Noncontact Specular Microscopy Research Articles

Living histopathology - interrogation of ocular tissues by light: a celebration of the slit-lamp and a repertoire of clinical techniques.

The evolution of the slit-lamp microscope has enabled ophthalmologists to examine the transparent tissues of the eye with histological detail. This paper considers the history and optics of the slit-lamp. Optical sectioning and retro-illumination are discussed; particularly, effective placement of the reflected light beam. A variety of less conventional slit-lamp examination techniques is described. These include remote dark-field retro-illumination, examination through refractive surfaces (particularly, meniscus retro-illumination to demonstrate tear cells and non-contact corneal endothelial specular microscopy), location of vitreous abnormalities by parallax, expanding radial cords of vitreous cells in lymphoma, mirror examination of the superior fornix and corneal epithelial folds in ocular hypotension. It concludes with brief discussions about haemoglobin video imaging, semi-quantification of aqueous outflow volume by aqueous column cross-section area, and autofocus for video-microscopy.

Compared to Trabeculectomy, Ex-Press® Surgery Significantly Decreased the Loss of Corneal Endothelial Cell Density in Low-Intraocular-Pressure Glaucoma: 3-Year Follow-Up.

We compared the corneal endothelial cell loss between trabeculectomy (Trab) and Ex-Press® surgery (EXP) for low-intraocular pressure (IOP) glaucoma patients. This was a single-facility retrospective study. We analyzed the cases of patients with primary open-angle glaucoma (POAG) and pre-operative IOP ≤ 21 mmHg who had undergone Trab or EXP surgery and were followed for >3 years. Noncontact specular microscopy was used to determine the corneal endothelial cell density (CED) before and after Trab or EXP surgery. We measured the CED at 12, 24, and 36 months post-surgery. We compared the CED values and CED survival ratio after both surgeries using paired t-tests. We included 39 eyes that underwent Trab and 36 eyes that underwent EXP surgery. In the Trab group, the mean CED value had decreased from 2333 ± 399 at baseline to 2066 ± 587 cells/mm2 after 3 years. In the EXP group, the mean CED value had decreased from 2320 ± 393 at baseline to 2229 ± 460 cells/mm2 after 3 years. The survival ratio of CED at >3 years was 89.3 ± 14.2% (Trab group) and 95.6 ± 11.1% (EXP group); compared to the Trab surgery, the EXP surgery thus significantly decreased the CED loss (p = 0.037). No case resulted in bullous keratopathy. Compared to trabeculectomy, Ex-Press® surgery appears to be a safer surgical method with regard to the endothelial cell loss risk.

Variations in anterior segment parameters among different phenotypes of polycystic ovary syndrome

PurposeThe objective of this study was to evaluate anterior segment parameters across various phenotypes of polycystic ovary syndrome (PCOS), considering body mass index (BMI), serum estradiol and testosterone levels.Materials and MethodsThis prospective study included 116 women with PCOS, with each of the four distinct phenotype comprising 29 women. Additionally, 29 healthy women were included in the control group. All participants underwent comprehensive ophthalmologic examinations, including intraocular pressure (IOP) measurements. Anterior segment parameters, such as central corneal thickness (CCT), axial length (AL), aqueous depth (AD), anterior chamber depth (ACD), and lens thickness (LT) were measured using optic biometry. Endothelial cell density (ECD) was assessed using non-contact specular microscopy. The BMI was calculated, and serum levels of estradiol and testosterone were noted.ResultsIOP was found to be significantly higher (p = 0.003) and CCT was significantly thicker (p = 0.004) in all phenotypes of PCOS compared to the control group. BMI, serum estradiol and free testosterone were found to correlate with both IOP and CCT. AL, AD, ACD and LT values showed no significant differences compared to the control group. Although ECD tend to be higher in the PCOS phenotypes, this difference was not statistically significant (p > 0.05).ConclusionGiven our findings that CCT and IOP are significantly elevated in PCOS phenotypes. PCOS should be considered as an important factor when evaluating female patients for anterior segment diseases and glaucoma.

A comparative study of central corneal thickness using an ultrasonic pachymeter and a noncontact specular microscope in adult patients coming to the ophthalmology outpatient department in a tertiary care hospital in Western India

Objective: To evaluate and compare the accuracy of measuring central corneal thickness (CCT) using an ultrasonic pachymeter and a noncontact specular microscope and whether they can be used interchangeably in adult patients with healthy cornea. Methodology: A comparative and observational study was carried out in adult patients coming to the ophthalmology outpatient department (OPD) in a tertiary care hospital in Western India. In all patients, CCT is measured using an ultrasonic pachymeter and a noncontact specular microscope to perform a comparative study. Statistical analysis was done using paired t-test. Two-tailed hypothesis was applied. Results: This study included a sample size of 300 eyes of 150 adult patients. We want to test whether CCT values by Ultrasound Pachymeter and Noncontact specular Microscope is significantly different for right eyes and left eyes of the same patients, therefor we applied paired t-test for statistical analysis. T value for the right eye CCT measurement was −0.4 and the value of P was 0.69. T value for the left eye CCT measurement was −0.79 and the value of P was 0.43. P > 0.05 suggested that the results were nonsignificant. Conclusion: Our study suggests that the noncontact specular microscope produces CCT values that do not vary significantly from ultrasonic pachymeter. In subjects with healthy cornea, ultrasound pachymeter and specular microscope can be used interchangeably.

Corneal Endothelial Cell Density and Morphology in Healthy Libyan Eyes

Background Endothelial cell density and morphology vary across ethnic groups. Aim This article investigates the corneal endothelial cell density and morphology in healthy Libyan eyes. Methods A 3-month cross-sectional observational study was conducted at Benghazi Teaching Eye Hospital, involving 198 eyes of 100 healthy Libyan participants. The noncontact Topcon specular microscope (SP-1P model) was used to assess the following parameters: the mean central corneal thickness (CCT), the mean cell density (MCD), the mean coefficient of variation (CV%), and the mean percentage of the hexagonal cell (Hex [%]). The variables were analyzed in relation to age and gender using the Statistical Package for the Social Sciences (SPSS version 25.0) Results The mean age of participants in this study was 47.4 ± 13.8 years (range 21–75 years). The mean CCT was 516.45 ± 43.04 μm, the MCD was 2664.30 ± 371.26 cells/mm2, the mean CV% was 32.3% ± 3.7, and the mean Hex (%) was 52.8% ± 9.6. There was no statistical difference in the age, CCT, and MCD across genders. Whereas CV (%) and Hex (%) showed significant gender differences (p < 0.01 for both). There was a significant negative weak correlation between CCT (r = –0.10) and age, as well as a significant negative moderate correlation between MCD and Hex (%) with age (r = –0.36 and r = –0.31, respectively). CV% exhibited a significant, moderately positive association with age (r = 0.35). The higher endothelial cell loss rate of 8.4% was in the third decade of life whereas other age groups ranged between 1.1 and 2.7%. Conclusion The normative data for the endothelium of Libyan eyes are reported, which can be used as a baseline for future studies.

Comparison of corneal endothelial cell density reduction between primary open-angle glaucoma and pseudo-exfoliation glaucoma patients at 3years after Ex-Press® surgery.

We compared corneal endothelial cell (CED) loss after Ex-Press (EXP) surgery between patients with primary open-angle glaucoma (POAG) and pseudo-exfoliation glaucoma (PEX). This was a single-facility retrospective study. We included glaucoma patients who had undergone EXP surgery and were followed up > 3years. We measured the CED before and after (at 12, 24, and 36months) EXP surgery by noncontact specular microscopy and compared the means of the CED values and CED survival ratios after EXP surgery by paired t-test. We included 119 eyes that underwent EXP surgery, including 60 POAG eyes and 59 PEX eyes. In the POAG group, the mean CED decreased from 2389 ± 321 at baseline to 2230 ± 424 cells/mm2 after 3years. In the PEX group, the mean CED decreased from 2111 ± 510 at baseline to 1845 ± 628 cells/mm2 after 3years. At the 3-year follow-up, the CED survival ratio was 93.3 ± 12.5% in the POAG group and significantly lower, at 85.0 ± 19.5%, in the PEX group (p = 0.0064). Two cases in the PEX group developed bullous keratopathy. EXP surgery decreased the corneal endothelial cell populations in PEX patients faster than POAG patients.

The effect of epilepsy and anti-epileptic drugs on the anterior and posterior segment of the eye

ABSTRACT Clinical relevance Understanding the causes of visual symptoms in epilepsy patients is important for early diagnosis and taking precautions. Background The aim of this study is to evaluate the anterior and posterior segment parameters in patients with generalized tonic-clonic epilepsy (GTCE). Methods This retrospective study included 50 eyes of 50 patients with GTCE and 55 eyes of 55 healthy controls. For all participants, detailed ophthalmic examinations were obtained from the files of patients. Anterior segment parameters were measured using corneal topography and non-contact specular microscopy, and posterior segment parameters were measured using swept-source optical coherence tomography. Results The mean age of the patients with GTCE was 43.3 ± 13.2 years, and in the healthy controls it was 47.6 ± 10.7 years (p = 0.405). In GTCE patients, 34 patients were treated with monotherapy (MT) and 16 patients with polytherapy (PT). Central macular thickness (CMT) was statistically significantly thin in GTCE patients (p = 0.001). The average and four quadrants (superior, inferior, nasal, temporal) retinal nerve fibre layer (RNFL) were thinner in GTCE patients than in the healthy controls, but there was no statistically significant difference (p > 0.05, all). The central corneal thickness was statistically significantly thin in GTCE patients (p = 0.04). Endothelial cell density (ECD), endothelial cell number (ECN), and average cell area (ACA) were statistically significantly lower in GTCE patients than in the healthy controls (p < 0.05, all). Although the CMT, average, and four-quadrants RNFL were thinner in the PT group compared to the MT group, no statistically significant difference was observed (p > 0.05, all). Total high-order aberrations (HOAs) were 0.6 ± 0.4 in the MT group and 0.4 ± 0.1 in the PT group (p = 0.01). ECD, ECN, and ACA measurements were observed to be lower in the PT group compared to the MT group, but no statistically significant difference was detected (p > 0.05, all). Conclusion There could be statistically significant differences between GTCE patients and healthy controls in anterior and posterior segment parameters. This situation may be due to the epilepsy itself or to the antiepileptic drugs.

The impact of systemic isotretinoin treatment on the tear film, meibomian glands, and corneal endothelium

Purpose The study aims to investigate changes in tear function, meibomian glands and corneal endothelium in patients receiving systemic isotretinoin therapy. Materials and methods This prospective study included 38 eyes from 38 patients (23 females and 15 males) treated with systemic isotretinoin (0.5–1 mg/kg/day) following the diagnosis of acne vulgaris. All patients underwent a comprehensive ophthalmologic examination at baseline, 1st month, and third month of treatment. Subjective complaints were assessed using the Ocular Surface Disease Index (OSDI). Tear functions were evaluated through non-invasive tear break up time (NIBUT) and Schirmer I test. Meibomian gland (MG) changes were examined using meibography. Corneal parameters, including endothelial cell density (ECD), coefficient of variation (CV), the number of cells with a hexagonal shape (6A), average cell area (AVG), and central corneal thickness (CCT) were assessed using non-contact specular microscopy. Results The mean age of the patients was 19.29 ± 2.83 years. Ocular surface-related discomfort, measured with OSDI scores, significantly worsened at the third month measurements compared to the pre-treatment values (p < 0.001). In the 1st month of treatment, there was a significant decrease in NIBUT (p < 0.05). No statistically significant difference was found in the Schirmer test results at each visit. According to the 1st and third-month analysis, there was a significant increase in MG loss compared to the pre-treatment period (p < 0.001). ECD, CV, 6 A, AVG measurements at the first and third months showed a significant change compared to the pre-treatment values (p < 0.001). No significant difference was observed in the CCT measurements during the treatment. Conclusion Systemic isotretinoin disrupted tear stability, caused MG loss, deterioration in corneal endothelium, and led to symptomatic complaints in patients.

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

Aim: To determine &amp; 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 &amp; 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 &amp; 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 &amp; 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 &amp; 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 &amp; 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/mm 2 ) 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.

Corneal and anterior segment parameters in patients with clinically unilateral pseudoexfoliation syndrome.

Pseudoexfoliation syndrome (PES) is an age-related systemic condition that predominantly affects ocular structures and is characterized by the deposition of material on the lens, ciliary body, zonules, corneal endothelium, iris, and pupillary margin. We compared the corneal endothelial morphology, anterior segment parameters, corneal densitometry, and corneal topographic characteristics between the clinically affected and apparently normal fellow eyes of patients with clinically unilateral PES. This was a comparative, cross-sectional study of 34 patients with clinically unilateral PES. The anterior segment was examined using a Scheimpflug imaging system, and the corneal endothelium was assessed using a noncontact specular microscope. Corneal endothelial cell density, polymegathism, and pleomorphism were assessed using the specular microscope. Furthermore, the Scheimpflug camera was used to measure the corneal power of the flat and steep axis, mean corneal power, maximum keratometry, anterior chamber angle, anterior chamber depth, anterior chamber volume, corneal volume, and the corneal thickness at the apex point, center of the pupil, and the thinnest point. Corneal densitometry was evaluated at two concentric zones (0-2 mm and 0-12 mm). In total, 68 eyes from 34 patients were ultimately included in the study. The mean (standard deviation) age of the patients was 73.38 (8.75) years (range: 50-87 years). Among the included patients, 17 (50%) were male and 17 (50%) were female. The anterior segment parameters did not significantly differ between eyes with PES and their clinically unaffected fellow eyes (all P > 0.05). Similarly, no statistically significant difference was observed in corneal endothelial morphology (all P > 0.05). Our measured parameters do not differ between the clinically affected eye and the clinically unaffected fellow eye. This supports the theory that PES is a bilateral disorder. Considering the variety of complications associated with PES, bilateral involvement should be assumed in the clinical and surgical management of patients with clinically unilateral PES. In the future, new research could increase our understanding of this syndrome.

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.