UV light-mediated corneal crosslinking as (lymph)angioregressive pretreatment to promote graft survival after subsequent high-risk corneal transplantation (CrossCornealVision): protocol for a multicenter, randomized controlled trial.

BACKGROUND: Good vision highly depends on the transparency of the cornea, which is the "windscreen" of the eye. In fact, corneal blindness due to transparency loss is the second most common cause of blindness worldwide, and corneal transplantation is the main cure. Importantly, the cornea is normally avascular but can secondarily be invaded by pathological (blood and lymphatic) vessels due to severe inflammation, and the survival prognosis of a corneal graft mainly depends on the preoperative vascular condition of the recipient's cornea. Whereas transplants placed into avascular recipient beds enjoy long-term survival rates of > 90%, survival rates significantly decrease in pathologically pre-vascularized, so-called high-risk recipients, which account for around 10% of all performed transplants in Germany and > 75% in lower and middle-income countries worldwide. METHODS: This parallel-grouped, open-randomized, multicenter, prospective controlled exploratory investigator-initiated trial (IIT) intends to improve graft survival by preconditioning pathologically vascularized recipient corneas by (lymph)angioregressive treatment before high-risk corneal transplantation. For this purpose, corneal crosslinking (CXL) will be used, which has been shown to potently regress corneal blood and lymphatic vessels. Prior to transplantation, patients will be randomized into 2 groups: (1) CXL (intervention) or (2) no pretreatment (control). CXL will be repeated once if insufficient reduction of corneal neovascularization should be observed. All patients (both groups) will then undergo corneal transplantation. In the intervention group, remaining blood vessels will be additionally regressed using fine needle diathermy (on the day of transplantation). Afterwards, the incidence of graft rejection episodes will be evaluated for 24 months (primary endpoint). Overall graft survival, as well as regression of corneal vessels and/or recurrence, among other factors, will be analyzed (secondary endpoints). DISCUSSION: Based on preclinical and early pilot clinical evidence, we want to test the novel concept of temporary (lymph)angioregressive pretreatment of high-risk eyes by CXL to promote subsequent corneal graft survival. So far, there is no evidence-based approach to reliably improve graft survival in the high-risk corneal transplantation setting available in clinical routine. If successful, this approach will be the first to promote graft survival in high-risk transplants. It will significantly improve vision and quality of life in patients suffering from corneal blindness. TRIAL REGISTRATION: ClinicalTrials.gov NCT05870566. Registered on 22 May 2023.

ZEISS PLEX Elite 9000 Widefield Optical Coherence Tomography Angiography as Screening Method for Early Detection of Retinal Hemangioblastomas in von Hippel-Lindau Disease.

Purpose: To evaluate early detection of retinal hemangioblastomas (RHs) in von Hippel-Lindau disease (VHLD) with widefield optical coherence tomography angiography (wOCTA) compared to the standard of care in ophthalmologic VHLD screening in a routine clinical setting. Methods: We conducted prospective comparisons of three screening methods: wOCTA, standard ophthalmoscopy, and fluorescein angiography (FA), which was performed only in uncertain cases. The numbers of detected RHs were compared among the three screening methods. The underlying causes for the lack of detection were investigated. Results: In 91 eyes (48 patients), 67 RHs were observed (mean, 0.74 ± 1.59 RH per eye). FA was performed in eight eyes. Ophthalmoscopy overlooked 25 of the 35 RHs detected by wOCTA (71.4%) due to the background color of the choroid (n = 5), small tumor size (n = 13), masking by a bright fundus reflex (n = 2), and masking by surrounding retinal scars (n = 5). However, wOCTA missed 29 RHs due to peripheral location (43.3%). The overall detection rates were up to 37% on the basis of ophthalmoscopy alone, up to 52% for wOCTA, and 89% for FA. Within the retinal area covered by wOCTA, the detection rates were up to 46.7% for ophthalmoscopy alone, up to 92.1% for wOCTA, and 73.3% for FA. Conclusions: The overall low detection rate of RHs using wOCTA is almost exclusively caused by its inability to visualize the entire peripheral retina. Therefore, in unclear cases, FA is necessary after ophthalmoscopy. Translational Relevance: Within the imageable retinal area, wOCTA shows a high detection rate of RHs and therefore may be suitable to improve screening for RHs in VHLD.

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 five days of supine head positioning (intervention) or to one 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 (co-primary endpoints) two weeks after surgery quantified using a validated neural network for image segmentation on anterior segment optical coherence tomography images; repeat air injection (rebubbling), subjective visual function, and adverse events (secondary endpoints). RESULTS: 86 participants received the allocated intervention (35 eyes intervention, 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 = 0.80). 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 DMEK for Fuchs' dystrophy may not be needed in routine practice.

[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.

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.

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.

Glaucoma Treatment in German Hospitals in 2019. / Glaukombehandlung in deutschen Krankenhäusern 2019.

BACKGROUND: Surgical procedures in ophthalmology are subject to fluctuations in their application and are dependent on new developments, availability, and success rates. In the field of glaucoma surgery in particular, numerous new procedures have been introduced over the last few years. So far, hardly any analyses have been done on the current application of these newer procedures. In this paper, we present the extent to which different glaucoma surgery procedures were used in German hospitals in 2019. METHODS: The quality reports of German hospitals from 2019 were evaluated regarding all glaucoma-specific procedure codes. In particular, laser procedures, "classic" glaucoma procedures, and "modern" procedures such as MIGS (minimally invasive glaucoma surgery) are compared below. RESULTS: In 2019, 49,031 glaucoma procedures were performed in German hospitals. Numerically, cyclodestructive procedures were used most frequently. MIGS accounted for approximately 10% of procedures according to the available data. Among filtering procedures, about 40% were implant-assisted. DISCUSSION AND CONCLUSION: On the one hand, the data analyzed show a mixed expansion of the spectrum with newer procedures such as the MIGS and implants; on the other hand, classic procedures such as cyclodestruction are still used. It can be assumed that further shifts in surgical methods will be seen in the coming years.

Influence of graft vascularization on graft survival following homologous limbo-keratoplasty.

PURPOSE: Limbo-keratoplasty enables visual improvement and limbal stem cell transplantation at the same. During follow-up, most grafts show vascularization of the limbus. However, it is unclear whether vascularization is harmful due to immunologic effects or helpful to nourish the limbal stem cells and is therefore necessary for a clear graft. The aim of our study is to analyze the influence of graft vascularization on graft survival following homologous limbo-keratoplasty. METHODS: In this retrospective study, we assessed all consecutive limbo-keratoplasties performed in our hospital. All eyes with suitable photo-documentation were included and divided into two groups (limbal stem cell deficiency and corneal dystrophy). We categorized the grade of vascularization (0, 1, 2, 3, 3b) and analyzed clear graft survival, recurrence of the underlying disease and the endothelial cell density (ECD) with regard to the reason for the graft. Event rates were estimated with the Kaplan-Meier method. RESULTS: A total of 79 eyes with limbal stem cell deficiency and 15 with corneal dystrophies were analyzed. A high degree of graft vascularization had a tendency for better graft survival in limbal stem cell deficiency, whereas in corneal dystrophies, grafts with no vascularization had preferable outcomes. Recurrence-free graft survival was only seen in grade 1 and 3 vascularization in corneal dystrophies. CONCLUSION: Vascularization of the limbus seems to have an impact on the long-term outcome of limbo-keratoplasty. The effect seems to be favorable in limbal stem cell deficiency and on recurrence rates in corneal dystrophies. However, the latter might be overshadowed by an unfavorable immunologic effect in corneal dystrophies where the baseline immunologic risk profile is commonly more favorable than in limbal stem cell deficiency.

[Early diagnosis of keratoconus]. / Frühdiagnose des Keratokonus.

Keratoconus is morphologically associated with increasing deformation, thinning and scarring of the cornea. This functionally leads to refractive changes and visual deterioration. In the early stages there are often no clear clinical signs in the slit-lamp examination; however, confirming the diagnosis as early as possible is important in order to provide patients with an appropriate treatment. For the early diagnosis of keratoconus, various diagnostic devices have been introduced in recent years and decades. These include keratometry with reflection-based or elevation-based systems and optical coherence tomography. High-frequency ultrasound microscopy and corneal biomechanics can also be used to establish the diagnosis of keratoconus by the measurement of other parameters. The necessity and the available possibilities for early diagnosis of keratoconus are presented in more detail in this article.

[Crosslinking and Keratoconus]. / Crosslinking und Keratokonus.

Keratoconus leads to a progressive protrusion and thinning of the cornea. In order to stop this, corneal crosslinking can be performed if the progression of the disease is proven. Crosslinking according to the "Dresden protocol" includes abrasion of the corneal epithelium, application of riboflavin eye drops and irradiation with UV-A light of an intensity of 3 mW/cm² for 30 minutes. The efficacy has been shown in several prospective randomized studies. One of the more recent developments is accelerated crosslinking, which allows a shorter irradiation time. On the other hand, the possibility of transepithelial crosslinking was presented, which does not require an abrasion of the cornea. This should reduce the occurrence of postoperative pain. The range of indications has also been expanded. Corneal crosslinking is used for post-LASIK keratectasia as well. It is also being considered for use in infectious keratitis. Topographically controlled crosslinking can likewise be used to try to positively influence the refractive power of the cornea. The risks of crosslinking include the occurrence of pain, haze or scarring, endothelial cell damage and, rarely, the occurrence of keratitis.

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.

Genotype-phenotype correlation in von Hippel-Lindau disease.

BACKGROUND/AIMS: Retinal haemangioblastomas (RH) remain a major cause of visual impairment in patients with von Hippel-Lindau (VHL) disease. Identification of genotype-phenotype correlation is an important prerequisite for better management, treatment and prognosis. METHODS: Retrospective, single-centre cohort study of 200 VHL patients. Genetic data and date of onset of RH, central nervous system haemangioblastomas (CNSH), pheochromocytoma/paraganglioma (PPGL), clear cell renal cell carcinoma (ccRCC) and pancreatic neuroendocrine neoplasm (PNEN) were collected. The number and locations of RH were recorded. RESULTS: The first clinical finding occurred at an age of 26 ± 14 years (y) [mean ± SD]. In 91 ± 3% (95% CI 88-94) of the patients, at least one RH occur until the age of 60y. A total of 42 different rare VHL gene variants in 166 patients were detected. A higher age-related incidence of RH, CNSH, ccRCC and PNEN was detected in patients with a truncating variant (TV) compared to patients with a single amino-acid substitution/deletion (AASD) (all p < 0.01), while it is reverse for PPGL (p < 0.01). Patients with a TV showed 0.10 ± 0.15 RH per y during their lifetime compared to 0.05 ± 0.07 in patients with AASD (p < 0.02). The median enucleation/phthisis-free survival time in patients with a TV was 56y (95% CI 50-62) compared to 78y (95% CI 75-81) in patients with AASD (p < 0.02). CONCLUSION: Compared to patients with AASD, patients with a TV develop RH, CNSH, ccRCC and PNEN earlier. They experience a higher number of RH and bear a higher risk of enucleation/phthisis. Thus, patients with a TV might be considered for a more intensive ophthalmological monitoring.

A decellularized human corneal scaffold for anterior corneal surface reconstruction.

Allogenic transplants of the cornea are prone to rejection, especially in repetitive transplantation and in scarred or highly vascularized recipient sites. Patients with these ailments would particularly benefit from the possibility to use non-immunogenic decellularized tissue scaffolds for transplantation, which may be repopulated by host cells in situ or in vitro. So, the aim of this study was to develop a fast and efficient decellularization method for creating a human corneal extracellular matrix scaffold suitable for repopulation with human cells from the corneal limbus. To decellularize human donor corneas, sodium deoxycholate, deoxyribonuclease I, and dextran were assessed to remove cells and nuclei and to control tissue swelling, respectively. We evaluated the decellularization effects on the ultrastructure, optical, mechanical, and biological properties of the human cornea. Scaffold recellularization was studied using primary human limbal epithelial cells, stromal cells, and melanocytes in vitro and a lamellar transplantation approach ex vivo. Our data strongly suggest that this approach allowed the effective removal of cellular and nuclear material in a very short period of time while preserving extracellular matrix proteins, glycosaminoglycans, tissue structure, and optical transmission properties. In vitro recellularization demonstrated good biocompatibility of the decellularized human cornea and ex vivo transplantation revealed complete epithelialization and stromal repopulation from the host tissue. Thus, the generated decellularized human corneal scaffold could be a promising biological material for anterior corneal reconstruction in the treatment of corneal defects.

[Necrotizing scleritis after acanthamoeba keratitis]. / Nekrotisierende Skleritis nach Akanthamöbenkeratitis.

Nodular scleritis and necrotizing scleritis are rare complications of acanthamoeba keratitis. This article presents the case of a 61-year-old female patient who had suffered from persistent keratitis in the right eye for more than 4 months. The patient was initially treated with propamidine isethionate and polyhexamethylene biguanide eye drops. A penetrating limbo-keratoplasty was performed. Examination of the corneal explant showed acanthamoeba cysts. In the following 5 months the sclera showed recurrent abscesses. A total of two thermal cauterizations and three amniotic membrane grafts were carried out. To our knowledge, this is the first case of sclerokeratitis after acanthamoeba keratitis which was treated with a combination of thermal cauterization and amniotic membrane transplantation. Further studies are necessary to investigate this procedure as an alternative to the established cryotherapy.

[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.

Comparison of Current Optical Coherence Tomography Angiography Methods in Imaging Retinal Hemangioblastomas.

Purpose: To compare spectral-domain (SD) and swept-source (SS) optical coherence tomography angiography (OCTA) for imaging retinal capillary hemangioblastomas (RCHs) in von Hippel-Lindau disease (VHLD). Methods: Prospective single-center cross-sectional study. Tumor size (TS) of perfused RCHs was assessed clinically in relation to the optic disc size. For both technologies, SD-OCTA and SS-OCTA, corresponding images with a scan size of 3 × 3 mm2 and 6 × 6 mm2, respectively, were overlaid according to the set of marker positions to determine the TS. Results: From 200 patients with VHLD, 48 patients showed 84 RCHs. SD-OCTA images of 39 RCHs (46.4%) and SS-OCTA images of 48 RCHs (57.2%) were suitable for analysis. The average in OCTA-measured TS of 1.60 ± 2.58 mm2 (range, 0.01-10.43) was congruent to the clinically assessed TS in 81.3% of cases (r = 0.86, P < 0.0001). TS measured in SD-OCTA compared to SS-OCTA showed similar values and a high correlation (all P < 0.0001). Nevertheless, despite the similarities, a slight trend in SS-OCTA was observed whereby with increasing TS, an elevated TS was detected compared to SD-OCTA (3 × 3-mm2 scans: mean difference of 0.03 ± 0.04  mm2, 6 × 6-mm2 scans: 0.08 ± 0.19 mm2). However, within the same imaging technology method, TS values almost did not differ (SD-OCTA: mean difference of 0.01 ± 0.02 mm2, SS-OCTA: 0.001 ± 0.01 mm2). Conclusions: OCTA may serve as an additional tool for diagnosis and monitoring of RCHs. Nevertheless, due to the differences between the technologies, the values cannot be used interchangeably. Translational Relevance: SD-OCTA and SS-OCTA are suitable to detect and monitor RCHs and provide a more detailed assessment about the TS than this is clinically possible.

Analysis of user behavior on the website of a university eye hospital in Germany.

Medical information websites are usually targeted toward patients, physicians, and medical students. Most of the latest studies researched the usability of such websites. However, reports on user numbers and behavior are rare.The goal of our study is to analyze the utility of a website of a large tertiary referral center in ophthalmology in terms of various target audiences (patients, applicants, medical students, referring ophthalmologists).The web access data from our institutional website was assessed with Google Analytics. Data collection started in 2016.From 2016 to 2018, we counted a total of 763,942 page views. The overall number of users dropped from 81,572 to 67,740. This drop's onset correlates with a change in the website structure. All target audience pages received constant traffic from 2016 to 2019, with the patients' and doctors' sites attracting the most traffic. The pages for medical students and job applicants, although not viewed often, revealed a long session duration.Our website is used by all our target audiences. The behavior and the user numbers of each target group differ. Changes to a website's structure can influence the number of users and their behavior. It is not possible to make a direct comparison to other institutions' websites as there are so few similar reports available. By adding more parameters to the analytics profile in a prospective setting, more detailed analyses of user behavior may be possible in the future.

Indications for intraoperative anterior segment optical coherence tomography in corneal surgery.

PURPOSE: Recently, intraoperative optical coherence tomography (iOCT) has evolved in the field of ophthalmic surgery. So far, the use of iOCT was mainly focused to lamellar keratoplasty, especially deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK). The aim of this study was to report our experiences with iOCT to introduce new possibilities of this application. METHODS: We used iOCT in 18 patients who underwent the following surgeries: DALK, DMEK, penetrating keratoplasty, autologous limbal transplantation, transscleral suture fixation of a posterior chamber lens, pannus removal on corneal surface and newborn investigation in Peters' anomaly. We obtained qualitative video data for all procedures. RESULTS: With the iOCT, the cannula placement during DALK preparation of the recipient cornea and bubble formation could be visualized to improve the success rate of the big bubble injection. In DMEK, the iOCT enables the visualization of Descemet's membrane removal in the recipient and graft orientation as well as better control of graft attachment. The iOCT enables intraoperative visualization of the graft-host interface during penetrating keratoplasty. During autologous limbal transplantation, transscleral suture fixation of a posterior chamber lens and removal of corneal surface pannus the iOCT is capable of showing the thickness of lamellar preparations to avoid penetrations and to save healthy recipient's tissue. CONCLUSION: The iOCT is a helpful device for intraoperative anterior segment imaging not only for DALK and DMEK. It is also beneficial in penetrating keratoplasty and every other form of lamellar preparation during corneoscleral surgery.

[Teleophthalmology Using Whole Slide Imaging (WSI): Clinical-Pathological Correlation Even Without Own Histological Laboratory]. / Teleophthalmopathologie mittels Whole Slide Imaging (WSI): klinisch-pathologische Korrelation auch ohne eigenes histologisches Labor.

Telepathology has experienced enormous growth over the last two decades due to significant advances in IT and has led to the introduction of innovative solutions for digital imaging in ophthalmology. Whole Slide Imaging (WSI), where conventional glass slides are fully scanned, offers a wide range of applications, including remote (conciliary) diagnostics, second opinions, (remote) teaching and research and presentation. In addition to qualified and experienced personnel, a comparatively expensive basic equipment has so far also been an essential requirement. The focus ophthalmology at the Eye Centre in Freiburg is able to involve a de facto unlimited number of users and consulting partners (also overseas) in the digital microscopy of identical sections independent of location, device and time. This is done simply by using the internet. This procedure has proven to be very successful and opens up completely new avenues, not only for correct diagnosis (clinical-pathological correlation), but also for education and training. Preparation and distribution of further histological slides in addition to the scanned slide is not required for small specimens with scant material, for example, nor is it necessary to purchase microscopes for the participants if funds are lacking or the infrastructure is unsuitable. When dealing with transferring data, it is essential to comply with data protection regulations.