Next-Generation Sequencing of the Human Aqueous Humour Microbiome.

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.

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.

Quality Control in the Corneal Bank with Artificial Intelligence: Comparison of a New Deep Learning-based Approach with Conventional Endothelial Cell Counting by the "Rhine-Tec Endothelial Analysis System". / Qualitätskontrolle in der Hornhautbank mit künstlicher Intelligenz: Vergleich eines neuen Deep-Learning-basierten Ansatzes mit der konventionellen Endothelzelldichtenbestimmung durch das "Rhine-Tec Endothelial Analysis System".

Endothelial cell density (ECD) is a crucial parameter for the release of corneal grafts for transplantation. The Lions Eye Bank of Baden-Württemberg uses the "Rhine-Tec Endothelial Analysis System" for ECD quantification, which is based on a fixed counting frame method considering only a small sample of 15 to 40 endothelial cells. The measurement result therefore depends on the frame placement and manual correction of the cells counted within the frame. To increase the sample size and create higher objectivity, we developed a new method based on "deep learning" that automatically detects all visible endothelial cells in the image. This study aims to compare this new method with the conventional Rhine-Tec system. 9375 archived phase-contrast microscopic images of consecutive grafts from the Lions Eye Bank were evaluated with the deep learning method and compared with the corresponding archived analyses of the Rhine-Tec system. Means, Bland-Altman and correlation analyses were compared. Comparable results were obtained for both methods. The mean difference between the Rhine-Tec system and the deep learning method was only - 23 cells/mm2 (95% confidence interval - 29 to - 17). There was a statistically significant positive correlation between the two methods, with a correlation coefficient of 0.748. What was striking in the Bland-Altman analysis were clustered deviations in the cell density range between 2000 and 2500 cells/mm2 - with higher values in the Rhine-Tec system. The comparable results for cell density measurement values underline the validity of the deep learning-based method. The deviations around the formal threshold for graft release of 2000 cells/mm2 are most likely explained by the higher objectivity of the deep learning method and the fact that measurement frames and manual corrections were specifically selected to reach the formal threshold of 2000 cells/mm2 when the full area endothelial quality was good. This full area assessment of the graft endothelium cannot currently be replaced by deep learning methods and remains the most important basis for graft release for keratoplasty.

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.

[Global ophthalmology : Update]. / Globale Ophthalmologie : Aktueller Stand.

The aim of global ophthalmology is to maximize vision, ocular health and functional ability, thereby contributing to overall health and well-being, social inclusion and quality of life of every individual worldwide. Currently, an estimated 1.1 billion people live with visual impairment, 90% of which can be prevented or cured through largely cost-effective interventions. At the same time, 90% of people affected live in regions with insufficient eye health coverage. This challenge drove the World Health Organization (WHO) and a group of nongovernmental organizations to launch "VISION 2020: the Right to Sight", a global campaign which recently concluded after 20 years. The achievements, challenges and lessons learned were identified and incorporated into the current campaign "2030 IN SIGHT".

[Bacterial Conjunctivitis: Current Aspects of Diagnosis and Therapy]. / Bakterielle Konjunktivitis: Aktuelle Aspekte der Diagnostik und Therapie.

Bacterial conjunctivitis is a leading cause of infectious conjunctivitis in children and second most common cause in adults. Although often self-limiting, it can lead to complications like corneal scarring and systemic infections in high-risk groups including newborns and immunocompromised patients. Thus, prompt diagnosis and treatment are essential for these vulnerable populations. Common bacterial causes are Staphylococcus aureus and Streptococcus pneumoniae in adults and Haemophilus influenzae and Moraxella catarrhalis in children. Clinical features alone do not reliably identify the causative pathogen. Microbiological testing is necessary for persistent or severe cases. Topical antibiotics like azithromycin or fluorochinolones are usually prescribed. However, gonococcal and chlamydial conjunctivitis warrant systemic antibiotics due to their potential for severe complications. Increasing antibiotic resistance might even necessitate tailored therapy based on antibiotic susceptibility profiles. Screening and treating pregnant women is an effective prevention strategy by reducing perinatal transmission (especially of gonococcal and chlamydial infections). In summary, while often self-limiting, potential complications and rising antibiotic resistance underscore the importance of timely diagnosis and treatment of bacterial conjunctivitis. Preventive measures including maternal screening are crucial public health initiatives to curb the risks associated with this common eye infection.

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.

P43-A106†Eyebank stripped vs. Surgeon stripped tissue for DMEK.

During the recent years Descemet membrane endothelial keratoplsty (DMEK) has replaced penetrating keratoplasty and more or less Descemet stripping automated endothelial keraoplasty (DSAEK) as the goldstandard for the treatment of endothlial corneal diseases. Following DMEK the clinical recovery is faster and patients reach higher visual acuities with a lower risk for graft rejection. However, the technique of preparing the graft for DMEK is more demanding and less standardised than the perparation of a DSAEK graft. Therefore, the preparation may take longer and risk of a preparation failure seems higher. For this reason surgeons look for prestripped tissue for DMEK to avoid the potential inconveniences with the graft preparation. However, prestripped tissue might not always be advantageous as the graft might loose endothelial cells during storage and transportation and the surgeon is not aware of the specific properties of the graft. Advantages and disadvantages of eyebank stripped and surgeon stripped tissue will be discussed.

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.

Characterization of the Immediate and Delayed Biomechanical Response to UV-A Crosslinking of Human Corneas.

PURPOSE: Keratoconus leads to visual deterioration due to irregular astigmatism and corneal thinning. Riboflavin-based corneal UV-A crosslinking (CXL) induces novel intramolecular and intermolecular links resulting in corneal tissue stiffening, thereby halting disease progression. The purpose of this study was to analyze the immediate and delayed biomechanical responses of human donor corneas to CXL. METHODS: CXL was performed according to the Dresden protocol to corneas not suitable for transplantation. Biomechanical properties were subsequently monitored by measuring the Young modulus using nanoindentation. The immediate tissue response was determined after 0, 1, 15, and 30 minutes of irradiation. Delayed biomechanical effects were investigated with follow-up measurements immediately and 1, 3, and 7 days after CXL. RESULTS: Young's modulus indicated a linear trend in direct response to increasing irradiation times (mean values: total 61.31 kPa [SD 25.53], 0 minutes 48.82 kPa [SD 19.73], 1 minute 53.44 kPa [SD 25.95], 15 minutes 63.56 kPa [SD 20.99], and 30 minutes 76.76 kPa [SD 24.92]). The linear mixed model for the elastic response of corneal tissue was 49.82 kPa + (0.91 kPa/min × time [minutes]); P < 0.001. The follow-up measurements showed no significant delayed changes in the Young modulus (mean values: total 55,28 kPa [SD 15.95], immediately after CXL 56,83 kPa [SD 18.74], day 1 50.28 kPa [SD 14.15], day 3 57.08 kPa [SD 14.98], and day 7 56.83 kPa [SD 15.07]). CONCLUSIONS: This study suggests a linear increase of corneal Young modulus as a function of CXL timing. No significant short-term delayed biomechanical changes posttreatment were observed.

Descemet Membrane Endothelial Keratoplasty in Eyes with an Artificial Iris.

The purpose of this study is to report the outcome of Descemet membrane endothelial keratoplasty (DMEK) in three eyes with a complex anterior segment and an artificial iris. A retrospective chart review of three cases was performed and clinically meaningful patient characteristics, clinical events, and therapeutic interventions were outlined. A literature search was performed and the clinical course of the three cases was discussed in the context of the published literature. DMEK in the presence of an artificial iris did not match the clinical results of DMEK in uncomplicated eyes. All three eyes experienced major complications, such as failure to achieve graft adherence, early graft failure, or an immune reaction. The indication for DMEK in complex anterior segments with an artificial iris should be made with the awareness of multiple possible complications and the potentially poor prognosis of the procedure.

Developing and validating a questionnaire to assess the symptoms of blepharitis accompanied by dry eye disease.

PURPOSE: To propose additional items for established dry eye disease (DED) instruments that cover blepharitis-specific signs and symptoms and to determine the association between the clinical findings and subjective complaints. METHODS: Thirty-one patients with blepharitis and DED were prospectively included in the pretest period for selecting suitable questions. In the main phase of the study, the selected questions were then tested on 68 patients with blepharitis and DED and 20 controls without blepharitis or DED. Pearson's coefficient of correlation was calculated between the blepharitis-specific questions, tear break-up time (TBUT), the Schirmer test score, and the ocular surface disease index (OSDI) score; and the similarity between the blepharitis-specific questions, OSDI questions, and objective parameters for DED was assessed via hierarchical clustering. Furthermore, the discriminatory power of the blepharitis-specific questions was investigated with the receiver operating characteristic (ROC) curve. RESULTS: The additional question about heavy eyelids revealed a significant correlation with the OSDI score (r = 0.45, p < 0.001) and Schirmer score (r = - 0.32, p = 0.006). Cluster analysis demonstrated the similarity between the question about heavy eyelids and TBUT. In addition, the OSDI questionnaire had the highest discriminatory power in ROC analysis, and the OSDI score significantly correlated with the specific questions about eyelids sticking together (r = 0.47, p < 0.0001) and watery or teary eyes (r = 0.34, p = 0.003). CONCLUSIONS: The blepharitis-specific additional questions were closely associated with objective parameters for DED. The question about heavy eyelids might be well suited for recording the symptoms of hyposecretory and hyperevaporative dry eye with blepharitis.

[Keratoconus: biomechanics ex vivo]. / Keratokonus: Biomechanik ex vivo.

BACKGROUND: Keratoconus is associated with an impairment in corneal biomechanics. Using nanoindentation, spatially resolved measurement of biomechanical properties can be performed on corneal tissue. The aim of this study is to assess the biomechanical properties of corneas with keratoconus in comparison to healthy controls. METHODS: 17 corneas with keratoconus and 10 healthy corneas unsuitable for transplantation were included in the study. After explantation, corneas were kept in culture medium containing 15% dextran for at least 24 h. Nanoindentation was then performed to a depth of 25 µm at a force increase of 300 µN/min. RESULTS: A total of 2328 individual indentations were performed for this study. In the keratoconus group; the mean modulus of elasticity was 23.2 kPa (± 15.0 kPa) for a total of 1802 indentations. In the control group, the mean modulus of elasticity was 48.7 kPa (± 20.5 kPa) with a total of 526 indentations. The Wilcoxon test showed that the differences were statistically significant. CONCLUSION: Using nanoindentation, a significantly lower elastic modulus was found in corneas with keratoconus compared to corneas without keratoconus. Further studies are needed to gain a better understanding of how keratoconus affects corneal biomechanics.

[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.

Current Practice in the Treatment of Epithelial and Melanocytic Tumours with Interferon-α2b: A Survey of Tertiary Eye Centres in Germany.

PURPOSE: To evaluate the standard of care, in particular the use of topical or subconjunctival interferon-α2b, in treating ocular surface squamous neoplasia or melanocytic tumours in tertiary eye centres in Germany. METHODS: A survey containing 14 questions was sent to 43 tertiary eye centres in Germany. The questions addressed the surgical and medical management of ocular surface squamous neoplasia and melanocytic tumours (primary acquired melanosis and malignant melanoma), as well as the clinical experiences and difficulties in prescribing off-label interferon-α2b eye drops and subconjunctival injections. RESULTS: Twenty-four tertiary eye centres responded to the survey. Eighty-three percent of centres had used interferon-α2b in their clinical practice and 25% prescribed it as the first-line cytostatic agent following surgical excision of ocular surface squamous neoplasia, while 10% would do so for melanocytic tumours. Correspondingly, the majority of respondents selected mitomycin C as their first-line agent. Side effects were uncommon with topical interferon-α2b eye drops but were more frequently reported after subconjunctival interferon-α2b injections. In total, eight centres had experience with interferon-α2b injections. The most significant obstacles perceived by ophthalmologists when prescribing interferon-α2b were its high cost and the reimbursement thereof. CONCLUSION: Off-label mitomycin C was the preferred adjuvant therapy for epithelial and melanocytic tumours, with interferon-α2b being the standard second-line option. Interferon-α2b has predominantly been used to treat ocular surface squamous neoplasia and, to a lesser extent, melanocytic tumours at German tertiary eye centres. Following its market withdrawal, supply shortages of interferon-α2b are likely to have a profound impact on patient care and their quality of life.

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.