Correlations of Corneal Endothelial Morphology and Corneal Thickness With Anterior Segment Parameters in Healthy Individuals.

PURPOSE: The purpose of this study was to investigate the associations between central corneal endothelial cell density (ECD), endothelial morphology, and corneal thickness (central corneal thickness) with the anterior chamber depth, corneal volume (CV), white-to-white (WTW) distance, mean anterior chamber angle (CAmean), and gender in healthy individuals. METHODS: This observational study included 136 healthy volunteers. The ECD, coefficient of variation of cell area, and hexagonal cell appearance ratio (%Hex) were measured by means of specular microscopy. The central corneal thickness, anterior chamber depth, CV, WTW distance, and the angle width of 12 points were taken by the Pentacam HR Scheimpflug anterior segment imaging. The arithmetical mean of the 12 points was considered as the CAmean. We used mixed effect linear regression model for the statistical analysis of the data. RESULTS: ECD was positively correlated with CV ( P = 0.028), while after adjusting for age, it was negatively correlated with age ( P < 0.001). Coefficient of variation of cell area was positively correlated with CAmean ( P = 0.036), while after adjusting for age, it was positively correlated with age ( P < 0.001) and CAmean ( P = 0.005). Hex was negatively correlated with WTW ( P = 0.023) and CAmean ( P = 0.025), and after adjusting for age, this correlation remained the same ( P = 0.029 when correlated with WTW and P = 0.035 with CAmean). CONCLUSIONS: There were significant changes in the morphology of the corneal endothelial cells in eyes with wider anterior chamber angle. Greater pleomorphism and polymegethism of the corneal endothelium was observed in healthy patients with wider CAmean. Deepening of the anterior chamber as myopia progresses could render the corneal endothelium more fragile and susceptible to mechanical stress, which is an area worthy of further study.

Assessing Fuchs Corneal Endothelial Dystrophy Using Artificial Intelligence-Derived Morphometric Parameters From Specular Microscopy Images.

PURPOSE: The aim of this study was to evaluate the efficacy of artificial intelligence-derived morphometric parameters in characterizing Fuchs corneal endothelial dystrophy (FECD) from specular microscopy images. METHODS: This cross-sectional study recruited patients diagnosed with FECD, who underwent ophthalmologic evaluations, including slit-lamp examinations and corneal endothelial assessments using specular microscopy. The modified Krachmer grading scale was used for clinical FECD classification. The images were processed using a convolutional neural network for segmentation and morphometric parameter estimation, including effective endothelial cell density, guttae area ratio, coefficient of variation of size, and hexagonality. A mixed-effects model was used to assess relationships between the FECD clinical classification and measured parameters. RESULTS: Of 52 patients (104 eyes) recruited, 76 eyes were analyzed because of the exclusion of 26 eyes for poor quality retroillumination photographs. The study revealed significant discrepancies between artificial intelligence-based and built-in microscope software cell density measurements (1322 ± 489 cells/mm 2 vs. 2216 ± 509 cells/mm 2 , P < 0.001). In the central region, guttae area ratio showed the strongest correlation with modified Krachmer grades (0.60, P < 0.001). In peripheral areas, only guttae area ratio in the inferior region exhibited a marginally significant positive correlation (0.29, P < 0.05). CONCLUSIONS: This study confirms the utility of CNNs for precise FECD evaluation through specular microscopy. Guttae area ratio emerges as a compelling morphometric parameter aligning closely with modified Krachmer clinical grading. These findings set the stage for future large-scale studies, with potential applications in the assessment of irreversible corneal edema risk after phacoemulsification in FECD patients, as well as in monitoring novel FECD therapies.

Structural Priors Guided Network for the Corneal Endothelial Cell Segmentation.

The segmentation of blurred cell boundaries in cornea endothelium microscope images is challenging, which affects the clinical parameter estimation accuracy. Existing deep learning methods only consider pixel-wise classification accuracy and lack of utilization of cell structure knowledge. Therefore, the segmentation of the blurred cell boundary is discontinuous. This paper proposes a structural prior guided network (SPG-Net) for corneal endothelium cell segmentation. We first employ a hybrid transformer convolution backbone to capture more global context. Then, we use Feature Enhancement (FE) module to improve the representation ability of features and Local Affinity-based Feature Fusion (LAFF) module to propagate structural information among hierarchical features. Finally, we introduce the joint loss based on cross entropy and structure similarity index measure (SSIM) to supervise the training process under pixel and structure levels. We compare the SPG-Net with various state-of-the-art methods on four corneal endothelial datasets. The experiment results suggest that the SPG-Net can alleviate the problem of discontinuous cell boundary segmentation and balance the pixel-wise accuracy and structure preservation. We also evaluate the agreement of parameter estimation between ground truth and the prediction of SPG-Net. The statistical analysis results show a good agreement and correlation.

[Corneal changes in Fuchs endothelial corneal dystrophy and bullous keratopathy]. / Izmeneniya rogovitsy pri endotelial'noi distrofii Fuksa i vtorichnoi bulleznoi keratopatii.

OBJECTIVE: Evaluation of structural and immunohistochemical features of cornea in Fuchs endothelial corneal dystrophy (FECD) and bullous keratopathy (BK). MATERIAL AND METHODS: Group 1 - 44 patients (46 eyes) with FECD, group 2 - 42 patients (42 eyes) with BK. All patients underwent keratoplasty. Preoperative anterior segment optical coherence tomography (AS-OCT, RTVue-100, Optovue, USA) was performed. Endothelium-Descemet membrane (EDM) complexes, corneal buttons were obtained intraoperatively. Morphological (H&E staining) and immunohistochemical (primary antibodies to pancytokeratin, vimentin, fibronectin) studies were performed at the light microscope level (Leica DM-2500, Leica Application Suite V4.8, Leica Microsystems, Switzerland). RESULTS: A direct correlation is found between the results of DM analysis in vivo with OCT and ex vivo with light microscopy. DM thickness (AS-OCT) was significantly greater in FECD (23.0 [19.0; 27.0] µm), than in BK (13.0 [12.0; 14.0] µm). Morphological study of EDM and corneal buttons showed similar difference in DM thickness: 17.9 [16.1; 20.0] µm in FECD and 11.9 [11.3; 13.0] µm in BK. Irregular optical density of stroma is a feature of edema and local fibrosis. In FECD and BK pancytokeratin is expressed in epithelial and endothelial cells, vimentin - in keratocytes, macrophages and vascular endothelium, fibronectin - in DM. In FECD, vimentin is expressed in endothelial cells. CONCLUSION: FECD and BK are associated with different DM' and endothelium' abnormalities, which lead to similar changes of stroma and epithelium. AS-OCT is a useful method of FECD and BK in vivo diagnostics and the selection of treatment option.

Assessing Corneal Endothelial Damage Using Terahertz Time-Domain Spectroscopy and Support Vector Machines.

The endothelial layer of the cornea plays a critical role in regulating its hydration by actively controlling fluid intake in the tissue via transporting the excess fluid out to the aqueous humor. A damaged corneal endothelial layer leads to perturbations in tissue hydration and edema, which can impact corneal transparency and visual acuity. We utilized a non-contact terahertz (THz) scanner designed for imaging spherical targets to discriminate between ex vivo corneal samples with intact and damaged endothelial layers. To create varying grades of corneal edema, the intraocular pressures of the whole porcine eye globe samples (n = 19) were increased to either 25, 35 or 45 mmHg for 4 h before returning to normal pressure levels at 15 mmHg for the remaining 4 h. Changes in tissue hydration were assessed by differences in spectral slopes between 0.4 and 0.8 THz. Our results indicate that the THz response of the corneal samples can vary according to the differences in the endothelial cell density, as determined by SEM imaging. We show that this spectroscopic difference is statistically significant and can be used to assess the intactness of the endothelial layer. These results demonstrate that THz can noninvasively assess the corneal endothelium and provide valuable complimentary information for the study and diagnosis of corneal diseases that perturb the tissue hydration.

DenseUNets with feedback non-local attention for the segmentation of specular microscopy images of the corneal endothelium with guttae.

Corneal guttae, which are the abnormal growth of extracellular matrix in the corneal endothelium, are observed in specular images as black droplets that occlude the endothelial cells. To estimate the corneal parameters (endothelial cell density [ECD], coefficient of variation [CV], and hexagonality [HEX]), we propose a new deep learning method that includes a novel attention mechanism (named fNLA), which helps to infer the cell edges in the occluded areas. The approach first derives the cell edges, then infers the well-detected cells, and finally employs a postprocessing method to fix mistakes. This results in a binary segmentation from which the corneal parameters are estimated. We analyzed 1203 images (500 contained guttae) obtained with a Topcon SP-1P microscope. To generate the ground truth, we performed manual segmentation in all images. Several networks were evaluated (UNet, ResUNeXt, DenseUNets, UNet++, etc.) and we found that DenseUNets with fNLA provided the lowest error: a mean absolute error of 23.16 [cells/mm[Formula: see text]] in ECD, 1.28 [%] in CV, and 3.13 [%] in HEX. Compared with Topcon's built-in software, our error was 3-6 times smaller. Overall, our approach handled notably well the cells affected by guttae, detecting cell edges partially occluded by small guttae and discarding large areas covered by extensive guttae.

Corneal and lenticular clarity in children with inflammatory disease as assessed by Scheimpflug imaging.

BACKGROUND: Corneal and lenticular optical properties are not well-documented in pediatric patients with inflammatory diseases. Here we aimed to evaluate corneal and lenticular optical density as well as corneal morphology in children with ocular and/or systemic inflammation by Scheimpflug imaging. METHODS: Fifty-five eyes of 29 children with non-infectious uveitis, 56 eyes of 28 children with systemic inflammation without uveitis and 60 eyes of 31 healthy children were included. Corneal/lenticular optical density, corneal volume, central corneal thickness, keratometry were analyzed by Pentacam HR. Corneal endothelial cell density, hexagonal cell ratio and coefficient of variation were measured by specular microscope. RESULTS: The mean age was 12.0 ± 3.1 years, 11.9 ± 4.0 years and 11.3 ± 3.4 years whereas the female/ratio was 15/14, 15/13 and 14/17 in uveitis, systemic inflammation and control groups respectively. Uveitis type was anterior uveitis in 16 (29.1%) eyes, intermediate uveitis in 32 (58.2%) eyes and panuveitis in 7 (12.7%) eyes. Twenty-two (40%) eyes had active uveitis whereas 33 (60%) eyes had inactive uveitis. Corneal optical density was greater in uveitis group compared with other groups (p = 0.001, Kruskal-Wallis test). Lenticular density and corneal parameters other than optical density were not different between the groups (p > 0.05). Corneal optical density was higher in active uveitis than inactive uveitis (22/33 eyes, p = 0.017). CONCLUSION: Children with uveitis had decreased corneal clarity compared with systemic inflammation group and healthy controls, while lenticular clarity was similar between the groups. Corneal endothelial parameters did not change significantly based on ocular/systemic inflammation. Scheimpflug imaging provides objective corneal and lenticular optical density measurements.

[Imaging features of posterior polymorphous corneal dystrophy observed by in vivo confocal microscopy].

Objective: To identify and analyze imaging features of posterior polymorphous corneal dystrophy (PPCD) by in vivo confocal microscopy (IVCM). Methods: This retrospective case series enrolled 27 eyes of 18 patients (including 10 males and 8 females) who were diagnosed with PPCD at the Department of Ophthalmology in Peking University Third Hospital between January 2013 and December 2019. The mean age was (23.61±14.81) years. There were 9 monocular and 9 binocular cases. All patients were examined by slit-lamp biomicroscopy and IVCM. The visual acuity, the mean endothelial cell density, and the images of IVCM were analyzed in all cases. Results: The mean best-corrected visual acuity was 0.76±0.33, and the mean endothelial cell density was (1 723.6±698.3) cells/mm2. The IVCM images of type 1 PPCD (vesicular lesions) showed hyperreflective, placoid or homocentric lesions at the level of the Descemet's membrane, hyporeflective, oval or round lesions at the level of the Descemet's membrane, and hyporeflective, crater-like lesions at the level of the endothelial cell layer. The IVCM images of type 2 PPCD (band lesions) displayed hyperreflective, band lesions and a fibrous strand structure at the level of the Descemet's membrane, hyporeflective, vesicular lesions at the level of the Descemet's membrane, and hyporeflective, trough-and ridge-like lesions at the level of the endothelial cell layer. The IVCM images of type 3 PPCD (geographic placoid opacities) showed loss of the hexagonal features of endothelial cells and epithelial-like cell transformation. Conclusions: PPCD primarily affects the endothelium and Descemet's membrane. IVCM could highlight the special characteristics of PPCD including hyperreflective lesions at the level of the Descemet's membrane, hyporeflective lesions at the level of the endothelial cell layer, and epithelial-like cell transformation of endothelial cells. IVCM is an invaluable tool for clinical diagnosis and dynamic monitoring of PPCD.

Penetrating Keratoplasty With Minimal Endothelial Replacement: A Novel Technique for High-Risk Large-Diameter Corneal Grafting.

PURPOSE: The purpose of this study was to analyze the outcome of large-diameter penetrating keratoplasty with minimal endothelial replacement (PKMER). METHODS: Two eyes (2 patients) with advanced keratoconus and central full-thickness pathology, namely, scar and failed graft, were studied. Both eyes had relatively healthy endothelium in the periphery. They were operated using the PKMER technique that involved a large-diameter keratoplasty with retained central island of endothelium in the donor corresponding to the visual axis, whereas the peripheral Descemet membrane was removed. In effect, the peripheral endothelium and deep stroma of the recipient were preserved. Patients were followed up using anterior segment optical coherence tomography and specular microscopy postoperatively for a minimum period of 6 months in one eye and 3 years in the other. RESULTS: In both eyes, the central cornea maintained clarity throughout follow-up. The astigmatism reduced significantly, and the final uncorrected and best-corrected vision improved from hand motions close to the face to 6/12/n8 in one eye and 6/12/n12 in the other. Anterior segment optical coherence tomography in both eyes showed satisfactory apposition of interfaces at 1 month postkeratoplasty, and the same was maintained throughout follow-up. Both eyes withstood phacoemulsification for preexisting cataracts, which was performed in the second sitting after the PKMER. There were no complications noted except a temporary initial detachment of the peripheral interface in some quadrants in the early postoperative period. CONCLUSIONS: PKMER may be considered as an alternative technique to large-diameter full-thickness keratoplasty. It is a relatively easier and cost-effective manual technique, which may be used as an alternative to traditional mushroom keratoplasty in selected cases.

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.

New Therapies for Corneal Endothelial Diseases: 2020 and Beyond.

ABSTRACT: Penetrating keratoplasty used to be the only surgical technique for the treatment of end-stage corneal endothelial diseases. Improvements in surgical techniques over the past decade have now firmly established endothelial keratoplasty as a safe and effective modality for the treatment of corneal endothelial diseases. However, there is a worldwide shortage of corneal tissue, with more than 50% of the world having no access to cadaveric tissue. Cell injection therapy and tissue-engineered endothelial keratoplasty may potentially offer comparable results as endothelial keratoplasty while maximizing the use of cadaveric donor corneal tissue. Descemet stripping only, Descemet membrane transplantation, and selective endothelial removal are novel therapeutic modalities that take this a step further by relying on endogenous corneal endothelial cell regeneration, instead of allogenic corneal endothelial cell transfer. Gene therapy modalities, including antisense oligonucleotides and clustered regularly interspaced short palindromic repeats-based gene editing, offer the holy grail of potentially suppressing the phenotypic expression of genetically determined corneal endothelial diseases at the asymptomatic stage. We now stand at the crossroads of exciting developments in medical technologies that will likely revolutionize the way we treat corneal endothelial diseases over the next 2 decades.

Prediction of corneal graft rejection using central endothelium/Descemet's membrane complex thickness in high-risk corneal transplants.

To determine whether measurements of Endothelium/Descemet complex thickness (En/DMT) are of predictive value for corneal graft rejection after high-risk corneal transplantation, we conducted this prospective, single-center, observational case series including sixty eyes (60 patients) at high risk for corneal graft rejection (GR) because of previous immunologic graft failure or having at least two quadrants of stromal vascularization. Patients underwent corneal transplant. At 1st, 3rd, 6th, 9th, and 12th postoperative month, HD-OCT imaging of the cornea was performed, and the corneal status was determined clinically at each visit by a masked cornea specialist. Custom-built segmentation tomography algorithm was used to measure the central En/DMT. Relationships between baseline factors and En/DMT were explored. Time dependent covariate Cox survival regression was used to assess the effect of post-operative En/DMT changes during follow up. A longitudinal repeated measures model was used to assess the relationship between En/DMT and graft status. Outcome measures included graft rejection, central Endothelium/Descemet's complex thickness, and central corneal thickness (CCT). In patients with GR (35%), the central En/DMT increased significantly 5.3 months (95% CI: 2, 11) prior to the clinical diagnosis of GR, while it remained stable in patients without GR. During the 1-year follow up, the rejected grafts have higher mean pre-rejection En/DMTs (p = 0.01), compared to CCTs (p = 0.7). For En/DMT ≥ 18 µm cut-off (at any pre-rejection visit), the Cox proportional hazard ratio was 6.89 (95% CI: 2.03, 23.4; p = 0.002), and it increased to 9.91 (95% CI: 3.32, 29.6; p < 0.001) with a ≥ 19 µm cut-off. In high-risk corneal transplants, the increase in En/DMT allowed predicting rejection prior to the clinical diagnosis.

Corneal endothelial cell density in patients receiving chemotherapy.

PURPOSE: This study aimed to determine if the corneal endothelium was affected by chemotherapy. METHODS: Chemotherapy patients were recruited to undergo specular microscopy before treatment and again at 1- and 2-year follow-up visits. One eye per patient, per follow-up, was selected for comparison to baseline. RESULTS: Forty-six volunteers completed baseline and at least one follow-up assessment. From 51 eyes, there was no significant change in endothelial cell density for 41 eyes assessed at one year (MD = 0.73%, 95% CI -1.33 to 2.78%) and 18 eyes at two years (MD = 0.31%, 95% CI -3.53 to 4.15%). CONCLUSION: Although other studies have shown that chemotherapy can adversely affect the corneal epithelium, this study showed no measurable change in endothelial cell density.

The effect of smoking on corneal densitometry and endothelial cell morphology.

PURPOSE: We investigated corneal endothelial morphology and corneal densitometry in smokers and compared our results with findings observed in non-smokers. MATERIALS AND METHODS: This cross-sectional observational study included 100 participants (50 smokers, 50 non-smokers) aged 18-80 years in whom corneal endothelial morphology was analysed using a non-contact Tomey EM-4000 specular microscope (Tomey Corporation, Japan). The Pentacam HR system was used to measure corneal densitometry spatially in three concentric zones (from the centre to the periphery) and at three different corneal depths (from the anterior to the posterior aspects). Endothelial morphology findings and corneal densitometry values were recorded in all participants, and these results were compared between smokers and non-smokers. RESULTS: Endothelial morphology and corneal densitometry analysis showed significantly lower endothelial cell counts (Num) in smokers (228 cells/mm2 vs. 246 cells/mm2, p = 0.02) in addition to increased maximum cell area (Max) values (986.5 µm2 vs. 935 µm2, p = 0.04). We observed no statistically significant intergroup difference in corneal densitometry values (p > 0.05 for each zone); however, we observed a moderately positive correlation between densitometry values in the 6-10 mm concentric zone and between the all total corneal zones and number of pack-years in smokers. CONCLUSIONS: Our study highlights that among the morphometric corneal endothelial variables analysed in this study, only the Num value was significantly correlated with smoking. We observed no statistically significant intergroup difference in corneal densitometry values in this study; however, a positive correlation was observed between the number of pack-years and corneal densitometry findings. Therefore, as the pack-years increase, the increase in corneal densitometry values may indicate a decrease in corneal clarity, considering the possible contribution of secondary factors such as age.

Cutting Edge: Novel Treatment Options Targeting Corneal Neovascularization to Improve High-Risk Corneal Graft Survival.

PURPOSE: Corneal neovascularization is an important risk factor for graft rejection after keratoplasty, although its role in posterior lamellar keratoplasty is not yet well defined. The aim of this work was to describe clinically available approaches that target corneal neovascularization preoperatively to improve graft survival after subsequent penetrating keratoplasty (PK) and to present findings on Descemet membrane endothelial keratoplasty (DMEK) in eyes with neovascularization. METHODS: Recent work on the use of anti-vascular endothelial growth factor agents, fine needle diathermy (FND), and corneal collagen crosslinking (CXL) to regress corneal neovascularization before PK is summarized. Furthermore, studies that have investigated the outcome of DMEK in vascularized eyes are presented. RESULTS: Pretreatment of recipient corneas with FND combined with anti-vascular endothelial growth factor agents is an effective method to reduce long-standing corneal neovascularization and results in relatively low rejection rates after subsequent high-risk PK. Peripheral CXL also seems to be a potent method to regress corneal neovascularization, although data on the impact of pretransplant CXL on long-term graft survival are not yet available. There are only limited data on graft rejection rates after DMEK in vascularized eyes, but initial studies indicate that DMEK seems to be a viable therapeutic option when no stromal scars are present. Furthermore, preexisting stromal neovascularization seems to regress after high-risk DMEK. CONCLUSIONS: Several angioregressive strategies to treat corneal neovascularization before PK have entered the clinic with promising initial results, which warrants larger trials with longer follow-up. Studies will also have to define the precise role of preexisting corneal neovascularization in high-risk DMEK.

Characteristics of endothelial corneal transplant rejection following immunisation with SARS-CoV-2 messenger RNA vaccine.

AIM: We report two cases of endothelial corneal allograft rejection following immunisation with SARS-CoV-2 messenger RNA (mRNA) vaccine BNT162b2 and describe the implications for management of transplant recipients postvaccination for COVID-19. METHODS: A 66-year-old woman with Fuchs endothelial corneal dystrophy (FECD) and a unilateral Descemet's membrane endothelial keratoplasty (DMEK) transplant received COVID-19 mRNA vaccine BNT162b2 14 days post-transplant. Seven days later, she presented with symptoms and signs of endothelial graft rejection. An 83-year-old woman with bilateral DMEK transplants for FECD 3 and 6 years earlier developed simultaneous acute endothelial rejection in both eyes, 3 weeks post second dose of COVID-19 mRNA vaccine BNT162b2. Rejection in both cases was treated successfully with topical corticosteroids. CONCLUSIONS: We believe this is the first report of temporal association between corneal transplant rejection following immunisation against COVID-19 and the first report of DMEK rejection following any immunisation. We hypothesise that the allogeneic response may have been initiated by the host antibody response following vaccination. Clinicians and patients should be aware of the potential of corneal graft rejection associated with vaccine administration and may wish to consider vaccination in advance of planned non-urgent keratoplasties. Patients should be counselled on the symptoms and signs that require urgent review to allow early treatment of any confirmed rejection episode.

Analysis of Immune Cells on Donor Corneal Endothelium After Corneal Transplantation Using the HRT-Rostock Cornea Module.

PURPOSE: The aim of this study was to investigate the immune cells on corneal endothelium of the graft in patients who underwent penetrating keratoplasty (PK), Descemet-stripping endothelial keratoplasty (DSEK), and Descemet membrane endothelial keratoplasty (DMEK). METHODS: A total of 43 eyes of 43 patients who underwent PK (17 eyes), DSEK (13 eyes), and DMEK (13 eyes) and who did not show any sign of graft rejection were recruited for the study. Patients who underwent cataract surgery (26 eyes) served as controls. Immune cells on the corneal endothelium were examined with laser in vivo confocal microscopy. The associations between the corneal endothelial cell density, type of keratoplasty, aqueous flare, repeated keratoplasty, and time after surgery versus the density of immune cells were investigated. RESULTS: In vivo confocal microscopy visualized similar numbers of immune cells on the corneal endothelium in the PK, DSEK, and DMEK groups, whereas no immune cells were observed in any of the control patients. The numbers of immune cells tended to be higher in regraft eyes in the PK group (P = 0.00221) and in the DSEK group (P = 0.168) than those in the primary graft eyes. No significant association was found between the density of immune cells and corneal endothelial cell density in the PK, DSEK, and DMEK groups. CONCLUSIONS: Immune cells were observed to a similar extent in the eyes of PK, DSEK, and DMEK subjects even in the absence of any clinical sign of immune rejection. A further prospective longitudinal study will evaluate the effect of immune cells on long-term graft survival and the risk for graft rejection.

Myopia, corneal endothelial cell density and morphology in a Japanese population-based cross-sectional study: the JPHC-NEXT Eye Study.

This population-based cross-sectional study was performed to determine the mean corneal endothelial cell density (ECD), coefficient of variation (CV), and hexagonality (HEX), and their associations with myopia in Japanese adults living in Chikusei city. Of 7109 participants with available data, 5713 (2331 male and 3382 female) participants were eligible for analysis. After assessing the relationship between participant characteristics and spherical equivalent refraction (SER), the association of SER with the abnormal value of ECD (< 2000 cells/mm), CV (≥ 0.40), and HEX (≤ 50%) were determined using the logistic regression models adjusting for potential confounders (age, intraocular pressure, keratometric power, height, and antihypertensive drug use). In male participants, there was no statistically significant relationships between SER and endothelial parameters. In female participants, compared to emmetropia, SER ≤ - 6 D had significantly higher odds ratio (OR) of having the abnormal value of CV (OR = 2.07, 95% confidence interval [CI] 1.39-3.10) and HEX (OR = 2.04, 95% CI 1.29-3.23), adjusted for potential confounders, indicating that the high myopia was associated with the abnormal values of CV and HEX. Further adjustment for contact lenses wear partly attenuated these associations. Association between the SER and ECD was not detected.

Comparación de las características de la córnea entre individuos chinos y cubanos / Comparison between corneal features of Chinese and Cuban subjects

Objetivo: Comparar las características de la córnea entre individuos chinos y cubanos adultos sanos. Métodos: Se realizó un estudio observacional, descriptivo, transversal, en 120 ojos de individuos sanos (60 chinos y 60 cubanos), entre 18 y 29 años de edad, entre septiembre del año 2016 y diciembre de 2017 en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer". Se evaluó la edad, el sexo, la queratometría, la paquimetría y las características del endotelio corneal. Resultados: Predominó el sexo femenino (53,3 por ciento en los cubanos y 66,6 por ciento en los chinos). La edad promedio fue de 24,4 años en ambos grupos. La queratometría promedio resultó mayor en el grupo de estudio de cubanos, con un valor de 44,7 y 44,6 dioptrías en ambos ojos, respectivamente. El espesor corneal fue de 607,3-629,9 en los cubanos y de 575,4-607,2 en los chinos. El coeficiente de variación, la desviación estándar y la densidad celular se diferenciaron mínimamente en ambos ojos para ambas nacionalidades, y resultaron superiores en los ojos izquierdos con un coeficiente de 32,0 (±11,0) en los chinos. La desviación estándar promedio fue de 112,0 (± 36,5) en ambos grupos y en el ojo derecho la densidad celular fue 2 857,1 (± 240,0 cél/mm2) en los chinos y 2 760,0 (± 367,2) en los cubanos. El average de los cubanos estuvo entre 369,0 y 380, y para los chinos entre 352,4 y 358,4 en los ojos derecho e izquierdo. Conclusiones: Existen diferencias significativas en los valores queratométricos. El espesor corneal resulta discretamente más reducido en los chinos. El coeficiente de variación, la densidad celular, el average y la desviación estándar no presentan diferencias estadísticamente significativas(AU)

Objective: Compare the corneal features of Chinese and Cuban healthy adult subjects. Methods: A cross-sectional observational descriptive study was conducted of 120 eyes of healthy 18-29 year old individuals (60 Chinese and 60 Cuban) from September 2016 to December 2017 at Ramón Pando Ferrer Cuban Institute of Ophthalmology. The variables analyzed were sex, keratometry, pachymetry and characteristics of the corneal endothelium. Results: Female sex prevailed (53.3 percent among Cuban and 66.6 percent among Chinese subjects). Mean age was 24.4 years in both groups. Mean keratometry was higher in the Cuban group, with values of 44.7 and 44.6 diopters for both eyes, respectively. Corneal thickness was 607.3-629.9 among Cuban and 575.4-607.2 among Chinese subjects. Variation coefficient, standard deviation and cell density were minimally different between the two eyes in both groups, and were higher in left eyes of Chinese subjects with a coefficient of 32.0 (±11.0). Mean standard deviation was 112.0 (± 36.5) in both groups, whereas right eye cell density was 2 857.1 (± 240.0 cell/mm2) among Chinese and 2 760.0 (± 367.2) among Cuban subjects. Average between right and left eyes ranged from 369.0 to 380 for the Cubans and from 352.4 to 358.4 for the Chinese. Conclusions: Significant differences were found between keratometric values. Corneal thickness was slightly lower among Chinese subjects. Variation coefficient, cell density, average and standard deviation did not show any statistically significant differences(AU)