Corneal Endothelium Status Research Articles

Glaucoma surgical procedure choice in vulnerable corneal endothelium

This talk will focus on the decision making in patients with vulnerable corneal endothelium requiring glaucoma surgical intervention. The effect of glaucoma surgical procedures on corneal endothelium will be briefly analysed and conditions with vulnerable corneal endothelium and co‐existent intraocular pressure (IOP) elevation, such as Fuchs corneal endothelial dystrophy with primary open angle glaucoma or post‐keratoplasty steroid response, will be adequately described. The aim of the talk is to indicate the most appropriate glaucoma surgical interventions depending on the status of corneal endothelium and the desired IOP lowering effect, covering a wide spectrum of surgical procedures including minimally invasive interventions, such as Preserflow implantation, as well as ab interno/ab externo viscocanaloplasty or conventional procedures such as trabeculectomy or big tube implantation. Finally, the talk will highlight useful surgical tips for the abovementioned surgical procedures, and it will provide suggestions for patient selection in order to optimize clinical outcomes.

Effect of Glaucoma on Corneal Endothelium

Background: Glaucoma is a group of diseases characterized by a specific pattern of optic nerve neuropathy and retinopathy which is permenant. There is increasing evidence of glaucoma-associated corneal endothelial changes. Decrease ECD has been reported in various types of glaucoma such as primary angle-closure glaucoma, primary open-angle glaucoma (POAG) and some types of secondary glaucoma. Objectives: The purpose of this study is to evaluate the status of corneal endothelium in different type of open angle glaucoma patients by using Specular microscope comparing with the normal ones. Patients and Methods: We included (120) subjects in this study of normal and open angle glaucoma patients. This present study was a case control study; conducted on 60 open angel glaucoma patients (22 male, 38 female) with age ranged from (28) to (60) and an average 53.56 ±7.6years, compared with 60 healthy control individuals matched in age and sex. Results: There is pоsitive relationship between ECD and glaucoma which is significant in open angle than normal pоpulation. This may be of value during оur daily clinic practice especially when dealing with refractive surgery and glaucоma suspects. Quantitative analysis of CEC morphology of glaucoma patient is necessary by specular microscopy. We should measure CCT and cоnsequently we can adjust IOP to judge the real IOP of the patient and take a good reasonable decision in the treatment of glaucoma patients. High IOP should be controlled as soon as possible to prevent optic neuropathy and corneal endothelial damage. Conclusion: Glaucoma and its management may have deleterious effects on the corneal endothelium. There is still much more to learn about how increased IOP, mechanical forces, and the aqueous environment contribute to corneal endothelial cell loss broadly observed in the milieu of glaucoma treatment. A history of glaucoma surgery poses a particularly significant risk to corneal endothelial cell health and cornea transplant graft survival.

Comparison of structural integrity and functional status of corneal endothelium stored in Cornisol and Optisol-GS

Purpose:To compare the structural integrity and functional status of the donor corneas stored in Cornisol and Optisol-GS.Methods:Fifteen optical grade corneal donor buttons (6 pairs; 3 individual) obtained from Rotary Aravind International Eye Bank were used for the study. The left eye of the paired sample was preserved in Cornisol and the right in Optisol-GS. The three individual buttons were used for the baseline data. The corneas were assessed with slit lamp and specular microscope before and after storage time (7, 10, or 14 days). They were then immunostained for markers of structural integrity (ZO-1, Phalloidin) and functionality (Na+/K+ ATPase). The images were acquired using confocal microscope and analyzed using ImageJ software.Results:There was no difference in the clinical evaluation of the corneal layers between the two media. No marked variation was observed in the immunostaining data with reference to the storage period. Intact cellular integrity was identified in 91% (51%, 98%) [Median (min, max)] of cells in Cornisol and 94% (38%, 98%) cells in Optisol based on ZO-1 staining, comparable to the baseline data [87% (76%, 97%)]. Stress fibers were detected in 42.5% (1%, 88%) cells in Cornisol stored corneas and in 55% (11%, 94%) in Optisol when stained for actin cytoskeleton, which correlated with the presence of epithelial defect before storage and vacuolated endothelial cells after storage. No difference was observed between the two media based on the staining pattern for Na+/K+ ATPase.Conclusion:Cornisol and Optisol-GS are equivalent in maintaining the structural integrity and functionality of the donor corneas.

Commentary: Comparison of structural integrity and functional status of corneal endothelium stored in Cornisol and Optisol-GS.

Commentary: Comparison of structural integrity and functional status of corneal endothelium stored in Cornisol and Optisol-GS.

Long-term changes of corneal endothelial cells following Artisan phakic intraocular lens implantation

Background Artisan phakic intraocular lens (pIOL) implantation was demonstrated to be safe and effective for the correction of high myopia in short-term.However, long-term corneal endothelium status after operation should be concerned. Objective This study was to investigate the long-term changes of corneal endothelial cell density (ECD) and morphology following Artisan pIOL implantation for the correction of high myopia. Methods Fifty-one eyes of 27 patients who received Artisan PIOL implantation for high myopia from January 2005 to December 2008 were retrospectively analyzed.The central corneal ECDs were detected by corneal endothelial cell counter before surgery and 6 months and 1 year, 2, 3, 4, 5, 6 years after surgery, and the coefficient of variation (CV) and standard deviation (SD) of cellular area were evaluated.ECD loss rate with time lapse was calculated ([preoperative ECD-postoperative ECD]/preoperative ECD×100%). Results Six years after surgery, there were 34 eyes with BCVA≥1.0, 14 eyes with BCVA higher than preoperative and 8 eyes with BCVA lower than preoperative.The mean intraocular pressure was (14.23±2.14)mmHg 6 years postoperative.The preoperative mean ECD was (3 184.05±233.55)/mm2, and the ECD was gradually reduced over time with the cell loss 2.34% in 6 months, 5.32% in 1 year, 6.32% in 2 years, 8.06% in 3 years, 12.59% in 4 years, 15.63% in 5 years and 19.49% in 6 years after operation.Before surgery, The mean CV of cellular area was 37.17±7.12, and the SD of cellular area was 118.77±21.39, and those 6 years after surgery were 32.24±4.62 and 125.60±18.49, respectively.The mean CV and SD of cellular area were significantly different among different time points (P=0.000, 0.036). Eight eyes with localized iris depigmentation, 6 eyes with IOL dyssymmetry, 3 eyes with transient high intraocular pressure and 2 eyes with Macular hemorrhage were obtained after surgery. Conclusions Corneal endothelial cells appear obvious changes in both number and morphology after Artisan pIOL implantation in high myopia.ECD is gradually reduced with time lapse, and the shape of the cells occur remodeling during 6-year fellow-up duration.Overall, endothelial specular microscopy is mandatory before and after surgery for a long term. Key words: Phakic; Intraocular lens; Cornea endothelial cell; High myopia

Corneal endothelium after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus: A four-year comparative study

Purpose:To compare the status of corneal endothelium and central corneal thickness within the first four postoperative years after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in patients with keratoconus.Materials and Methods:Thirty-nine eyes (Group A) which had PK and 44 eyes (Group B) which had DALK for the treatment of keratoconus were included in this retrospective study. The endothelial cell density (ECD), the mean endothelial cell area and the coefficient of variation of cell area were assessed with a non-contact specular microscope, and the central corneal thickness (CCT) was measured with an ultrasound pachymeter.Results:Mean ECD loss rate at two years was 36.24% in Group A and 18.12% in Group B (P<0.001). Mean ECD loss rate at four years was 47.82% in Group A and 21.62% in Group B (P<0.001). Mean annual ECD loss rate was calculated 14.12% per year in Group A and 5.78% per year in Group B. In the PK group, increase in mean CCT was 15.60% in two years and 15.03% in four years, while in the DALK group, mean CCT increased by 8.05% in two years and 9.31% in four years.Conclusions:As the majority of ectatic disorders such as keratoconus occur in young people, long-term endothelial cell survival following treatment with keratoplasty is essential for the long-term visual ability. Our finding that corneal endothelial cell loss in the DALK group occurs at a slower rate than in the PK group suggests DALK as a safer alternative to PK in these selected patients.

Corneal Endothelium in Patients with Diabetes Mellitus: A Historical Cohort Study

Retinopathy is the major cause of ocular morbidity in patients with diabetes mellitus. Chronic hyperglycemia spares no organ and can affect the morphology and function of the various corneal layers, compromising its transparency. This study was conducted to associate the status of corneal endothelium to diabetes mellitus (DM) and identify risk factors of compromised corneal endothelium. A total of 220 eyes of randomly selected patients (110 diabetic and 110 nondiabetic) were subjected to detailed slitlamp and fundus evaluation. Corneal endothelial status was evaluated using the Nidek Confoscan 2. Cell density, percentage polymegathism, and pleomorphism were calculated. The findings in diabetic patients were compared to those without disease. The outcome was correlated to diabetic retinopathy (DR). The effects of hypertension, hyperlipidemia, age, gender, type, duration, glycemic control, and grades of DR was also considered. The mean corneal endothelial cell density was -175 cells/mm2 (95% CI -317 to -33 cells/mm2) less in eyes of diabetic patients. The number of endothelial cells with polymegathism was significantly greater among eyes of diabetic patients. There were less corneal endothelial cells with pleomorphism in nondiabetic patients. Polymegathism and pleomorphism of corneal endothelial cells seems to be positively associated with DM type II. Cell density was significantly lower in eyes with DR than those without DR. Corneal endothelium in diabetic patients seems to be compromised. Evaluation of corneal endothelium should be part of protocol for eye care of diabetic patients.

Granulometric analysis of corneal endothelium specular images by using a germ–grain model

Specular microscopy is widely used to study the human corneal endothelium status in vivo. In this paper, the corneal endothelium is represented as a binary image composed of the cell inscribed circles. The granulometric distribution function of the complement of this image is used as a functional descriptor, which provides information about the shape, size and spatial arrangement of cells. Experimental evaluation using bootstrap techniques shows its ability to discriminate between controls and pathological cases. It represents a reliable and graphical alternative to the classical indices (cell density, hexagonality and coefficient of variation of cell areas), which behave poorly when detecting subtle abnormalities.

A granulometric analysis of specular microscopy images of human corneal endothelia

The inner layer of the human cornea, called the corneal endothelium, plays an important role in the maintenance of corneal transparency. Specular microscopy is the most widely used technique to study the corneal endothelium in vivo. Improvements in technology have allowed us to obtain good quality specular images, but the detection and quantification of small size–shape cell changes is not obvious, specially when the physician wants to evaluate endothelial cell changes after some surgical procedures. This paper proposes a methodology to analyze specular microscopy images. Every corneal endothelium is described by means of different cumulative distribution functions or some moments (mean, standard deviation, kurtosis, and skewness) of these distribution functions. These distributions are defined from different granulometries based on successive structural openings of the corneal endothelium. Changes in cell morphology are pointed out by comparing the cumulative distribution function (or the corresponding moments) of a given patient with the corresponding cumulative distribution functions (or their moments) of a group of age-matched controls. Different comparison procedures are given, providing us with different numerical evaluations of the corneal endothelium status. These new indices are compared with the classic descriptors used in commercial packages (density, hexagonality, and coefficient of variation of cell areas). Detailed analysis of different images of corneal endothelia are given using the classic and new indices jointly.

Effects of Phacoemulsification and Intraocular Lens Implantation on the Corneal Endothelium in Primary Angle-closure Glaucoma

Background Phacoemulsification and intraocular lens implantation (P-IOL) is an option for intraocular pressure (IOP) control for primary angle-closure glaucoma (PACG). This study examined the effects of P-IOL on the corneal endothelium in eyes with PACG. Patients and Methods Ultrasound biometry and pachymetry, as well as specular microscopy, were performed preoperatively and 3 months after surgery in 24 eyes with PACG that underwent P-IOL. The postoperative changes in central corneal endothelial density and central corneal thickness (CCT) were evaluated. The correlations between postoperative endothelial changes and both preoperative IOP control and biometric features were analyzed. Results After surgery, corneal endothelial cell density decreased significantly (p 0.001), with a mean cell loss of 15.7%, and mean CCT increased by 7 μm (p = 0.034). A greater postoperative corneal endothelial loss was correlated with a higher preoperative mean IOP and more glaucoma medications (correlation coefficients=0.487 and 0.427, p = 0.016 and 0.038, respectively). The corneal endothelial changes did not correlate with preoperative biometric features including anterior chamber depth, lens thickness, and axial length. Conclusion Significant corneal endothelial cell loss after P-IOL in PACG patients suggests that corneal endothelium status should be carefully evaluated before performing this surgery in these patients, especially those with poor preoperative IOP control.

Classifying human endothelial cells based on individual granulometric size distributions

Abstract This paper presents an application to a medical problem of methods of shape analysis based on mathematical morphology. The medical problem consists on the detection of abnormalities in the corneal endothelium, a tissue composed by quasi-planar cells of ideally regular hexagonal shape. Images of this tissue are taken by a specular microscope and used to evaluate the corneal endothelium status. Up to now, cell density, hexagonality and an analysis of cell areas are the usual descriptors of a corneal endothelium. These parameters are not sensitive enough to detect subtle lesions. What this paper proposes is an analysis based on granulometries, which are size-shape descriptors widely used in Mathematical Morphology. Applications of granulometries lead to distribution functions whose moments are used as shape descriptors. Former approaches proposed a global evaluation of the whole corneal endothelium but irregularities affecting to a few cells could be ignored. Differently to that approach, this paper uses the granulometric size distribution of each cell. A group of normal cells is chosen as controls and a given cell is classified as normal or abnormal by comparing its granulometric size distribution with the corresponding distributions of the controls. The technique is illustrated with the analysis of some images of corneal endothelia.

Set Descriptors for Visual Evaluation of Human Corneal Endothelia

Images of corneal endothelium obtained from specular microscopy are of great importance in the evaluation of the corneal endothelium status. Several commercial tools provide some numerical descriptors to characterize these images in terms of cell density, hexagonality, and some descriptive statistics of the cell areas. However, it is a too simple analysis that only detects severe abnormal endothelia with many irregular and large cells. Detection of subtle abnormalities needs a more refined analysis. This paper proposes a shape-size descriptor based on some modified versions of the geometric covariogram. This descriptor is presented as a valid alternative to the classical analysis that provides a reliable, visual, and easy evaluation of the corneal endothelium. Control images of normal endothelia can be used to classify a given image as normal or abnormal with respect to these controls by means of a graphical test.

Granulometric moments and corneal endothelium status

Specular microscopy is a common practice in Ophthalmology. The corneal endothelium status is usually evaluated by means of the density, the hexagonality, the mean, the standard deviation and the coefficient of variation of cell areas. We propose to replace the cell area moments by the corresponding moments of a different probability distribution, the granulometric size distribution associated to a disc. All cells touching the frame are ignored by the area moments but used by the granulometric moments. Twenty images have been analyzed. When the size of the focused region is reduced, the area moments show a greater variation than the corresponding granulometric moments.

Pseudophakic Bullous Keratopathy: Relationship to Preoperative Corneal Endothelial Status

Pseudophakic bullous keratopathy is one of the complications of intraocular lens implantation. A knowledge of the preoperative status of corneal endothelium may help to minimize the incidence of this complication. The preoperative corneal endothelial status of 118 eyes of 102 patients who received Worst-Medallion intraocular lenses more than five years ago was analyzed retrospectively. This data was then correlated with the postoperative clinical status of the cornea. Twelve eyes (10%) underwent penetrating keratoplasty for irreversible corneal edema, and 28 of the remaining eyes (22%) had clinical evidence of peripheral corneal edema. No correlation was found between the preoperative endothelial cell density or the degree of postoperative cell loss and the development of corneal edema. Significant correlation was found between variation in cell size (pleomorphism) and the development of postoperative corneal edema. Greater density of precipitates on endothelium and abnormality in cell shape postoperatively were also frequently seen in corneas that developed edema subsequently.