Mean Central Corneal Thickness Values Research Articles

Do intravitreal anti-VEGF injections have an effect on corneal endothelial remodeling in children with premature retinopathy?

This study was carried out to investigate the effects of retinopathy of prematurity (ROP) and intravitreal antivascular endothelial growth factor (VEGF) injections on the corneal endothelium in the childhood period of patients who have had ROP. The material of comparative case-control clinical study consisted of patients followed up with ROP between February 2013 and February 2023. The eyes in the study group were divided into two subgroups consisting of those who received intravitreal anti-VEGF injections (subgroup 1) and those who were followed up only (subgroup 2). Central corneal endothelial cell density (ECD), coefficient of variation (CV), central corneal thickness (CCT), and pleomorphism parameters in the childhood period were evaluated by corneal specular microscopy and compared with age-matched healthy control subjects. There were 84 eyes of 42 patients with ROP in the study group and 80 eyes of 40 healthy children in the control group. Mean CCT was significantly higher in subgroup 1 and the control group than in subgroup 2 (p = 0.037), and mean ECD was significantly higher in subgroup 2 than in subgroup 1 and the control group (p < 0.001). There was no significant difference between subgroup 1 and the control group in mean ECD and CCT values (p = 1.000 for both cases). Considering that ROP patients who received intravitreal anti-VEGF injections had more advanced-stage ROP than ROP patients who were followed up only, these findings suggest that intravitreal anti-VEGF applications in ROP cases may lead to corneal endothelial parameters similar to those of healthy eyes.

Comparison of central corneal thickness measured by ultrasound pachymetry, corneal topography, spectral domain- optical coherence tomography, and non-contact specular microscopy

BackgroundThis study aims to investigate the compatibility of central corneal thickness (CCT) measurements obtained with spectral-domain optical coherence tomography (SD-OCT), Scheimpflug-Placido-based corneal topography (CT), non-contact specular microscopy (NCSM), and ultrasonic pachymetry (UP). These four corneal measurement techniques have not been compared in a single study on these many subjects. MethodsCCT was measured in 185 eyes of 185 volunteers with each of the four devices by a single observer. CCTs from Optovue® iVue SD-OCT, Sirius corneal topography, NonconRobo NCSM, and Accutom UP devices were recorded. Compatibility between devices was evaluated with intraclass correlation coefficient (ICC) and Bland-Altman plots. Pairwise comparisons were performed using the Bonferroni test. Measurement differences between devices were analyzed with the Pearson correlation coefficient. ResultsOf the 185 volunteers, 103 were men, and 82 were women. Their mean age was 48.55 ± 16.6 (18–70) years. Mean CCT values measured by UP, CT, OCT, and NCSM were 546.77 ± 39.2, 535.29 ± 39.2, 526.49 ± 39.05, 505.15 ± 46.1 µm, respectively. Statistically significant differences were found between the mean CCT values obtained from the paired devices (p <0.001). The highest difference between pairs was found between UP and NCSM (43.63 ± 1.8 µm; CI 38.74 to 48.5 µm; p <0.001), while the lowest difference was found between OCT and CT (7.3 ± 1.5 µm; 95%CI 3.1 to 11.6 µm; p <0.001). In pairwise comparisons of four devices, the highest ICC value was between UP and CT (ICC: 0.899, 95%CI 0.759–0.947; p <0.001). ConclusionDespite the high correlation between measurements obtained from different methods, notable differences in CCT values exist, rendering devices non-interchangeable. Therefore, alternative brands of the same device may yield different outcomes.

Comparison of Central Corneal Thickness Measurement using Optical and Ultrasound Pachymetry in Primary Open Angle Glaucoma Patients

Introduction: A thinner Central Corneal Thickness (CCT) is an important criterion in determining the probability of progression from Ocular Hypertension (OHT) to Primary Open Angle Glaucoma (POAG). The most common devices for measuring CCT are ultrasound and optical pachymeters. Ultrasound pachymetry is a quick and precise approach to quantify corneal thickness that is also portable and inexpensive. The advantages of optical method include operator independency and noninvasiveness. Aim: To compare central corneal thickness using optical and ultrasound pachymetry in patients with POAG. Materials and Methods: This cross-sectional study was conducted at the Department Ophthalmology, ESI Post Graduate Institute of Medical Sciences and Research, Basaidarapur, Delhi, India, from October 2020 to April 2022. There were 105 POAG patients (210 eyes), divided into three subgroups of 35 subjects each (70 eyes each), based on the number of anti-glaucoma medications being instilled, topically (one/two/three drugs), and 35 healthy antiglaucoma controls (70 eyes). Central corneal thickness measurements were taken by Ultrasonic Pachymeter (USP) TOMEY SP-100, and by CEM-530 Non Contact Specular Microscope (NCSM) (optical). Statistical analysis was performed by the Statistical Package for Social Sciences (SPSS) program for Windows, version 17.0 (SPSS, Chicago, Illinois). Results: The mean CCT taken with NCSM and USP was 540.83±35.51 µm and 538.74±36.22 µm, respectively, in Right Eyes (RE) of 35 glaucoma patients on one drug, (p-value=0.80). Similarly, Left Eyes (LE), mean CCT with NCSM was 544.17±33.98 µm, and with USP was 541.69±36.6 µm (p-value=0.76). Mean CCT taken with NCSM and USP was 539.83±30,85 µm and 537.66±30.5 µm, respectively in RT eyes of 35 glaucoma patients on two drugs (p-value=0.76). Left eyes, mean CCT was 541.91±29.79 µm with NCSM as compared to USP which was 540.11±29.89 µm (p-value=0.80). On comparing the mean CCT values of RE in glaucoma subjects who were controlled on three antiglaucoma drugs it was found to be 528.37±26.44 µm using NCSM and 527.09±26.17 µm using USP (p-value=0.84). The meanvalues of CCT for LE was 521.94±26.53 µm with NCSM and with USP was 520±26.52 µm, respectively (p-value=0.81). Comparison of mean CCT measurements using NCSM and USP in 35 age-matched controls RE eye was found to be 517.83±21.27 µm and 515.97±20.91 µm, respectively (p-value=0.71). Similarly, for LE mean CCT values were 518.8±24.21 µm and 516.8±24.37 µm, respectively (p-value=0.73). Conclusion: The CCT measured using NCSM was found to be higher than that measured using USP in POAG subgroups patients as well as healthy age-matched controls, however the difference was not statistically significant. There was highly significant linear correlation between the CCT measured using NCSM and USP in all POAG subgroups as well as healthy controls. This suggests that the devices could be used interchangeably in glaucoma patients as well as healthy subjects of similar age group.

Comparison of Central Corneal Thickness Measurements with Four Different New Devices and Ultrasound Pachymetry

To assess the central corneal thickness (CCT) with 5 different devices, evaluate the repeatability of the devices, and determine the possible relationship between thickness values and sex. The study included 308 eyes of 154 patients (76 women, 78 men) between the ages of 18-30 who presented to the Ophthalmology Clinic of Muğla Sıtkı Koçman University Training and Research Hospital. Autorefractor (Topcon, Japan), ultrasound pachymetry (UP) (Ceniscan, USA), high-resolution Pentacam (Oculus, USA), anterior segment-optical coherence tomography (AS-OCT) (Optovue, USA), and Spectralis AS-OCT (Heidelberg, Germany) measurements were assessed. The mean age of the study participants was 23.2±0.2 years and the mean CCT was 540±14.1 μm, with no statistically significant difference in CCT between sexes (p&gt;0.05). Mean CCT values were 557.0±26.7 μm with the autorefractor, 543.6±32.9 μm with UP, 533.8±30.2 μm with the Oculus Pentacam, 519.8±30.1 μm with Optovue AS-OCT, and 547.5±31.6 μm with Heidelberg AS-OCT. Pairwise comparisons between devices showed that the Optovue AS-OCT gave significantly lower CCT measurements than the autorefractor and Heidelberg AS-OCT device (p=0.027 and p=0.033, respectively). The coefficient of repeatability for autorefractor, UP, high-resolution Pentacam, Optovue AS-OCT, and Heidelberg AS-OCT CCT measurements were 1.51%, 2.46%, 3.72%, 2.57%, and 3.34%, respectively. Measurements made with five different devices showed that CCT was comparable and clinically usable. However, it was determined that the Optovue AS-OCT showed lower CCT values compare to other devices. When compared in terms of repeatability, it was found to be lower in the Pentacam than other devices.

Central Corneal Thickness Changes in Diabetic Retinopathy. A Prospective Observational and Correlative Study

Generally, there is a delay of 4 to 7 years in the diagnosis of type 2 diabetes and about 20% of patients would have already developed some micro vascular complications at the time of diagnosis. To study the central corneal thickness (CCT) variation and correlate with grades of diabetic retinopathy in an adult South Indian population. The study was conducted on 184 eyes each of T2DM patients of duration more than 5 years. 98 males (53.26%) &amp; 86 females (46.73%) were recruited. After recording age, sex and duration of diabetes, fundus examination was done. CCT measurements were determined using Ultrasonic Pachymetry. Diabetic retinopathy was classified based on ETDRS (Early diabetic retinopathy study) and mean CCT values of each group were correlated and statistically analysed using SPSS software Version 17. Out of 184 subjects recruited, 72 patients were with no diabetic retinopathy (NDR), 107 patients were with non-proliferative diabetic retinopathy (NPDR) and 5 patients were with proliferative diabetic retinopathy (PDR). The mean CCT of no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) were found to be 526.14μm, 533.98μm and 555.20μm respectively. CCT was found to be thicker for diabetics with proliferative diabetic retinopathy compared to those with no retinopathy; the difference was not statistically significant (p=0.16). Uncontrolled diabetics (HbA1c &gt;7%) had thicker corneas compared with diabetics with good control which was statistically significant (p=0.003). CCT was higher in diabetics having duration &gt; 10 years than with duration &lt;10 years but was not statistically significant (p=0.117).

Effect of Age Under 20-60 years on Central Corneal Thickness

The measurement of central corneal thickness is an important measure for the diagnosis of corneal pathologies. 510–520 microns is the standard central corneal thickness. Optical or ultrasound techniques are used for the measurement of thickness CCT. Objectives: To evaluate the effect of age on central corneal thickness in normal population visiting The University of Lahore Teaching Hospital, Raiwind road Lahore. Methods: Descriptive study design was used. Data was obtained from The University of Lahore Teaching Hospital, Raiwind road Lahore. The sample size of patients was 147 with ages ranging from 20 to 60 years. All genders were included in the data collection. Data were collected through convenient sampling technique by using researcher administrative performa and study was finalized in three months after the approval of synopsis. Data entry and analysis were done using computer software SPSS version 25.0. CCT was measured by non-contact Pachymeter (Canon TX-20P) and values were represented in the form of frequency tables and bar charts. Results: CCT drops over time, resulting in thinner corneas in older people. The dependence of CCT on age is greater in men. Mean CCT in male individuals were 538.66 µm and in females mean CCT was 540.37µm. In this study mean central corneal thickness values of right and left eyes were also compared. In males right mean CCT value was 537.94 µm and left mean CCT was 539.39µm. In females the mean CCT value of right was540.28µm and left mean CCT value was 540.47µm. Conclusions: The Central Corneal Thickness decreases with age. Men have thinner corneas than females in every age group.

Comparison of central corneal thickness measurements with different non-contact devices in healthy children

PurposeTo investigate the agreement of the Combined Scheimpflug-Placido Disk System (Sirius), specular microscopy (Tomey EM-4000), non-contact tono-pachymetry (Canon TX-20P), and optical low-coherence reflectometry (Lenstar LS 900) devices in the measurement of central corneal thickness (CCT) in healthy children. MethodEighty-three eyes from 83 healthy children were included in the study. The mean age of the children was 11.1 ± 2.8 (range, 7–17) years. CCT was measured using the Sirius topography, Tomey specular microscopy, Canon TX-20P, and Lenstar LS 900 devices. To examine the agreement among these devices, 95% limits of agreement (LoA) and intraclass correlation coefficients (ICC) were determined. ResultsThe mean CCT values obtained using the Sirius topography, Tomey SM, Canon TX-20 P, and Lenstar 900 devices were 555.9 ± 37 µm, 553.5 ± 39 µm, 569.3 ± 33 µm, and 559.7 ± 38 µm, respectively. With the ICC method, the agreement rates were determined as 0.875 between Canon TX-20P and Sirius topography, 0.903 between Canon TX-20P and Lenstar LS 900, 0.842 between Canon TX-20P and Tomey EM-4000, 0.979 between Sirius Topography and Lenstar LS 900, 0.978 between Sirius topography and Tomey EM-4000, and 0.969 between Lenstar LS 900 and Tomey EM-4000. ConclusionThe devices with the closest results to each other were the Sirius and Tomey EM-4000 devices, with a statistically strong agreement. There was also a strong agreement between Sirius and Lenstar LS 900, although there was a 3.7-unit difference between them. Nevertheless, despite the strong agreements among these devices, because their CCT values varied statistically significantly, these devices should not be used interchangeably in clinical practice.

Anterior Ocular Biometrics Using Placido-scanning-slit System, Rotating Scheimpflug Tomography, and Swept-source Optical Coherence Tomography.

PurposeTo compare anterior biometry measurements using placido-scanning-slit topography, rotating Scheimpflug tomography, and swept-source optical coherence tomography.MethodsA retrospective review consisted of 80 eyes of 49 participants who underwent anterior chamber depth (ACD), central corneal thickness (CCT), and keratometry examination on the same day. We used placido-scanning-slit topography (ORBscan II), rotating Scheimpflug tomography (Pentacam HR), and swept-source optical coherence tomography (CASIA SS-1000). The intraclass correlation coefficients and Bland-Altman plots were used to evaluate the agreement and differences between measurements.ResultsThe mean ACD values were 2.88 ± 0.43, 2.82 ± 0.50, and 2.68 ± 0.44 mm; and the mean CCT values were 536.96 ± 31.19, 543.79 ± 31.04, and 561.41 ± 32.60 μm; and the mean keratometry (Km) were 43.81 ± 1.69, 43.81 ± 1.77, and 44.65 ± 1.95 diopters; as measured by CASIA SS-1000, Pentacam HR, and ORBscan II, respectively. Among the three devices, ACD was deepest to shallowest in the order of CASIA SS-1000, Pentacam HR, and ORBscan II (p < 0.05). The CCT was thickest to thinnest in the order of ORBscan II, Pentacam HR, and CASIA SS-1000 (p < 0.05). No significant differences in Km values were examined between CASIA SS-1000 and Pentacam HR, whereas ORBscan II overestimated Km with a statistically significant difference compared to the other two devices.ConclusionsHigh level of agreement was found between CASIA SS-1000 and Pentacam HR for anterior parameters, including ACD, CCT, and Km, suggesting interchangeability. However, ORBscan II measurements differed considerably with the measurements obtained from the other two devices; therefore, it should not be used interchangeably. However, further studies with repeatability test should be considered in order to elucidate the reliability of each device.

The short-term effects of intravitreal bevacizumab injection on intraocular pressure, cornea, iridocorneal angle, and anterior chamber.

Transient increase in intraocular pressure (IOP), changes in anterior chamber parameters, and changes in aqueous humor dynamics may occur after intravitreal injections because of intravitreal volume changes. In this observational study, we investigated the early effects of intravitreal bevacizumab (IVB) injection on IOP, central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), and iridocorneal angle (ICA). The patients who had one single-dose IVB (2.5 mg/0.1 mL) injection were included in the study. The patients underwent IOP, CCT, CV, ACD, and ICA measurements before and 1 h and 1 day after the injection. Pre-injection and post-injection values were compared. Forty-two eyes of 42 patients were included in the study, and the mean age of patients was 60.1 ± 7.4 years. The mean IOP measurements before and after injection at 1 h and day 1 were 15 ± 2.4, 17.4 ± 2.4, and 14.7 ± 2.3, respectively. The mean IOP, CCT, and CV values 1 h after injection were significantly higher than pre-injection values (p < 0.05, p < 0.05, and p = 0.02, respectively). Conversely, mean ACD and ICA values 1 h after injection were significantly lower than pre-injection values (p = 0.01 for both). There were no statistically significant differences on the first day after injection for all parameters. IVB (2.5 mg/0.1 mL) injection causes transient increases in IOP and transient decreases in ACD and ICA at the first hour after injection. Related to elevation in IOP, CCT and CV may increase transiently. These changes return to baseline values on the first day after injection.

Assessment of the reliability (repeatability) of corneal thickness measurements in soft contact lens wearers using a non-contact specular microscope

PurposeTo assess variability across 3 measures of central corneal thickness (CCT) obtained with a non-contact specular microscope and taken over a few minutes from habitual soft contact lens wearers. MethodsOne eye from 200 healthy adults (with an average age of 21 y, half of whom had a 3.5 ± 2.1 year history of successful daily wear of soft contact lenses while the control group had nominally normal eyes) were assessed using the auto-focus Topcon 2000P instrument to obtain an image of the endothelium and CCT. ResultsThe individual CCT values encountered in the 200 subjects ranged from 0.449 mm to 0.591 mm, with the average of 3 measures ranging from 0.459 to 0.591 mm in the control group and between 0.449 and 0.585 mm for the SCL wearers. The group mean CCT values were the same for both groups (at 0.524 mm), but the group mean SD value was marginally higher (at 0.028 mm) for the SCL group as compared to controls (SD = 0.026 mm). The normalized intra-subject variability (as the group-mean coefficient of variation, COV value) was 0.843 ± 0.401 for the control group and higher at 1.08 ± 0.546 for the SCL group (p < 0.001). ConclusionsRepeat measures of central corneal thickness, using a non-contact specular microscope, is very similar to those taken on age-matched non-contact lens wearers. These results may not equally apply to similar pachymetry measures in patients wearing RGP lenses or for older patients wearing soft contact lenses.

Thinning of the inner and outer retinal layers, including the ganglion cell layer and photoreceptor layers, in obstructive sleep apnea and hypopnea syndrome unrelated to the disease severity.

The aim of this study was to analyze the segmented layers of the macula in patients with obstructive sleep apnea and hypopnea syndrome (OSAS) using spectral domain optical coherence tomography (SD-OCT). This single-center, cross-sectional study included 31 OSAS patients and 31 age- and gender-matched control subjects. SD-OCT and overnight polysomnography were performed on all participants. The OSAS patients were categorized according to disease severity (mild, moderate, severe). The groups were compared in respect of each segmented macular layer through the use of segmentation software on SD-OCT. Total retinal thickness (RT), peripapillary retina nerve fiber layer (pRNFL) thickness, central corneal thickness (CCT) and intraocular pressure (IOP) values were also compared between the groups. Mean CCT (p:0.015) and nasal pRNFL values (p:0.042) were lower and mean IOP was higher (p:0.018) in OSAS patients than in the control group. The statistical analysis revealed significantly thinner total RT, inner retinal layers (IRL), outer retinal layers (ORL), photoreceptor layers (PRL) and ganglion cell layer (GCL) thicknesses in the OSAS groups compared to healthy subjects. No significant differences were found between the three OSAS subgroups in all segmented macular layers and pRNFL measurements. The results of this study showed relatively thinner nasal pRNFL, total RT, IRL, ORL, PRL and GCL layers in OSAS patients compared to healthy subjects. Moreover, this thinning of the segmented layers was unrelated to disease severity.

Comparison of Central Corneal Thickness Measurements Using Specular Microscope, Optical Biometer and Corneal Topographer

Purpose: To compare the Central Corneal Thickness (CCT) measurements by three different devices in normal eyes.&#x0D; Study Design: Cross sectional observational study.&#x0D; Place and Duration of Study: Dow University of Health Sciences and Dr. Ruth K.M. Pfau Civil Hospital, Karachi, from October 2020 to January 2021.&#x0D; Methods: 80 eyes of healthy subjects aged between 20 to 50 years were included in the study. Patients with corneal pathologies, systemic disease, history of ocular surgery or trauma, high intraocular pressure and high refractive error were excluded. Subjects underwent full ophthalmic examination. Central Corneal Thickness was measured by specular microscope (Shin-Nippon SPM-700; Rexxam Co. Ltd, Takamatsu, Japan), optical biometer (AL-Scan; Nidek, Gamagori, Japan) and corneal topographer (TMS-5; Tomey corporation, Nagoya, Japan). All data entry and analysis was done on SPSS version 23. For correlation among devices, Pearson correlation coefficient was used. Scatter plot was drawn for graphical presentation.&#x0D; Results: 80 eyes of 80 healthy subjects (50 males, 30 females) were recruited in the study by convenient sampling. The mean age was 37.76 ± 8.35 years. Mean Central Corneal Thickness values were 515.57 ± 31.54 µm, 510.21 ± 30.11 µm, 522.03 ± 29.78 µm with specular microscope, optical biometer and corneal topographer respectively. Measurements by these devices strongly correlate with each other using Pearson correlation coefficient (r = 0.927 to 0.966, p ≤ 0.001).&#x0D; Conclusion: The results of Central Corneal Thickness measurements obtained from these three devices positively correlate with each other so any of these devices can be used for its measurement.&#x0D; Key Words: Central Corneal Thickness (CCT), Specular microscope, Optical biometer, Corneal topographer.

Agreement of Ocular Biometry Measured by LenStar LS 900 and CASIA2 Optical Coherence Tomography

Introduction:The present study aimed to compare the anterior segment measurements between optical low-coherence reflectometry (LenStar LS900) and anterior segment optical coherence tomography (CASIA2 OCT). Methods:A total of 198 right eyes of 198 healthy participants were used for the current study, according to the inclusion and exclusion criteria. Ocular biometry parameters, such as central corneal thickness (CCT), anterior chamber depth (ACD), keratometry, and anterior chamber width (ACW), were measured usingLenStar LS 900 and CASIA2 OCT. The differences and correlations were assessed between these two instruments. The agreement was calculated as the 95% limits of agreement (LoA). Results: Among 198 subjects with a mean age of 29.39±7.88 years who enrolled in the study, 106 individuals (53.5%) were women. The mean CCT values were 531.7±35.25 and 527.3±37.82 µm for LenStar and OCT, respectively (P˂0.0001). The ACD measurements showed 2.92±0.40 and 2.95±0.43 mm for LenStar and OCT, respectively (P=0.0549). The ACW mean values were 12.04±0.52 and 11.79±0.49 mm by LenStar and OCT (P˂0.0001). The 95% LoA between the two instruments were within the ranges of -20.79 to 29.43 µm, -0.50 to -0.43 mm, -0.32 to 0.82 mm, and -0.70 to 0.87 D for CCT, ACD, ACW, and astigmatism, respectively. Conclusion: LenStar and OCT showed to have interchangeable ACD measurements; however, the results of CCT, ACW, and corneal astigmatism measured by these two instruments demonstrated clinically significant differences

Comparison of central corneal thickness and intraocular pressure measured with two different tono/pachymeter devices in non-glaucomatouse children.

The goal of this research is to compare the intraocular pressure (IOP) and the mean central corneal thickness (CCT) values obtained from the measurements with Nidek NT-530P and Canon TX-20P devices with the values obtained by ultrasound pachymetry (UP) and Goldmann applanation tonometry (GAT) in children. This prospective study was conducted with 119 healthy children. The measurements were repeated three times for each eye. The intraclass correlation coefficient (ICC) was used to assess the correlation between the measurements obtained from different devices. The Bland-Altman plot was used to analyze the agreement between two different devices graphically. The measurements were taken in the same order in all subjects: TX-20P, NT-530P, UP, and GAT. The mean age of the children was 10.1 ± 3.2 (6-17) years. The mean CCT values for the eyes were 568.90 and 569.68 (TX-20P), 571.44 and 566.37 (NT-530P), 564.77 and 564.67 μm UP, (right and left, respectively). The highest correspondence observed for CCT was between UP and NT-530P devices (ICC, 0.982, the left eye). The mean IOP measurements for Canon TX-20P, NT-530P, and GAT were 16.5 ± 3.2, 16.3 ± 3.2, and 16.8 ± 3.6 mmHg for the right eyes, respectively, while those for the left eyes were 16.6 ± 3.1, 16.2 ± 3.3, and 16.8 ± 3.7 mmHg. The highest correspondence was noted between measurements obtained using GAT and Nidek NT-530P devices (ICC, 0.945, in the left eye). Tono/pachymetry devices in the healthy children are provides significant agreements with the gold standard methods for IOP and CCT measurements.Clinical Trial Registration number: 2016-94.

Comparison of central corneal thickness measurements with three different optical devices.

Purpose:The purpose of this study was to compare and evaluate the agreement of central corneal thickness (CCT) values obtained with three different devices working according to optical principle in healthy eyes.Methods:60 eyes of 60 individuals (30 men and 30 women) were enrolled in this study. CCT measurements performed with Scheimpflug–Placido topographer (Sirius), spectral-domain optical coherence tomography (RTVue) with an anterior segment module, and optical biometer (AL-Scan) were compared. Bland–Altman analysis was used to demonstrate agreement between methods.Results:The mean age was 30.07 ± 7.313 years (range, 18–47 years). The mean CCT values obtained by RTVue, Sirius, and AL-Scan were 518.25 ± 36.38 µm, 526.08 ± 36.33 µm, and 513.50 ± 39.09 µm, respectively. The mean differences in CCT were 7.83 ± 14.15 µm between Sirius and RTVue, 12.58 ± 11.87 µm between Sirius and AL-Scan, and 4.75 ± 4.50 µm between RTVue and AL-Scan. The mean CCT was statistically different among the three groups (p < 0.05). All three modalities of CCT measurements correlated closely with each other, with Pearson’s correlation coefficients ranging from 0.924 to 0.961. The 95% limits of agreement were −19.90 to 35.56 µm between Sirius and RTVue, −10.69 to 35.85 µm between Sirius and AL-Scan, and −4.07 to 13.58 µm between RTVue and AL-Scan.Conclusion:Different results could be obtained through different noncontact devices in CCT measurements. Although the measurement values obtained by these devices show a high level of correlation, it would be a more correct approach to not use them directly interchangeably in clinical practice. Evaluation and follow-up of CCT should be performed using the same device.

Objective evaluation of corneal and lens densitometry in children with Down syndrome

The goal of this study was to compare anterior segment topographic measurements and densitometry measurements of the cornea and lens of patients with Down syndrome (DS) with those of healthy individuals. Forty patients with DS (study group) and 43 healthy subjects (control group) were enrolled in this prospective study. Topographic measurements, including central corneal thickness (CCT), corneal volume (CV), anterior chamber depth, corneal densitometry (CD) and lens densitometry (LD) values, of the right eye of each participant were obtained. The CCT and CV values were significantly lower in the study group compared to those in the control group. The mean LD-horizontal, LD-vertical, LD-areal, three dimensional (3D), peak and CD values were higher in the patients with DS (5.90±0.7, 6.01±0.7, 5.61±0.54, 9.70±2.1, 20.94±7.53 and 15.61±1.34, respectively) than in the healthy control subjects (5.72±0.65, 5.83±0.60, 5.56±0.75, 8.63±1.83, 17.29±5.40 and 14.3±1.03, respectively) (LD-horizontal P=0.144, LD-vertical P=0.184, LD-areal P=0.743, 3D P=0.033, peak P=0.029 and CD P=0.001). The DS patients had higher CD and LD values. Additionally, the mean CCT and CV values in the DS group were less than those in the control group.

Central Corneal Thickness in Females Using Oral Contraceptive Pills

Purpose: To compare the central corneal thickness in females using oral contraceptive pills (OCP) with age matched controls.&#x0D; Study Design: Descriptive Observational study.&#x0D; Place and Duration of Study: Department of ophthalmology, University of Lahore teaching hospital, from August 2018 to December 2018.&#x0D; Material and Methods: Fifty-one females who used OCP within last one year and 38 age-matched controls were included in this study after approval from the ethical review board. Females with any systemic disease, pregnancy and lactating mothers were excluded from the study. Females with ocular diseases, like trachoma, cataract, keratitis, uveitis, corneal dystrophies, Keratoglobus, Keratoconus, ocular trauma, and high refractive errors were also excluded. Each subject underwent full ocular examination including best-corrected visual acuity using Snellen acuity chart and Bio-microscopic examination of anterior segment and the fundus. Central corneal thickness (CCT) was measured with ultrasonic pachymeter and the intraocular pressure was measured with noncontact tonometer at the time of examination. The data was collected by self-designed proforma and analyzed by using SPSS version 20.&#x0D; Results: Mean age of the females using OCP was 31.4 ± 6.8 years and mean age of age-matched controls was 32.9 ± 5.5 years (p = 0.38). Mean Central corneal thickness values were higher in OCP group when compared to controls (541.8 ± 31.39μm and 518.7 ± 36.7 μm, respectively). P value was 0.004, which was statistically significant. The mean IOP value was 14.5 ± 2.6 mm Hg in OCP group and 14.4 ± 2.8 mm Hg in the control group (P = 0.86), which was not statistically significant.&#x0D; Conclusion: Central corneal thickness values are significantly higher in patients using OCP.

Effect of Obstructive Sleep Apnea on Corneal Morphological Characteristics.

To determine central corneal thickness (CCT) and the corneal parameters in patients with obstructive sleep apnea (OSA), evaluate the relationship between the severity of OSA, minimum peripheral capillary oxygen saturation (min. SpO2), and corneal morphological characteristics. Patients with OSA diagnosed by full-night polysomnography before treatment were included. Patients with OSA were divided into 3 groups according to the Apnea-Hypopnea Index (AHI). The control group (CG) was examined to exclude the possibility of OSA and ocular diseases. The following data were recorded: age, sex, body mass index, ophthalmologic evaluation, and the results of polysomnography. A total of 114 eyes were studied: 74 eyes of patients with OSA and 40 eyes of the CG. The mean age was 57 ± 6 years. The mean values of CCT and endothelial cell density (ECD) varied significantly between the patients and the CG (P < 0.001). The mean values of CCT, ECD, cell variation coefficient (CV), and hexagonal cell percentage (HEX) in the group of patients with OSA were 535.28 ± 21.32 μm, 2632 ± 333, cells/mm. 31.8 ± 3.9, and 55.6 ± 6.9%, respectively. The mean CCT and ECD values for each group were lower than those for the CG. A significant negative correlation was found between CCT and ECD for AHI values (r = -0.390, P = 0.011 and r = -0.109, P = 0.040, respectively), and a weak positive correlation between CCT and ECD was found for min. SpO2 (r = 0.282, P = 0.020 and r = 0.332, P = 0.018, respectively). CV and HEX did not significantly differ between the groups and did not correlate with the results of polysomnography. Hypoxia is associated with significant changes in CCT and ECD. In patients with OSA, these parameters varied significantly when compared with the subjects in the CG. The severity of hypoxemia and the increase in AHI values reduce CCT and ECD in patients.

Comparison of changes in corneal endothelial cell density and central corneal thickness between conventional and femtosecond laser-assisted cataract surgery: a randomised, controlled clinical trial

Background/AimTo identify changes in endothelial cell density (ECD) and central corneal thickness (CCT) in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification surgery (CPS).MethodsThis is an intraindividual...

Functional outcome of repeat Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following graft failure after primary DMEK.

PurposeTo evaluate if repeat Descemet membrane endothelial keratoplasty (DMEK) is appropriate to achieve functional improvements in patients with corneal decompensation from secondary graft failure after primary DMEK.MethodsThis is a retrospective monocentric cohort study including 13 eyes of 13 patients with repeat DMEK for corneal decompensation following primary DMEK. Eyes with primary DMEK only and comparable preoperative corrected distance visual acuity (CDVA) served as control. Main outcome parameter was CDVA. Secondary outcome measures were central corneal thickness (CCT), endothelial cell density, and rebubbling rate (RR).ResultsThe average time interval (±SD) between primary and secondary DMEK was 12.5±6 months. Preoperative CDVA (logMAR) was 1.97±0.90 in the repeat DMEK group and 1.38±0.92 in the primary DMEK group. At 6 months, both groups showed significant improvement in visual acuity (repeat DMEK group, 0.49±0.35, P<0.01 and primary DMEK group, 0.40±0.36, P<0.01). CDVA did not differ significantly between both groups at all time points examined (1, 3, and 6 months postoperatively). Mean CCT values at 3 and 6 months postoperatively did not differ significantly between the two groups (P>0.05). The RR was 23% (n=3) in both groups.ConclusionRepeat DMEK is a useful therapeutic approach in the setting of corneal decompensation following primary DMEK. Functional results of repeat DMEK, visual acuity in particular, are comparable to patients with single DMEK only.