The influence of obesity, diabetes mellitus and smoking on fuchs endothelial corneal dystrophy (FECD)

To detect environmental factors, which may be possible risk factors in the disease course of Fuchs' endothelial corneal dystrophy (FECD). Evaluation of patients with FECD registered in the FECD genetics database of the Center for Ophthalmology, University Hospital Cologne. For the evaluation, disease onset, central corneal thickness, best spectacle corrected visual acuity (BSCVA, logMAR), and modified Krachmer grading (grades 1-6) were correlated with the presence of diabetes mellitus (DM), body mass index (BMI), and smoking behavior. To put the age-related increase in Krachmer grading into perspective, a correction of grading were formed. Depending on the variables studied, differences between groups were examined by Mann-Whitney U test and chi-square test. The significance level was 5%. 403 patients with FECD were included in the analysis. The mean age of the patients was 70.0 ± 10.32 (range 28-96) years. The mean age at diagnosis of those patients was 63.1 ± 13.2 years. The female-to-male ratio was 1.46:1. Patients with a BMI > 30.0 kg/m2 developed FECD significantly earlier than patients with a BMI < 30 kg/m2, p = 0.001. Patients with DM showed significantly more often an Krachmer grade of 5, p = 0.015. Smoking had a negative effect on Krachmer grading (p = 0.024). Using the mediation analysis, the presence of DM correlated Krachmer Grade 5 (p = 0.015), and the presence of DM correlated with BMI > 30.0 kg/m2 (p = 0.012). In addition to smoking and DM our study shows for the first time that obesity may have a negative impact on the development of FECD. Whether dietary interventions and hormones can influence the development or progression of the disease needs to be investigated in future studies.

Corneal Infantile Myofibromatosis Caused by Novel Activating Imatinib-Responsive Variants in PDGFRB

Purpose

To investigate the genetic cause, clinical characteristics, and potential therapeutic targets of infantile corneal myofibromatosis.

Design

Case series with genetic and functional in vitro analyses.

Participants

Four individuals from 2 unrelated families with clinical signs of corneal myofibromatosis were investigated.

Methods

Exome-based panel sequencing for platelet-derived growth factor receptor beta gene (PDGFRB) and notch homolog protein 3 gene (NOTCH3) was performed in the respective index patients. One clinically affected member of each family was tested for the pathogenic variant detected in the respective index by Sanger sequencing. Immunohistochemical staining on excised corneal tissue was conducted. Functional analysis of the individual PDGFRB variants was performed in vitro by luciferase reporter assays on transfected porcine aortic endothelial cells using tyrosine kinase inhibitors. Protein expression analysis of mutated PDGFRB was analyzed by Western blot.

Main Outcome Measures

Sequencing data, immunohistochemical stainings, functional analysis of PDGFRB variants, and protein expression analysis.

Results

We identified 2 novel, heterozygous gain-of-function variants in PDGFRB in 4 individuals from 2 unrelated families with corneal myofibromatosis. Immunohistochemistry demonstrated positivity for alpha-smooth muscle actin and β-catenin, a low proliferation rate in Ki-67 (< 5%), marginal positivity for Desmin, and negative staining for Caldesmon and CD34. In all patients, recurrence of disease occurred after corneal surgery. When transfected in cultured cells, the PDGFRB variants conferred a constitutive activity to the receptor in the absence of its ligand and were sensitive to the tyrosine kinase inhibitor imatinib. The variants can both be classified as likely pathogenic regarding the American College of Medical Genetics and Genomics classification criteria.

Conclusions

We describe 4 cases of corneal myofibromatosis caused by novel PDGFRB variants with autosomal dominant transmission. Imatinib sensitivity in vitro suggests perspectives for targeted therapy preventing recurrences in the future.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Künstliche Intelligenz bei lamellierenden Keratoplastiken

Das Training von Künstlicher Intelligenz (KI) wird auch in der Vorderabschnittschirurgie populärer. Zunehmend werden auch Studien zu lamellierenden Keratoplastiken veröffentlicht. Insbesondere die Möglichkeit der nicht-invasiven und hochauflösenden Bildgebungstechnologie der Optischen Kohärenztomographie prädestiniert die lamellierenden Keratoplastiken zur Anwendung von KI. Obwohl technisch einfach durchführbar, existieren bisher nur wenige Studien zum Einsatz von KI zur Optimierung lamellierender Keratoplastiken. Die vorhandenen Studien konzentrieren sich dabei vor allem auf die Vorhersagewahrscheinlichkeit eines Rebubblings bei DMEK und DSAEK bzw. auf deren Transplantatadhärenz sowie auf die Formation einer Big Bubble bei der DALK. Zudem ist die automatisierte Erfassung von Routineparametern wie Hornhautödem, Endothelzelldichte oder Größe der Transplantatablösung mittels KI inzwischen möglich. Die Optimierung der lamellierenden Keratoplastiken mittels KI birgt ein großes Potential. Dennoch bestehen Limitationen der veröffentlichten Algorithmen insofern, dass diese bisher nur eingeschränkt zwischen Zentren, Chirurgen sowie unterschiedlichen Geräteherstellern übertragbar sind. The training of artificial intelligence (AI) is becoming increasingly popular. More and more studies on lamellar keratoplasty are also being published. In particular, the possibility of non-invasive and high-resolution imaging technology of optical coherence tomography predestines lamellar keratoplasty for the application of AI. Although technically easy to perform, there are only a few studies on the use of AI to optimize lamellar keratoplasty. The existing studies focus primarily on the prediction probability of rebubbling in DMEK and DSAEK and on their graft adherence as well as on the formation of a big bubble in DALK. In addition, the automated recording of routine parameters such as corneal edema, endothelial cell density or the size of the graft detachment is now possible using AI. The optimization of lamellar keratoplasty using AI holds great potential. Nevertheless, there are limitations to the published algorithms in that they can only be transferred between centers, surgeons and different device manufacturers to a limited extent.

Influence of Donor Factors on Descemet Membrane Endothelial Keratoplasty (DMEK) Graft Preparation Outcome

Purpose

To determine which donor characteristics, like previous diseases and surgeries, influence the severity of the DM/endothelial lamella preparation prior to DMEK-surgery.

Patients and Methods

Retrospective cross-sectional single-center study is presented. Eight hundred and forty-six eyes with DMEK-surgery between 01/2018 and 01/2021 performed at the University Hospital Cologne, Germany, were included. Information regarding the donors' previous diseases and surgeries were provided by a large database of a cornea bank (Multi Tissue Bank Mecklenburg-Vorpommern) and merged with the Cologne DMEK database, which contains information regarding preparation characteristics of the surgeon-prepared graft directly preoperatively. Three preparation groups (easy, difficult and very difficult) were correlated to the donors' previous diseases and surgeries. The following characteristics were used for the assignment in one of the three groups: stripping difficulty, rolling and staining behavior, central and peripheral adherences, tissue fragility and DM-splitting.

Results

Significant risk factors for DM-splitting were diabetes mellitus (DMel) type II, heart failure, chronic kidney disease and previous cataract surgery (p=0.022, p=0.012; p=0.047 and p<0.001 respectively). Previous DMel (especially type 2) was significantly associated with the occurrence of central adherences (p=0.009). Several cardiovascular diseases (p-values between <0.001 and p=0.038), DMel type II, chronic kidney disease and previous cataract-surgery were associated with peripheral adherences (p=0.004; p=0.020 and p<0.001 respectively). Furthermore, pseudophakic donor eyes presented a higher degree of fragility of the graft (p<0.001). Age was a significant risk factor for difficult preparation (p<0.001). The staining of the graft was poorer in donors with chronic kidney disease (p=0.037).

Conclusion

Donor diabetes mellitus type 2, heart failure, previous cataract surgery, chronic kidney disease and age are associated with a difficult DMEK graft preparation. For every one-year increment in donor age, the odds of having very difficult preparation were increased by 3%. Also, chronic kidney disease predisposes to a poor tissue staining with trypan blue during preparation.

Collagen type XII is undetectable in keratoconus Bowman's layer

PURPOSE

Corneal biomechanical failure is the hallmark of keratoconus (KC); however, the cause of this failure remains elusive. Collagen type XII (COL12A1), which localises to Bowman's layer (BL), is thought to function in stress-bearing areas, such as BL. Given the putative protective role of COL12A1 in biomechanical stability, this study aims to characterise COL12A1 expression in all corneal layers involved in KC.

METHODS

TaqMan quantitative PCR was performed on 31 corneal epithelium samples of progressive KC and myopic control eyes. Tissue microarrays were constructed using full-thickness corneas from 61 KC cases during keratoplasty and 18 non-KC autopsy eyes and stained with an antibody specific to COL12A1. Additionally, COL12A1 was knocked out in vitro in immortalised HEK293 cells.

RESULTS

COL12A1 expression was reduced at transcript levels in KC epithelium compared with controls (ratio: 0.58, p<0.03). Immunohistochemical studies demonstrated that COL12A1 protein expression in BL was undetectable, with reduced expression in KC epithelium, basement membrane and stroma.

CONCLUSIONS

The apparent absence of COL12A1 in KC BL, together with the functional importance that COL12A1 is thought to have in stress bearing areas, suggests that COL12A1 may play a role in the pathogenesis of KC. Further studies are necessary to investigate the mechanisms that lead to COL12A1 dysregulation in KC.

Allogeneic limbo-deep anterior lamellar keratoplasty (Limbo-DALK)-A novel surgical technique in corneal stromal disease and limbal stem cell deficiency

PURPOSE

To describe a novel corneal surgical technique combining Deep Anterior Lamellar Keratoplasty (DALK) with grafting of allogeneic limbus (Limbo-DALK) for the treatment of eyes with corneal stromal pathology and limbal stem cell deficiency (LSCD).

METHODS

Clinical records of six Limbo-DALKs performed in five patients diagnosed with LSCD and corneal stromal pathology requiring keratoplasty were retrospectively reviewed. All patients were diagnosed with LSCD due to various pathologies including thermal and chemical burns, congenital aniridia or chronic inflammatory ocular surface disease. Parameters analysed included demographics, diagnoses, clinical history, thickness measurements using anterior segment OCT, visual acuity, and epithelial status. Regular follow-up visits were scheduled at 6 weeks as well as 3, 6, 9, and 12 and 18 months postoperatively. Main outcome measures were time to graft epithelialisation and the occurrence of corneal endothelial decompensation.

RESULTS

Two grafts showed complete epithelial closure at 2 days, two at 14 days. In one eye, complete epithelial closure was not achieved after the first Limbo-DALK, but was achieved one month after the second Limbo-DALK. No endothelial decompensation occurred except in one patient with silicone oil associated keratopathy. Endothelial graft rejection was not observed in any of the grafts.

CONCLUSION

Based on the data from this pilot series, limbo-DALK appears to be a viable surgical approach for eyes with severe LSCD and corneal stromal pathology, suitable for emergency situations (e.g. corneal ulceration with impending corneal perforation), while minimising the risk of corneal endothelial decompensation.

Excimer Laser Phototherapeutic Keratectomy for Anterior Corneal Opacification After Descemet Membrane Endothelial Keratoplasty

PURPOSE

The aim of this study was to assess the long-term outcome of excimer laser phototherapeutic keratectomy (PTK) for treating remaining anterior corneal opacities after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

This cohort study analyzed 67 eyes of 66 patients undergoing PTK in addition to and after DMEK between 2012 and 2021 at the Department of Ophthalmology, University of Cologne. Patients who were treated by PTK after previous DMEK on the same eye were included. The outcome parameters were best corrected visual acuity (BCVA), changes in refraction, endothelial cell density, corneal densitometry, central corneal thickness, and total corneal higher order aberrations. Patients with visual limitations in addition to anterior opacification were analyzed separately for their visual outcome. Eyes with severe visual limitations that have a very limited visual potential were excluded from the study. In addition, patients with not at least 1 postoperative follow-up examination were excluded from the study.

RESULTS

In this study, 67 eyes of 66 patients met all inclusion criteria. The median follow-up period was 13.1 (quartiles: 4.1; 30.7; interquartile range 26.6) months. The mean (±SD) BCVA improved from (logarithm of the minimum angle of resolution) 0.54 (±0.32) to 0.38 (±0.27) at the first postoperative visit ( P < 0.001) and remained significantly improved at all follow-up examinations compared with preoperative BCVA. Refraction and endothelial cell density did not change significantly after PTK. There was a significant decrease in corneal backscatter in the anterior corneal layer ( P < 0.001), and the total higher order aberration ( P = 0.02) and central corneal thickness were significantly reduced at the most recent postoperative visit ( P < 0.001). No immune reactions were observed.

CONCLUSIONS

Excimer laser PTK after DMEK for persisting anterior corneal opacities has the potential to significantly improve patients' vision without affecting refractive parameters or endothelial cell density.

Immediate postoperative topical lidocaine gel for the treatment of eye pain following corneal abrasion in descemet membrane endothelial keratoplasty (DMEK) under general anaesthesia: a pilot retrospective analysis

BACKGROUND

Patients undergoing corneal abrasion as part of Descemet membrane endothelial keratoplasty (DMEK) under general anesthesia suffer from early burning pain postoperatively. This pain appears to be poorly treatable with systemic analgesics. This study aims to evaluate postoperative pain management using topical lidocaine gel after DMEK with iatrogenic corneal abrasion.

METHODS

Retrospective analysis of 28 consecutive patients undergoing DMEK with corneal abrasion from October 19, 2021, to November 12, 2021, at a German university hospital. Patients during week 1 and 2 received peri-operative standard pain treatment (cohort S) and additional local lidocaine gel during week 3 and 4 immediately postoperatively (cohort L).

RESULTS

13 patients were included in cohort S and 15 patients in cohort L. At awakening all patients (100%) in cohort S reported burning pain, and six of 15 patients (40%) in cohort L reported burning pain. Burning pain scores were significantly lower in cohort L (p < 0.001 at awakening, p < 0.001 at 10 min, p < 0.001 at 20 min, p < 0.001 at 30 min, p = 0.007 at 40 min after awakening, and p < 0.001 at leaving recovery room). No significant differences between cohort S and cohort L were detected concerning surgical outcome during 1-month-follow-up (p = 0.901 for best corrected visual acuity).

CONCLUSION

Patients undergoing DMEK with corneal abrasion suffer significant pain in the recovery room. A single dose of topic lidocaine gel reduces the early postoperative burning pain sufficiently and does not affect the surgical outcome.

Planung und Durchführung von Big Data gestützten Studien in der Augenheilkunde im Lichte der DSGVO

Die Verarbeitung des retrospektiven Datenpools für die Augenheilkunde birgt enormes Potential, insbesondere für den Forschungsbereich. „Big Data“ ermöglicht es der medizinischen Wissenschaft, aus vergangenheitsbezogenen Daten Schlüsse für die Zukunft zu ziehen. Auf Grundlage der Auswertung solcher Daten ließen sich etwa Algorithmen trainieren, die in der Lage wären, mithilfe künstlicher Intelligenz Entscheidungen zu treffen. So könnte beispielsweise der ärztliche Entscheidungsfindungsprozess für gewisse Fragestellungen beschleunigt, in qualitativer und quantitativer Hinsicht bereichert oder gar übernommen werden. Die Augenheilkunde ist ein Fachgebiet, das sich rapide weiterentwickelt. Aufgrund der Vielzahl an teils automatisierten Bildgebungstechnologien und der prädestinierten Zugänglichkeit des Auges für diese, eignet sich die Augenheilkunde ähnlich wie die Radiologie oder Dermatologie für die von künstlicher Intelligenz assistierte Bilddatenanalyse und damit oft einhergehende Diagnosestellung und Therapieeinleitung. Es existieren inzwischen viele Studien, die sich auf die AI-gestützte Bilddatenanalyse von ophthalmologischen Bilddaten stützen. Soweit die Algorithmen durch Rechenregeln aus den Datenmengen der jeweiligen Datenpools Ergebnisse herausfiltern und sogar dazu fähig sind, auf der Basis von Entscheidungsbäumen eigenständig Entscheidungen zu treffen, liegt der enorme Nutzen und gleichsam der Gewinn für die wissenschaftliche Forschung auf der Hand. Entsprechend wäre eine möglichst ungehinderte und umfassende Möglichkeit entsprechender Datenverarbeitungen dieser Gesundheitsdaten für die augenheilkundliche Forschung wünschenswert. An das nur auszugsweise dargestellte Potenzial für die Augenheilkunde schließt sich die Frage nach der praktischen Umsetzbarkeit an. Dabei sind insbesondere die rechtlichen Maßgaben und Grenzen des europäischen und nationalen Datenschutzrechts zu berücksichtigen, die vor einer unreflektierten Verarbeitung personenbezogener (Gesundheits-)Daten umzusetzen sind. Nur so können vorhandene Hürden und Fallstricke, die zu empfindlichen Bußgeldern führen können, ausgeräumt werden. Ausschlaggebend sind insbesondere die Maßgaben zweier Gesetzestexte: Die Datenschutzgrundverordnung (DSGVO) sowie das Bundesdatenschutzgesetz (BDSG). Der Artikel liefert einen Überblick über die einschlägigen gesetzlichen Vorgaben, die es im Bereich der Augenheilkunde gibt und zeigt die wesentlichen Fallstricke und Umsetzungserfordernisse auf. The processing of the retrospective data pool for ophthalmology holds huge potential, especially for the research sector. "Big Data" enables medical science to draw conclusions for the future from historical data. Based on the evaluation of such data, algorithms could be trained, for instance, capable of making decisions with the help of artificial intelligence. As a result, the medical decision-making process on certain issues could be accelerated, enriched in qualitative and quantitative terms, or even completely be taken over. Ophthalmology is a rapidly evolving field. Due to the multitude of partly automated medical imaging technologies and the predestined accessibility of the eye for such technologies, ophthalmology, similar to radiology or dermatology, is well suited for artificial intelligence assisted image data analysis and frequently associated diagnosis and therapy initiation. Meanwhile, numerous studies exist based on AI-assisted image data analysis of ophthalmologic image data. To the extent that the algorithms filter out results from the data pools by means of calculation rules and even are capable of making independent decisions on the basis of decision trees, the enormous benefit and, simultaneously, the profit for scientific research is quite obvious. Accordingly, a preferably unrestricted and comprehensive possibility of corresponding data processing of these health data for ophthalmological research would be desirable. Subsequent to the potential for ophthalmology, illustrated only in fragmentary manner, the question of practical feasibility arises. In particular, the legal requirements and limits of European and national data protection law must be taken into account, prior to any unreflective processing of personal (health) data. Only by doing so existing obstacles and pitfalls, which can lead to severe fines, can be avoided. Most important are the requirements of two legal texts: The General Data Protection Regulation (GDPR) and the Federal Data Protection Act (BDSG). This article provides an overview of the relevant legal requirements applicable in the field of ophthalmology and highlights the major pitfalls and implementation requirements.

The novel role of lymphatic vessels in the pathogenesis of ocular diseases

Historically, the eye has been considered as an organ free of lymphatic vessels. In recent years, however, it became evident, that lymphatic vessels or lymphatic-like vessels contribute to several ocular pathologies at various peri- and intraocular locations. The aim of this review is to outline the pathogenetic role of ocular lymphatics, the respective molecular mechanisms and to discuss current and future therapeutic options based thereon. We will give an overview on the vascular anatomy of the healthy ocular surface and the molecular mechanisms contributing to corneal (lymph)angiogenic privilege. In addition, we present (i) current insights into the cellular and molecular mechanisms occurring during pathological neovascularization of the cornea triggered e.g. by inflammation or trauma, (ii) the role of lymphatic vessels in different ocular surface pathologies such as dry eye disease, corneal graft rejection, ocular graft versus host disease, allergy, and pterygium, (iii) the involvement of lymphatic vessels in ocular tumors and metastasis, and (iv) the novel role of the lymphatic-like structure of Schlemm's canal in glaucoma. Identification of the underlying molecular mechanisms and of novel modulators of lymphangiogenesis will contribute to the development of new therapeutic targets for the treatment of ocular diseases associated with pathological lymphangiogenesis in the future. The preclinical data presented here outline novel therapeutic concepts for promoting transplant survival, inhibiting metastasis of ocular tumors, reducing inflammation of the ocular surface, and treating glaucoma. Initial data from clinical trials suggest first success of novel treatment strategies to promote transplant survival based on pretransplant corneal lymphangioregression.

P49-A103 Allogeneic limbo-DALK: a novel surgical technique for patients with corneal stromal disease and limbal stem cell deficiency

PURPOSE

To describe a novel corneal surgical technique combining Deep Anterior Lamellar Keratoplasty (DALK) with grafting of allogeneic limbal stem cells (limbo-DALK) as treatment for eyes with corneal stromal pathology and limbal stem cell deficiency (LSCD).

METHODS

This is a series of six Limbo-DALKs in five eyes of five patients. One patient received a second limbo-DALK after graft failure following the first procedure. Two of the donor corneae were HLA matched. Clinical records of included patients were reviewed retrospectively. All patients had been diagnosed with LSCD due to various pathologies. Analysed data included demographic data, diagnoses and clinical history, graft visualization and thickness measurements by anterior segment OCT, visual acuity and epithelial status. Follow-up visits were 6 weeks and 3, 6, 9, 12 and 18 months postoperatively with final suture removal at 18 months and further follow-up examinations twice yearly thereafter.

RESULTS

Two grafts showed total epithelial closure after 2 days, two after 14 days. In one eye, full closure of corneal epithelium did not occur after the first limbo-DALK, but could be achieved one month after second limbo-DALK. No endothelial graft rejection was seen.

CONCLUSION

Based on data from this pilot series, limbo-DALK seems to be a novel viable surgical approach for eyes with severe LSCD and stromal corneal pathology.

Influence of Descemet Membrane Endothelial Keratoplasty Graft Preparation Patterns on Postoperative Clinical Outcome

PURPOSE

The aim of this study was to quantify preparation difficulties and complications during DMEK graft preparation and their influence on clinical outcome.

METHODS

A retrospective evaluation of 214 consecutive DMEK surgeries from the prospective Cologne DMEK database was performed between July 2018 and December 2019. Preparation conditions (such as central and peripheral adherences, tissue fragility, and Descemet membrane splitting) were quantified and divided into 3 groups: easy, difficult, and very difficult preparation. At follow-up (3, 6, and 12 months after DMEK), best spectacle-corrected visual acuity, endothelial cell count (ECC), and rebubbling rates were evaluated and compared between groups.

RESULTS

An easy preparation was possible in 41.6% of cases (group 1, n = 89), a difficult preparation of the DMEK graft occurred in 30.8% (group 2, n = 66), and a very difficult preparation occurred in 27.6% (group 3, n = 59). There was no difference between groups for best spectacle-corrected visual acuity at 3, 6, and 12 months ( P = 0.179, P = 0.325, and P = 0.682, respectively) or for ECC at 3 and 6 months ( P = 0.537 and P = 0.606, respectively). Only at 12 months, the ECC was slightly significant between groups ( P = 0.045). Regarding the rebubbling rate, there was no difference ( P = 0.585). 17.9% of eyes from group 1, 25.7% of eyes from group 2, and 23.7% of eyes from group 3 received at least 1 rebubbling.

CONCLUSIONS

These data suggest that difficult preparation conditions do not lead to any worsening of visual acuity or rebubbling rate in the 1-year outcome after DMEK. The endothelial cell density at 12 months showed slightly poorer results in the cases of very difficult preparation.

Corneal Hydrops - Aetiology and Advanced Therapeutic Strategies

Acute hydrops refers to sudden corneal edema caused by rupture of Descemet's membrane (DM) - often in progressive keratectasia. It leads to a sudden decrease in visual acuity, pain, and foreign body sensation as well as an increased glare sensation. Acute hydrops usually heals with scarring within months, but complications such as corneal perforation, infectious keratitis, and corneal vascularization may occur. The prevalence in keratoconus patients is 2.6 to 2.8%. Risk factors include keratoconjunctivitis vernalis, atopic dermatitis, high keratometry, male gender, and eye rubbing. Keratoplasty should be avoided in the acute phase. The prognosis of the graft is reduced, and after scar healing of the hydrops, wearing contact lenses or glasses may be possible again. Conservative therapy alone with lubricants and hyperosmolar eye drops, prophylactic antibiotic eye drops to prevent superinfection, and topical steroids was long considered the only possible form of treatment. However, healing under conservative therapy takes an average of over 100 days. In the meantime, there are different surgical strategies that rapidly shorten the healing and thus the recovery phase of the patients to a few days. If the DM is detached without tension, a simple injection of gas into the anterior chamber can already lead to reattachment and thus to almost immediate deswelling of the cornea. If the DM is under tension, predescemetal sutures combined with a gas injection into the anterior chamber can flatten the cornea and reattach the DM. Mini-Descemet membrane endothelial keratoplasty (mini-DMEK) allows for sutureless closure of the DM defect by transplantation of a small (< 5 mm) graft. In cases of particularly large DM tears and very pronounced hydrops, suture loosening and relapse may occur after the placement of predescemetal sutures. Mini-DMEK can then lead to permanent healing, but in contrast to simple corneal sutures, it is usually performed under general anesthesia and by aid of intraoperative optical coherence tomography. The very good results with regard to the rapid healing prove that surgical therapy makes sense in the vast majority of patients with acute hydrops and should be initiated quickly.

Transferability of an Artificial Intelligence Algorithm Predicting Rebubblings After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To develop an artificial intelligence (AI) algorithm enabling corneal surgeons to predict the probability of rebubbling after Descemet membrane endothelial keratoplasty (DMEK) from images obtained using optical coherence tomography (OCT).

METHODS

Anterior segment OCT data of patients undergoing DMEK by 2 different DMEK surgeons (C.C. and B.B.; University of Cologne, Cologne, Germany) were extracted from the prospective Cologne DMEK database. An AI algorithm was trained by using a data set of C.C. to detect graft detachments and predict the probability of a rebubbling. The architecture of the AI model used in this study was called EfficientNet. This algorithm was applied to OCT scans of patients, which were operated by B.B. The transferability of this algorithm was analyzed to predict a rebubbling after DMEK.

RESULTS

The algorithm reached an area under the curve of 0.875 (95% confidence interval: 0.880-0.929). The cutoff value based on the Youden index was 0.214, and the sensitivity and specificity for this value were 78.9% (67.6%-87.7%) and 78.6% (69.5%-86.1%).

CONCLUSIONS

The development of AI algorithms allows good transferability to other surgeons reaching a high accuracy in predicting rebubbling after DMEK based on OCT image data.

Blood-Aqueous Barrier Disruption in Penetrating and Posterior Lamellar Keratoplasty: Implications for Clinical Outcome

BACKGROUND

The blood-aqueous barrier (BAB) separates immunoprivileged tissue of the eye from the blood circulation. Disruption of the BAB is therefore a risk factor for rejection after keratoplasty.

PURPOSE

The present work provides a review of the work of our group and others on BAB disruption in penetrating and posterior lamellar keratoplasty and its implications for clinical outcome.

METHODS

A PubMed literature search was performed to generate a review paper.

RESULTS

Laser flare photometry provides an objective and reproducible method to assess the integrity of the BAB. Studies of the flare after penetrating and posterior lamellar keratoplasty demonstrate a mostly regressive disruption of the BAB in the postoperative course, which is influenced in extent and duration by multiple factors. Persistently elevated flare values or an increase in flare after initial postoperative regeneration may indicate an increased risk of rejection.

DISCUSSION

In case of persistent or recurrent elevated flare values after keratoplasty, intensified (local) immunosuppression may potentially be useful. This could become important in the future, especially for the monitoring of patients after high-risk keratoplasty. Whether an increase of the laser flare is a reliable early indicator of an impending immune reaction after penetrating or posterior lamellar keratoplasty has to be shown in prospective studies.

Correlation of Clinical Fibrillar Layer Detection and Corneal Thickness in Advanced Fuchs Endothelial Corneal Dystrophy

Central subendothelial geographic deposits are formed as a fibrillar layer (FL) in advanced Fuchs endothelial corneal dystrophy (FECD). Previous studies demonstrated a significant decrease in corneal endothelial cell (CEC) density and an increase in focal corneal backscatter in the FL area. The present study investigated the association of the FL with edema formation and its localization. Patients (n = 96) presenting for Descemet membrane endothelial keratoplasty (DMEK) for advanced FECD were included. Slit-lamp biomicroscopy with FECD grading was followed by Scheimpflug imaging with en face backscatter analysis and pachymetric analysis. FL dimensions were measured, and correlation with pachymetric values was performed. An FL was detected in 74% of all eyes (n = 71). Pachymetric values in FL-positive versus FL-negative eyes were for corneal thickness at the apex (ACT) 614 ± 52 µm and 575 ± 46 µm (p = 0.001), for peripheral corneal thickness at 1 mm (PCT_1mm) 616 ± 50 µm and 580 ± 44 µm (p = 0.002), for PCT_2mm 625 ± 48 µm and 599 ± 41 µm (p = 0.017), for PCT_3mm 651 ± 46 µm and 635 ± 40 µm (p = 0.128) and for PCT_4mm 695 ± 52 µm and 686 ± 43 µm (p = 0.435), respectively. Correlation analysis indicated a weak correlation for the FL maximum vertical caliper diameter with ACT and PCT_1mm values but no further relevant correlations. In FL-positive eyes, increased focal corneal backscatter and increased corneal thickness showed primarily central and inferotemporal localization. In conclusion, Scheimpflug imaging shows an association of the FL with increased corneal thickness in advanced FECD and shows localization of the FL and increased corneal thickness in the central and inferotemporal region. This may provide important information for progression assessment and therapeutic decision making in FECD patients in the future.

Outcomes of deep anterior lamellar keratoplasty and penetrating keratoplasty in keratoconic eyes with and without previous hydrops

PURPOSE

The study aims to compare outcomes after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in keratoconic eyes with or without previous hydrops.

METHODS

Retrospective analysis of 211 eyes who received PK (group 1, n = 74 [history of hydrops: n = 33]) or DALK (group 2, n = 137 [history of hydrops: n = 9]) from 2012 to 2019 at the Department of Ophthalmology, University of Cologne, Germany. Analysis included best spectacle-corrected visual acuity (BSCVA), complications, immune reactions, graft survival and keratometry, and subgroup analyses for subjects with or without previous hydrops.

RESULTS

Follow-up was 34.0 ± 23.6 months in group 1 and 30.7 ± 22.5 months in group 2. No significant difference was found in the course of BSCVA between groups 1 and 2 (p = 0.182) and in postoperative BSCVA between eyes with and without previous hydrops, regardless of the surgical method (p = 0.768). Endothelial immune reactions occurred exclusively in group 1 and did not occur more frequently in eyes with previous hydrops (p = 0.377). A higher risk of complications for eyes with previous hydrops was observed (p = 0.022). There was no difference in astigmatism and maximum keratometry (K_max) preoperatively and postoperatively between eyes with and without history of hydrops.

CONCLUSION

The prognosis for visual outcome after keratoplasty including visual acuity, astigmatism, and K_max for keratoconic eyes with previous hydrops is as good as for keratoconic eyes without previous hydrops, irrespective of the surgical method. However, eyes after hydrops seem to have an increased risk of complications.

[Diagnostics, clinical aspects and genetics of congenital corneal opacities]

BACKGROUND

Congenital corneal opacities are comparatively rare diseases with high amblyogenic potential.

PURPOSE

The present work provides an overview of the diagnostics, clinical aspects and genetics of congenital corneal opacities.

METHODS

A literature search was carried out to compile an overview and illustration with own clinical case examples.

RESULTS

Differentiated diagnostics are of high importance in the treatment of patients with congenital corneal opacities. A close cooperation between the medical departments involved and also the parents is absolutely essential. The structured classification of congenital corneal opacities provides the basis for a targeted treatment.

DISCUSSION

The causes and the clinical symptoms of congenital corneal opacities are manifold. The correct diagnosis should be made early and in an interdisciplinary manner. Based on this, conservative and surgical treatment measures can be planned and an impending development of amblyopia can be specifically counteracted.

Scheimpflug Backscatter Imaging of the Fibrillar Layer in Fuchs Endothelial Corneal Dystrophy

A central collagen-rich subendothelial fibrillar layer (FL) correlates with areas of accentuated loss of corneal endothelial cells in advanced Fuchs endothelial corneal dystrophy (FECD). The present study sought to investigate whether the FL may be visualized by en face Scheimpflug backscatter imaging in vivo.

DESIGN

Retrospective analysis of a prospective observational case series.

METHODS

A total of 34 eyes (34 subjects) undergoing Descemet membrane endothelial keratoplasty (DMEK) surgery with preoperative high-quality Scheimpflug backscatter imaging data were included. The Descemet endothelium complex (DEC) was retrieved during DMEK surgery, and immunofluorescence staining was performed for collagens I, III, and IV. The FL morphology in en face Scheimpflug backscatter and immunofluorescence imaging was compared and agreement of FL parameters was analyzed using intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Scheimpflug backscatter imaging delineated the FL in 26 eyes and was FL negative in 8 eyes with deviation compared to immunofluorescence in 1 case and good agreement of morphology characteristics. Horizontal caliper diameter ± SD was 4.84 ± 0.85 mm, vertical caliper diameter was 3.92 ± 0.78 mm, maximum caliper diameter was 5.12 ± 0.82 mm, and surface area was 12.43 ± 4.74 mm². Compared to immunofluorescence imaging, mean difference (95% limits of agreement) and intraclass correlation coefficients were for horizontal caliper diameter 0.13 mm (-0.81 to 1.1 mm) and 0.88, vertical caliper diameter 0.23 mm (-0.76 to 1.2 mm) and 0.81, maximum caliper diameter 0.06 mm (-1.1 to 1.2 mm) and 0.86, and surface area 1.4 mm² (-3.9 to 6.7 mm²) and 0.85.

CONCLUSIONS

Scheimpflug backscatter imaging facilitates visualization of the FL in advanced FECD eyes, offering the potential to identify particularly diseased areas of the FECD endothelium in vivo.

Comparison of Mini-DMEK versus predescemetal sutures as treatment of acute hydrops in keratoconus

PURPOSE

To compare two surgical treatment options for acute corneal hydrops in keratoconus: Mini-DMEK versus predescemetal sutures.

METHODS

Sixteen patients were treated by either Mini-Descemet membrane endothelial keratoplasty (Mini-DMEK) (n = 7, group 1) or predescemetal sutures (n = 9, group 2) early after onset of acute hydrops. Visual acuity, maximum corneal thickness (SD-OCT) in the affected oedematous area, complications and recurrence rates were retrospectively compared between both groups. Measurements were taken immediately preoperatively as well as 1 day, 1 week and 1 month postoperatively (Table 1).

RESULTS

Both groups showed reductions in corneal thickness and increased visual acuity shortly after surgery. In group 1 (average age 33 years ± 7 years), the best corrected visual acuity (BCVA) increased from logMAR 1.65 ± 0.7 before Mini-DMEK to logMAR 0.93 ± 0.6 30 days after Mini-DMEK (p = 0.046). During that period, maximum corneal thickness decreased from 1159 ± 338 µm before surgery to 531 ± 75 µm after Mini-DMEK (p = 0.046). Patients from group 2 (average age 34 ± 10 years) had a BCVA of logMAR 1.59 ± 0.8 which increased to logMAR 0.97 ± 0.5 (p = 0.014) 30 days after surgery. At the same time, the preoperative maximum corneal thickness decreased from 1439 ± 272 µm to 476 ± 162 µm (p = 0.014). There was no difference in corneal thickness or BCVA one month after the surgical intervention between both groups (p = 0.394 and p = 0.871).

CONCLUSIONS

Both techniques, Mini-DMEK and predescemetal sutures, are effective in the treatment of an acute hydrops in keratoconus. Mini-DMEK appears to be beneficial in large DM tears.

Transcriptomic and Immunohistochemical Analysis of Progressive Keratoconus Reveal Altered WNT10A in Epithelium and Bowman's Layer

Purpose

To identify global gene expression changes in the corneal epithelium of keratoconus (KC) patients compared to non-KC myopic controls.

Methods

RNA-sequencing was performed on corneal epithelium samples of five progressive KC and five myopic control patients. Selected results were validated using TaqMan quantitative PCR (qPCR) on 31 additional independent samples, and protein level validation was conducted using western blot analysis on a subset. Immunohistochemistry was performed on tissue microarrays containing cores from over 100 KC and control cases. WNT10A transcript levels in corneal epithelium were correlated with tomographic indicators of KC disease severity in 15 eyes. Additionally, WNT10A was overexpressed in vitro in immortalized corneal epithelial cells.

Results

WNT10A was found to be underexpressed in KC epithelium at the transcript (ratio KC/control = 0.59, P = 0.02 per RNA-sequencing study; ratio = 0.66, P = 0.03 per qPCR) and protein (ratio = 0.07, P = 0.06) levels. Immunohistochemical analysis also indicated WNT10A protein was decreased in Bowman's layer of KC patients. In contrast, WNT10A transcript level positively correlated with increased keratometry (Kmax ρ = 0.57, P = 0.02). Finally, WNT10A positively regulated COL1A1 expression in corneal epithelial cells.

Conclusions

A specific Wnt ligand, WNT10A, is reduced at the mRNA and protein level in KC epithelium and Bowman's layer. This ligand positively regulates collagen type I expression in corneal epithelial cells. The results suggest that WNT10A expression in the corneal epithelium may play a role in progressive KC.

[Treatment of vascularized high-risk eyes with a Boston keratoprosthesis]

BACKGROUND

In severely compromised and vascularized high-risk eyes, the Boston keratoprosthesis procedure is often the last treatment option. The transparency of the optics is not impaired by endothelial immune reactions.

METHODS

This review article discusses relevant literature as well as our own data and experiences with the Boston keratoprosthesis in high-risk eyes. The relevant complications as well as the postoperative management are discussed.

RESULTS

In more than 60% of the high-risk eyes a long-term increase in visual acuity can be achieved. Keratoprosthesis retention rates show a variable span with reported mean 5‑year retention rates of 75%. The most common postoperative complications include the formation of a retroprosthetic membrane and keratolysis in up to 50% each. More than 70% of the eyes already suffer from (secondary) glaucoma preoperatively, so that glaucoma surgery is performed simultaneously in at least 20% of cases and in the postoperative course further antiglaucomatous surgery is necessary in up to 31%. Vitreoretinal complications include, in particular, sterile vitritis and infectious endophthalmitis but persistent hypotonia is also described in one third of patients.

CONCLUSION

The Boston keratoprosthesis is an alternative to conventional corneal replacement if the prognosis for allogeneic transplants is poor. Postoperative complications are common; therefore, postoperative management plays an important role. For vascularized high-risk eyes, however, it is often the only remaining option for visual rehabilitation.

Fibrillar Layer as a Marker for Areas of Pronounced Corneal Endothelial Cell Loss in Advanced Fuchs Endothelial Corneal Dystrophy

PURPOSE

We sought to assess the correlation of corneal endothelial cell (CEC) density to alterations of collagen composition of Descemet membrane (DM) in advanced Fuchs endothelial corneal dystrophy (FECD) and to image such changes by slit-lamp biomicroscopy in vivo.

DESIGN

Prospective, observational consecutive case series.

METHODS

Fifty eyes (50 subjects) with advanced FECD were enrolled. After slit-lamp biomicroscopy and corneal Scheimpflug imaging, the Descemet endothelium complex (DEC) was retrieved during DM endothelial keratoplasty (DMEK) surgery. The expression of collagens I, III, and IV (COL I, COL III, and COL IV) and corresponding CEC density were analyzed by immunofluorescence flat mount-staining. Presence, diameter and surface area of collagen expression, and CEC density served as the main outcome measures.

RESULTS

Immunofluorescence staining revealed central coherent collagen positive areas (mean surface area = 10 mm² ± 6 mm²) corresponding to a fibrillar layer burying the guttae of DM in 84% (42/50) of DECs. CEC density overlying the fibrillar layer compared with the periphery was significantly reduced (-54.8%, P < .0001) with a steep decline of CEC density at its borders. Subgroup analysis revealed that the fibrillar layer may be imaged by slit-lamp biomicroscopy in vivo with significant positive correlation of mean maximum diameter detected by slit-lamp biomicroscopy (d_{SL max} = 4.1 mm ± 0.9 mm) and by immunofluorescence staining (d_{IF max} = 4.7 mm ± 1.1 mm; r = 0.76; P = .001).

CONCLUSION

A fibrillar layer with a clear geographic pattern marks areas of pronounced loss of CEC density in advanced FECD eyes and may be imaged by slit-lamp biomicroscopy in vivo.

Long-term outcome of descemet membrane endothelial keratoplasty (DMEK) following failed penetrating keratoplasty (PK)

PURPOSE

To assess the long-term outcome of Descemet membrane endothelial keratoplasty (DMEK) following failed penetrating keratoplasty (PK).

METHODS

Retrospective review of 1840 consecutive DMEK surgeries from the prospective Cologne DMEK database performed between 07/2011 and 08/2017 at the Department of Ophthalmology, University of Cologne.

RESULTS

Fifty-two eyes received a DMEK surgery after failed PK. Main indications for initial PK were Fuchs endothelial corneal dystrophy (23.1%), keratoconus and herpetic keratitis (each 15.4%). Best-corrected visual acuity (BCVA) at 3, 6 and 12 months was 0.72 ± 0.39 (n = 33), 0.56 ± 0.36 (n = 32) and 0.38 ± 0.28 (n = 23), respectively. Two- and 3-year BCVA was 0.37 ± 0.21 (n = 21) and 0.32 ± 0.18 (n = 10). Mean improvement in visual outcome in logMAR lines was +4.3 ± 3.4 at 6 months, +5.0 ± 3.6 at 12 months, +6.0 ± 2.3 at 24 months and +5.4 ± 2.7 at 36 months, respectively. 59.6% received at least one rebubbling and 40.4% did not necessitate a rebubbling. Endothelial cell density (ECD)-decrease at 6 months was 36% (n = 17), 37% at 12 months (n = 17), 40% at 2 years (n = 8) and 32% at 3 years (n = 2). 34.6% of transplants needed a regraft.

CONCLUSION

Descemet membrane endothelial keratoplasty (DMEK) is a feasible treatment option after failed PK having a relatively good long-term outcome.

The Cologne rebubbling study: a reappraisal of 624 rebubblings after Descemet membrane endothelial keratoplasty

Background/Aims

To analyse graft detachments prior to rebubbling, the influence of rebubbling on the postoperative outcome after Descemet membrane endothelial keratoplasty (DMEK) and the need for rebubbling on the contralateral eye.

Methods

In this retrospective cohort study, out of 1541 DMEKs, optical coherence tomography scans and clinical records of 499 eyes undergoing rebubbling after DMEK at the University Hospital of Cologne, Cologne, Germany, were examined. Main Outcome measures were (a) number, localisation and size of graft detachments; (b) influence of rebubbling/s on postoperative outcome after 12 months; and (c) rebubbling risk of the contralateral eye after DMEK.

Results

Mean number of detachment areas was 2.02±0.9. Mean lateral diameter of all detachments was 4534.76±1920.83 μm. Mean axial diameter was 382.53±282.02 μm. Detachments were equally distributed over all regions of the cornea. Best spectacle corrected visual acuity ( BSCVA) after 12 months was 0.197±0.23 logarithm of the minimum angle of resolution, endothelial cell density (ECD) was 1575.21±397.71 cells/mm2and mean central corneal thickness (CCT) was 566.37±68.11 μm. BSCVA, CCT, ECD or endothelial cell loss of all rebubbled patients were not influenced by the number of rebubblings or the time between DMEK and rebubbling. Of the rebubbled patients, which received a DMEK subsequently on the other eye, 193 (58.8%) also received a rebubbling, which was significantly higher, when compared to the overall rebubbling rate of 32.3% (p=0.000).

Conclusions

The overall number of rebubblings has no influence on the postoperative outcome after DMEK, if a rebubbling becomes necessary. Patients who received a rebubbling on one eye have an elevated risk for a rebubbling on the fellow eye.

[Efficient Use of Corneal Grafts through Multimodal Donor Tissue Splitting]

BACKGROUND

The reduced availability of corneal donor tissue in Ukraine requires the most effective use of the available grafts. The present work describes and evaluates a method to obtain several small diameter corneal grafts from a single donor cornea ("multimodal donor tissue splitting").

MATERIAL AND METHODS

This retrospective cohort study includes keratoplasty procedures performed at the Department of Corneal Pathology, State Institution, "The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine", Odessa, Ukraine. The method of graft preparation includes either lamellar dissection of the entire graft or partial lamellar dissection to obtain two lamellar and/or full-thickness grafts. Grafts were not only cut in a circular manner, but the individual shape was also adjusted to match the shape of non-circular corneal defects.

RESULTS

A total of 324 keratoplasties between January 2016 and December 2017, using 270 grafts, were included. In 54 cases (including 34 emergency situations), one transplant was used for two recipients. Of these, 43 were therapeutic keratoplasties and 11 peripheral lamellar keratoplasties due to grade III - IV recurrent pterygia. In two cases, two grafts for one patient were dissected from a single donor cornea. Out of 43 patients with curative keratoplasty, visual acuity improved in 28 eyes (65.1%) or remained unchanged in 15 eyes (34.9%). Postoperative visual acuity was dependent on the initial state of the eye, the localisation, the depth and the area of the corneal defect. In eyes with peripheral corneal localisation of ulcerations, even in the presence of corneal perforation, good functional results were obtained.

CONCLUSION

If two or more grafts are obtained from a single donor cornea for different kinds of keratoplasty procedures, this reduces the need for corneal graft tissue and, consequently, the cost of preservation. Especially in regions with a high shortage of donor tissue, this provides additional tissue capacities for emergency situations.

New Technologies in Clinical Trials in Corneal Diseases and Limbal Stem Cell Deficiency: Review from the European Vision Institute Special Interest Focus Group Meeting

To discuss and evaluate new technologies for a better diagnosis of corneal diseases and limbal stem cell deficiency, the outcomes of a consensus process within the European Vision Institute (and of a workshop at the University of Cologne) are outlined. Various technologies are presented and analyzed for their potential clinical use also in defining new end points in clinical trials. The disease areas which are discussed comprise dry eye and ocular surface inflammation, imaging, and corneal neovascularization and corneal grafting/stem cell and cell transplantation. The unmet needs in the abovementioned disease areas are discussed, and realistically achievable new technologies for better diagnosis and use in clinical trials are outlined. To sum up, it can be said that there are several new technologies that can improve current diagnostics in the field of ophthalmology in the near future and will have impact on clinical trial end point design.

Risk factors for endothelial cell loss after Descemet membrane endothelial keratoplasty (DMEK)

This study aimed to identify the risk factors for endothelial cell density (ECD) loss after Descemet membrane endothelial keratoplasty (DMEK) and analyse whether donor tissues from cold versus organ culture differ in terms of ECD loss after DMEK. Consecutive DMEK cases from a prospective database for Fuchs’ endothelial corneal dystrophy were retrospectively analysed between 2011 and 2016 at the University of Cologne, and the possible risk factors for ECD loss, including patient-related factors, type of tamponade (air or 20% sulphur hexafluoride gas), type of surgery (triple DMEK or DMEK alone), re-bubbling, immune rejection, and donor-related factors were determined. Eight hundred and forty-one eyes were selected. There was no significant difference in the best-corrected visual acuity (logarithm of the minimal angle of resolution) and corneal thickness (P = 0.540 and P = 0.667) between groups. Immune reactions were more common in cold cultures (P = 0.019), but ECD loss (1 year after DMEK) was greater in organ cultures (38.3 ± 0.8%) than in cold cultures (34.7 ± 1.4%) (P = 0.022). Only re-bubbling was significantly associated with ECD loss (P < 0.001). Re-bubbling was found to be a key factor for ECD loss at 1 year after DMEK.

Fuchs Endothelial Corneal Dystrophy: Clinical, Genetic, Pathophysiologic, and Therapeutic Aspects

Fuchs endothelial corneal dystrophy (FECD) is a bilateral corneal endothelial disorder and the most common cause of corneal transplantation worldwide. Professor Ernst Fuchs described the first 13 cases of FECD more than 100 years ago. Since then, we have seen far-reaching progress in its diagnosis and treatment. In the field of diagnostics, new technologies enable the development of more accurate classification systems and the more detailed breakdown of the genetic basis of FECD. Laboratory studies help in deciphering the molecular pathomechanisms. The development of minimally invasive surgical techniques leads to a continuous improvement of the postoperative result. This review highlights and discusses clinical, genetic, pathophysiologic, and therapeutic aspects of this common and important corneal disorder.

Morning Myopic Shift and Glare in Advanced Fuchs Endothelial Corneal Dystrophy

PURPOSE

Impaired subjective morning visual acuity with improvement of symptoms during the day is pathognomonic for corneal endothelial dysfunction in advanced Fuchs endothelial corneal dystrophy (FECD). This study aimed to analyze the daily fluctuations of corneal thickness, refraction, and (glare) visual acuity in advanced FECD.

DESIGN

Prospective cohort study.

METHODS

Patients with advanced FECD (FECD group) and patients with normal cornea (control group) were enrolled. Routine clinical examination was performed using slit-lamp biomicroscopy, funduscopy, and macular optical coherence tomography. In addition, assessment using corneal Scheimpflug tomography (Pentacam), refraction, corrected distance visual acuity (CDVA), and glare CDVA was performed at 4 PM (afternoon) and the following day at 8 AM (morning).

RESULTS

A total of 29 FECD eyes and 22 control eyes were included. Diurnal variations from afternoon to morning were Δ corneal thickness (apex) ± standard deviation (SD) 41.45 ± 34.1 μm (P < .001, FECD group) and 5.5 ± 6.72 μm (P = .001, control group); Δ spherical equivalent ± SD -0.64 ± 0.6 diopters (D) (P < .001, FECD group) and -0.01 ± 0.50 D (P = .461, control group); Δ total corneal refractive power ± SD 0.60 ± 0.83 D (P = .001, FECD group) and -0.01 ± 0.49 D (P = .602, control group), Δ CDVA ± SD 0.15 ± 0.18 logarithm of minimal angle of resolution (logMAR) (P < .001, FECD group) and 0.02 ± 0.04 logMAR (P = .174, control group), Δ CDVA glare ± SD 0.34 ± 0.25 logMAR (P < .001, FECD group) and 0.05 ± 0.11 logMAR (P = .106, control group).

CONCLUSION

A morning myopic shift and increased glare paralleling increased corneal thickness may particularly contribute to subjective visual impairment in advanced FECD in the first hours after awaking. This should be taken into account during assessment and surgical decision-making in patients with FECD.

[Boston type I keratoprosthesis implantation technique : Video article]

BACKGROUND

Keratoprosthetics refer to the replacement of human corneal tissue with an artificially produced exchange product. The most widely implanted keratoprosthesis worldwide is the Boston Type I Keratoprosthesis (BI-KPro, Massachusetts Eye and Ear Infirmary, Boston, MA, USA).

METHODS

This video article demonstrates the surgical technique of BI-KPro implantation as routinely performed at this institution. In addition, an overview of the surgical indications, patient consent, anesthesia and positioning, postoperative treatment and complications as well as the evidence of the technique is provided in the article based on experience with 31 BI-KPro implantations.

RESULTS

The indications for BI-KPro primarily include patients in a high-risk keratoplasty setting particularly after repeatedly failed keratoplasty. A thorough patient examination and assessment of the indications as well as detailed disclosure of information to the patient about the individual prognosis, the risk profile, the postoperative therapy and follow-up enable a positive postoperative result.

CONCLUSION

The BI-KPro provides an established and relatively standardized option for surgical treatment of eyes in a high-risk keratoplasty setting. Patients should be preoperatively informed with respect to the individual prognosis, complication profile and life-long follow-up.

Immune reactions after modern lamellar (DALK, DSAEK, DMEK) versus conventional penetrating corneal transplantation

In the past decade, novel lamellar keratoplasty techniques such as Deep Anterior Lamellar Keratoplasty (DALK) for anterior keratoplasty and Descemet stripping automated endothelial keratoplasty (DSAEK)/Descemet membrane endothelial keratoplasty (DMEK) for posterior keratoplasty have been developed. DALK eliminates the possibility of endothelial allograft rejection, which is the main reason for graft failure after penetrating keratoplasty (PK). Compared to PK, the risk of endothelial graft rejection is significantly reduced after DSAEK/DMEK. Thus, with modern lamellar techniques, the clinical problem of endothelial graft rejection seems to be nearly solved in the low-risk situation. However, even with lamellar grafts there are epithelial, subepithelial and stromal immune reactions in DALK and endothelial immune reactions in DSAEK/DMEK, and not all keratoplasties can be performed in a lamellar fashion. Therefore, endothelial graft rejection in PK is still highly relevant, especially in the "high-risk" setting, where the cornea's (lymph)angiogenic and immune privilege is lost due to severe inflammation and pathological neovascularization. For these eyes, currently available treatment options are still unsatisfactory. In this review, we will describe currently used keratoplasty techniques, namely PK, DALK, DSAEK, and DMEK. We will summarize their indications, provide surgical descriptions, and comment on their complications and outcomes. Furthermore, we will give an overview on corneal transplant immunology. A specific focus will be placed on endothelial graft rejection and we will report on its incidence, clinical presentation, and current/future treatment and prevention options. Finally, we will speculate how the field of keratoplasty and prevention of corneal allograft rejection will develop in the future.

Transcanalicular laser dacryocystorhinostomy for acquired nasolacrimal duct obstruction: an audit of 104 patients

PURPOSE

External dacryocystorhinostomy (DCR) is considered as the gold standard in the treatment of acquired nasolacrimal duct obstruction. However, many advances have been made towards the development of modern minimally invasive therapies. These new techniques were proven less harmful to the patients' skin and medial palpebral structures with their palpebral-canalicular pump mechanism. Options include endonasal and transcanalicular procedures. Here, we report on our 2-year experience with the surgical technique, results and complications of transcanalicular laser-assisted DCR.

METHODS

This is a retrospective study. A total of 104 patients with acquired nasolacrimal duct obstruction underwent transcanalicular laser-assisted DCR combined with bicanalicular silicon intubation. We then analyzed intra-/post-operative complications and subjective and objective success rates. The institutional ethics committee ruled that approval was not necessary. The trial was registered with the German Clinical Trials Register (DRKS00012879).

RESULTS

Transcanalicular laser-assisted DCR in combination with bicanalicular silicon intubation could be performed surgically successfully in 101 patients (97%). In three cases (3%) using the superior canalicular approach, positioning of the laser instrument at the anteroinferior rim of the middle turbinate failed. Complications included thermal injury to the canaliculus (one), canalicular infection (two) and silicon tube prolapse (ten). Functional success (resolution of preoperative symptoms) was achieved in 80 cases (77%), functional failure occured in 24 cases with all patients reporting persisting epiphora, 15 reporting failure to irrigate the nasolacrimal duct and 15 requiring secondary external DCR.

CONCLUSIONS

Laser-assisted DCR shows promising results with few complications. It seems well suited as a second-step procedure after failed recanalization and before external DCR.

Detection of Pro- and Antiangiogenic Factors in the Human Sclera

PURPOSE

Avascular tissues can be used to identify antilymph- or antihemangiogenic factors. The human sclera-the outer covering layer of the eye, lacks lymphatic vessels and contains only a superficial network of blood vessels and was used here to identify endogenous antiangiogenic factors.

METHODS

Expression levels of a panel of 96 known pro- and antiangiogenic factors were analyzed in 12 scleral or conjunctival control samples from normal human donors using real-time PCR. In vitro, scleral homogenate was cocultured with blood- and lymphatic endothelial cells (BECs and LECs) and immunohistochemistry was performed of scleral fibroblasts and BECs.

RESULTS

Three antiangiogenic factors were significantly upregulated in the human sclera compared to the conjunctiva, including FBLN5 (fibulin 5), SERPINF1 (serpin peptidase inhibitor, clade F, member 1 = pigment epithelium derived factor) and TIMP2 (Tissue inhibitor of metalloproteinases 2). Six proangiogenic factors were significantly downregulated in the sclera, including FLT4 (Fms-related tyrosine kinase 4=VEGF-R3), HGF (hepatocyte growth factor), KIT (CD117 / c-kit), PROX1 (prospero homeobox 1), SEMA3F (semaphorin-3F) and TGFA (transforming growth factor alpha). In vitro, scleral homogenate inhibited the growth of both BECs and LECs. Immunohistochemistry labeling of three major antiangiogenic factors from scleral tissue confirmed TIMP3 and PEDF expression both in scleral fibroblasts and in blood endothelial cells, whereas TIMP2 was not detectable.

CONCLUSION

Balancing anti- and proangiogenic factors actively regulates human scleral avascularity, inhibits endothelial cell growth in vitro, and thus may help maintaining the vascular privilege of the inner eye.

Die Bedeutung der intraoperativen optischen Kohärenztomografie (MI-OCT) bei der Behandlung von Hornhautdystrophien

Hintergrund Die chirurgische Behandlung von Hornhautdystrophien entwickelt sich mit zunehmender Anwendung von lamellären Techniken der Hornhauttransplantation rasant weiter. War vor einigen Jahren noch die penetrierende Keratoplastik der Goldstandard zur Therapie einer Vielzahl von Dystrophien, so können heutzutage selektiv die betroffenen Schichten der Hornhaut ersetzt oder mittels Lasertechnik abladiert werden. Einen besonderen Stellenwert nimmt für diese Verfahren die optische Kohärenztomografie ein, die neuerdings auch in Operationsmikroskope integriert sein kann (MI-OCT).

Methoden Literaturübersicht aus PubMed und Google.scholar.de ergänzt mit eigenen Bildgebungsdaten.

Ergebnisse Die MI-OCT ermöglicht das intraoperative Echtzeit-Monitoring unterschiedlicher ophthalmochirurgischer Prozeduren wie der tiefen, anterioren lamellären Keratoplastik, der Descemet-Membran-Endothel-Keratoplastik (DMEK), aber auch minimalinvasiver Verfahren wie der phototherapeutischen Keratektomie (PTK). Darüber hinaus ermöglicht sie eine Evaluation der Hornhaut wie auch der Vorderkammer, insbesondere in Situationen einer getrübten Hornhaut.

Schlussfolgerung Die mikroskopintegrierte intraoperative optische Kohärenztomografie (MI-OCT) stellt eine sinnvolle Ergänzung zum normalen Operationsmikroskop dar. Sie ist insbesondere bei bereits stark getrübten Hornhäuten dem alleinigen Operationsmikroskop überlegen und stellt gerade bei neuartigen lamellären Transplantationsverfahren eine sinnvolle Ergänzung dar. Randomisierte prospektive Studien sind nötig, um die erhöhte Sicherheit und gesteigerte Effektivität durch den Einsatz der MI-OCT bei verschiedenen Indikationen zu belegen.

Intraoperative changes in corneal structure during excimer laser phototherapeutic keratectomy (PTK) assessed by intraoperative optical coherence tomography

PURPOSE

Excimer laser phototherapeutic keratectomy (PTK) is a safe treatment for superficial corneal opacities, e.g., in corneal dystrophies or degenerations. Nevertheless, no standardized treatment protocols are available and intraoperative monitoring was not possible, so far. Here we evaluate the potential benefits of the intraoperative assessment by microscope-integrated intraoperative optical coherence tomography (MI-OCT) of corneal optical properties during PTK.

METHODS

Retrospective study of eight patients (one male, seven females; age range, 43-80 years, mean = 66.1 years) using an 840-nm microscope-integrated spectral-domain OCT (iOCT; OptoMedical Technologies, Luebeck, Germany adapted to HS Hi-R Neo 900A, Haag Streit Surgical, Wedel, Germany). Images were acquired before and after corneal abrasion and after PTK. For PTK, a SCHWIND Amaris 750S excimer laser (SCHWIND eye-tech-solutions GmbH und KO. KG) was used. Parameters assessed were the central corneal thickness (CCT), changes in central depth-dependent corneal tissue intensity (TI), and corneal surface roughness (SR) in cross-sectional images of the cornea.

RESULTS

Intraoperative monitoring using microscope-integrated OCT was possible in all patients at all time points. TI of the anterior corneal stroma decreased significantly (p = 0.037) after PTK (T1 = 15.1 ± 3.6, T2 = 15.0 ± 3.84, T3 = 13.7 ± 3.38), but not after corneal abrasion alone, indicating increased transparency caused by excimer laser PTK. CCT was significantly lower after corneal abrasion (p = 0.017), but not after PTK (T1 = 630.4 ± 70 μm, T2 = 544.1 ± 59.4 μm, T3 = 558.3 ± 52.5 μm. SR significantly decreased (p = 0.043) after PTK (T1 = 614.4 ± 37.5 pixels, T2 = 634.4 ± 35.6 pixels, T3 = 611.0 ± 40.3 pixels).

CONCLUSIONS

Intraoperative OCT allows real-time imaging during PTK and the assessment of corneal optical transparency and its surface roughness. It has to be clarified in larger studies if these parameters correlate with later postoperative visual outcomes.

DMEK: Probleme vermeiden, erkennen, lösen

Seit der ersten erfolgreichen Descemet Membrane endothelial Keratoplasty (DMEK) vor über 10 Jahren hat sich diese Technik in vielen Regionen zu einem Routineeingriff entwickelt, der mittlerweile einen festen Platz im ophthalmochirurgischen Armamentarium bei der Behandlung von Hornhautendothelerkrankungen einnimmt. Im Vergleich mit der etwas älteren Methode der Descemetʼs Stripping (automated) endothelial Keratoplasty (DS[A]EK), bei der das Transplantat im Gegensatz zur DMEK noch eine Stromalamelle besitzt, wird bei der DMEK eine schnellere und bessere Visuserholung erzielt und gleichzeitig ist das Risiko der Abstoßungsreaktion deutlich reduziert. Dennoch birgt die Technik einige Schwierigkeiten, die ein besonderes Vorgehen zur Vermeidung intra- und postoperativer Komplikationen notwendig machen. Hierzu zählen Strategien zur Vermeidung von Endothelschädigungen während der Präparation, die richtige Spender-Patienten-Allokation ist wichtig für eine schonende Entfaltung der Transplantatrolle in der Vorderkammer, die Verwendung von SF6-Gas zur Transplantatanlage vermindert die Transplantatablösungsrate und damit die Notwendigkeit erneuter Vorderkammertamponaden (Rebubblings), und die richtige postoperative Behandlung mit topischen Steroiden hat maßgeblichen Einfluss auf die Entwicklung von zystoidem Makulaödem und Abstoßungsreaktionen. Durch die weitere Standardisierung, aber auch Individualisierung der DMEK kann sie mittlerweile auch bei Patienten mit schwierigen anatomischen Voraussetzungen des vorderen Augenabschnitts (anteriore Synechien, größere Irisdefekte, Glaukomdrainageimplantate) regelmäßig durchgeführt werden, wodurch gerade solche Patienten mit tendenziell erhöhtem Risiko von Wundheilungsstörungen und Abstoßungsreaktionen im Übermaß profitieren.

Modified Hughes procedure for reconstruction of large full-thickness lower eyelid defects following tumor resection

Background

Tarsoconjunctival flap advancement, or the Hughes procedure, is among the techniques of choice for reconstructing full-thickness lower eyelid defects so as to restore normal anatomy and function with the best possible cosmetic outcome. The purpose of this study is to report the outcome of a series of patients treated with a modified Hughes procedure following malignant tumor removal.

Methods

This retrospective study included 45 consecutive cases of modified Hughes procedures performed between January 2013 and October 2015. During Hughes flap creation an incisional plane was chosen in all cases, which left Müller’s muscle attached to the superior tarsal margin, while disinserting the levator aponeurosis. All cases were grouped according to the horizontal length of the lower lid defect to be reconstructed, as well as to the type of anterior lamella reconstruction (free graft vs. inferiorly based advancement flap). Grouped data were compared for the rate of surgical success, defined as achievement of normal lid function and satisfactory cosmesis without needing further surgical interventions, and for the frequency of specific complications.

Results

Surgical success was achieved in 39 cases (87 %). The remaining cases required additional surgery for minor complications including lower-lid ectropion (4 %), pyogenic granuloma (4 %), or lower lid margin hypertrophy (2 %). Donor-site complications were not detected apart from one case of mild entropion with focal trichiasis. No case of premature flap rupture was seen. Neither the horizontal length of the lower lid defect (p = 0.489), nor the type of anterior lamella reconstruction (p = 0.349) significantly affected the surgical success. Particularly, there was no increased onset of lower-lid ectropion among patients receiving an advancement flap.

Conclusions

The modified Hughes procedure remains a well-suited technique for reconstructing lower eyelid defects involving up to 100 % of the horizontal lid length. Leaving Müller’s muscle attached to the Hughes flap might prevent premature flap dehiscence without increasing the frequency of upper lid retractions in turn. Whether using a free skin graft or a skin-muscle advancement flap for anterior lamella reconstruction, seems to be insignificant for the functional-aesthetical outcome.

Epithelial-Mesenchymal Transition (EMT)-Related Cytokines in the Aqueous Humor of Phakic and Pseudophakic Fuchs' Dystrophy Eyes

PURPOSE

The present study aimed to analyze the expression of epithelial-mesenchymal transition (EMT)-related cytokines in the aqueous humor of phakic and pseudophakic Fuchs' endothelial corneal dystrophy (FECD) eyes and their correlation to FECD severity.

METHODS

Aqueous humor samples from phakic FECD eyes (FECDph, n = 9), from pseudophakic FECD eyes more than 1 year after cataract surgery (FECDpsph, n = 13), and from cataract controls without FECD (Controlcat, n = 28) were obtained during Descemet membrane endothelial keratoplasty (DMEK) or cataract surgery. Expression of EMT-related cytokines (TGF-β1, TGF-β2, TGF-β3, MCP-1, BFGF, TNF-α, IL-1β) was measured using multiplex bead assay. Corneal central-to-peripheral thickness ratio at 3.5 mm from the center (CPTR3.5) was determined as an objective metric for FECD severity before surgery by slit-scanning pachymetry.

RESULTS

Pseudophakic FECD eyes showed significantly elevated expression compared with Controlcat and FECDph eyes for TGF-β1 (P < 0.001, respectively), for TGF-β2 (P < 0.05, respectively), and MCP-1 (P < 0.001, respectively). Levels of TGF-β1 (r = 0.6116, P < 0.05) and MCP-1 (r = 0.5934, P < 0.05) were positively correlated with CPTR3.5. No differences in EMT-associated protein levels were detected comparing FECDph eyes and Controlcat eyes.

CONCLUSIONS

Simultaneous elevation of TGF-β1, TGF-β2, and MCP-1 concentrations in FECDpsph eyes confirms that cataract surgery leads to long-term alterations of the intraocular microenvironment. Positive correlation of increased aqueous TGF-β1 and MCP-1 levels with CPTR3.5 in pseudophakic FECD eyes suggests that changed cytokine levels may be involved in corneal decompensation after cataract surgery. Unchanged aqueous humor levels of EMT-related proteins analyzed in phakic FECD patients indicate that there is no primary role of these aqueous cytokines in FECD pathogenesis.

Benign orbital angiomatous tumors with intracranial extension

Orbital neoplasms with associated bone erosions and intracranial extension are generally considered suspicious for malignancies. Here, we describe the clinical and radiological findings, as well as the surgical management of two extraordinary cases, in which such bony perforations with subsequent intracranial tumor growth resulted from benign angiomatous orbital neoplasms. Two female patients, 69 years old (case 1) and 51 years old (case 2), had both developed visual symptoms (visual field restrictions and/or visual acuity loss) over several months. Computed tomography revealed an orbital tumor of the anterosuperior orbit with painless swelling of the medial upper eyelid of the right eye in case 1, and a posterior intraconal tumor close to the orbital apex of the left eye in case 2, respectively. In both cases, the tumor was associated with a perforation of the orbital roof connecting the orbit with the anterior cranial fossa. An interdisciplinary ophthalmologic and neurosurgical approach allowed for complete tumor removal, in both patients with no signs for local recurrence during the subsequent follow-up of 15 and 18 months, respectively, as well as for a satisfactory visual rehabilitation.