The effect of irrigation and aspiration on the corneal endothelial cell density in patients undergoing Implantable Collamer Lens with a central hole implantation for myopia correction.

PURPOSE: In the conventional technique, viscoelastic agents are typically rinsed away with balanced salt solution (BSS), but it may lead to a series of complications such as viscoelastic residue, anterior chamber instability and intraoperative TICL rotation. The utilization of irrigation and aspiration (I/A) has been shown to be effective in maintaining anterior chamber stability, reducing the incidence of postoperative high intraocular pressure, and minimizing postoperative fundus complications. However, there is a lack of previous studies investigating the impact of I/A on corneal endothelial cells during ICL implantation. The objective of this study was to examine the effect of I/A on corneal endothelial cells in patients undergoing myopia correction through implantation of Implantable Collamer Lens with a central hole (V4c ICL). METHODS: A retrospective selection was made of 344 eyes from 172 patients who underwent V4c ICL implantation and I/A to remove viscoelastic agent from the anterior chamber between 2021 and 2022. The intraocular pressure (IOP) was measured at 1 h, 2 h and 3 h after surgery. Corneal endothelial cell density (ECD), coefficient of variation in cell size (CV), standard deviation of cell area (SD), and percentage of hexagonal cells (HEX) were evaluated at 1 week postoperatively to assess corneal endothelial cells. The first two represent polymegethism or morphological variation, while the third parameter represents the degree of polymorphism of the corneal endothelial cells. Electronic medical records were utilized for data collection purpose. RESULTS: All surgeries proceeded without complications. The IOP was 16.50 ± 3.42 mmHg (range: 11.5-22.3 mmHg) prior to surgery and increased to 21.25 ± 5.61 mmHg (range: 9.5-34.8 mmHg), 19.85 ± 5.18 mmHg (range: 11.4-36.2 mmHg) and finally settled at an average of 18.81 ± 4.57 mmHg (range: 10.1-38.8 mmHg) at the respective time points of 1 h, 2 h and 3 h after surgery. The preoperative ECD was recorded as being approximately 3004 ± 295 cell/mm2, which exhibited a marginal decreased of 1.17% postoperatively, resulting in an average ECD value of 2969 ± 303 cell/mm2 one week after surgery (P = 0.12). Similarly, the preoperative CV was determined as 31.10 ± 3.78%, and it experienced a slight reduction with an average CV value of 30.74 ± 3.77% at week after surgery (P = 0.21). And, the preoperative SD was reported as 104.76 ± 17.26, and it remained virtually unchanged with an average SD value of 104.85 ± 18.75 at one week after surgery (P = 0.95). The preoperative HEX was calculated as 55.38 ± 8.94%, and it remained its stability with an average HEX value of 55.45 ± 8.73% one week after surgery (P = 0.92). CONCLUSION: The utilization of I/A led to a slight decrease in postoperative ECD when compared to conventional surgical techniques. Nevertheless, the reduction in ECD remained within acceptable limits, taking into accout the avervantaged it offered, such as stabilization of the anterior chamber and decreased occurrence of viscoelastic residue after surgery. It is challenging to anticipate the long-term safety of corneal endothelial cells based on current short-term studies. However, this study provides a valuable reference indicating that neither anterior chamber irrigation nor I/A aspiration have an adverse impact on the safety of corneal endothelial cells in the short term. Further research is imperative to enhance our understanding of their effects over an extended period.

Corneal endothelial validation in the eye bank: differences in automated methods and repeatability.

PURPOSE: To evaluate reproducibility of endothelial cell density (ECD) measurements using the Konan Cell Check D in donor corneas by two different ophthalmologists and to compare the two automated cell count methods (center and flex-center) available in the software of this specular microscope. METHODS: ECD values were quantified in 54 donor corneas by two independent investigators using the Cell Check D (Konan Medical USA Inc) with both automated cell count methods. In the center method, at least 30 contiguous cells are marked. For the flex-center method, an area is delineated and only the cells within the designated area are counted. RESULTS: The mean ECD was 2473.81±378.22 cells/mm2. Good ECD intergrader reproducibility for the center (ICC=0.821) and the flex-center method (ICC=0.784) were noted. Poor reliability was observed for coefficient of variation and hexagonality (ICC≤0.265). When both methods for ECD analysis were compared, a moderate correlation for the two independent graders using the two manual (center and flex-center) methods was detected (correlation coefficient of 0.678 and 0.745 for each of the investigators). Comparison between methods yielded significantly higher ECD with the flex-center method (P=0.013). When corneas were divided by ECD, those under 2200 cells/mm2 and those between 2200 and 2700 cells/mm2 also had significantly higher ECD with the flex-center method (P<0.022). CONCLUSIONS: ECD values are reproducible with both methods, although the flex-center method ECDs tend to be higher, particularly in cases of low ECD. Eye banks and surgeons should exercise caution in making decisions based only on small differences in ECD.

Comparisons of the clinical outcomes of Centurion® active fluidics system with a low IOP setting and gravity fluidics system with a normal IOP setting for cataract patients with low corneal endothelial cell density.

Background: During cataract phacoemulsification surgery, the Alcon Centurion with Active Sentry can achieve a more stable anterior chamber, which allows a lower intraocular pressure (IOP) setting than the gravity fluidics system. In this randomized controlled trial, we compared these two systems' damage to the cornea under different IOP settings. Methods: Seventy-eight eyes of 53 patients with corneal endothelial cell density (ECD) of 500∼1500/mm2 were enrolled and randomly divided into the active fluidics system (AFS) group using an Active Sentry handpiece with 30 mmHg IOP setting (40 eyes) and the gravity fluidics system (GFS) group using an Ozil handpiece with 80 cmH2O IOP setting (38 eyes). Intraoperative parameters, visual acuity, corneal edema ratio, central corneal thickness (CCT) changes as well as loss rate of ECD were analyzed. Results: We observed no significant differences in best corrected visual acuity (BCVA), cumulative dissipated energy (CDE), total case time, estimated fluidics usage (EFU) and ophthalmic viscoelastic devices (OVDs) usage between the two groups. The enrolled eyes were further divided into soft nucleus (27 eyes) and hard nucleus (51 eyes) subgroups. And we found less pain complaint during surgeries, lower corneal edema ratio at 1-day and 1-week visit, smaller CCT changes at 1-day visit and lower ECD loss rate at 1-month visit (p < 0.05) in both subgroups of the AFS group than in the GFS group, implying higher intraoperative comfort levels and less corneal damage of the AFS group with a low IOP setting. Conclusion: Owing to a lower IOP setting, Centurion® Vision System with Active Sentry handpiece causes less corneal damage and pain perception during phacoemulsification for patients with low pre-operative ECD. Clinical Trial Registration: https://www.chictr.org.cn, identifier ChiCTR2300077865.

Long-term safety and efficacy of a foldable iris-fixated phakic intraocular lens for the correction of myopia.

PURPOSE: To analyze and report the long-term outcomes in terms of efficacy and safety of eyes implanted with the spherical version of a foldable iris-fixated phakic intraocular lens (pIOL) for the correction of myopia. METHODS: Retrospective analysis of the results of 56 eyes of 32 patients (age, 19-45 years) who underwent implantation of the spherical model of the Artiflex pIOL (Ophtec B.V., Groningen, The Netherlands) for the correction of myopia. Visual, refractive, biometric, intraocular pressure (IOP) and corneal endothelial changes were evaluated during a long-term follow-up: 2, 7, 10 and 12 years for more than 50, 30, 20 and 10 eyes, respectively. RESULTS: At 4 weeks postoperatively, a significant reduction of manifest sphere and spherical equivalent (SE), with a significant improvement of uncorrected distance visual acuity were found (all p < 0.001). No significant changes were found during the rest of follow-up in sphere (p ≥ 0.072). The percentage of eyes with SE within ± 1.00 D was over 83% during the whole follow-up. A non-significant trend to IOP increase was observed at 4 weeks postoperatively (p = 0.530), with a significant reduction at 1 year after (p = 0.039) and no significant changes during the rest of follow-up (p = 0.180). There was a significant reduction of anterior chamber depth at 4 weeks after surgery (p < 0.001), with no significant changes during the following 9 years of follow-up (p = 0.118). However, an additional significant decrease of this parameter was observed between 10 and 13 years after surgery (p = 0.027). Mean endothelial cell loss changed from 2.01 ± 4.49% at 4 weeks after surgery to 9.11 ± 2.24% at the end of the follow-up. No complications were reported during the follow-up. CONCLUSIONS: Myopia correction with the Artiflex pIOL is an effective and safe procedure in the long term.

Micropulse Cyclophotocoagulation vs Selective Laser Trabeculoplasty: Effects on Corneal Endothelial Cells and Intraocular Pressure.

Purpose: To evaluate the effects of micropulse transscleral cyclophotocoagulation (mCPC) and selective laser trabeculoplasty (SLT) on endothelial cell density (ECD) and reduction of the intraocular pressure (IOP) in patients with primary-open angle glaucoma (POAG). Patients and Methods: In this observational, retrospective study, 40 eyes with POAG were included. Patients were divided into three groups-group I was treated with SLT (n = 13), group II was treated with mCPC (n = 13), and group III included age-matched patients with medically treated glaucoma (n = 14) (control group). In both treatment groups (SLT and mCPC) preoperative and postoperative findings of best-corrected visual acuity (BCVA), ECD, and IOP were compared to the control group. Results: The mean time interval before and after the treatment was 215 ± 120 days in group I (SLT) and 273 ± 177 days in group II (mCPC). The follow-up for group III (control group) was 209 ± 103 days. In both treatment groups (SLT and mCPC) there was a statistically significant reduction of the IOP postoperatively (group I: 3.5 ± 3.7 mm Hg (p = 0.005) and group II: 4.3 ± 4.1 mm Hg (p = 0.003)). The mean IOP for group III was 12.9 ± 3.7 mm Hg at visit 1 and did not change significantly (p = 0.353) at visit 2. In all three groups, there was no statistically significant change in ECD at the last visit. Conclusion: According to our results, both SLT and mCPC seem to be effective in lowering the IOP, without showing any statistically significant effect on ECD in patients with POAG.However, larger and longer-term studies are necessary to understand the effects of the SLT and mCPC procedures on ECD. How to cite this article: Garip Kuebler A, Priglinger S, Reznicek L. Micropulse Cyclophotocoagulation vs Selective Laser Trabeculoplasty: Effects on Corneal Endothelial Cells and Intraocular Pressure. J Curr Glaucoma Pract 2023;17(1):40-43.

The Biologic Character of Donor Corneal Endothelial Cells Influences Endothelial Cell Density Post Successful Corneal Transplantation.

Purpose: Corneal endothelial cell density (ECD) gradually decreases after corneal transplantation by unknown biologic, biophysical, or immunologic mechanism. Our purpose was to assess the association between donor corneal endothelial cell (CEC) maturity in culture and postoperative endothelial cell loss (ECL) after successful corneal transplantation. Design: Prospective cohort study. Participants: This cohort study was conducted at Baptist Eye Institute, Kyoto, Japan, between October 2014 and October 2016. It included 68 patients with a 36-month follow-up period who had undergone successful Descemet stripping automated endothelial keratoplasty (DSAEK) or penetrating keratoplasty. Methods: Human CECs (HCECs) from remaining peripheral donor corneas were cultured and evaluated for maturity by surface markers (CD166+, CD44-/dull, CD24-, and CD105-) using fluorescence-activated cell sorting. Postoperative ECD was assessed according to the mature-differentiated HCEC contents: high-maturity group: > 70%, middle-maturity group: 10% to 70%, low-maturity group: < 10%. The successful rate of ECD maintained at 1500 cells/mm2 at 36 months postoperative was analyzed using the log-rank test. Main Outcome Measures: Endothelial cell density and ECL at 36 months postoperative. Results: The 68 included patients (mean [standard deviation] age 68.1 [13.6] years, 47.1% women, 52.9% DSAEK). The high, middle, and low-maturity groups included 17, 32, and 19 eyes, respectively. At 36 months postoperative, the mean (standard deviation) ECD significantly decreased to 911 (388) cells/mm2 by 66% in the low-maturity group, compared with 1604 (436) by 40% and 1424 (613) cells/mm2 by 50% in the high and middle-maturity groups (P < 0.001 and P = 0.007, respectively) and the low-maturity group significantly failed to maintain ECD at 1500 cells/mm2 at 36 months postoperative (P < 0.001). Additional ECD analysis for patients who underwent DSAEK alone displayed a significant failure to maintain ECD at 1500 cells/mm2 at 36 months postoperative (P < 0.001). Conclusions: The high content of mature-differentiated HCECs expressed in culture by the donor peripheral cornea was coincident with low ECL, suggesting that a high-maturity CEC content predicts long-term graft survival. Understanding the molecular mechanism for maintaining HCEC maturity could elucidate the mechanism of ECL after corneal transplantation and aid in developing effective interventions. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

Risk factors associated with corneal endothelial cell density in Posner-Schlossman syndrome.

PURPOSE: To investigate the risk factors related to corneal endothelial cell density (ECD) in patients with Posner-Schlossman syndrome (PSS). PATIENTS AND METHODS: It was an observational retrospective study. We reviewed the medical records of patients with PSS who attended the ophthalmology department at Wuhan University Zhongnan Hospital from January 2019 to December 2021. 42 eyes of 42 patients with PSS were included in the study. Demographic characteristics and clinical manifestations were recorded. The clinical characteristics of PSS patients with reduced ECD were compared with PSS patients with normal ECD. Simple and multiple linear regression analyses were carried out to identify the risk factors for ECD in PSS. RESULTS: The ECD-lowered group had a longer disease duration (P = 0.000), higher rate of occurrence of corneal edema (P = 0.039), higher cytomegalovirus (CMV) deoxyribonucleic acid (DNA) copy number (P = 0.044), higher interleukin-10 (IL-10) level in the aqueous humor (P = 0.044), and thinner average retinal nerve fiber layer (RNFL) thickness (P = 0.016) than the control group. The results of multiple linear regression analysis indicated that disease duration (ß = - 0.287, P = 0.024) and level of IL-10 in the aqueous humor (ß = - 0.408, P = 0.001) were significantly negatively associated with ECD, while average RNFL thickness (ß = 0.330, P = 0.007) was significantly positively related to ECD in PSS. CONCLUSION: A longer disease duration, higher degree of glaucomatous damage and elevated level of IL-10 in the aqueous humor were associated with reduced ECD in PSS.

Corneal Endothelial Cell Loss after Ciliary Sulcus Placement of Ahmed Glaucoma Valve in Patients with Noninfectious Uveitic Glaucoma.

This study was performed to investigate the corneal endothelial cell density (CECD) reduction and treatment efficacy in patients with uveitic glaucoma treated by the ciliary sulcus placement of the Ahmed glaucoma valve (AGV). This retrospective study included 27 eyes of 27 patients with noninfectious uveitis who underwent the sulcus placement of the AGV. Each patient underwent a clinical assessment including a CECD measurement before surgery and at 3, 6, 9, and 12 months after surgery. The mean CECD was 2431.4 ± 367.5 cells/mm2 at preoperative baseline and 2360.5 ± 391.3 cells/mm2 at 12 months (p = 0.074), with a reduction rate of 2.73 ± 9.29%. The CECD reduction was significantly greater in patients with unilateral uveitis than that with bilateral uveitis. The rate of successful intraocular pressure control was 88% at 12 months, and the number of intraocular pressure-lowering medications was significantly reduced (p < 0.001). The current study showed that the implantation of an Ahmed tube into the ciliary sulcus provided stable intraocular pressure control in patients with glaucoma secondary to noninfectious uveitis, and CECD reduction was moderate in most patients at 12 months.

Long-Term Changes in Corneal Endothelial Cell Density after Ex-PRESS Implantation: A Contralateral Eye Study.

Our purpose is to evaluate long-term changes in corneal endothelial cells after Ex-PRESS shunt implantation for the treatment of glaucoma in Chinese patients by comparison with the contralateral eye. In this retrospective observational study, glaucoma patients with a single eye undergoing Ex-PRESS shunt implantation surgery were consecutively enrolled. For each patient, the clinical assessment, including corneal endothelial cell density (CECD) before surgery and at 6, 12 months, and at last follow-up (2.43 ± 0.63 years) after surgery was reviewed. The operated eyes were in the study group and the unoperated contralateral eyes were used as the control group to compare the CECD change. A total of 48 subjects (age, 51.02 ± 17.96 years) were included. The follow-up period was 2.08~3.17 years, with an average of 2.43 ± 0.63 years. At the last follow-up after the surgery, the CECD decrease in the operated eyes (5.0%) was similar to that in the contralateral eyes (3.2%) (p = 0.130). There were no significant differences in CECD reduction between the two groups at baseline and each postoperative follow-up (6 months, 12 months and at the last follow-up) (all p > 0.05). The average IOP reduction after the surgery was 50.8%, and the number of IOP-lowering medications was significantly reduced (p < 0.05). In addition, visual acuity showed no significant differences during follow-up (p > 0.05). In this study, we found that the CECD reduction of Ex-PRESS shunt-implanted Chinese eyes was similar to that of contralateral eyes without surgery.

Corneal endothelial cell density and its correlation with birth weight, anthropometric parameters, and ocular biometric parameters in Chinese school children.

BACKGROUND: To describe the distribution of corneal endothelial cell density (ECD), and to explore its correlation with birth weight (BW), anthropometric parameters, and ocular biometric parameters in Chinese school children. METHODS: In the population-based cross-sectional Nanjing Eye Study, children were measured for anthropometric information, for ECD by the noncontact specular microscope and for ocular biometric parameters by the optic low-coherent reflectometer. Data from right eyes were analyzed to illustrate the distribution of ECD and for determining correlated factors with ECD using univariate and multiple linear regression analysis. Comparisons among three different BW groups were performed using a one-way ANOVA analysis followed by the Bonferroni correction for pairwise comparisons. RESULTS: Of 1171 children, the mean (± standard deviation) ECD was 2875.34 ± 195.00 cells/mm2. In the Multiple Linear Regression analysis, BW, gender and central corneal thickness were significantly associated with ECD. The ECD increased by 36.16 cells/mm2 with BW increasing by 1 kg (P = 0.001) and increased by 0.44 cells/mm2 for every additional 1 mm in central corneal thickness (P = 0.01). The ECD of girls was 54.41 cells/mm2 higher than boys (P < 0.001). Children born with low BW presented significantly lower ECD than those born with normal BW (P < 0.05) and high BW (P < 0.05). Age and axial length were not significantly associated with ECD (P = 0.06 and P = 0.21, respectively). CONCLUSIONS: In Chinese school children aged 82 to 94 months, the ECD is positively correlated with BW and central corneal thickness, in which BW is a newly identified associated factor. It is like that gender plays an important role in ECD distribution while girls have relatively greater ECD than boys.

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.

Corneal Endothelial Cell Density in Normal Tension Glaucoma Compared to Healthy Controls.

The purpose of this study was to investigate corneal endothelial cell density (ECD) and morphology between normal tension glaucoma (NTG) and controls. A cross-sectional, single center study of 24 NTG and 26 age-matched healthy eyes were included. ECD, mean cell size (MCA) and coefficient of variance (CV) were analyzed, controlling for age and number and duration of concurrent glaucoma medications. NTG subjects had significantly lower ECD (2307 ± 514.7 vs. 2558 ± 278.5, p = 0.044) and larger MCA (458.3 ± 94.8 vs. 386.7 ± 57.3, p = 0.004), but no difference in CV compared to healthy subjects. NTG subjects stratified by number of glaucoma medications showed significant differences in ECD (p = 0.024) and MCA (p = 0.021), but no difference in CV. There were no significant differences in ECD, MCA or CV between subjects stratified by duration of glaucoma medication usage. After age-adjusting, there was no dose-dependent relationship between mean ECD or MCA and number of glaucoma medications. Post hoc analysis demonstrated only NTG subjects on three or more glaucoma medications had statistically significant differences in ECD (p = 0.032) and MCA (p = 0.037) compared to NTG subjects on two glaucoma medications. This study suggests that NTG is associated with lower corneal endothelial cell density and mean cell size.

The Effect of Fluorosecein on Corneal Endothelial Structure and Morphology in Diabetic Retinopathy Patients undergone Fundus Fluoresecein Angiography.

Objectives: To evaluate fluorescein effect on the corneal endothelium by endothelial specular microscopy in diabetic retinopathy patients undergone fundus fluoresecein anjiography (FFA). Methods: One hundred thirthy four diabetic retinopathy patients undergone FFA aged between 42 and 74 years were included study. We checked the corneal endothelial cell density (ECD), coefficient of variation of cell area (CV/polymegethism) and percentage of hexagonal cells (6A/pleomorphysm) before FFA and 1 hour, 1 day, 1 week after the procedure. Results: The mean baseline ECD was 2223±216 cells/mm2. The mean ECD before and 1 hour (2234±224 cells/mm2), 1 day (2237±231 cells/mm2), 1 week (2226±219 cells/mm2) after the procedure weren't significantly different (p=0.243; repeated measure ANOVA). The mean of the coefficient variations of the endothelial cell size before and 1 hour,1 day, 1 week after the procedure were 0.327±0.07, 0.319±0.06, 0.322±0.06, 0.325±0.07 respectively (p=0.281; repeated measure ANOVA). The mean of the baseline percent of hexagonal cells (pleomorphism) in the endothelium was 61.7±5.2, and the postoperative 1 hour, 1 day, 1 week percent were 62.3±5.7, 61.9±6.1, 61.3±5.9, respectively (p= 0.317; repeated measure ANOVA). Conclusion: The results of this study demonstrated that fluorescein has no toxic effect on corneal endothelium.

Risk factors for fluctuations in corneal endothelial cell density (Review).

The cornea is a transparent, avascular and abundantly innervated tissue through which light rays are transmitted to the retina. The innermost layer of the cornea, also known as the endothelium, consists of a single layer of polygonal endothelial cells that serve an important role in preserving corneal transparency and hydration. The average corneal endothelial cell density (ECD) is the highest at birth (~3,000 cells/mm2), which then decrease to ~2,500 cells/mm2 at adulthood. These endothelial cells have limited regenerative potential and the minimum (critical) ECD required to maintain the pumping function of the endothelium is 400-500 cells/mm2. ECD < the critical value can result in decreased corneal transparency, development of corneal edema and reduced visual acuity. The condition of the corneal endothelium can be influenced by a number of factors, including systemic diseases, such as diabetes or atherosclerosis, eye diseases, such as uveitis or dry eye disease (DED) and therapeutic ophthalmological interventions. The aim of the present article is to review the impact of the most common systemic disorders (pseudoexfoliation syndrome, diabetes mellitus, cardiovascular disease), eye diseases (DED, uveitis, glaucoma, intraocular lens dislocation) and widely performed ophthalmic interventions (cataract surgery, intraocular pressure-lowering surgeries) on corneal ECD.

Interocular Symmetry and Repeatability of Central Corneal Thickness and Corneal Endothelial Cell Morphology and Density in Healthy Eyes of Congolese.

PURPOSE: To determine the limits of normal interocular symmetry and the repeatability of central corneal thickness (CCT) and endothelial cell morphology and density. METHODS: Two hundred and seventy-eight subjects (age: 10.9-80.7 years) with healthy eyes were studied. CCT as well as endothelial cell morphology and density were measured by non-contact specular microscopy. Three measurements were obtained per eye per participant. Upper and lower tolerance limits of normal interocular symmetry were defined as the 2.5th and 97.5th percentiles of the interocular differences in CCT, endothelial cell density (CECD), coefficient of variation (CoV), hexagonality, and cell size. Repeatability was determined using the intraclass coefficient correlation (ICC), the coefficient of variation (CV), and the test-retest variability standard deviation (TRTSD). RESULTS: The mean interocular differences were -1.05 ± 17.5 µm (p = .32) for CCT and 0.5 ± 90.8 cells/mm2 (p = .76) for CECD. The 2.5th and 97.5th percentiles of the interocular differences were -13.9 and 15.4 µm for CCT and -177.4 cells/mm2 to 182.0 cells/mm2 for CECD. Only interocular difference in CoV correlated weakly with age (r = -0.22, P < .001). ICCs were 0.93 (95% CI: 0.89-0.96, P < .001) for CCT and 0.95 (0.94-0.96, P < .001) for CECD. CV and TRTSD were 1.2% ± 5.3% and 4.4 ± 3.4 µm for CCT and 2.4% ± 3.9% and 17.7 ± 7.7 cells/mm2 for CECD, respectively. CONCLUSIONS: CCT and CECD showed good repeatability and interocular symmetry in normal Congolese subjects. Absolute interocular differences in CCT and CECD exceeding 15.5 µm and 182 cells/mm2, respectively, should be considered suspicious and investigated. When comparing two intrasession measurements from the same eye, a difference of approximately 4.5 µm in CCT and 18 cells/mm2 or greater may be considered statistically significant.

Overestimation of corneal endothelial cell density by automated method in glaucomatous eyes with impaired corneal endothelial cells.

PURPOSE: To determine between-method differences in corneal endothelial cell parameters using center and automated methods of non-contact specular microscopy (CellCheck software of Konan, Inc.) in glaucomatous eyes. METHODS: We analyzed the central corneal endothelial cell density (ECD) of 245 glaucomatous eyes using center (ECD-Ce) and automated methods (ECD-Au). Based on the ECD-Ce, we allocated subjects to Groups 1 to 10 (at 250 cells/mm2 intervals) and evaluated the ECD, coefficient of variation in cell area (CV), and percentage of hexagonal cells (HEX). RESULTS: There was a close correlation (r = 0.91) between the ECD values measured using both methods. However, ECD-Au were significantly higher than those measured by the center method when ECD-Ce was less than 2500 (in Groups 1 to 8; P < 0.001 to P = 0.006). The regression equation of (ECD-Au-ECD-Ce) = 1028-0.397*ECD-Ce shows greater deviation in eyes with lower ECD, and this difference became 0 when ECD -Ce was 2593 cells/mm2. None of the 44 subjects with an ECD-Ce of < 1000 cells/mm2 recorded an ECD-Au < 1000 cells/mm2. Compared with the center method, the automated method had higher and lower median CV and HEX values, respectively (P < 0.001). The between-method differences in both CV and HEX were negatively correlated with ECD-Ce (r = -0.49, P < 0.001 and r = -0.25, P < 0.001, respectively). CONCLUSION: The automated method of the CellCheck software overestimates ECD in eyes with lower ECD values and may overlook risk of corneal decompensation.

Long-term influence of donor graft thickness and size on corneal endothelial cell density of Descemet stripping automated endothelial keratoplasty / 中华实验眼科杂志

Objective:To explore the long-term influence of donor central graft thickness (CGT) and donor graft size on corneal endothelial cell density (ECD) after Descemet stripping automated endothelial keratoplasty (DSAEK).Methods:An observational case series study was conducted.One hundred and forty-four eyes of 134 patients who underwent DSAEK in Peking University Third Hospital from January 2013 to December 2017 with at least 24-month follow-up were enrolled.Preoperative donor ECD was evaluated by specular microscopy, and ECD was determined by in vivo confocal microscopy at 1, 3, 6, 12, and 24 months postoperatively.Donor CGT was measured by anterior segment optical coherence tomography.According to the 3-month postoperative donor CGT, the subjects were divided into thinner graft group (45 eyes with CGT<100 μm), medium-thick graft group (66 eyes with CGT≥100-<150 μm) and thicker graft group (33 eyes with CGT≥150 μm). According to the donor trephination size, the subjects were divided into smaller graft group (31 eyes with trephination size≥7-<8 mm) and larger graft group (113 eyes with trephination size≥8-<9 mm). The changes of the donor CGT and corneal endothelial cell loss rate were compared at different time points after surgery.The relationships between 24-month postoperative ECD and donor ECD, donor graft size and donor CGT were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Peking University Third Hospital (No.IRB00006761-2008025). Written informed consent was obtained from each subject prior to any medical examination. Results:The donor CGT was 129.0 (90.8, 160.8), 115.5 (93.0, 146.0), 115.5 (89.0, 151.0), 112.5 (94.3, 146.8) and 114.0 (89.0, 144.5) μm at 1, 3, 6, 12 and 24 months after surgery, showing a statistically significant difference ( H=37.369, P<0.001). There was a statistically significant difference between 1-month and 3-month postoperative CGT ( P<0.001). There was no statistically significant difference in the endothelial cell loss rate among the three different donor CGT groups and between the two different donor graft size groups at any postoperative time points (all at P>0.05). Spearman correlation analysis showed that the 24-month postoperative ECD was strongly positively correlated with the preoperative donor ECD( rs=0.783, P<0.001), which was not associated with donor graft size and donor CGT ( rs=0.141, P=0.093; rs=-0.044, P=0.600). Conclusions:Larger postoperative ECD is correlated with larger preoperative ECD of donor graft.Lower long-term corneal endothelial cell loss rate after DSAEK is associated with thinner and larger diameter of donor graft.

Analysis of aqueous humor total antioxidant capacity and its correlation with corneal endothelial health.

Corneal endothelial decompensation is a serious condition that frequently requires treatment via corneal transplantation which contributes to a global shortage in donor corneas. Therefore, the purpose of this study was to analyze the influence of aqueous humor total antioxidant capacity (TAC) on corneal endothelial health. There is an urgent need for discovering protective factors to combat corneal endothelial cell (CEC) loss. For methods, we developed a cupric ion-based TAC (CuTAC) assay to analyze TAC level in a small volume of aqueous humor, that is, 10 µL per test, and examined the influences of ascorbic acid (AA) and antioxidant proteins on aqueous humor TAC. To broaden the investigation, we conducted a case-control study with patients classified into two groups, an insufficient endothelial cell density (ECD < 2100 cells/mm2) group, and a control group. These groups were formed based on baseline ECD values and were used to evaluate the influence of aqueous humor TAC and AA on overall corneal endothelial health. A CuTAC assay was used to accurately measure aqueous humor TAC without the need for sample dilution. After analyzing a total of 164 human aqueous humor samples, we found that AA was the major contributor to aqueous humor TAC (73.2%). In addition, TAC and AA levels in the IECD and control groups were both found to be significantly different (1.168 vs. 1.592 mM, p = 0.009 and 0.856 vs. 1.178 mM, p = 0.016). TAC and AA were considered independent protective factors against IECD with adjusted odds ratios of 0.02 (p = 0.017) and 0.023 (p = 0.033), respectively. In conclusion, aqueous humor TAC and AA contribute to the maintenance of sufficient corneal ECD, and our CuTAC assay can be a useful tool for analyzing TAC using only a small aqueous humor sample volume.

Is Pterygium Morphology Related to Loss of Corneal Endothelial Cells? A Cross-Sectional Study.

PURPOSE: To determine the difference in mean corneal endothelial cell density (CECD) between the healthy and diseased eyes of the patients with unilateral pterygium with different morphology patterns by using a non-contact specular microscope (SP2000: Topcon Corporation, Japan) and to find out any relationship between severity of pterygium and daily sunlight exposure with the CECD loss. METHODS: A descriptive cross-sectional prospective study was carried out at Al-Shifa Trust Eye Hospital (ASTEH), Rawalpindi, Pakistan from 21st January 2019 to 22nd January 2020. Two hundred eyes (n= 100 patients) of age range18 -68 years with unilateral pterygium were selected. Necessary demographic data and essential variables like age, smoking status, occupation, and daily direct sunlight exposure were determined. The severity of pterygium (grading) based on its morphology was determined by slit-lamp examination. CECD of each patient was carried out using a non-contact Specular Microscope. The healthy eye (without pterygium) of a patient was considered as control. RESULTS: The age range in this study was 18-68 years, with a mean age of 43.80 ± 24.37 years with a male to female ratio of 1.6:1 (62.00% males vs 38% females). Out of six occupations, the most common occupation was labour/construction work (n=31) followed by farming (n=27). The study reported a mean corneal endothelial cell density (CECD) of 2411.61±143.64 vs 2751.41 ± 123.674 cells/mm2 in diseased and normal eyes, respectively (p-value = 0.0001). CECD was lower in grade 3 pterygium compared to less severe pterygium { grade 3 (Fleshy) =2261 cells/mm2 vs grade 2 (Intermediate)= 2413 cells/mm2 vs grade 1 (Atrophic)=2459 cells/mm2} although this difference between the groups was not found to be significant (p=0.065). No significant association between sunlight exposure and CECD loss was observed (p=0.065). CONCLUSION: This study concluded that the mean corneal endothelial cell density in patients with unilateral pterygium using a non-contact specular microscope were 2411.61±143.64 cells/mm2.

Profile of central corneal thickness and corneal endothelial cell morpho-density of in healthy Congolese eyes.

PURPOSE: To determine the pachymetric and corneal endothelial cell morphometric features and their relationship to ocular and systemic factors in healthy Congolese subjects. METHODS: Non-contact specular microscopy was used in 278 healthy eyes (278 subjects) to measure central corneal thickness (CCT), corneal endothelial cell density (CECD) along with cell size, coefficient of variation (CV) in cell size, and hexagonality (HEX). The lower and upper reference limits and average values for each parameter were determined. Correlation and association of average values with anthropo-demographic and clinical variables were assessed. RESULTS: The mean age was 38.9 ± 17.2 years (10.9-80.7 years). Average values were 504.2 ± 30.7 µm (CCT), 2907.1 ± 290.9 cells/mm2 (CECD), 348.5 ± 38.4 µm2 (cell size), 32.9 ± 3.6% (CV), and 51.8 ± 7.2% (HEX). CCT was 504.9 ± 33.6 µm in men and 503.6 ± 28.3 µm in women (p = .73); values for CECD were 2917.1 ± 253.5 cells/mm2 and 2899.2 ± 317.8 cells/mm2 (p = 0.61), respectively. Lower and upper reference limits were 449.6 µm and 566.0 µm for CCT, and 2165.3 cells/mm2 and 3414.4 cells/mm2 for CECD, respectively. CCT correlated with body mass index (BMI), (r = - 0.12, P = 0.04). CECD decreased with age (r = - 0.49, P < 0.001), BMI (r = - 0.20, P = 0.001), intraocular pressure (r = - 0.13, P = 0.029) and ocular perfusion pressure (r = - 0.28, P = 0.028). CECD decayed by 8.3 cells/mm2 or 0.30% per year of age and CCT decreased by 0.72 µm per kg/m2. CONCLUSIONS: Mean central cornea was thinner, CECD higher, and references limits lower than reported in other African populations. The CCT and CECD normative values reported herein will be useful for both clinical and research purposes in this population.