Expression and Impact of Fibronectin, Tenascin-C, Osteopontin, and Type XIV Collagen in Fuchs Endothelial Corneal Dystrophy.

Purpose: Fuchs endothelial corneal dystrophy (FECD) is characterized by Descemet's membrane (DM) abnormalities, namely an increased thickness and a progressive appearance of guttae and fibrillar membranes. The goal of this study was to identify abnormal extracellular matrix (ECM) proteins expressed in FECD DMs and to evaluate their impact on cell adhesion and migration. Methods: Gene expression profiles from in vitro (GSE112039) and ex vivo (GSE74123) healthy and FECD corneal endothelial cells were analyzed to identify deregulated matrisome genes. Healthy and end-stage FECD DMs were fixed and analyzed for guttae size and height. Immunostaining of fibronectin, tenascin-C, osteopontin, and type XIV collagen was performed on ex vivo specimens, as well as on tissue-engineered corneal endothelium reconstructed using healthy and FECD cells. An analysis of ECM protein expression according to guttae and fibrillar membrane was performed using immunofluorescent staining and phase contrast microscopy. Finally, cell adhesion was evaluated on fibronectin, tenascin-C, and osteopontin, and cell migration was studied on fibronectin and tenascin-C. Results: SPP1 (osteopontin), FN1 (fibronectin), and TNC (tenascin-C) genes were upregulated in FECD ex vivo cells, and SSP1 was upregulated in both in vitro and ex vivo FECD conditions. Osteopontin, fibronectin, tenascin-C, and type XIV collagen were expressed in FECD specimens, with differences in their location. Corneal endothelial cell adhesion was not significantly affected by fibronectin or tenascin-C but was decreased by osteopontin. The combination of fibronectin and tenascin-C significantly increased cell migration. Conclusions: This study highlights new abnormal ECM components in FECD, suggests a certain chronology in their deposition, and demonstrates their impact on cell behavior.

Comparative posterior corneal profile of keratoconus hydrops versus Haab's striae in congenital glaucoma.

Keratoconus eyes develop corneal decompensation more often compared to eyes with primary congenital glaucoma (PCG) following Descemet's membrane (DM) tear. This study was conducted to compare the posterior corneal morphology in areas with DM breaks with regards to DM and pre-Descemet's layer (PDL) between the two. In this cross-sectional comparative study, anterior segment optical coherence tomography (AS-OCT) scans of the posterior cornea of advanced keratoconus eyes with hydrops ( n = 12), PCG eyes with Haab's striae ( n = 15), and healthy control eyes ( n = 14) were compared for DM-PDL morphology. These were further corroborated by the histopathology of corneal buttons from keratoconus ( n = 14) and PCG ( n = 13) cases obtained following penetrating keratoplasty and compared with controls (enucleated retinoblastoma globes, n = 6) on light microscopy and collagen IV immunostaining. AS-OCT showed a thicker median DM/PDL complex in PCG (80 µm) versus keratoconus eyes (36 µm, P = 0.01; Kruskal-Wallis test). The median height and length of detached DM-PDL were significantly more in keratoconus versus PCG (145 µm, 1766.1 ± 1320.6 µm vs. 26.5 µm, 453.3 ± 303.2 µm, respectively, P = 0.012; Kruskal-Wallis test). Type-1 DM/PDL detachment (seen as a characteristic taut chord) in keratoconus (90%) was the most common morphological pattern versus intracameral twin protuberance (92%) following DM breaks in PCG. Histopathology confirmed thicker DM in PCG (median: 63.4 µm) versus keratoconus eyes (median: 33.2 µm) or controls (27.1 µm) ( P = 0.001; Kruskal-Wallis test). Greater height/length of DM/PDL detachment compounded by poor healing response (lower DM/PDL thickness) probably causes more frequent corneal decompensation in keratoconus eyes when compared to PCG eyes following DM tears.

Corneal Guttae After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: The aim of this study was to report on the occurrence of corneal guttae after Descemet membrane endothelial keratoplasty (DMEK). METHODS: In this retrospective case series, 13 eyes of 13 patients who underwent DMEK at 2 tertiary referral centers between 2007 and 2021 (average available follow-up 73 ± 52 months, range 18-174 months) and showed corneal guttae during postoperative examinations were included. Eye bank images were retrospectively reviewed. RESULTS: Occurrence of guttae was observed by specular microscopy in 13 eyes. In 11 cases, presence of guttae was confirmed by confocal microscopy and in 1 case by histology. Five eyes showed an increase in guttae density during the postoperative course. Surgery indications were Fuchs endothelial corneal dystrophy (n = 11), pseudophakic bullous keratopathy (n = 1), and DMEK graft failure after allograft rejection (n = 1); the latter eye had shown no signs of guttae after primary DMEK. Two eyes with guttae required a repeat DMEK due to graft failure. At the last available follow-up, all 11 remaining eyes had clear corneas and 10 eyes had a best-corrected visual acuity of ≥0.9 (decimal). During donor cornea processing in the eye bank, no guttae were observed on the donor tissue. CONCLUSIONS: Corneal guttae can occur after DMEK including in eyes operated for indications other than Fuchs endothelial corneal dystrophy and most likely guttae were present on the donor graft but were not detectable by routine slit-lamp and light microscopy evaluation in the eye bank. Postoperative guttae density varies among patients and especially small isolated guttae do not seem to affect clinical outcomes.

Use of a Single Radial Incision to Improve Curvature Matching and Graft Adhesion in Descemet Membrane Endothelial Keratoplasty in a Patient With Keratoconus.

PURPOSE: The purpose of this study was to report a novel surgical technique for altering donor Descemet membrane endothelial keratoplasty (DMEK) curvature to match host posterior stroma in a patient with advanced keratoconus (KC) and endothelial decompensation. METHODS: We report a 56-year-old man with Fuch endothelial dystrophy and KC, who underwent DMEK due to endothelial decompensation. A triangular area of graft detachment centered on the apex of cones persisted after repeat gas tamponade. A radial incision from the graft edge to the apex was used to allow overlapping of the graft, thereby increasing the grafts curvature. RESULTS: The use of a radial incision in the Descemet membrane (DM) graft was made to allow the graft overlap and adapt to the new shape. By matching the donor curvature to that of the hosts posterior curvature, full adhesion of the graft was achieved with the use of a short-acting air bubble by 1 week after the procedure. CONCLUSIONS: The mismatch in the curvature of the DM graft and the host posterior corneal surface, in cases with KC or very steep corneas, should be taken into consideration because it can lead to redundancy folds. These can result in atypical, conical detachments, distinct from the typical peripheral detachments seem commonly in DMEK. A single radial incision in the DM graft combined with air tamponade is a feasible treatment option in cases where DMEK fails to attach because of apparent curvature mismatch between the donor and host.

Management of Late Descemet's Membrane Detachment After Penetrating Keratoplasty in Keratoconus.

PURPOSE: The purpose of this study was to describe the feasibility of Descemet membrane endothelial keratoplasty (DMEK) as a treatment modality for spontaneous detachment of DM (DMD) decades after penetrating keratoplasty (PK) for keratoconus. METHODS: We describe the clinical characteristics and therapeutic surgical approach in 6 eyes of 5 patients with DMD. Clinical images, anterior segment optical coherence tomography scans, and histological findings are presented. RESULTS: Mean age of patients at time of diagnosis was 60 years (range 56-66 years). Mean interval between PK and occurrence of DM detachment was 36 years (range 29-45 years). In 4 of 6 eyes, air injections into the anterior chamber were initially attempted to reattach DM to the stroma but without long-lasting effect. Two eyes underwent repeat PK because of pronounced ectasia after long-standing DMD and stromal scars. DMEK was performed successfully in 4 eyes leading to an increase in visual acuity and a reduction in central corneal thickness. Electron microscopy showed abnormal vacuolar inclusions and collagenous material in the posterior nonbanded layer and a separation of the anterior banded layer from the posterior nonbanded layer. CONCLUSIONS: This case series provides evidence that DMEK is a viable option in eyes with spontaneous DM detachment after PK. Visual outcome is limited by the persisting high astigmatism in the ectatic cornea. Illustrated by a small series of patients, the results of DMEK in this condition are presented and new findings about the pathophysiology are given.

The Descemet Membrane in Primary Congenital Glaucoma.

PURPOSE: To evaluate Descemet membrane (DM) morphology in eyes with primary congenital glaucoma (PCG) in vivo using high-definition anterior segment optical coherence tomography (ASOCT) and on histopathology. METHODS: Corneal scans of patients with PCG (22 eyes of 15 patients) were evaluated for DM morphology and anterior chamber angle using ASOCT. The DM thickness in PCG eyes was compared with fellow eyes (8 eyes) of unilateral patients with PCG and healthy controls (12 eyes) on ASOCT. The DM morphology was also compared on the histopathology of corneal tissues (9) obtained from PCG eyes after keratoplasty and enucleated eyes of retinoblastoma (6 controls) on light microscopy with immunostaining for collagen IV. RESULTS: On ASOCT, all affected eyes showed the presence of either a thickened DM complex or a hyper-reflective double layer representing the thickened DM and pre-Descemet layer (PDL), unlike a single membrane in the controls and fellow eyes. On ASOCT, among patients with PCG, the DM showed significant thickening (32.0 ± 11.2 µm) versus fellow eyes (14.4 ± 3.3 µm) and controls (11.5 ± 1 µm) (P < 0.001; analysis of variance). The thickened DM complex continued peripherally into the trabecular meshwork as an abnormal membrane in 16/22 affected eyes. On histopathology, thickening of DM was also more among PCG eyes (median: 67.9 µm range: 27.2-214.9) versus controls (median: 27.7 µm, range: 22.1-36.1; P = 0.005) as also of PDL (median: 14 µm, range: 5.9-30.5) of PCG versus (median 3.5, range: 1.3-6.7 µm) in controls; P = 0.014. CONCLUSIONS: Thickening of DM and PDL occurs in eyes with PCG and is seen to have a peripheral extension upto the angle recess.

Automated Clinical Assessment of Corneal Guttae in Fuchs Endothelial Corneal Dystrophy.

PURPOSE: To describe the validation and implementation of an automated system for the detection and quantification of guttae in Fuchs endothelial corneal dystrophy (FECD). DESIGN: Observational reliability study. METHODS: Patients with FECD underwent retroillumination corneal photography, followed by determination of the distributions and sizes of corneal guttae by an automated image analysis algorithm. Performance of the automated system was assessed via (1) validation against manual guttae segmentation, (2) reproducibility studies to ensure consistency, and (3) evaluation for agreement with the Krachmer scale. It was then deployed to perform large-scale guttae assessment with anatomic subregion analysis in a batch of 40 eyes. RESULTS: Compared to manual segmentation, the automated system was reasonably accurate in identifying the correct number of guttae (mean count of 78 guttae per 1 × 1 mm test frame, overestimation: +10 per frame), but had a tendency to significantly overestimate guttae size (mean guttae size 1073 µm2, overestimation: +255 µm2). Automated measurements of guttae counts and sizes were reproducible within a 1% discrepancy range across repeat intra-eye assessments. Automated guttae counts, interguttae distances, and density of interguttae gaps lesser than 40 µm (ie, D40 density) were highly correlated with the Krachmer scale (P < .001 for all). Large-scale guttae assessment demonstrated the automated system's potential to selectively identify a region of the corneal endothelium most affected by densely packed guttae. CONCLUSIONS: Automated guttae assessment facilitates the precise identification and quantification of guttae characteristics in FECD patients. This can be used clinically as a personalized descemetorrhexis zone for Descemet stripping only and/or Descemet membrane transplantation.

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/mm2 and 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.

[Descemet's membrane detachment after phacoemulsification: Series of 9 cases]. / Décollement descemétique post-phakoémulsification : à propos de 9 cas.

PURPOSE: Descemet's membrane detachment (DMD) is a rare but potentially serious complication of cataract surgery. Although there are no consensual guidelines regarding the diagnosis or treatment of DMD, incorrect treatment may result in irreversible corneal changes with visual sequellae. The purpose of our study is to describe the diagnosis and treatment of DMD. METHODS: We report a series of 9 cases of DMD, their diagnosis, treatment and outcomes. We tested the HELP protocol retrospectively against our 9 real-life cases. RESULTS: Two cases recovered with simple medical management, 4 required air-bubble descemetopexy, and three required keratoplasty. Our study revealed that the main factor associated with poor outcomes is late diagnosis and management. CONCLUSION: Our series illustrates the importance of proactive management and timely diagnosis by performing anterior segment OCT in the setting of persistent postoperative corneal edema.

Factors associated with endothelial cell density loss post Descemet membrane endothelial keratoplasty for bullous keratopathy in Asia.

PURPOSE: To investigate the factors associated with endothelial survival after Descemet's membrane endothelial keratoplasty (DMEK) in eyes of Asian patients with bullous keratopathy (BK). METHODS: In this retrospective, consecutive interventional case series, 72 eyes of 72 patients who underwent DMEK were evaluated. Best corrected visual acuity (BCVA) and corneal endothelial cell density (ECD) were assessed at 12 months postoperatively. Multiple regression analysis was performed to assess parameters such as age, sex, axial length, preoperative visual acuity, re-bubbling, the ratio of graft to cornea area, iris damage scores, types of filling gases, air or SF6 volume in the anterior chamber (AC) on postoperative day 1, and ECD loss rates at 12 months postoperatively. RESULTS: BCVA improved significantly at 12 months after DMEK (P < .001). The rate of ECD loss at 12 months after DMEK was 54.4 ± 16.1%. Multiple linear regression analysis showed that a larger ratio of graft to corneal area (P = 0.0061) and higher donor ECD (P = 0.042) were the primary factors for a lower ECD loss rate at 12 months after DMEK. CONCLUSION: A relatively larger graft size compared to the host cornea and more donor ECD might help endothelial survival in patients with BK. Moreover, for such patients, the surgeon should attempt to use a relatively larger graft size when performing DMEK, particularly in Asian eyes.

Descemet's membrane development, structure, function and regeneration.

Basement membranes are layers of extracellular matrix which anchor the epithelium or endothelium to connective tissues in most organs. Descemet's membrane- which is the basement membrane for the corneal endothelium- is a dense, thick, relatively transparent and cell-free matrix that separates the posterior corneal stroma from the underlying endothelium. It was historically named Descemet's membrane after Jean Descemet, a French physician, but it is also known as the posterior limiting elastic lamina, lamina elastica posterior, and membrane of Demours. Normal Descemet's membrane ultrastructure in humans has been shown to consist of an interfacial matrix that attaches to the overlying corneal stroma, an anterior banded layer and a posterior non-banded layer-upon which corneal endothelial cells attach. These layers have been shown to have unique composition and morphology, and to contribute to corneal homeostasis and clarity, participate in the control of corneal hydration and to modulate TGF-ß-induced posterior corneal fibrosis. Pathophysiological alterations of Descemet's membrane are noted in ocular diseases such as Fuchs' dystrophy, bullous keratopathy, keratoconus, primary congenital glaucoma (Haab's striae), as well as in systemic conditions. Unrepaired extensive damage to Descemet's membrane results in severe corneal opacity and vision loss due to stromal fibrosis, which may require penetrating keratoplasty to restore corneal transparency. The purpose of this article is to highlight the current understanding of Descemet's membrane structure, function and potential for regeneration.

"Descemet Membrane Detachment": A Novel Concept in Diagnosis and Classification.

PURPOSE: To examine the optical coherence tomography (OCT) and histologic features of Descemet membrane detachment (DMD) to ascertain the involvement of the pre-Descemet layer (PDL). DESIGN: Retrospective, observational case series. METHODS: Clinical, histopathologic, and OCT features of a cohort of 41 cases with diagnosis of DMD from 4 centers were studied. OCT images were evaluated independently by 3 observers for number of detached layers (1 or 2), reflectivity, configuration (straight line or wavy), distance from posterior stroma, and presence or absence of a tear with any scrolling of the torn edges. Five had a histology specimen. The main outcome measure was the involvement of the PDL in DMD and its confirmation by histology. RESULTS: Three types of DMD were identified: type 1, where the PDL and DM were detached together; type 2, where only the DM was detached; and mixed, where the PDL and DM were detached but also separated from each other. These were further found to be rhegmatogenous or nonrhegmatogenous depending on the presence of absence of a tear in DM or both layers. Histology confirmed involvement of PDL in all 5 cases and showed it to be infiltrated by cells in 3 of 5 cases. CONCLUSIONS: The PDL is involved in DMD. This fact significantly changes our understanding of DMD and could have implications for management. The detached PDL can be infiltrated with cells. A prospective study in relation to etiology and types of DMD is needed.

Multimodal Imaging of Pre-Descemet Corneal Dystrophy Associated With X-Linked Ichthyosis and Deletion of the STS Gene.

PURPOSE: To investigate the presence of pre-Descemet corneal dystrophy (PDCD) in association with X-linked ichthyosis (XLI) in an 11-year-old boy using multimodal imaging and genetic analysis. METHODS: Corneal opacities were examined and imaged with slit-lamp biomicroscopy, anterior segment optical coherence tomography, noncontact specular microscopy, and in vivo confocal microscopy. Cytogenomic array analysis was performed using genomic DNA isolated from the patient. RESULTS: Corneal opacities characteristic of PDCD located in the posterior corneal stroma just anterior to Descemet membrane were identified by slit-lamp biomicroscopy. A pre-Descemet hyper-reflective line, consistent with these opacities, was seen with anterior segment optical coherence tomography. Scheimpflug tomography revealed a bimodal peak light scattering. In vivo confocal microscopy findings were unremarkable. Copy number analysis identified a 4389 kbp hemizygous deletion on the X chromosome (chr. X: 6,540,898-8,167,604), resulting in the deletion of 4 genes, including the known locus of XLI, the STS gene. CONCLUSIONS: This report demonstrates that PDCD-associated XLI may present in children and that the diagnosis may be confirmed through multimodal imaging in conjunction with genetic analysis.

Descemet Membrane Detachment After Penetrating Keratoplasty for Keratoconus.

PURPOSE: To describe the risk factors, management, and outcome of delayed Descemet membrane (DM) detachment after penetrating keratoplasty (PK) for keratoconus. METHODS: We report 7 eyes from 6 cases and combine these data with 7 previous case reports identified by a search of PubMed. RESULTS: DM detachment occurred at a median of 25 years (range, 7-33 years) after PK. One individual had bilateral detachments. There was typically a mild ocular discomfort accompanied in some cases by a rapid onset of visual blur. Cases were often treated for allograft rejection before a DM detachment was suspected and confirmed by optical coherence tomography. Detachments were limited to the donor tissue in 11 eyes, but a DM break was identified at the time of onset in only 4 eyes. Thinning of the host corneal rim with ectasia was reported in 8 eyes (57%). In 3 eyes, the detachment resolved spontaneously, but in 2 eyes, a detachment was still present at 12 months. Gas tamponade to reattach the DM was performed in 9 eyes and was effective in 4 eyes. Five eyes underwent a repeat PK or endothelial keratoplasty. Histology showed fibroblastic proliferation on the stromal surface of the folded DM. CONCLUSIONS: The cause for DM detachment many years after PK is unknown, although progressive thinning of the host cornea and secondary graft ectasia may be implicated. Gas tamponade can be effective, but a repeat keratoplasty might be necessary. DM detachment should be included in the differential diagnosis for late-onset corneal edema after PK.