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Background
Central corneal thickness (CCT) can be used to assess the corneal physiological condition as well as the pathological changes associated with ocular diseases. It has an influence on the measurement of intraocular pressure and is being used as a screening tool for refractive surgery candidates. The aim of this study was to determine the m...
Citations
... Their conclusion is contrary to our study results because we found CCT to be thicker in the hypermetropic group than in the emmetropic one. According to a study by Hashmani et al., (23) astigmatism significantly correlates with CCT. These findings are in accordance with our study. ...
Background: This study aimed to determine the correlation between central corneal thickness (CCT) and axial length (AL) in patients with refractive anomalies and emmetropes.
Methods and Results: The study included 330 respondents, with a total of 660 eyes, divided into two groups. The test group (TG) included 180 respondents with refractive anomalies (65 respondents with hypertropia, 65 with myopia, and 50 with astigmatism); the control group (CG) included 150 respondents with uncorrected visual acuity – 6/6 in both eyes.
The CCT values were higher in the hypermetropic group compared to the myopic group (561.5±25.3 vs. 517.9±37.3 mm, P
... However, the anterior and posterior corneal surfaces are neither spherical nor concentric; therefore, if the patient's head deviates, the devices will measure along a different axis and produce different values. In addition, differences in the device type, age, and sex can affect the CCT measurements [20]. In this study, to ensure high-quality data, we excluded patients with severe keratoconus. ...
Background:
To compare the characteristics of corneal thickness measurements among the RTVue, Casia-2, and Pentacam in patients with mild-to-moderate keratoconus.
Methods:
We recruited 46 eyes of 46 patients diagnosed with mild-to-moderate keratoconus at our hospital between January and March 2022. The central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Differences and correlations between the CCTs and TCTs, based on the device and influencing factors, were explored.
Results:
The CCTs were highly consistent among the groups (p = 0.434) and correlated with one another (p < 0.001). The TCTs measured by OCTs were thinner than those measured by the Pentacam (p < 0.001); however, all three devices were highly correlated (p < 0.001). The thinnest point location measurements with RTVue and Casia-2 differed significantly from the measurements with the Pentacam. Bland-Altman plots demonstrated a significant agreement between Pentacam and OCTs in TCT measurement (p < 0.001); the 95% limits of agreement were - 3.1 μm to + 33.1 μm for Pentacam and RTVue and - 8.6 μm to + 36.5 μm for Pentacam and Casia-2. RTVue and Casia-2 showed no difference in corneal thickness (p = 0.633) and thinnest point location measurement (p > 0.05). Multivariate analysis identified that the TCT measurement difference between the RTVue and Pentacam was related to the difference between the CCT and TCT (b = 0.490, 95% confidence interval [CI]: 0.033 to 0.948, p = 0.036), whereas the difference between the Casia-2 and Pentacam was related to the anterior radius for curvature (A) grade (b = 3.9, 95% CI: 1.753 to 6.074, p = 0.001), corneal pachymetry at the thinnest (C) grade (b = - 7.875, 95% CI: - 11.404 to - 4.346, p < 0.001), and the difference between the CCT and TCT (b = 0.425, 95% CI: 0.1 to 0.751, p = 0.012).
Conclusions:
CCTs in patients with mild-to-moderate keratoconus were similar among all three devices, but the TCTs and the thinnest point locations were not. Furthermore, the TCT measurement differences between the OCT devices and the Pentacam were more pronounced in keratoconus cases with a steeper anterior surface, thicker TCTs, and a larger difference between the CCT and TCT.
Trial registration:
Number: 2021118-1. Retrospectively registered: September 01, 2021.
... CCT had been previously studied to show the variability in age, sex, refractive status of different populations, and corneal thickness decrease with age. [25][26][27][28][29] A thicker CCT had greater resistance; therefore, it led to an overestimation of IOP when measured through applanation tonometry. CCT and CH were two essential corneal parameters of biomechanical property. ...
This retrospective cross-sectional study, which enrolled 124 normal tension glaucoma (NTG) eyes and 68 healthy eyes as the control, determined the association between central corneal thickness (CCT) and ocular parameters in NTG. CCT was measured using the Pentacam® system, optical coherence tomography angiography (OCT-A) was adopted to measure the peripapillary and macular area VDs, and spatial data were based on the Garway–Heath map as illustrated in OCT-A. Univariate and multivariate linear regressions were used to statistically analyze for associations between CCT and other factors. In this study, the mean age was similar for both the NTG and control groups. The mean CCT of the NTG group was significantly thinner than that of the control group (533.97 ± 33.11 µm vs. 546.78 ± 38.21 µm; p = .022). Considering all the factors, CCT negatively correlated with visual field (VF) pattern standard deviation (univariate, p = .045). To analyze structural and functional factors separately, we found a significant positive correlation between CCT and whole disc radial peripapillary capillary VD (VDRPC; multivariate, p = .019). To analyze the relationship between all factors and sectoral changes in VDRPC, a significant positive correlation was observed between CCT and inferior temporal VDRPC (univariate, p = .039) and inferior nasal VDRPC (VDRPC IN; univariate, p = .048). In conclusion, this novel study shows that among NTG participants, a thinner cornea correlated with weaker biomechanical properties susceptible to optic nerve tissue displacement, especially in response to mild transient elevation of IOP, leads to compromised ocular microcirculation.
... On the other hand, the related factors of CCT have not been definitively identified. The relationship between CCT and some demographic, ocular factors, and also systemic diseases such as age, sex, refractive errors, ocular biometric components, corneal curvature, diabetes, and hyperglycemia was studied in some previous studies but has been associated with conflicting results [12][13][14][15]. One possible reason for these discrepancies is that each of the previous studies examined a limited number of factors, and the confounding effects of different variables on each other were not controlled by a comprehensive multivariable model. ...
Purpose:
To determine the distribution of central corneal thickness (CCT) and its determinants in an Iranian geriatric population.
Methods:
This population-based study was conducted in 2019 in Tehran, the capital of Iran, using stratified multistage random cluster sampling. The study population was all residents ≥60 years of age. First, preliminary optometric and ocular health examinations were performed including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, anterior and posterior segment examination. The study participants then underwent corneal imaging using Pentacam HR.
Results:
Out of 3791 invitees, 3310 participated in this study (response rate: 87.3%). The mean CCT and apex corneal thicknesses were 528 µ (95% CI: 526-529) and 529 µ (95% CI: 527-530), respectively. The highest and lowest mean corneal thickness was related to the superior (620 µ: 95% CI: 618-622) and the temporal (591 µ: 95% CI: 590-592) paracentral points, respectively. According to the multiple linear regression model, the CCT was significantly inversely related to keratometry readings (K1 and K2) and had a statistically significant direct relationship with intraocular pressure (IOP), corneal eccentricity (ECC), and corneal volume (CV) (all p values <0.05). The CCT was significantly higher in diabetic patients (p = 0.043).
Conclusion:
The CCT values in the geriatric Iranian population were lower than the values reported in most previous studies. The CCT is mostly influenced by IOP and corneal parameters (curvature, shape factor, and volume) and is not affected by demographic factors, refractive error, and ocular biometric components.
... This is well explained in previously published articles by demonstrating that CT as an independent factor is poorly associated with CC and refractive error development [8]. Even in the presence of a high degree of refractive error, multiple studies have shown an insignificant and poor correlation between CT and refractive error [14]. However, one should remember that a healthy CT represents rigidity, acts as a decisive factor for refractive error surgeries, and significantly affects intraocular pressure evaluation [15,16]. ...
... Several researchers reported that central corneal thickness does not correlate with myopia magnitude (Al-Mezaine et al. 2009;Dogan et al. 2017;Mostafa et al. 2018), while others reported that it is thicker in high myopia (Wang et al. 2015). These differences could be due to several factors that are known to influence corneal thickness, such as age (Hashmani et al. 2017;Kadhim & Farhood 2016;Lim et al. 2010), refractive error, corneal curvature, and intraocular pressure (Chen et al. 2009;Cho & Lam 1999). ...
Axial length of the eye correlates with the magnitude of myopia. However, there are conflicting reports on the relationship between certain corneal parameters with myopia magnitude. The objective of this study was to compare ocular biometry and corneal parameters between emmetropic and myopic groups. Participants (n=127) were categorized as emmetropia (spherical equivalent, SE, ±0.50D), low myopia (-0.75D≤SE<-6.00D) and high myopia (SE≥-6.00D). The difference in axial length, anterior chamber depth, and vitreous chamber depth between emmetrope, low myope, and high myope were highly significant (one-way ANOVA, all p<0.001) with significant correlations between SE and all these parameters (simple regressions, all p<0.001). However, central corneal thickness, corneal radius of curvature, and corneal asphericity between these groups, and the correlations between the ocular parameters with SE were not significantly different (all p>0.05). Corneal curvature correlated significantly with axial length (p=0.001) but not with myopia magnitude (p=0.91). Rather than myopia magnitude, axial length appears to be more sensitive to detect changes in corneal curvature in myopes. In conclusion, myopic patients’ axial length should be carefully considered for interventions that involve the cornea, such as orthokeratology and refractive surgery.
... Several factors can affect CCT such as age, gender, daytime changes, refractive error, genetic influence, and conditions like diabetes [7,8,23,24]. In our study, we did not find any significant association between age, gender and average CCT. ...
Aim:
To study the central corneal thickness of a Tunisian population and determine the influence of age, gender, axial length and refractive error on central corneal thickness (CCT) values.
Methods:
An observational, cross-sectional study was conducted on 608 eyes of consecutive Tunisian patients without ophthalmic disease. Corneal tomography (Oculus Pentacam, USA) and a complete eye examination were performed on all patients. The relationship between the central corneal thickness values and variables of age, refractive error, axial length and gender was assessed.
Results:
The mean central corneal thickness was 522±37.17μm (range 461 to 655 μm). No statistical association was found between central corneal thickness values and variables of age, refractive error, axial length and gender.
Conclusions:
The normal CCT value in the Tunisian population was of 522±37.17 µm. We have analyzed, for the first time, normal central corneal thickness values of a healthy Tunisian population.
... Numerous studies have been carried out to measure corneal thickness; most of which have involved a contact method, ultrasound pachymetry 5 . Other researchers have employed an instrument called "Corneal Topographer" for the same purpose 6 . Although it is more sensitive than pachymetry, a topographer has a different set of limitations 5 . ...
... A more recent study on corneal thickness was performed by Hashmani et al in 2017, which shows a median thickness value of 541microns. These findings are quite significant because they performed it on a very large group of individuals (sample size = 5,171 eyes) 6 . However, they used data from participants with varying ages and the median age was 26 with the youngest age group between 11 to 20 years. ...
... The males showed nonsignificant results 20 . In a retrospective study on 5,171 eyes from Pakistani population, Hashmani and colleagues found a weak but negative correlation of CCT and age 6 . This can be explained by considering the fact that they included much younger participants as compared to our study participants. ...
Objective: To measure central corneal thickness and study its association with intraocular pressure (IOP), age and gender. Study Design: Cross-sectional study Place and Duration of Study: This study was conducted at the tertiary eye care health centre during Feb 2019 and Feb 2020 for one year. Materials and Methods: 324 normal individuals were recruited. They followed the routine eye examination protocol and in the end we performed anterior segment OCT on one eye of each participant. Results: The mean CCT was found to be 533.01µm and mean the IOP was 12.6mmHg. When we compared CCT with age, significant correlation was not found (Pearson's correlation coefficient (R) = 0.022, P-value = 0.692). Similar results were obtained when CCT was tested against IOP (Pearson's correlation coefficient (R) = 0.056, P-value = 0.315). The difference of CCT between the two gender was also not significant (p-value = 0.774). Conclusion: The CCT from our study was not found to be associated with age and intraocular pressure. Also the difference in CCT values of males and females was not statistically significant.
... The subjects were divided 16 into a broad range of myopia (SE≤-0.5 D) and hyperopia (SE≥+0.5D). Then, the myopic eyes divided into low (SE>-3.0D), ...
... These values are relatively higher compared to that recorded in other studies (other ethnic groups). 6,[16][17][18][19][20] Values of the CCT of different ethnical groups vary and are summarised in Table 5. Also, it reports that myopic and hyperopic subjects show a statistically non-significant reduction in CCT with ageing, females have thinner corneas than males, with no significant differences as recorded in other studies. ...
Aim
To generate reference values of the central corneal thickness (CCT) with different refractive errors for the adult eastern Egyptian population.
Subjects and Methods
This study was a retrospective, observational, and cross-sectional study. It included 1166 eyes (1166 subjects) scheduled for LASIK, who came to private refractive eye centre, Ismailia, Egypt. The study period was from January 2018 to January 2020. The subjects were divided into a broad range of myopia with spherical equivalent (SE) ≤-0.5D and hyperopia (SE) ≥+0.5D. Then, the myopic eyes divided into low (SE>-3.0D), moderate (SE-3.0D to >-6.0D), and high (SE≤-6.0D). Similarly, the hyperopic eyes were divided into low (SE<+3.0D) and moderate (SE+3.0D to <+6.0D) and high ≥+6.0D. The refractive error was measured by an auto-refractometer, and CCT was measured using ultrasonic pachymetry.
Results
The data of 556 myopic eyes in 556 subjects (31.1% males and 68.9% females) and 610 hyperopic subjects (34.4% males and 65.6% females) were included in this study. The mean±SD of CCT for the total myopic subjects was 532.8±32.6μm, range (470 to 627μm). The mean±SD of SE was -4.06±2.50D, range (−0.50 to −14.00D). The mean±SD of CCT for the total hyperopic subjects was 530.8±37.2μm, range (471 to 616μm). The mean±SD of SE was +3.57±1.98D, range (+0.50 to +8.50D). About 16.2% of the myopic eyes and 12.7% of the hyperopic eyes have CCT less than 500μm.
Conclusion
The mean of the central corneal thickness of the eastern Egyptian population was 532.8μm for myopic and 530.8μm for hyperopic subjects, respectively. The myopic and hyperopic subjects show a reduction in CCT with age. Females have a thinner cornea than males, 16.2% of the myopic eyes and 12.7% of the hyperopic eyes have CCT less than 500μm.
... In this study, reference values for the central corneal thickness of the Egyptian population with different refractive errors were 531.9 μm for myopic and 529μm for hyperopic subjects, respectively. These values are relatively higher compared to that recorded in other studies (other ethnic groups) [11][12][13][14][15]. Also, it reports that the myopic and hyperopic subjects show a statistically signi cant reduction in CCT with aging, females have thinner corneas than males, with no signi cant differences between the right and left eyes in all the subjects as recorded in other studies [12,16,17]. ...
Background: To generate reference values of the central corneal thickness (CCT) with different refractive errors for the adult Egyptian population.
Methods: A retrospective, observational, and cross-sectional study of 2200 eyes in 1166 subjects scheduled for LASIK, who came to private refractive eye center, Ismailia, Egypt. The study period was from January 2018 to January 2020. The subjects were divided into a broad range of myopia with spherical equivalent (SE) <-0.5D and hyperopia SE> +0.5D. Then, the myopic eyes divided into low (SE>-3.0D), moderate (SE-3.0D to >-6.0D), and high (SE<-6.0D). Similarly, the hyperopic eyes were divided into low (SE<+3.0 D) and moderate (SE+3.0D to <+6.0D) and high >+6.0D. The refractive error was measured by an auto-refractometer (Topcon, Tokyo Optical Co., Ltd., Japan), and CCT was measured using Sirius (CSO, Florence, Italy).
Results: The data of 1100 myopic eyes in 556 subjects (30.5% males and 69.5% females) and 1100 hyperopic eyes in 610 subjects (33.6% males and 66.4% females). The mean+SD of CCT for the total myopic subjects was 531.98+32.92μm, range (406 to 636μm). The mean+SD of SE was -4.1±2.5D, range (-0.5 to -12.0D). The mean+SD of CCT for the total hyperopic subjects was 529±38.8μm, range (448 to 619 μm). The mean+SD of SE was +3.65+1.97D, range (+0.5 to +8.5D).
Conclusion: In this study, the mean of CCT of the Egyptian population was 531.9 μm for myopic and 529μm for hyperopic subjects respectively. The myopic and hyperopic subjects show a reduction in CCT with age. Females have a thinner cornea than males, 23.6% of the myopic eyes, and 16.5% of the hyperopic eyes have CCT less than 500μm.
