolution after DMEK using Scheimpflug measurement to identify patients benefitting most from DMEK.

[Keratoplasty in Germany: Systematic Analysis of the Quality Reports of German Hospitals between 2006 and 2017]. / Die Keratoplastik in Deutschland: systematische Auswertung der Krankenhausqualitätsberichte der Jahre 2006 bis 2017.

BACKGROUND: Keratoplasty is considered the most frequently performed type of transplantation in humans. Traditionally, penetrating keratoplasty has been the most common procedure. However, over the last 15 years, the importance of posterior lamellar keratoplasty has increased for the treatment of Fuchs endothelial dystrophy and bullous keratopathy. In Germany, based on national surveys, it was suggested that there was a trend towards lamellar keratoplasty. OBJECTIVE: The main objective of this study was to determine whether the proportion of lamellar keratoplasties carried out in Germany between 2006 and 2017 had increased. Furthermore, the number of keratoplasties carried out as HLA-matched (HLA: human leukocyte antigen) keratoplasties should be calculated. MATERIALS AND METHODS: The numbers of all keratoplasties carried out as lamellar/penetrating and HLA-matched keratoplasties was extracted from the hospital quality reports published between 2006 and 2017. Descriptive statistical analysis was carried out in R (www.r-project.org). RESULTS: Between 2006 and 2017, 43,021 keratoplasties were carried out in Germany. The number of keratoplasties increased from 2,849 (2006) to 8,231 (2017). The number of penetrating keratoplasties remained stable. The proportion of lamellar keratoplasties increased from 6.5% (2006) to 61.4% (2017). The proportion of HLA-matched keratoplasties was below 20% and declined between 2010 and 2017 (2010: 19.7%; 2017: 9.8%). DISCUSSION: In Germany, posterior lamellar keratoplasty has become increasingly important. Since 2014, the number of lamellar keratoplasties has exceeded the number of penetrating keratoplasties. However, the number of penetrating keratoplasties remained stable between 2006 and 2017 and still plays an important role in the management of patients with predominantly stromal or corneal defects affecting all layers. The decreasing number of HLA-matched keratoplasties is most likely due to the lack of clear evidence of a significant reduction in the rejection rates in cases of normal risk keratoplasty.