Noncontact Specular Microscopy Research Articles

Corneal Endothelial Changes Following Anterior Chamber Intraocular Lens Implantation in Extracapsular Cataract Surgery

Aim: To determine & quantify corneal endothelial changes after primary or secondary implantation of anterior chamber intraocular lenses (AC IOLs) in extracapsular cataract surgery complicated by loss of capsule support. Setting: Ibn Al- Heythem teaching eye hospital, Baghdad. Patients & Methods: This prospective study comprised 125 patients underwent extracapsular cataract surgery complicated by loss of capsular support. Of them 76 patients had primary implantation of open-loop AC IOLs. The other 49 patients were kept aphakic after similar complicated cataract surgery & had secondary AC IOL implantation (open-loop), this was performed 10 weeks to 2 years from initial cataract surgery. At least 2 weeks post AC IOL implantation, non-contact specular microscopy was performed at the center of the cornea for eyes with primary & secondary AC IOLs implantation, their fellow eyes (phakic or pseudophakic with posterior chamber PC IOL) taken as control. Results: The mean endothelial cell density (ECD) was significantly lower in eyes with primary or secondary AC IOL implantation than in unoperated phakic eyes. Patients with primary AC IOL implantation in 1 eye & PC IOL implantation in fellow eye had a difference in ECD that was not statistically significant. The ECD difference was significantly greater in eyes with secondary AC IOL implantation compared to fellow pseudophakic eyes (PC IOL). The coefficient of variation (CV) in cell size & percentages of hexagonality showed no significant changes in the various groups. Conclusion: AC IOL implantation didn't appear to alter corneal endothelial function. Results indicate that endothelial cell loss was related to surgical trauma rather than the presence of AC IOL.

Corneal Stroma Analysis and Related Ocular Manifestations in Recovered COVID-19 Patients.

The purpose of this study was to assess the impact of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) on corneal stroma characteristics, ocular manifestations, and post-recovery refractive surgery outcomes after varying recovery durations. Fresh corneal lenticules from patients with post-coronavirus disease 2019 (COVID-19; recovered within 135days) and healthy controls (HCs) after small incision lenticule extraction (SMILE) surgery were obtained for experimental validation of SARS-CoV-2 susceptibility, morphological changes, and immune response of the corneal stroma. Corneal optical density (CD) was measured using the Pentacam HR. Corneal epithelium thickness (ET) and endothelium parameters were evaluated by wide-field optical coherence tomography (OCT) and non-contact specular microscopy (SP-1P), respectively. All the patients were assessed after SMILE surgery until 3 month of follow-up. The cornea was susceptible to SARS-CoV-2 with the presence of SARS-CoV-2 receptors (CD147 and ACE2) and spike protein remnants (4 out of 58) in post-recovery corneal lenticules. Moreover, SARS-CoV-2 infection triggered immune responses in the corneal stroma, with elevated IL-6 levels observed between 45 and 75days post-recovery, which were then lower at around day 105. Concurrently, corneal mid-stromal nerve length and branching were initially higher in the 60D to 75D group and returned to control levels by day 135. A similar trend was observed in CD within zones 0 to 2 and 2 to 6 and in the hexagonal cells (HEX) ratio in endothelial cells, whereas ET remained consistent. Notably, these changes did not affect the efficacy, safety, or predictability of post-recovery SMILE surgery. SARS-CoV-2 induces temporal alterations in corneal stromal morphology and function post-recovery. These findings provided a theoretical basis for corneal health and refractive surgery management in the post-COVID-19 milieu.

Long-Term Corneal Endothelial Parameters of COVID-19 Patients With Ocular Surface Symptoms.

This study aimed to investigate the long-term effects of COVID-19 on corneal endothelial cell morphology in patients with ocular symptoms to assess possible corneal involvement in patients who recovered. The COVID-19 group included patients diagnosed and treated at Istanbul University Cerrahpasa Medical Faculty with confirmed SARS-CoV-2 infection and ocular irritation symptoms. The control group was comprised of age- and sex-matched individuals. The controls had no ocular pathologies. Noncontact specular microscopy (Konan Cell Check SL, Hyogo, Japan) was performed using the center method after 156 ± 16 days of COVID-19 diagnosis. Parameters such as endothelial cell density (ECD), hexagonality (HEX), coefficient of variation, and central corneal thickness were analyzed. Specular microscopy results of 54 COVID-19 patients with ocular irritation symptoms and 72 controls were evaluated. Ocular symptoms in COVID-19 patients included conjunctival hyperemia, foreign body sensation, tearing, ocular secretion, and chemosis. Mean (±SD) ECD was 2770 ± 31 (cells/mm2) in the COVID-19 group and 2897 ± 26 in the control group, and mean (±SD) HEX was 46.52 ± 6.38 in the COVID-19 group and 58.22 ± 13.94 in the control group. COVID-19 patients exhibited significantly lower endothelial ECD and HEX levels than controls (P = 0.003 and P < 0.001, respectively). Coefficient of variation and central corneal thickness analyses did not reach statistical significance. COVID-19 can cause long-term alterations in the corneal endothelial cells, leading to decreased ECD and HEX. Future research should focus on the long-term implications of COVID-19 on the corneal health and visual outcomes.

Corneal endothelial cell morphology in children with autosomal recessive Alport syndrome: a longitudinal study

ABSTRACT Purpose To evaluate the corneal endothelial cell morphology in children with autosomal recessive Alport syndrome (ARAS). Methods This is a longitudinal, prospective cohort study that evaluated pediatric patients with genetically diagnosed ARAS. Fifty-eight eyes of 29 pediatric patients (12 patients, 17 controls) underwent a full ophthalmic examination. Corneal endothelial cell density (ECD) (cells/mm²), coefficient variation (CV) of cell area (polymegathism), the percentage of hexagonal cells (HEX) (pleomorphism), and central corneal thickness (CCT) were analyzed automatically using a noncontact specular microscopy. Results The mean ECD was 2904 ± 355.48 cell/mm² in the ARAS group and 3263.20 ± 261.71 cell/mm² in the control group (p = 0.004). In the ARAS group, the mean CV was 46.53 ± 10.43, which was significantly higher than that in controls (p = 0.026). The mean HEX was 48.86 ± 14.71 in the ARAS group and 59.06 ± 10.64 in the control group (p = 0.038). The mean CCT was 565.26 ± 39.77 µm in the ARAS group and 579.66 ± 31.65 µm in the control group (p = 0.282). The comparison of endothelial cell characteristic of the ARAS group with 1-year follow-up is as follows: The mean ECD decreased from 2904 ± 355.48 cell/mm² to 2735 ± 241.58 cell/mm² (p = 0.003). The mean CV increased from 46.53 ± 10.43 to 47.93 ± 10.50 (p = 0.471). The mean HEX decreased from 48.86 ± 14.71 to 48.50 ± 10.06 (p = 0.916). The mean CCT decreased from 565.26 ± 39.77 µm to 542.86 ± 40.39 µm (p = 0.000). Conclusion Measurement of ECD and percentage of hexagonality can also be used as an indicator of the health of the corneal endothelium. In this study, the mean ECD and HEX were significantly lower in ARAS group than in age-matched pediatric controls. Polymegathism, which reflects cellular stress, was statistically significantly higher in ARAS group. The mean ECD and CCT decreased significantly at 1-year follow-up. This study may demostrated that endothelial damages and stress in ARAS patients appear in childhood and show a rapid increase with age.

The Effect of Tobacco Smoking on Corneal Endothelium and Central Corneal Thickness

We aimed to study the impact of tobacco smoking towards central corneal thickness, morphology, and corneal endothelial cell density (ECD) in healthy subjects. This cross-sectional study recruited consecutive patients who visited the Ophthalmology Clinic, Universiti Kebangsaan Malaysia Medical Centre, from April 2017 to August 2018 who were active smokers and non-smokers. Active smokers were further divided into heavy and light smokers according to the number of pack-years smoked. The nicotine dependency level was measured using the Fagerstrom test and divided into low, moderate, and severe dependency. Non-contact specular microscopy was performed. Parameters studied included the ECD, percentage of hexagonality (HEX), coefficient of variation of cell size (COV), and central corneal thickness (CCT). A total of 84 eyes from 84 subjects were included, with 42 in the smoker and 42 in the non-smoker groups. The mean age was 38.3 ± 6.7 and 39.2 ± 10.7 years in the smoker and non-smoker groups, respectively. The mean ECD, HEX, and COV were 2783 ± 316 vs. 2877 ± 333 cells/mm2, 55.0 ± 6.7% vs. 55.0 ± 7.7% and 32.7 ± 4.4% vs. 32.2 ± 4.1% in the smoker and non-smoker group, respectively. However, none were statistically significant (p&gt;0.05). The mean CCT was also not statistically different, with 532.6 ± 30.8 μm in the smoker group and 530.5 ± 30.8 μm in the non-smoker group. No statistically significant difference was found between light and heavy smokers and addiction levels. There was a statistically significant but weak negative correlation between ECD and duration of smoking (r = -.370, p = 0.016) and a weak positive correlation between COV and number of pack-years smoked (r = .344, p = 0.025). Smoking did not significantly affect corneal ECD, cellular morphology, or CCT.

Association Between Endothelial Cell Density and Corneal Thickness in Medium, Short, and Long Eyes of Han Chinese Cataract Patients

To evaluate the association between the endothelial cell density (ECD) and central corneal thickness (CCT) in medium, short, and long eyes of preoperative Han Chinese cataract patients. Retrospective cross-sectional study. We consecutively enrolled 410 eyes, namely, 50 short eyes (axial length [AL]<22.0 mm), 150 medium eyes (22.0≤AL<24.0 mm), 120 medium-long eyes (24.0≤AL<26.0 mm), and 90 long eyes (AL≥26.0 mm), of 410 adult patients scheduled for cataract surgery. The ECD and CCT were determined preoperatively with a noncontact specular microscope. The association between the CCT and ECD was identified by using a multivariable regression analysis. A thin cornea was defined as having a CCT less than 500 µm. After adjusting for age, the presence of arterial hypertension, the presence of diabetes mellitus, intraocular pressure, and AL, a positive association between the CCT and ECD was identified in short eyes (linear regression coefficient [B]=3.40; standardized B [β]=0.52; P = .03), medium eyes (B = 2.33; β=0.28; P = .002), medium-long eyes (B = 1.84; β=0.25; P = .02), and long eyes (B = 2.69; β=0.41; P = .04). In the total group, the multivariable logistic analysis showed a significant link between the presence of a thin cornea and a lower ECD (odds ratio [OR]=0.80 per 100 cells/mm2 increase; P = .001). For cataract patients of Han ethnicity, a significant association between a thin CCT and a lower ECD was shown across the AL spectrum and was most prominent in short eyes. Eyes with a thin cornea are more likely to have a lower ECD.

Evaluation of corneal endothelial cell morphology off and on treatment by specular microscopy in children and adolescents with attention deficit hyperactivity disorder

Purpose To determine the structure and properties of corneal endothelial cells in children and adolescents with ADHD who received methylphenidate treatment at least six months. Method The prospective, observational study included 33 eyes of 33 patients diagnosed with ADHD who received methylphenidate treatment for at least six months, 33 eyes of 33 patients newly diagnosed with ADHD who did not start medication treatment, and 33 eyes of 33 healthy individuals. Average cell density, coefficient of variation, maximum cell area, normal cell area, minimum cell area, average cell area, and hexagonality ratio values were evaluated by non-contact specular microscopy. The parameters recorded in all three groups were compared. Results The average age of children in the ADHD + MPH, ADHD, and control groups is 9 ± 1.7, 8.9 ± 2.3, and 8.9 ± 1.8 years, respectively. (p > 0.05) The average MPH treatment dose is 0.94 ± 0.19 mg/kg, the average daily MPH intake is 34.12 ± 14.04 mg, and the average duration of use of MPH is 24.03 ± 12.46 months. Central corneal thickness (CCT) was measured as an average of 540.45 ± 31.23 in the ADHD + MPH group, 540.61 ± 29.69 in the ADHD group, and 546.58 ± 27.72 in the control group. (p = 0.499) The average coefficient of variation (CV) values were measured as 25.48 ± 4.22 in the ADHD + MPH group, 26.12 ± 3.48 in the ADHD group, and 26.12 ± 3.64 in the control group. (p = 0.491) The average hexagonality ratio (%) (HEX) values were measured as 69.45 ± 8.41 in the ADHD + MPH group, 68.21 ± 6.82 in the ADHD group, and 68.91 ± 7.97 in the control group. (p = 0.892) No statistically significant difference was observed between all three groups in terms of all parameters. Conclusion Methylphenidate treatment administered for at least six months with a diagnosis of ADHD did not have a toxic effect on the corneal endothelium.

Assessment of Age Changes in Corneal Endothelial Cell Count among Emmetropes Using Non-Contact Specular Microscope in Suez Canal University Ophthalmology Outpatient Clinic

Assessment of Age Changes in Corneal Endothelial Cell Count among Emmetropes Using Non-Contact Specular Microscope in Suez Canal University Ophthalmology Outpatient Clinic

Analysis of Corneal Endothelial Cells Measured by Noncontact Specular Microscopy in 20s

Analysis of Corneal Endothelial Cells Measured by Noncontact Specular Microscopy in 20s

Evaluation of the corneal thickness and endothelial changes following uncomplicated phacoemulsification in diabetic and non-diabetic patients with pseudo-exfoliation syndrome by specular microscopy.

To evaluate corneal endothelial cell changes following uncomplicated phacoemulsification in diabetic patients with PEX, compared with diabetic patients and non-diabetic patients with PEX. This prospective, comparative, non-randomized cohort study included 61 eyes of 61 patients who were diagnosed as having senile cataract. Patients were divided into three groups: Group (1) included 19 eyes of patients with DM and PEX, group (2) included 22 eyes of diabetic patients, and group (3) included 20 eyes of patients with PEX. All included patients had uncomplicated phacoemulsification with IOL implantation. Patients were examined by non-contact specular microscopy (NIDEK, CEM-530, Japan), preoperatively and postoperatively at regular follow-up periods (one, three, and six months postoperatively) with analysis of the endothelial cell density, percentage of hexagonal cells, CV, and CCT. By the end of follow-up period, there was a statistically significant reduction in ECD and HEX with a significant increase in CV and CCT in group one (DM-PEX). In group two (DM), a statistically significant decrease in ECD and HEX with a significant increase in CCT was reported, while in group three (PEX), the only significant difference was found in the form of ECD reduction. Patients with DM and PEX had significant changes regarding ECD, CV, HEX, and CCT which were more pronounced than in patients with DM only or PEX only. More attention should be paid while operating on diabetic patients with PEX to save corneal endothelium and decrease postoperative complications. The study was retrospectively registered (16 July 2021) on ClinicalTrials.gov (NCT04965168).

Deep Learning-Based Automatic Diagnosis of Keratoconus with Corneal Endothelium Image.

The primary objective of this study was to develop an end-to-end model that can accurately identify corneal endothelial cells and diagnose keratoconus based on corneal endothelial images acquired from a non-contact specular microscope. This was a retrospective case-control study performed at the Refractive Surgery Center of West China Hospital. A total of 403 keratoconus eyes (221 patients) and 370 myopic eyes (185 normal controls) were consecutively recruited from January 2021 to September 2022. Specular microscopy was used to image and measure the morphometric parameters of the corneal endothelial cells. A Fully Convolutional Network model with a ResNet50 (FCN_ResNet50) was established to perform the endothelial segmentation. The images were then classified using an ensemble machine learning system consisting of four pre-trained deep learning networks: DenseNet121, ResNet50, Inception_v3, and MobileNet_v2. The performance of the models was evaluated based on different metrics, such as accuracy, intersection over union (IoU), and mean IoU. We established a fully end-to-end deep-learning model for the segmentation of endothelial and diagnosis of keratoconus. For endothelial segmentation, the accuracy of the FCN_ResNet50 model achieved near 90% with mean IoU converging to about 80%. The ensemble machine learning system can achieve over 92% accuracy, and > 98% area under curve (AUC) values to diagnose keratoconus with endothelial cell images. In addition, we constructed a diagnostic model based on deep-learning features and developed an associated nomogram which manifested an excellent performance for diagnosis and monitoring the progression of keratoconus. Our research developed an end-to-end model to automatically identify and assess corneal endothelial morphological changes in keratoconus eyes. Moreover, we also constructed a novel nomogram, which can provide valuable information for the diagnosis, monitoring, and management of the disease.

Comparison of implantation of posterior chamber phakic IOL implantation and laser vision correction in terms of corneal endothelial cells: 3-year observational paired-eye study.

To compare the postoperative endothelial cell counts of EVO-implantable collamer lenses (ICLs) with a central hole (V4c and V5) and laser vision correction surgery (laser in situ keratomileusis or photorefractive keratectomy). B&VIIT Eye Center, Seoul, South Korea. Retrospective observational and paired contralateral study. 62 eyes of 31 patients who underwent EVO-ICLs with a central hole implantation in one eye (phakic intraocular lens [pIOL] group) and laser vision correction in the contralateral eye (LVC group) to correct refractive errors were retrospectively reviewed. Central endothelial cell density (ECD), percentage of hexagonal cells (HEX), coefficient of variation (CoV) in cell size, and adverse events were evaluated for at least 3 years. The endothelial cells were observed using a noncontact specular microscope. All surgeries were performed, without complications during the follow-up period. The mean ECD loss values compared with the preoperative measurements were 6.65% and 4.95% during the 3 years after pIOL and LVC, respectively. There was no significant difference in ECD loss compared with the preoperative values (paired t test, P = .188) between the 2 groups. No significant loss in ECD was observed at any timepoint. The pIOL group showed higher HEX ( P = .018) and lower CoV ( P = .006) values than the LVC group at the last visit. According to the authors' experience, the EVO-ICL with a central hole implantation was a safe and stable vision correction method. Moreover, it did not induce statistically significant changes in ECD at 3 years postoperatively compared with LVC. However, further long-term follow-up studies are required to confirm these results.

Evaluation of Corneal Endothelial Cell Density Changes in Eyes with Silicone Oil Tamponade after Pars Plana Vitrectomy

Aim To assess the changes in corneal endothelium by non-contact specular microscopy in eyes treated by pars plana vitrectomy (PPV) with temporary silicone oil (SO) tamponade with or without phacoemulsification. Patients and Methods We enrolled 24 patients, assigned into two groups: 12 patients underwent pars plana vitrectomy with SO injection (group 1) and 12 patients underwent combined phaco-vitrectomy with SO injection (group 2). All of them underwent an ophthalmological examination, which included: best corrected visual acuity (BCVA), intraocular pressure measurement, fundus examination and specular microscopy follow ups at the 1st week,1st month and 3rd month visits. Results The initial count of endothelial cell density (ECD) in group 1 was 2543.58 ± 759.62 cell/mm2 which decreased at 3rd month visit to 2299.33 ± 729.87 cell/mm2, while in group 2 was 2621.08 ± 514.50 &amp; 2307.50 ± 575.55 cell/mm2 respectively. We found statistically significant decrease in the mean cell density (MCD) in group 1 and group 2, at the 3rd month than at the 1st week. Three months after operation, coefficient of variation (CV) was 34.58 ± 4.29 % and 35.75 ± 4.16%, hexagonality (HEX) was 46.83 ± 8.67 % and 47.83 ± 10.50%, while mean central corneal thickness (CCT) was 553.08 ± 22.13 μm and 548.17 ± 33.12 for group 1 and 2 respectively, and no corneal edema reported at the study end. Conclusion The pars plana vitrectomy (PPV) with silicone oil (SO) injection procedure caused changes in corneal endothelial cells in varying between pleomorphism (decreased HEX), polymegathism (increased CV) and endothelial cell loss. A higher incidence of CV increase (polymegathism) reported after combined phaco-vitrectomy than pars plana vitrectomy alone with silicone tamponade. We recommend SO removal after achieving the proposed tamponading action of SO to avoid SO keratopathy.

Corneal Endothelial Morphological Alterations in Type 2 Diabetes: Associations with Glycemic Control, Disease Duration, and Diabetic Retinopathy Severity—A Cross-Sectional Study in Benghazi, Libya

Background The corneal endothelium is essential for maintaining corneal transparency and fluid regulation, and its dysfunction can lead to corneal edema and decreased visual acuity. Corneal specular microscopy is used to detect corneal disorders early. Aim This study aimed to evaluate morphological changes in the corneal endothelium of patients with type 2 diabetes mellitus (DM) using specular microscopy. Methods This study enrolled 50 individuals with type 2 diabetes and 50 nondiabetic individuals as control subjects. Patients with certain ocular and systemic conditions were excluded. The collected data included demographic information, medical history, recent hemoglobin A1c (HbA1c) values, visual acuity, ophthalmological examination, and diabetic retinopathy (DR) staging. The corneal endothelial morphology was evaluated using a noncontact specular microscope, which measured corneal endothelial cell density (ECD), central corneal thickness (CCT), coefficient of variation of cell size (CV), and hexagonality. The data were analyzed using SPSS software, and the results were presented as mean ± standard deviation, numbers, and percentages. An unpaired t-test was used to compare different means, and a p-value less than 0.05 was considered statistically significant. Results A majority of diabetic patients (62%) had diabetes for more than 10 years, and 58% of them had higher than 7.5% HbA1c levels. In terms of DR severity, 46% of patients had mild nonproliferative diabetic retinopathy (NPDR), 36% had moderate NPDR, and 10% had severe NPDR. There were significant differences between diabetic and nondiabetic groups in corneal ECD (2480 ± 223 cells/mm2 for DM group vs. 2652 ± 234 cells/mm2 for non-DM), hexagonality (39.6 ± 2.8% for DM group vs. 47 ± 2.1% for non-DM), CV (42 ± 2.9% for DM group vs. 35.5 ± 2.3% for non-DM), and CCT (550 ± 14.8 µm for DM group vs. 530 ± 9.6 µm for non-DM). Patients who had diabetes for more than 10 years had significantly lower ECD (2356 cells/mm2 vs. 2689 cells/mm2), lower hexagonality (39 vs. 41%), and higher CV (43 vs. 41%) and higher CCT (553.9 ± 4.6 vs. 545.5 ± 4.0) than those with less than 10 years of diabetes. As the severity of DR increased, there was a significant decrease in ECD (from 2641 ± 194 cells/mm2 for mild NPDR to 2310 ± 82 cells/mm2 for severe PDR), a decrease in hexagonality (from 40.9 ± 3.2% for mild PDR to 37.4 ± 1.1% for severe PDR), an increase in CV (from 40.1 ± 2.3% for mild PDR to 44 ± 2.9% for severe PDR), and an increase in CCT (from 543.7 ± 13.8 for mild PDR 563.8 ± 2.9 for severe PDR). Conclusion This study revealed that type 2 diabetes is associated with significant reductions in ECD and hexagonality, as well as an increase in CV and CCT. The severity of DR and the duration of diabetes were correlated with changes in these parameters. These findings underscore the need for a comprehensive evaluation of corneal health in diabetic patients.

Assessment of Age Changes in Corneal Endothelial Cell Count among Emmetropes Using Non-Contact Specular Microscope in Suez Canal University, Ophthalmology Outpatient Clinic

Assessment of Age Changes in Corneal Endothelial Cell Count among Emmetropes Using Non-Contact Specular Microscope in Suez Canal University, Ophthalmology Outpatient Clinic

The Impact of Severe COVID–19 on Corneal Endothelial Cells–Analysis of the In Vivo Noncontact Specular Microscopy

ABSTRACT Purpose This study aimed to investigate the effects of severe COVID-19 infection on the corneal endothelium via in vivo specular microscopy. Methods This was an observational, prospective, and controlled study including 56 eyes of 56 severe COVID-19 patients, compared to after-recovery and 56 eyes of 56 age- and gender-matched healthy controls. Results Endothelial cell density was lower in the active disease period compared to healthy controls (p = .001) and decreased even more after recovery (p < .0001). After recovery, the average cell area and coefficient of variation were higher compared to the active disease period (p < .0001 and p = .008, respectively) and the healthy controls (for both, p < .0001), whereas hexagonality was lower (p < .0001). Central corneal thickness increased in the active disease period compared to after recovery (p < .0001) and healthy controls (p = .002). Conclusions These results may be due to direct host-virus interaction or linked to immune dysregulation, subclinical corneal endotheliitis, or still yet a viral-mediated inflammation.

Comparison of Central Corneal Thickness Measurement by Specular Microscopy, Optical Coherence Tomography, Optical Biometry and Ultrasound Pachymetry in Normal Eyes

BACKGROUND&#x0D; Precise central corneal thickness (CCT) measurement is of utmost importance in various corneal diseases and refractive procedures. Various methods are available to measure CCT. But studies comparing CCT measurements with different devices have shown variable results. This study compares the CCT measurements by different devices and Ultrasound Pachymetry (USP).&#x0D; METHODS&#x0D; This prospective study that was conducted from October 2017 to June 2019 included 100 subjects aged more than 18 years and CCT was measured by non-contact specular microscopy (NCSM), spectral domain optical coherence tomography (SD-OCT), optical biometry (OB) and USP in normal eyes. For every patient and with each device, three readings were taken and an average was recorded. The data recorded per protocol was analyzed using Intraclass correlation coefficient and Bland-Altman analysis.&#x0D; RESULTS&#x0D; The mean value of CCT with NCSM, SD-OCT, OB, USP was 528.98±32.18µm, 532.64±30.49µm, 517.47±31.89µm and 533.39±33.44µm, respectively. The intraclass correlation was found to be maximum between NCSM and USP (0.953, p&lt;0.001). The mean paired difference of CCT values with SD-OCT and USP was statistically insignificant (-0.75±14.73, p=1.00) whereas the difference obtained with all other devices was statistically significant.&#x0D; CONCLUSIONS&#x0D; A statistically significant positive correlation (p&lt;0.001) was observed on comparing all the four devices with each other for measurement of CCT. The OCT had the best agreement and also positively correlated with USP. Hence, we conclude that OCT can be an effective alternative to USP for measuring CCT.

Evaluation of corneal endothelium and correlation with disease severity in patients with Graves’ ophthalmopathy: A specular microscopy-based study

PurposeTo investigate the possible corneal endothelial damage in Graves’ ophthalmopathy (GO) and its relationship with GO activity. MethodsThis cross-sectional study included 101 eyes of 55 patients with GO. Each eye was assigned a specific clinical activity score (CAS). Accordingly, they were classified as active (CAS ≥ 3) or inactive (CAS< 3). The corneal endothelium was measured using a non-contact specular microscope (Tomey EM-4000; Tomey Corp.). Endothelial cell density (ECD), average cell area (ACA), standard deviation of cell area (SD), coefficient of variation in cell area (CV), hexagonal cell ratio (HEX), and central corneal thickness (CCT) were recorded. ResultsAmong the eyes included in the study, 71 had inactive GO and 30 had active GO. ACA and HEX levels were lower (p<0,001) and CV values were higher (p<0.001) in patients with GO than in healthy subjects. Corneal endothelial cell morphology was altered in active GO compared to inactive GO. The SD (p = 0,009) and CV (p<0,001) were significantly higher in active GO than in inactive GO. When the parameters examined were correlated with CAS, a statistically significant positive correlation was observed between proptosis (p = 0,036, r = 0,385) and CV (p = 0,001, r = 0,595). ConclusionOur study confirmed that morphological changes occur in the corneal endothelium of patients with GO. CV and SD values, in conjunction with CAS, can be used as non-invasive and quantitative indices to examine the activity status of GO. The demonstration of endothelial changes even in GO eyes with low CAS may be considered an incentive to include non-contact specular microscopy in the routine clinical evaluation of all patients with GO.

Comparative Study of Corneal Endothelial Changes Among Contact Lens Wearers and Spectacle Users Using Non-Contact Specular Microscopy

Comparative Study of Corneal Endothelial Changes Among Contact Lens Wearers and Spectacle Users Using Non-Contact Specular Microscopy

Effects of chewing tobacco on corneal endothelium in patients with diabetes mellitus.

To determine the impact of tobacco chewing on corneal endothelial structure in patients with diabetes mellitus (DM). Corneal endothelial parameters (endothelial cell count, ECD; coefficient of variation, CV; hexagonality, Hex, and central corneal thickness, CCT) were analysed in 1234 eyes of 1234 patients using non-contact specular microscopy (EM 4000 Tomey Nishi-Ku, Nagoya, Aichi, Japan). The study group (with a present history of tobacco chewing) comprising of 948 subjects, with 473 having DM was compared with age and gender-matched control group comprising of 286 subjects (139 having DM) with no history of tobacco use in any form. Tobacco chewers had a significantly reduced ECD (P = 0.024) and Hex (P = 0.009) as compared with non-chewers. Similar results were noted in ECD (P = 0.004) and Hex (P = 0.005) in patients with DM. Tobacco chewers had a significantly decreased ECD values among males, HbA1C ≤ 7.5% and duration of DM ≤ 20 years, and significantly decreased Hex among those with >50 years of age, females, and duration of DM > 20 years. The CV and CCT values were comparable between the study and the control groups. Tobacco chewers showed a significant association of ECD with age, HbA1C, and duration of DM; CV with HbA1C; Hex with age and duration of DM; and CCT with gender, age, HbA1C and duration of DM. Tobacco chewing may negatively impact corneal health, especially confounded by additional factors like age and DM. These factors must be accounted for in the pre-operative evaluation of such patients prior to any intra-ocular surgery.