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Purpose Methods Results Conclusion To compare the parameters and indices of a novel swept‐source optical coherence tomography device (SS‐OCT, ANTERION) with those of a rotating Scheimpflug camera (RSC)‐based tomograph (Pentacam) in normal and keratoconic (KC) eyes.This prospective, monocentric, cross‐sectional study included individuals with unoperated normal and KC eyes, selecting one eye per subject. Ectasia‐specific parameters analysed with the SS‐OCT were difference in mean keratometry (Kmean) in the inferior and superior meridians, maximum keratometry value (Kmax), elevation of the posterior surface at the thinnest point, screening corneal objective risk of ectasia (SCORE) and thinnest point thickness. With the RSC, parameters determined were Belin/Ambrosio total deviation value (BAD‐D), index of height decentration and index of vertical asymmetry. KC classification with the SS‐OCT was based on the anterior and posterior radii of curvature and thinnest point thickness according to the ABCD classification of the RSC system.This study included 117 individuals with healthy eyes and 335 eyes with KC. The indices with the highest diagnostic discriminatory ability between the two cohorts were SCORE, difference of Kmean in the inferior and superior meridians and posterior elevation of the thinnest point (SS‐OCT), as well as the index of height decentration, index of vertical asymmetry and BAD‐D (RSC). The classifications using SS‐OCT defined mild‐stage KC as Kmax, posterior elevation of the thinnest point and thinnest point thickness as ≤50.9 D, ≤30 and ≥472 μm, respectively. Moderate stage values were 51–55.9 D, 31–69 and 471–438 μm, respectively, while respective advanced stage were ≥56 D, ≥70 and ≤437 μm.The diagnostic capabilities for both devices were found to be comparable. KC classification using SS‐OCT can be independently based on the anterior surface, posterior surface and corneal thickness. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the diagnostic value of iTrace visual function analyzer, Pentacam 3D anterior segment analysis system and Lens Opacities Classification System III (LOCS III) in assessing lens opacity in patients with age-related cataract (ARC). Methods: A total of 129 patients with ARC admitted to Anonymized from May 2019 to April 2021 were selected as the research objects. The degree of lens opacity was evaluated by LOCS III classification, iTrace and anterior segment analysis. Results: The Pentacam nucleus staging (PNS) grade was strongly correlated with nuclear color (NC) (r = 0.537, p < 0.05) and moderately correlated with nuclear opalescence (NO) (r = 0.473, p < 0.05). The integrated density (IntDen) in 3-mm nuclear region was strongly correlated with NC (r = 0.548, p < 0.05) and NO (r = 0.539, p < 0.05). The dysfunctional lens index (DLI) in 3-mm area was negatively correlated with NC (r=-0.252, p < 0.05), NO (r=-0.239, p < 0.05) and posterior subcapsular cataract (r=-0.271, p < 0.05). PNS was weakly negatively correlated with the DLI in 3-mm area (r=-0.219, p < 0.05), and IntDen in 3-mm core area was weakly negatively correlated with the DLI in 3-mm area (r=-0.291, p < 0.05). Conclusion: A combination of iTrace, anterior segment analysis and LOCS III may be beneficial in objectively assessing the opacity of different regions of the lens. [ABSTRACT FROM AUTHOR]

AIM: To explore the diagnostic value of visualized corneal biomechanical analysis combined with Pentacam related-index in the diagnosis of subclinical keratoconus and forme fruste keratoconus, and to provide evidence for early screening and diagnosis of keratoconus.METHODS: A total of 65 patients(128 eyes)with keratoconus in Ningxia Eye Hospital from November 2018 to November 2019 were enrolled in a diagnostic trial design. According to the course of disease, these eyes were divided into clinical, subclinical and forme fruste groups. A total of 89 subjects(89 eyes)who received preoperative refractive examination at the same period were selected as the normal control group. Pentacam combined with Corvis ST was used for detection. Corneal dilatation indexes, including belin/ambrosio enhanced ectasia display(BAD-D), the thinnest point thickness(TP), max keratometry(Kmax), deviation of normality of the front elevation(Df), deviation of normality of the back elevation(Db), deviation of normality of pachymetric progression(Dp), deviation of normality of corneal thinnest point(Dt), deviation of normality of relational thickness(Da), and Ambrósio relational thickness horizontal(ARTh), corneal biomechanical indexes, including Corvis biomechanical index(CBI), deformation amplitude ratio(DA Ratio), stiffness parameters at applanation 1(SP-A1)and Integrated radius, biomechanical intraocular pressure(bIOP)and tomographic and biomechanical index(TBI)were recorded. The keratoconus at different stages was statistically analyzed, the diagnostic valve of TBI, CBI and BAD-D was explored by receiver operating curve, and the diagnostic value of each parameters was evaluated.RESULTS:The TBI, BAD-D, TP, Kmax, Df, Db, Dp, Dt, Da, ARTh, CBI and SP-A1 of the clinical keratoconus group had strong diagnostic ability, the BAD-D, Da, Dp, TP, TBI, CBI, ARTh and Integrated radius of the subclinical keratoconus group had strong diagnostic ability, and the BAD-D, Dp and TBI of the forme fruste keratoconus group had certain diagnostic and predictive ability.CONCLUSION:TBI, BAD-D, Dp and other index have a certain sensitivity and specificity for early keratoconus diagnosis, and can be used for screening and early diagnosis of keratoconus.

AIM: To evaluate the reliability of measurements of corneal changes with accommodation in healthy eyes using a Scheimpflug imaging-based system and how these measurements distribute in the normal population.METHODS: Prospective, non-randomized, comparative study including 27 healthy subjects(54 eyes), including emmetropia(13 eyes), myopia(17 eyes), hyperopia(4 eyes)and astigmatism(20 eyes)groups. In all cases, a complete eye examination was performed, including the analysis of corneal changes with different accommodative stimuli(+2.00, 0.00 and -3.00 D)using the Pentacam AXL system. The investigation was structured in 2 phases: repeatability analysis and characterization of accommodation-related corneal changes in healthy populations.RESULTS: In the repeatability analysis, the index of height asymmetry(IHA)showed the greatest variability with the three accommodative stimuli, being the results for the rest of parameters acceptable. The group of emmetropes showed significant differences with accommodative changes in the position of maximum keratometry(Kmax; P

Purpose: To evaluate the effect of night shifts on the biomechanical properties of the cornea using Scheimpflug camera-based imaging (Corvis and Pentacam). Methods: Thirty-four participants from the medical staff who had at least six night shifts per month as a case group and fifty-two participants as a control group participated in the study. The biomechanical characteristics of the cornea using the Corvis device and the topographical characteristics of the cornea using the Pentacam device were investigated in the participants. Results: The main indices of corneal biomechanics including Corvis Biomechanical Index (0.17 ± 0.18 vs. 0.15 ± 0.14; P = 0.66 [adjusted] and 0.66 [unadjusted]) and Tomographic and Biomechanical Index (0.16 ± 0.19 vs. 0.14 ± 0.19; P = 0.78 [adjusted] and 0.63 [unadjusted]) were not significantly different between case and control groups. Conclusion: Our study showed that night shifts do not independently affect corneal biomechanical indices.

Taher K Eleiwa,1,2 Mona Abd El-Azim Mohammed,3 Ahmed Sherin M Bayoumy1 1Department of Ophthalmology, Benha University, Benha, Egypt; 2Department of Ophthalmology, Magrabi Eye and Dental Hospital, Qassim, Kingdom of Saudi Arabia; 3Department of Ophthalmology, Mansoura Ophthalmic hospital, Mansoura, EgyptCorrespondence: Taher K Eleiwa, Email taher.eleiwa@fmed.bu.edu.egPurpose: To determine if Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict the occurrence of corneal edema following uneventful phacoemulsification surgery in Fuchs endothelial corneal dystrophy (FECD).Design: Observational prospective case–control study.Participants: Fifty FECD eyes (50 patients) with visually significant cataract: 25 with subclinical corneal edema (SCE) versus 25 without SCE.Methods: Preoperatively, FECD was clinically assessed, and only patients devoid of clinical corneal edema were enrolled. Utilizing the Mayo Clinic classification for subclinical corneal edema (SCE), eligible FECD eyes were stratified based on Scheimpflug imaging pachymetry map and posterior elevation map characteristics, including loss of regular isopachs, displacement of the cornea’s thinnest point, and the presence of posterior surface depression, into two groups: Group A representing FECD with SCE, and Group B: FECD without SCE. One week postoperatively, clinical and tomographic evaluation was performed. Regression analysis was conducted to evaluate predictors of corneal edema after uneventful phacoemulsification surgery in both groups.Results: All patients were successfully imaged before and 1 week after surgery. Visual acuity was significantly improved in both groups (P < 0.001). No postoperative clinical edema was observed in Group B, while 23 (92%) had mild edema and 2 (8%) had moderate edema in Group A. Both groups showed a significant increase in postoperative central corneal thickness (CCT) and thinnest corneal thickness (TCT) (both P < 0.001). Compared to Group B, Group A showed a significant central flattening of the anterior corneal surface (P = 0.007 and P = 0.04 for K1 and K2 respectively), and a significant increase in the postoperative posterior surface depression. Multivariate analysis showed that 94% of postoperative corneal edema could be predicted by the presence of preoperative posterior surface depression (P = 0.04, ARR = 5.8 (1.89– 35.7)).Conclusion: Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict corneal edema after uneventful phacoemulsification surgery in FECD with subclinical corneal edema.Keywords: phacoemulsification, cataract surgery, corneal edema, Scheimpflug tomography, pentacam, Fuchs endothelial corneal dystrophy

Abstract Background Accurate prediction of postoperative vault in implantable collamer lens (ICL) implantation is crucial; however, current formulas often fail to account for individual anatomical variations, leading to suboptimal visual outcomes and necessitating improved predictive models. We aimed to verify the prediction accuracy of our new predictive model for vaulting based on anterior and posterior chamber structural parameters. Methods This retrospective observational study included 137 patients (240 eyes) who previously underwent ICL surgery. Patients were randomly divided into the model establishment (192 eyes) or validation (48 eyes) groups. Preoperative measurements of the anterior and posterior chamber structures were obtained using Pentacam, CASIA2 anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy, and other devices. Stepwise multiple linear regression analysis was used to evaluate the relationship between the vault and each variable (WL formula). The Friedman test was performed for the vaulting prediction results of the WL, NK (Ver. 3), and KS formulas (Ver. 4) in CASIA2 AS-OCT, as well as the Zhu formula and vault measurements. The proportions of prediction error within ± 250 μm per formula were compared. Results The predicted vault values of the WL, NK, KS, and Zhu formulas and vault measurements were 668.74 ± 162.12, 650.85 ± 248.47, 546.56 ± 128.99, 486.56 ± 210.76, and 716.06 ± 233.84 μm, respectively, with a significant difference (χ2 = 69.883, P = 0.000). Significant differences were also found between the measured vault value and Zhu formula, measured vault value and KS formula, WL formula and Zhu formula, WL formula and KS formula, NK formula and KS formula, and NK formula and Zhu formula (P NK formula (70.8%) > KS formula (66.7%) > Zhu formula (54.2%). Conclusions The WL formula, which considers the complexity of the anterior and posterior chamber structures, demonstrates greater calculation accuracy, compared with the KS (Ver. 4) and Zhu formulas. The proportion of absolute prediction error ≤ 250 μm is higher with the WL formula than with the NK formula (ver. 3). This enhanced predictive capability can improve ICL sizing decisions, thereby increasing the safety and efficacy of ICL implantation surgeries.

Abstract Aim This study aimed to differentiate moderate to high myopic astigmatism from forme fruste keratoconus using Pentacam parameters and develop a predictive model for early keratoconus detection. Methods We retrospectively analysed 196 eyes from 105 patients and compared Pentacam variables between myopic astigmatism (156 eyes) and forme fruste keratoconus (40 eyes) groups. Receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and a logistic regression model was used to refine the diagnostic accuracy. Results Statistically significant differences were observed in most Pentacam variables between the groups (p

Background: Accurate prediction of postoperative vault in implantable collamer lens (ICL) implantation is crucial; however, current formulas often fail to account for individual anatomical variations, leading to suboptimal visual outcomes and necessitating improved predictive models. We aimed to verify the prediction accuracy of our new predictive model for vaulting based on anterior and posterior chamber structural parameters. Methods: This retrospective observational study included 137 patients (240 eyes) who previously underwent ICL surgery. Patients were randomly divided into the model establishment (192 eyes) or validation (48 eyes) groups. Preoperative measurements of the anterior and posterior chamber structures were obtained using Pentacam, CASIA2 anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy, and other devices. Stepwise multiple linear regression analysis was used to evaluate the relationship between the vault and each variable (WL formula). The Friedman test was performed for the vaulting prediction results of the WL, NK (Ver. 3), and KS formulas (Ver. 4) in CASIA2 AS-OCT, as well as the Zhu formula and vault measurements. The proportions of prediction error within ± 250 μm per formula were compared. Results: The predicted vault values of the WL, NK, KS, and Zhu formulas and vault measurements were 668.74 ± 162.12, 650.85 ± 248.47, 546.56 ± 128.99, 486.56 ± 210.76, and 716.06 ± 233.84 μm, respectively, with a significant difference (χ2 = 69.883, P = 0.000). Significant differences were also found between the measured vault value and Zhu formula, measured vault value and KS formula, WL formula and Zhu formula, WL formula and KS formula, NK formula and KS formula, and NK formula and Zhu formula (P < 0.001) but not between other groups. The proportions of prediction error within ± 250 μm per formula were as follows: WL formula (81.3%) > NK formula (70.8%) > KS formula (66.7%) > Zhu formula (54.2%). Conclusions: The WL formula, which considers the complexity of the anterior and posterior chamber structures, demonstrates greater calculation accuracy, compared with the KS (Ver. 4) and Zhu formulas. The proportion of absolute prediction error ≤ 250 μm is higher with the WL formula than with the NK formula (ver. 3). This enhanced predictive capability can improve ICL sizing decisions, thereby increasing the safety and efficacy of ICL implantation surgeries. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to differentiate moderate to high myopic astigmatism from forme fruste keratoconus using Pentacam parameters and develop a predictive model for early keratoconus detection. Methods: We retrospectively analysed 196 eyes from 105 patients and compared Pentacam variables between myopic astigmatism (156 eyes) and forme fruste keratoconus (40 eyes) groups. Receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and a logistic regression model was used to refine the diagnostic accuracy. Results: Statistically significant differences were observed in most Pentacam variables between the groups (p < 0.05). Parameters such as the Index of Surface Variance (ISV), Keratoconus Index (KI), Belin/Ambrosio Deviation Display (BAD_D) and Back Elevation of the Thinnest Corneal Locale (B.Ele.Th) demonstrated promising discriminatory abilities, with BAD_D exhibiting the highest Area under the Curve. The logistic regression model achieved high sensitivity (92.5%), specificity (96.8%), accuracy (95.9%), and positive predictive value (88.1%). Conclusion: The simultaneous evaluation of BAD_D, ISV, B.Ele.Th, and KI aids in identifying forme fruste keratoconus cases. Optimal cut-off points demonstrate acceptable sensitivity and specificity, emphasizing their clinical utility pending further refinement and validation across diverse demographics. [ABSTRACT FROM AUTHOR]

IntroductionThis study aimed to compare the consistency of pupil offset measurements obtained using the Pentacam, Keratron Scout, and Sirius devices.MethodsThis retrospective cross-sectional study included 146 young myopic individuals (292 eyes) scheduled for refractive surgery at Dalian Third People’s Hospital between January 2023 and December 2023. Three devices were utilized to measure the chord mu of the pupil deviation along with the Cartesian distances of the X and Y coordinates (Px, Py) associated with the pupil offset. Repeated-measures analysis of variance was used to compare differences in pupil offset acquisition across various devices. Additionally, the intraclass correlation coefficient (ICC) and Bland–Altman plot were utilized to assess the consistency among the three devices.ResultsChord mu, measured using the Pentacam, Keratron Scout, and Sirius devices, were 0.18 ± 0.10, 0.21 ± 0.11, and 0.18 ± 0.11, respectively. The Px values were 0.00 ± 0.14, -0.02 ± 0.16, and -0.01 ± 0.13, respectively, while the Py values were 0.09 ± 0.13, 0.10 ± 0.15, and 0.10 ± 0.13. The ICCs for the three device measurements, chord mu, Px, and Py, were 0.817, 0.900, and 0.855, respectively. When comparing the three devices, the 95% limits of agreement (LoA) for mu and Px measured using the Sirius and Keratron Scout were the narrowest, ranging from −0.15 to 0.08 and −0.11 to 0.13, respectively. Additionally, the 95% LoA for Py measured using the Sirius and Pentacam was the narrowest, ranging from −0.13 to 0.15. The pupil centers in both eyes were predominantly located above the apex of the cornea.ConclusionSirius, Keratron Scout, and Pentacam have good consistency in pupil shift measurement in young myopic patients, and the three devices can be used as references in clinical practice.

Purpose: To study the effect of corneal white-to-white diameter on Pentacam Scheimpflug cornea tomography and Corvis ST corneal visualization Scheimpflug technology parameters in myopic eyes. Methods: In this retrospective cross-sectional study, 190 eyes of 190 Chinese myopic patients (spherical equivalent range: −1.25 D to −11.00 D) assessed for refractive surgery using Pentacam and Corvis ST devices were included. Patients were divided into groups based on corneal diameter: group A

Purpose: The purpose of this study was to evaluate the correlations and consistency among the central corneal thickness (CCT) of healthy myopic patients measured with three different anterior segment analysis systems. Design: This was a retrospective study. The study included myopia patients who had undergone preoperative examinations in the refractive surgery department of our hospital between January 2021 and December 2023. The CCT was measured separately using Pentacam, Sirius, and IOLMaster 700. Methods: Statistical analysis was conducted using SPSS software. Correlations among the three groups of measured values were assessed using the Pearson method, and a simple scatter plot and fitting line were drawn. Bland‒Altman scatter plots and 95 % limits of agreement (LoAs) were used to evaluate consistency in the data among the systems. Results: A total of 269 patients participated in the study, including 134 males (49.8 %) and 135 females (50.2 %). The CCT measurements by Pentacam, Sirius, and IOLMaster 700 instruments were found to be 541.63 ± 31.67 μm, 541.74 ± 33.36 μm, and 548.90 ± 34.19 μm respectively; significant differences were observed among these measurements (p < 0.05). Significant differences were also observed in CCT between Pentacam and IOLMaster 700 as well as between Sirius and IOLMaster 700 (p < 0.05). The CCT measurements by all three devices showed high positive correlation with all p values less than 0.001: Pentacam and Sirius, r = 0.972; Pentacam and IOLMaster 700, r = 0.966; and Sirius and IOLMaster 700, r = 0.962. The respective 95 % LoAs were -0.18∼0.18; -1.51∼-1.11; and -1.52∼-1. Conclusion: The results indicate that there is a high correlation in measuring CCT for healthy myopic eyes using three different anterior segment analysis systems. However, the differences in the values measured by the three devices were statistically significant. Therefore, in actual clinical practice, it is suggested that the same device should be used to measure and evaluate the CCT across visits.

Abstract Purpose: To investigate the effect of the near visual task of movie-watching in the straight gaze position on corneal topographic parameters. Methods: Thirty myopic young adults with an average age of 25.10 ± 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. Corneal topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis. Results: Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P > 0.130). Also, watching the movie had no effect on other corneal topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P > 0.163). Conclusion: The results of the present study showed that watching movies in the straight gaze position had no effect on corneal topographic parameters and did not cause errors in corneal topographic measurements.

Purpose: To assess the differences and similarities in the corneal curvature obtained by two swept-source optical coherence tomography (SS-OCT) devices, Scheimpflug imaging system and one ray tracing aberrometer in patients with cataracts. Moreover, this study aimed to compare the differences in posterior corneal (PK), total corneal (TK) and true net power (TNP) measurements among the IOLMaster 700, CASIA2, and Pentacam. Methods: A total of 200 eyes of 200 patients (116 female, 58%) were enrolled in this study, with a mean age of 65.9 ± 9.5 years. The flattest (Kf), steepest (Ks), and mean cornal powers (Km), J0, and J45 were obtained using two SS-OCT-based biometric devices, one rotating camera system and one ray-tracing aberrometer. The PK, TK and TNP values were also measured using these devices. To evaluate the differences and similarities between the devicves, the Friedman test, Pearson correlation coefficient (r), intraclass coefficient correlation (ICC) and Bland‒Altman plots with 95% limits of agreement (LoA) were used, and boxplots and stacked histograms were generated to describe the distributions of the data. Results: There were no significant differences between the IOLMaster 700 and Pentacam for any of the keratometry values. Additionally, there were no significant differences between the IOLMaster 700 and iTrace in evaluating J0 and J45. Bland‒Altman plots revealed relatively wide LoA widths, almost larger than 1 diopter for the keratometry values and almost larger than 0.5 diopter for J0 and J45 values among the four devices. In terms of PK and TK values, significant differences and low ICCs were found among the three devices. Conclusions: Although strong correlations and good agreement were found among the IOLMaster700, CASIA2, Pentacam and iTrace for Kf, Ks, Km and J0, J45, it seems that the measurements should not be used interchangeably because of the wide LoA widths and the presence of significant differences among the devices. Similarly, due to significant differences and low ICCs, the PK, TK and TNP values obtained by IOLMaster 700, CASIA2, and Pentacam should not be used interchangeably. [ABSTRACT FROM AUTHOR]

Keratoconus (KC) is the most common corneal ectasia. Optical coherence tomography angiography (OCT-A) is a relatively new non-invasive imaging technique that allows the visualization and quantification of retinal and choriocapillary blood vessels. The aim of this study is to assess retinal and choriocapillary vessel density (VD) differences between KC patients and healthy controls and to investigate correlations between VD and KC severity. Fifty-two eyes were included in this exploratory study: twenty-six eyes from 26 KC patients and twenty-six eyes from 26 age- and gender-matched healthy controls. All patients underwent Scheimpflug corneal topography with Pentacam, axis lengths measurement and optical coherence tomography angiography (OCT-A). The thinnest spot in corneal pachymetry, maximum K (Kmax) and KC severity indices from the Belin/Ambrósio enhanced ectasia display (BAD) were also assessed. There was a distinct reduction particularly in the retinal VD of the superficial capillary plexus (SCP). Correlation analyses showed strong and moderate negative correlations between the VD in the macular SCP and BAD KC scores and between the SCP VD and Kmax. There was no difference in retinal thickness between the KC and healthy controls. With this study, further evidence for altered VD measurements by OCT-A in KC patients is given. For the first time, we demonstrated negative correlations between BAD KC scores and retinal blood vessel alterations. A major limitation of the study is the relatively small sample size. Since an artefactual reduction of the quantitative OCT-A measurements due to irregular corneal topography in KC must be assumed, it remains to be investigated whether there are also actual changes in the retinal microcirculation in KC. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of the near visual task of movie-watching in the straight gaze position on corneal topographic parameters. Methods: Thirty myopic young adults with an average age of 25.10 ± 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. Corneal topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis. Results: Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P > 0.130). Also, watching the movie had no effect on other corneal topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P >0.163). Conclusion: The results of the present study showed that watching movies in the straight gaze position had no effect on corneal topographic parameters and did not cause errors in corneal topographic measurements. [ABSTRACT FROM AUTHOR]

Purpose: To assess and compare the effects of cycloplegia using 0.5% tropicamide and 1% tropicamide on intraocular pressure (IOP) in patients with diabetes mellitus, with and without considering adjustments for central corneal thickness (CCT). Methods: A total of 98 eyes of 98 patients with open angles were included. Patients were randomly assigned to receive either 0.5% tropicamide (49 eyes) or 1% tropicamide (49 eyes). IOP was measured by Goldmann applanation tonometry. Pupillary diameter and CCT were measured by a Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) before and 30 min after tropicamide administration. Results: The mean IOP change was 0.12 ± 1.71 mmHg in the 0.5% tropicamide group and 0.25 ± 1.70 mmHg in the 1% tropicamide group. These two values were not significantly different, even after adjusting IOP for CCT using all formulae (P > 0.05). Without adjustment, the mean post-dilation IOP was similar to the mean pre-dilation IOP in both groups (P > 0.5), and none of the patients experienced an IOP increase of 5 mmHg or more. With adjustment, the mean IOP increased significantly after administration of 0.5% tropicamide, as determined by the Ehlers formula (P = 0.02). Similarly, the mean IOP increased significantly after administration of 1% tropicamide, as determined by the Ehlers formula (P = 0.008), the Doughty formula (P = 0.03), and the Kohlhaas formula (P = 0.04). In each study group, a single patient encountered an increase in IOP ≥5 mmHg when IOP adjustment was performed using the Ehlers formula. Conclusion: Cycloplegia with 0.5% and 1% tropicamide leads to similar mean changes in IOP in patients with diabetes. However, the statistical significance of the change and the occurrence of the significant increases in IOP, as determined by a predefined cut-off point, are dependent upon the method used to adjust the IOP.

Majid Moshirfar,1– 3 Michael S Herron,4 David S Cha,5 Jordan M Santos,6 Levi T Miller,7 Phillip C Hoopes Sr1 1Hoopes Vision Research Center, Hoopes Vision, Draper, UT, 84020, USA; 2John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA; 3Utah Lions Eye Bank, Murray, UT, USA; 4University of Nevada, Reno School of Medicine, Reno, NV, USA; 5Saint Louis University School of Medicine, St. Louis, MO, USA; 6University of Arizona, Phoenix School of Medicine, Phoenix, AZ, USA; 7Utah State University, Department of Electrical and Computer Engineering, Logan, UT, USACorrespondence: Majid Moshirfar, Hoopes Vision Research Center, 11820 S. State St. &num;200, Draper, UT, 84020, USA, Tel\Fax +1 801-568-0200, Email cornea2020@me.comPurpose: We assess the relationship between preoperative myopic sphere, astigmatism, and spherical equivalent and effective optical zone (EOZ) size, shape, and decentration within individual populations of post-LASIK, PRK, and SMILE patients.Patients and Methods: A retrospective chart review was conducted with 118 LASIK, 144 PRK, and 41 SMILE eyes from 179 total patients that underwent compound myopic ablation. One-year postoperative Pentacam tangential difference maps were used for EOZ data measurements. Correlational analysis between compound myopic measures [sphere, cylinder, manifest refractive spherical equivalent (MRSE)] and EOZ parameters was performed, and differences between groups of myopic sphere and cylinder within each surgery type were assessed.Results: An increase in absolute myopic sphere (and subsequent MRSE) is associated with a smaller EOZ area in SMILE (r=0.454, p=0.003) and a more circular EOZ shape in LASIK (r=0.396, p< 0.001) and PRK (r=0.563, p< 0.001). An increase in absolute myopic cylinder is associated with an increased EOZ area in all three surgery types [LASIK (r=− 0.459, p< 0.001), PRK (r=− 0.716, p< 0.001), SMILE (r=− 0.429, p=0.005)] and a more elliptical EOZ in LASIK (r=− 0.491, p< 0.001) and PRK (r=− 0.538, p< 0.001).Conclusion: While astigmatism may be correlated to EOZ size within all three refractive surgery types, myopic sphere alone is insufficient to estimate EOZ size differences for procedures with a large blend zone of ablation like LASIK or PRK. Shape is just as important a factor as size to consider when examining corneal EOZ differences; reported correlative findings likely result from inherent differences in surgical technique and abruptness of planned surgical ablation borders.Keywords: EOZ, OZ, Pentacam, tangential difference map

Purpose: To assess the feasibility and reliability of biometric measurements taken with the Eyestar 900 device in keratoconus eyes in comparison with those taken with the Pentacam HR and IOLMaster 700. Methods: Seventy-five eyes of 75 patients with keratoconus were included. The central corneal thickness (CCT), thinnest point of corneal thickness (TCT), axial length (AL), flat (K1) and steep (K2) anterior and posterior (Kp1, Kp2) keratometry, maximal keratometry (KMax) and anterior chamber depth (ACD) were compared between the Eyestar 900, Pentacam HR and IOLMaster 700. Reliability parameters such as the coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated. Pearson's r was determined to assess the correlation between devices. Results: A high repeatability (CoV < 1%) and intraclass correlation (ICC > 0.9) was found for all devices, led by AL, TCT, K1 and K2 (CoV 0.01–0.36%; ICC 0.994–1.00). The largest correlation between devices was found for AL (Eyestar vs. IOLMaster, r = 1.0), K1 (Eyestar vs. IOLMaster, r = 0.997) and ACD (Eyestar vs. IOLMaster, r = 0.995; Pentacam vs. IOLMaster, r = 0.987; Eyestar vs. Pentacam, r = 0.983), but there were significant differences in measured values between devices (p < 0.001), whereas the correlation was only slightly lower (r = 0.947 to 0.994) for KMax, CCT, TCT, K2, Kp1 and Kp2. Conclusion: Keratometric and axial length measurements with the Eyestar 900 were feasible and revealed a high repeatability and a good correlation to the other devices in eyes with keratoconus. [ABSTRACT FROM AUTHOR]

Assessing the consistency of pupil offset measurements between the Pentacam and Keratron Scout is essential for the refractive surgery design of young myopic patients. Accurate preoperative measurement of pupil offset is critical to achieving a better quality of vision after refractive surgery. The Pentacam and Keratron Scout are commonly used in hospitals, and evaluating their consistency is essential for accurate measurement of pupil offset. Six hundred eyes (600 subjects) were included in this study. Pupil offset and its X, Y-component were measured by Pentacam and Keratron Scout, respectively. Agreement and repeatability between the two devices were identified by intraclass correlation coefficient and Bland-Altman plots with 95% limits of agreement. Paired t-tests and Pearson analysis were used to compare the differences and correlations between the two devices. The mean age of all subjects was 23 ± 5 years. The mean pupil offset magnitude obtained from Pentacam and Keratron Scout was 0.16 ± 0.08 mm and 0.15 ± 0.07 mm. The 95% limits of agreement (−0.11–0.13, −0.09–0.11, and −0.11–0.12) and intraclass correlation coefficient (0.82, 0.84, and 0.81) demonstrated good agreement and repeatability of the two devices in measuring pupil offset and its X, Y-component. A significant correlation between the two devices was found (r = 0.71, 0.73, and 0.70). The direction of pupil offset measured by the devices was both predominately towards the superonasal quadrant. Pentacam and Keratron Scout showed good agreement in measuring pupil offset and its X, Y-component, which can be used interchangeably in clinical practice. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the corneal morphological parameters before and after lower eyelid malposition correction using the lateral tarsal strip technique. Materials and Methods: 60 eyes of 60 patients with involutional entropion (30 eyes) and involutional ectropion (30 eyes) correction procedures with lateral tarsal strip included in this prospective study. Detailed ophthalmologic examination was performed including best corrected visual acuity (BCVA), slit lamp examination and dilated fundoscopy. Measurements were made before and one month after the surgeries using Pentacam. Central corneal thickness (CCT) and pachymetry of thinnest location, cornea front astigmatism (AST), flat keratometry (K1), steep keratometry (K2) and mean keratometry (Km) values were all evaluated. Results: Ectropion patients exhibited higher postoperative Km (p=0.019). Additionally, postoperative AST values were significantly lower in both ectropion and entropion groups (p=0.001, p=0.001, respectively). Increased pachymetry values of pupil center and the thinnest location were found in entropion cases (p=0.002, p=0.023, respectively). Conclusion: Surgical repositioning of the lower eyelids for malposition correction may result with statistically significant decrease in corneal astigmatism postoperatively also some fundamental changes in corneal topography. Awareness of these changes after eyelid surgery is very important in-patient management. [ABSTRACT FROM AUTHOR]

Objectives: To retest the performance of Pentacam parameters in the detection of eyes with subclinical keratoconus (KC) and mild KC based on different definitions from the Amsler-Krumeich (AK), Collaborative Longitudinal Evaluation of Keratoconus (CLEK), and ABCD systems. Materials and Methods: This cross-sectional university-based study comprised 24 eyes with subclinical KC, 144 eyes with mild KC (based on AK in 101 eyes, CLEK in 28 eyes, and ABCD in 15 eyes), and 70 controls. Diagnostic ability of the thinnest point (TP) pachymetry, KISA% index, inferior-superior asymmetry, corneal aberrations, Pentacam indices, front/back elevations, pachymetric progression index, Ambrósio-Relational Thickness (ARTmax), and Belin/Ambrósio Enhanced Ectasia Display scores (Df, Db, Dp, Dt, Da, and D-final) were evaluated. Results: ARTmax (83.3% sensitivity/74.3% specificity) had the highest ability in distinguishing subclinical KC from normal, followed by TP pachymetry, Dt, and Da. D-final showed excellent sensitivity/specificity in mild KC diagnosis based on AK (98%/100%) and CLEK (97.4%/100%) descriptions. In the mild KC-ABCD group, index of vertical asymmetry accurately detected all eyes with mild KC and 97.1% of the controls. Conclusion: This study points out the gray zone in the detection of eyes with subclinical and mild KC due to overlapping terminology and grading criteria. Pentacam parameters seem to have modest capability in subclinical KC detection, indicating the necessity for additional diagnostic modalities. However, eyes with mild KC can be diagnosed with high accuracy using Pentacam parameters, although the strongest parameters may vary according to the definition of “mild KC.” Nevertheless, uniform and definitive criteria for subclinical and clinical KC classification are required for a diagnostic and therapeutic consensus in KC.

Abstract Purpose To investigate the agreement between Pentacam and CASIA2 in the evaluation of corneal densities (CDs) and lens densities (LDs) in myopes. Methods Fifty-three patients (106 eyes) underwent comprehensive ophthalmologic examinations. CDs and LDs were measured using Pentacam and CASIA2, respectively, based on the grayscale percentage of the obtained images. Agreement between Pentacam and CASIA2 was evaluated using the consistency intraclass correlation coefficient (ICC) and represented using Bland-Altman plots. Results Compared to Pentacam, CASIA2 showed significantly higher CD and LD values in all measured zones. The ICC of the average CD and LD measured by the Pentacam and CASIA2 were 0.726 and 0.757, respectively. The ICC values of all corneal zones and lenses were above 0.7, except for the measurement of the cornea in the 0–2 mm zone (0.455), suggesting good consistency between the two devices, whose results were of different levels of linear correlation. Bland-Altman plots showed mean percentages of 3.93% for the points falling outside the limits of agreement among the densitometry results. The ICCs in different age groups were similar, but the agreement was poorer in the high myopia group (low and moderate myopia, CD: 0.739, LD: 0.753; high myopia, CD: 0.621, LD: 0.760). Conclusions CASIA2 demonstrated good consistency with Pentacam in the measurement of CD and LD, except for measurement of CD in the central cornea and in high myopia. Despite difference in the numerical results compared with Pentacam, which made the two devices uninterchangeable, CASIA2 provides a reliable alternative densitometric measurement method.

Abstract Purpose: This study aimed to assess the agreement between topographic indices of healthy subjects and keratoconus (KCN) patients using a swept-source optical coherence tomography (SS-OCT CASIA2) versus a Scheimpflug camera (Pentacam). Methods: 40 eyes of 23 patients with KCN and 40 eyes of 20 healthy subjects were included and evaluated with the CASIA2, followed by the Pentacam. Two consecutive modalities were obtained for one eye of each patient. Corneal parameters, including anterior keratometry at steep (Ks) and flat meridians (Kf), anterior astigmatism, anterior and posterior corneal elevation values, thinnest corneal thickness, and apex corneal thickness, were evaluated. Results: CASIA2 and Pentacam showed perfect agreement (95% limits of agreement (LoA): -0.22 to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; P < 0.01) for anterior (Ks) in normal and ectatic corneas, respectively. The cylinder amount had moderate agreement and correlation (95% LoA: -0.55 to 0.47D, ICC: 0.797, P < 0.01) in normal, and moderate to strong agreement and correlation (95% LoA: -1.57 to 0.87D, ICC=0.911, P < 0.01) in Keratoconic eyes. There was a fair agreement for anterior and posterior corneal elevation values in normal subjects (95% LoA: -3.09 to 4.59, 95% LoA: -6.91 to 7.31D). The thinnest corneal thickness amount had an excellent agreement in normal and KCN patients (ICC: 0.983, 0.953; respectively). Conclusions: Although the devices had different mean indices values, they had a good agreement based on the Bland–Altman plots. Since Pentacam is accepted as the standard tool for diagnosing ectatic cornea, pentacam CASIA2 is also helpful for early diagnosis of KCN.

Abstract Background To investigate the difference between the predicted preoperative corneal ablation depth and the measured ablation depth for femtosecond laser in situ keratomileusis (FS-LASIK) in patients with different degrees of myopia, and to analyze the source of the difference. Methods A total of 55 patients (109 eyes) were included in this study. Multiple logistics regression was applied to analyze the sources affecting postoperative refractive outcomes. The difference between the preoperative predicted corneal ablation depth and the 1-day postoperative ablation depth in patients with different degrees of myopia was explored using linear regression. Corneal biomechanical parameters influencing error in ablation depth calculation were examined using multiple linear regression. Results One hundred and nine eyes were divided into low to moderate myopia (55 eyes, myopia of 6 D or less), high myopia (45 eyes, myopia ranging from 6 D to a maximum of 9 D), and very high myopia group (9 eyes, myopia greater than 9 D) based on preoperative refractive error (spherical equivalent). Postoperative visual outcomes were comparable among the three groups of patients, with no significant difference in uncorrected visual acuity (UCVA). We did find notable disparities in spherical equivalent (SE) and central corneal thickness (CCT) in patients with different degrees of myopia at 1 day postoperatively (all p

Abstract Purpose The present study was conducted to determine the corneal topographic indices of Scheimpflug camera in type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic elderly populations. Methods A total of 1105 participants were selected using random cluster sampling from Tehran, Iran and categorized into three groups including type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic. The diabetic group had HbA1c levels ≥ 6.4% with no other systemic problems. The non-diabetic participants had normal eye findings and no systemic diseases. The pachymetric progression index (PPI) values were measured using the Pentacam AXL. Results A total of 1105 participants including 429 diabetes patients (38.46% male) and 676 non-diabetic (38.76% male) subjects entered the study. Only PPIavg and PPImax were higher in the diabetics versus non-diabetics (P = 0.019 and 0.010, respectively). There was a significant difference in PPImax between the three groups (P = 0.036). There were significant differences only in index of vertical asymmetry (IVA), central keratoconus index (CKI), PPI average, and PPI max between different stages of diabetic retinopathy (DR) (P = 0.045, 0.005, 0.002, and 0.004, respectively). There was a significant difference in index of Surface Variance (ISV), index of vertical asymmetry (IVA), PPIavg, and PPImax between diabetes patients with and without DR (P = 0.016, 0.022,

AIM: To compare the corneal backward light scattering values in type 2 diabetes mellitus (DM) patients with those of age and sex-matched healthy controls. METHODS: The study included 30 patients (30 eyes) with type 2 DM and 30 control subjects (30 eyes). Duration of diabetes, most recent hemoglobin A1c levels, along with the status of diabetic retinopathy, and existing medical treatment of all subjects were recorded. All subjects underwent a complete ophthalmologic examination. In addition, backward light scattering (densitometry) was measured to assess changes in corneal transparency using tomography (Pentacam HR). RESULTS: The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females. The age was 50.40±7.80y (range: 40-68y) of the diabetic group and 49.30±9.50y (rang: 40-73y) of control group. The diabetic group demonstrated significantly higher mean densitometry values of the anterior (6-10 mm) zone (P=0.047), the total anterior layer (P=0.036) and the total cornea (P=0.043) than control group. The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration. CONCLUSION: Diabetic group has higher densitometry in anterior corneal (6-10 mm) zone, total anterior cornea, and total cornea and with no correlation with hemoglobin A1c levels and DM duration.

Background: Comparison of OPD-Scan III and Pentacam measurements of relevant parameters guiding the selection of multifocal intraocular lenses in cataract patients. Methods: A retrospective study included 120 patients (120 eyes) with cataract. Their chord kappa, chord alpha, corneal spherical aberration, and pupil size were measured by OPD-Scan Ⅲ and Pentacam. Pairwise t-tests, Pearson tests, and Bland-Altman analyses were used, respectively, to assess the difference, correlation, and agreement between the devices. Results: There was no significant difference in photopic chord kappa and corneal spherical aberration between the two instruments (P = 0.054, P = 0.065). Chord alpha and pupil size varied significantly between the two instruments (P

Purpose: To compare the consistency of Pentacam Scheimpflug system (Pentacam® HR), ray-tracing aberrometry (iTrace), and swept source optical coherence tomography (IOLMaster 700) measurements for Angle Kappa and angle Alpha. Methods: A prospective randomized cohort study. 86 individuals (86 eyes) aged 19–45 years with best corrected vision of 4.9 or better were randomly selected from January 2022 to December 2022 in a tertiary-level hospital. Angle Kappa and angle Alpha were measured or calculated using Pentacam, iTrace, and IOLMaster 700, respectively. Results: The mean difference of angle Kappa between any two instruments was not statistically significant, but the mean difference of angle Alpha between both Pentacam and iTrace, Pentacam and IOLMaster 700, and iTrace and IOLMaster 700 was statistically significant (p value

The cornea is the human eye’s transparent outermost layer. It plays a significant role in keeping the eyeball’s shape and preventing infections with protective functions for the different structures within the eye. Cornea, like other tissue in the body, is affected by different diseases such as keratoconus. Detection of this disease is important for that reason variety of techniques and tools such as anterior and posterior topographical images of the human cornea are used. They are becoming more critical in categorizing healthy/unhealthy corneas. The outcomes of topographic device contain four different maps as well as other valuable parameters. Elevation maps are representing the elevation of corneal surfaces above and below reference surface. They were used along with elevation values by the researchers for both interior/posterior surfaces. These maps are affected by any change in other topographic parameters such as asphericity and toricity. These parameters were found to be essential to distinguish between normal and diseased eyes with the help of different feature selections or feature extraction, which is used to determine the most influential parameters that will contribute to the final decision. Some researchers highlighted the importance of the skewing angle of the bowtie shape, which indicates the cornea’s health. This paper aims to explain the importance of elevation maps, artificial intelligent techniques and different parameters collected from different methods to identify if the cornea is diseased or healthy.

Purpose: To evaluate preoperative risk factors (mainly those related to corneal topography/tomography) for post-LASIK ectasia development.Methods: A retrospective case review for post-LASIK ectasia for myopia or myopic astigmatism. The evaluated data included preoperative subjective refraction, method of flap creation, and topometric/tomographic parameters from Oculus Pentacam, including subjective curvature pattern, topometric, elevation, and pachymetric indices from the Belin Ambrosio display "BAD", and the Pentacam Random Forest Index (PRFI). Moreover, preoperative ectasia detection indices were calculated (including Percentage of Tissue Altered "PTA" index, Randleman Ectasia Risk Score System "ERSS", and Navarro Index for Corneal Ectasia "NICE").Results: Twenty-four eyes of 15 patients were enrolled. Concerning the risk factors, age was lower than 25 in 19 eyes (79%); flaps were created using a microkeratome in 17 eyes (70.8%); thinnest pachymetry was lower than 510μm in eight eyes (33%); total deviation from BAD was higher than 1.6 in 50%; Ambrósio's relational thickness (ART) max was lower than 340 in 45.83%; PTA index was higher than 40% in 16%; ERSS was more than 3 points in 62.5%; NICE was higher than 8 points in three eyes (12.5%); PRFI index was more than 0.125 in 87.5%; two eyes (8%) had no identifiable risk factors.Conclusion: Current ectasia risk assessment criteria were insufficient for detecting a relatively large number of cases. There is an unequivocal need for more information, which may be derived from biomechanical assessment and epithelial thickness mapping. Novel corneal tomography indices derived from artificial intelligence may increase accuracy in characterizing ectasia susceptibility. [ABSTRACT FROM AUTHOR]

Objectives: To retest the performance of Pentacam parameters in the detection of eyes with subclinical keratoconus (KC) and mild KC based on different definitions from the Amsler-Krumeich (AK), Collaborative Longitudinal Evaluation of Keratoconus (CLEK), and ABCD systems. Materials and Methods: This cross-sectional university-based study comprised 24 eyes with subclinical KC, 144 eyes with mild KC (based on AK in 101 eyes, CLEK in 28 eyes, and ABCD in 15 eyes), and 70 controls. Diagnostic ability of the thinnest point (TP) pachymetry, KISA% index, inferior-superior asymmetry, corneal aberrations, Pentacam indices, front/back elevations, pachymetric progression index, Ambrosio-Relational Thickness (ARTmax), and Belin/Ambrosio Enhanced Ectasia Display scores (Df, Db, Dp, Dt, Da, and D-final) were evaluated. Results: ARTmax (83.3% sensitivity/74.3% specificity) had the highest ability in distinguishing subclinical KC from normal, followed by TP pachymetry, Dt, and Da. D-final showed excellent sensitivity/specificity in mild KC diagnosis based on AK (98%/100%) and CLEK (97.4%/100%) descriptions. In the mild KC-ABCD group, index of vertical asymmetry accurately detected all eyes with mild KC and 97.1% of the controls. Conclusion: This study points out the gray zone in the detection of eyes with subclinical and mild KC due to overlapping terminology and grading criteria. Pentacam parameters seem to have modest capability in subclinical KC detection, indicating the necessity for additional diagnostic modalities. However, eyes with mild KC can be diagnosed with high accuracy using Pentacam parameters, although the strongest parameters may vary according to the definition of "mild KC." Nevertheless, uniform and definitive criteria for subclinical and clinical KC classification are required for a diagnostic and therapeutic consensus in KC. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the corneal morphological parameters before and one month after the upper eyelid (UE) blepharoplasty and external levator resection (ELR) for ptosis surgery. Materials and Methods: Seventy eyes of 70 patients with dermatochalasis (50 eyes) and acquired aponeurotic ptosis (AAP) (20 eyes) included in this prospective study. Detailed ophthalmologic examination was performed including the best corrected visual acuity (BCVA), slit lamp examination and dilated fundoscopy. Measurements were made before and one month after the surgeries using Pentacam. Central corneal thickness (CCT), pupil center pachymetry (PCP) and thinnest pachymetry (TP), cornea front astigmatism (AST), flat keratometry (K1), steep keratometry (K2) and mean keratometry (Km) values were evaluated. Results: Higher postoperative Km measurements were observed in dermatochalasis (p = 0.038) patients. Postoperative AST values were significantly lower in both dermatochalasis and ptosis cases (p = 0.034, p = 0.003, respectively). Increased PCP and TP were found in the AAP patients (p = 0.014, p = 0.015, respectively). Discussion: UE blepharoplasty and ELR surgeries both lead to some significant changes on corneal structure post-operatively. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. [ABSTRACT FROM AUTHOR]

We aimed to compare the predictive effect of pre-injection intraocular pressure (IOP) and anterior segment parameters on post-injection IOP values after intravitreal bevacizumab injection for neovascular age-related macular degeneration (NVAMD) in phakic and pseudophakic patient groups. This retrospective cross-sectional study included 65 eyes of 65 treatment-naive NVAMD patients. Patients were divided into two groups according to their lens status (35 phakic and 30 pseudophakic patients). Pre-injection IOP, anterior segment parameters measured with PENTACAM, and post-injection IOP values measured at the 5th minute were recorded. Univariate and multivariate regression analyses were used to recognise the predictive effect of pre-injection IOP and anterior segment parameters on post-injection IOP for each group. Multivariate regression analyses showed that the decrease in anterior chamber depth (ACD), and the increase in pre-injection IOP were significantly correlated with higher post-injection IOP in the phakic patient group (p = 0.019 and 0.031; respectively). No correlation was found in the pseudophakic patient group. Pre-injection ACD and IOP values may be predictive of higher post-injection IOP in phakic patients. Preoperative assessment of these parameters could be beneficial in patients at risk of glaucoma. [ABSTRACT FROM AUTHOR]

Background: To investigate the difference between the predicted preoperative corneal ablation depth and the measured ablation depth for femtosecond laser in situ keratomileusis (FS-LASIK) in patients with different degrees of myopia, and to analyze the source of the difference. Methods: A total of 55 patients (109 eyes) were included in this study. Multiple logistics regression was applied to analyze the sources affecting postoperative refractive outcomes. The difference between the preoperative predicted corneal ablation depth and the 1-day postoperative ablation depth in patients with different degrees of myopia was explored using linear regression. Corneal biomechanical parameters influencing error in ablation depth calculation were examined using multiple linear regression. Results: One hundred and nine eyes were divided into low to moderate myopia (55 eyes, myopia of 6 D or less), high myopia (45 eyes, myopia ranging from 6 D to a maximum of 9 D), and very high myopia group (9 eyes, myopia greater than 9 D) based on preoperative refractive error (spherical equivalent). Postoperative visual outcomes were comparable among the three groups of patients, with no significant difference in uncorrected visual acuity (UCVA). We did find notable disparities in spherical equivalent (SE) and central corneal thickness (CCT) in patients with different degrees of myopia at 1 day postoperatively (all p < 0.001). Logistic regression analysis showed that error in ablation depth calculation was an independent risk factor for refractive outcomes one day after surgery (OR = 1.689, 95% CI: 1.366 – 2.089). There was a substantial discrepancy in error in ablation depth calculation at 1 day postoperatively between the three groups. The measured ablation depth of the laser platform was lower than the predicted ablation depth in the low to moderate myopia and very high myopia groups, but the opposite was true in the high myopia group. Pre-operative SE (p < 0.001) and corneal front minimum radius of curvature (Front Rmin) (p = 0.007) obviously influenced the error in ablation depth calculation. Conclusions: Error in ablation depth calculation values vary significantly between patients with different degrees of myopia and correlate highly with preoperative SE and Front Rmin. At the same time, the available evidence suggests that error in ablation depth calculation is an influential factor in postoperative refractive status, so it is imperative to control error in ablation depth calculation. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the agreement between Pentacam and CASIA2 in the evaluation of corneal densities (CDs) and lens densities (LDs) in myopes. Methods: Fifty-three patients (106 eyes) underwent comprehensive ophthalmologic examinations. CDs and LDs were measured using Pentacam and CASIA2, respectively, based on the grayscale percentage of the obtained images. Agreement between Pentacam and CASIA2 was evaluated using the consistency intraclass correlation coefficient (ICC) and represented using Bland-Altman plots. Results: Compared to Pentacam, CASIA2 showed significantly higher CD and LD values in all measured zones. The ICC of the average CD and LD measured by the Pentacam and CASIA2 were 0.726 and 0.757, respectively. The ICC values of all corneal zones and lenses were above 0.7, except for the measurement of the cornea in the 0–2 mm zone (0.455), suggesting good consistency between the two devices, whose results were of different levels of linear correlation. Bland-Altman plots showed mean percentages of 3.93% for the points falling outside the limits of agreement among the densitometry results. The ICCs in different age groups were similar, but the agreement was poorer in the high myopia group (low and moderate myopia, CD: 0.739, LD: 0.753; high myopia, CD: 0.621, LD: 0.760). Conclusions: CASIA2 demonstrated good consistency with Pentacam in the measurement of CD and LD, except for measurement of CD in the central cornea and in high myopia. Despite difference in the numerical results compared with Pentacam, which made the two devices uninterchangeable, CASIA2 provides a reliable alternative densitometric measurement method. [ABSTRACT FROM AUTHOR]

Keratoconus appears to be a rare corneal disease with a prevalence previously estimated at 1:2000. The aim of our study was to investigate the prevalence of keratoconus in a large German cohort and to evaluate possible associated factors. Method: In the population-based, prospective, monocentric cohort study, Gutenberg Health Study, 12,423 subjects aged 40–80 years were examined at the 5-year follow-up. Subjects underwent a detailed medical history and a general and ophthalmologic examination including Scheimpflug imaging. Keratoconus diagnosis was performed in two steps: all subjects with conspicuous TKC analysis of corneal tomography were included in further grading. Prevalence and 95% confidence intervals were calculated. Logistic regression analysis was carried out to investigate association with age, sex, BMI, thyroid hormone, smoking, diabetes, arterial hypertension, atopy, allergy, steroid use, sleep apnea, asthma, and depression. Results: Of 10,419 subjects, 75 eyes of 51 subjects were classified as having keratoconus. The prevalence for keratoconus in the German cohort was 0.49% (1:204; 95% CI: 0.36–0.64%) and was approximately equally distributed across the age decades. No gender predisposition could be demonstrated. Logistic regression showed no association between keratoconus and age, sex, BMI, thyroid hormone, smoking, diabetes, arterial hypertension, atopy, allergy, steroid use, sleep apnea, asthma, and depression in our sample. Conclusion: The prevalence of keratoconus disease in a mainly Caucasian population is approximately tenfold higher than previously reported in the literature using latest technologies (Scheimpflug imaging). Contrary to previous assumptions, we did not find associations with sex, existing atopy, thyroid dysfunction, diabetes, smoking, and depression. [ABSTRACT FROM AUTHOR]

Purpose: The present study was conducted to determine the corneal topographic indices of Scheimpflug camera in type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic elderly populations. Methods: A total of 1105 participants were selected using random cluster sampling from Tehran, Iran and categorized into three groups including type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic. The diabetic group had HbA1c levels ≥ 6.4% with no other systemic problems. The non-diabetic participants had normal eye findings and no systemic diseases. The pachymetric progression index (PPI) values were measured using the Pentacam AXL. Results: A total of 1105 participants including 429 diabetes patients (38.46% male) and 676 non-diabetic (38.76% male) subjects entered the study. Only PPIavg and PPImax were higher in the diabetics versus non-diabetics (P = 0.019 and 0.010, respectively). There was a significant difference in PPImax between the three groups (P = 0.036). There were significant differences only in index of vertical asymmetry (IVA), central keratoconus index (CKI), PPI average, and PPI max between different stages of diabetic retinopathy (DR) (P = 0.045, 0.005, 0.002, and 0.004, respectively). There was a significant difference in index of Surface Variance (ISV), index of vertical asymmetry (IVA), PPIavg, and PPImax between diabetes patients with and without DR (P = 0.016, 0.022, < 0.001, and < 0.001, respectively). Conclusion: According to the results, diabetes and DR change several topographic indices. In addition, the HbA1c level may affect pachymetric progression index max. Therefore, special attention should be paid to these patients for different treatment strategies. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the agreement between topographic indices of healthy subjects and keratoconus (KCN) patients using a swept-source optical coherence tomography (SS-OCT CASIA2) versus a Scheimpflug camera (Pentacam). Methods: 40 eyes of 23 patients with KCN and 40 eyes of 20 healthy subjects were included and evaluated with the CASIA2, followed by the Pentacam. Two consecutive modalities were obtained for one eye of each patient. Corneal parameters, including anterior keratometry at steep (Ks) and flat meridians (Kf), anterior astigmatism, anterior and posterior corneal elevation values, thinnest corneal thickness, and apex corneal thickness, were evaluated. Results: CASIA2 and Pentacam showed perfect agreement (95% limits of agreement (LoA): -0.22 to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; P <0.01) for anterior (Ks) in normal and ectatic corneas, respectively. The cylinder amount had moderate agreement and correlation (95% LoA: -0.55 to 0.47D, ICC: 0.797, P <0.01) in normal, and moderate to strong agreement and correlation (95% LoA: -1.57 to 0.87D, ICC=0.911, P <0.01) in Keratoconic eyes. There was a fair agreement for anterior and posterior corneal elevation values in normal subjects (95% LoA: -3.09 to 4.59, 95% LoA: -6.91 to 7.31D). The thinnest corneal thickness amount had an excellent agreement in normal and KCN patients (ICC: 0.983, 0.953; respectively). Conclusions: Although the devices had different mean indices values, they had a good agreement based on the Bland--Altman plots. Since Pentacam is accepted as the standard tool for diagnosing ectatic cornea, pentacam CASIA2 is also helpful for early diagnosis of KCN. [ABSTRACT FROM AUTHOR]

Aim of the study: To evaluate the results and recurrence of pterygium after surgical treatment of the primary condition with autotransplantation of the conjunctival tissue of the ipsilateral eye to the defect site at our workplace with a follow-up period of at least one year. Material and methods: The medical documentation of all patients who underwent primary pterygium surgery with conjunctival autograft in the monitored period February 2018 to July 2019 was retrospectively evaluated. The authors mainly studied the recurrence of the disease using this surgical technique. Furthermore, the influence on visual functions, refractive parameters and possible complications of therapy was evaluated. The average follow-up time of our cohort was 21.8 months. Results: We did not observe recurrence in any patient during the entire follow-up period. Uncorrected visual acuity was improved by at least one line of the logMAR optotype in 5 eyes and corrected visual acuity in 2 eyes. According to Wilcoxon's paired test, changes in uncorrected and corrected visual acuity were not statistically significant at a significance level of 0.05. In 5 patients the astigmatism was reduced by at least 0.5 cylindrical diopters (Dcyl), while in other patients the astigmatism remained stable after surgery. We did not observe any complications during or after surgery. Conclusions: Excision with conjunctival autograft is an effective and safe method of treatment of primary pterygium. This technique has a low incidence of disease recurrence. We did not observe the return of the pathology in any of our patients during the follow-up. It was possible to stabilize or improve the patients' visual functions and refraction. [ABSTRACT FROM AUTHOR]

Abstract Background Keratoconus (KC) is easily recognized by its unique topographic pattern, but it can be difficult to distinguish subclinical form of the disease from the normal cornea. Optovue anterior segment optical coherence tomography (AS-OCT) helps diagnose KC. Aim of the work To assess and the level of agreement of Keratometry-readings (K), Central Corneal Thickness (CCT) and Thinnest Corneal Thickness (TCT) measurements obtained by Optovue AS-OCT and Wavelight Oculyzer Pentacam HR in two groups: KC eyes and normal eyes. Patients and methods This is a prospective clinical observational study. The study included 110 eyes divided into two groups. The study group included 62 eyes with topographic evidence of KC. The control group included 48 eyes of normal subjects with no topographic evidence of KC. All of the participants underwent full cycloplegic refraction, spectacle best-corrected distance visual acuity, comprehensive slit-lamp biomicroscopy and fundoscopy. All participants underwent corneal topography by Pentacam HR and AS-OCT. Results There were highly significant differences between the studied groups as regarding BCVA, intraocular pressure and CCT measurements which were found to be lower among KC group compared to the control one. There were highly significant differences between the studied groups regarding TCT measurement detected by Pentacam HR and AS-OCT which was found to be lower among the keratoconus group compared to the control one (470.9, 455.7 versus 541.9 and 518.7 respectively). Conclusion Both Scheimpflug-based imaging and AS-OCT provide comparable readings with a good agreement regarding corneal pachymetry in keratoconus group with accurate identification of KC eyes and healthy ones. However, there was a significant difference in K readings between both devices in Keratoconus and control group.

Purpose: This study aimed to investigate the features of progressive keratoconus by means of machine learning.Methods: In total, 163 eyes from 127 patients with at least 3 examination records were enrolled in this study. Pentacam HR was used to measure corneal topography. Steepest meridian keratometry (K1), flattest meridian keratometry (K2), steepest anterior keratometry (Kmax), central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior radius of cornea (ARC), posterior elevation (PE), index of surface variation (ISV), and index of height deviation (IHD) were input for analysis. Support vector machine (SVM) and logistic regression analysis were applied to construct prediction models.Results: Age, PE, and IHD showed statistically significant differences as the follow-up period extended. K2, PE, and ARC were selected for model construction. Logistic regression analysis presented a mean area under the curve (AUC) score of 0.780, while SVM presented a mean AUC of 0.659. The prediction sensitivity of SVM was 52.9%, and specificity was 79.0%.Conclusion: It is feasible to use machine learning to predict the progression and prognosis of keratoconus. Posterior elevation exhibits a sensitive prediction effect.

Purpose: To analyze using Pentacam®, the corneal and anterior chamber changes following periocular botulinum toxin injection in patients with facial dystonia. Methods: Prospective study that included patients with facial dystonia that were going to receive a periocular botulinum toxin injection for the first time or six months or more after the previous injection. A Pentacam® examination was carried out in all patients before and 4 weeks after the injection. Results: Thirty-one eyes were included. Twenty-two had a diagnosis of blepharospasm and nine of hemifacial spasm. Analysis of corneal and anterior chamber parameters revealed a significant decrease in iridocorneal angle after botulinum toxin injection (from 35 ± 10º to 33.8 ± 9.7º, p = 0.022). No other corneal or anterior chamber parameters changed significantly after the injection. Conclusions: Periocular botulinum toxin injection causes narrowing of the iridocorneal angle. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study is to investigate the changes in topometry, tomography, and corneal densitometry in subclinical keratoconus (SK) at the 6-month interval. Methods: The clinical keratoconus and SK groups included 25 eyes; the control group included 22 eyes from 22 patients. Corneal topographic, tomographic, topometric, and densitometric values obtained using the Pentacam HR imaging system were analyzed. Results: Posterior elevation (PE), Keratoconus index (KI), index of height asymmetry (IHA), index of height decentration (IHD), Dp, Da, Final D, maximum pachymetric progression index (PPImax), and maximum Ambrósio relational thickness parameters showed significant changes between the baseline and the 6th-month follow-up in SK group (p<0.05 for all values). There were significant changes in all zones except a central layer of 6-10 zone, anterior, and central layer of 10-12 zone between the baseline and the 6th-month follow-up in the SK group (p<0.05, for all values). The changes in mean±standard deviation of KI, IHA, IHD, PPImax parameters, and corneal densitometry values of the posterior layer of 0-2 mm and 2-6 mm zones were significant in the SK group compared to the controls (p<0.05, for all values). Conclusion: PE, KI, IHA, IHD, and PPImax parameters as well as increasing corneal light backscatter of the posterior central layer might be useful for follow-up of progression of SK. New multimeric parameters created by combinations of topometric, tomographic, and corneal densitometry parameters could be the future of SK follow-up. [ABSTRACT FROM AUTHOR]

Purpose: To determine the efficacy and safety of pediatric accelerated cross linking (CXL). Methods: A prospective study on progressive keratoconus (KC) cases under ≤18 years of age. Sixty four eyes of thirty nine cases underwent epithelium-off accelerated CXL protocol. Visual acuity (VA), slit-lamp examination, refraction, pentacam reading of keratometry (K), corneal thickness, and thinnest location pachymetry were noted. Cases were followed up on days 1, 5, and at 1st, 3rd, 6th, and 12th-month post procedure. Results: Statistically, significant improvement of the mean aided VA, K, and mean corneal astigmatism (p < 0.0001) was noted. Mean Kmax reading reduced from 55.5 ± 5.64 (47.4–70.4) diopter (D) preoperatively to 54.41 ± 5.51 (46–68.3) D at 12 months postaccelerated CXL. Two cases had progression. Complications encountered were sterile infiltrate and persistent haze. Conclusion: Accelerated CXL is effective and efficacious in pediatric KC.

Purpose: The purpose of the study is to investigate the effects of combined 0.8% tropicamide and 5% phenylephrine on the corneal parameters using Pentacam. Methods: The study was performed on 200 eyes of 100 adult patients visiting the ophthalmology clinic for evaluation of refractive errors or cataract screening. Mydriatic drops (Tropifirin; Java, India) containing tropicamide 0.8%, phenylephrine hydrochloride 5%, and chlorbutol 0.5% (as a preservative) were instilled into the eyes of the patients three times every 10 minutes. The Pentacam was repeated after 30 minutes. The measurement data of various corneal parameters from different Pentacam displays (keratometry, pachymetry, densitometry, and Zernike analysis) was manually compiled on an Excel spreadsheet and analyzed using Statistical Package for the Social Sciences (SPSS) 20 software. Results: Analysis of Pentacam refractive maps revealed a statistically significant increase (P < 0.05) in the values of radius peripheral (cornea front), pupil center Pachymetry, pachymetry apex, thinnest location Pachymetry, and cornea volume. However, pupil dilation did not affect the Q-value (asphericity). Analysis of the densitometry values revealed significant increase in all zones. Aberrations maps revealed statistically significant increase in the value of spherical aberration after the induction of mydriasis, but the values of Trefoil 0º, Trefoil 30º, Koma 90º, and Koma 0º were not affected significantly. We did not observe any untoward effect of the drug, except transient blurring of vision. Conclusion: The current study showed that routine mydriasis in the eye clinics leads to a significant increase in various corneal parameters including corneal pachymetry, cornea densitometry, and spherical aberration as measured by Pentacam, which can influence the decision-making in the management of various corneal diseases. The ophthalmologists should be aware of these issues and make adjustments in their surgical planning accordingly.

Abstract Purpose To compare the intra-device repeatability and inter-device reproducibility between two anterior segment imaging instruments, the CASIA SS-1000 (Tomey Corp., Nagoya, Japan) and Pentacam (OCULUS, Arlington, WA) in measuring anterior segment parameters. Methods Single-center, prospective clinical trial. Participants ≥20 years of age were included. One eye was randomly selected, each imaged by three CASIA SS-1000 devices and three Pentacam devices by three different examiners. Each photographer operated a pair of devices, one CASIA SS-1000 and one Pentacam. The image order for each participant was determined by a random permutation table. Three images were taken from each device. A total of 18 images were taken for each eye. Ratios of the standard deviations, referenced as (CASIA/Pentacam), were calculated to compare the repeatability and reproducibility of the two imaging instruments. Results In all, 66 participants with a mean age of 46.4 years (±21.7) were enrolled in the study. All repeatability ratios and intra-device variability were less than 1 (anterior corneal curvature: flat = 0.86, steep = 0.85; posterior corneal curvature: flat = 0.43, steep = 0.61; and map: thinnest = 0.22; central = 0.24, 2 mm = 0.26, 4 mm = 0.27, and 6 mm = 0.30). All reproducibility ratios, which measure the inter-device variability, were less than 1 (anterior corneal curvature: flat = 0.58, steep = 0.73; posterior corneal curvature: flat = 0.25, steep = 0.31; and pachymetry map: thinnest = 0.20; central = 0.20; 2 mm = 0.20; 4 mm = 0.19; and 6 mm = 0.22). A ratio of less than 1 indicates that the CASIA SS-1000 has more consistent measurements. Conclusions The CASIA SS-1000 was found to have better repeatability and reproducibility compared to the Pentacam for both corneal curvature and pachymetry maps. This greater consistency may require further study to determine whether the decreased variability can be translated into improved clinical results.

Abstract Background To ascertain the agreement of corneal aberrations obtained from the Pentacam and the KR-1W in myopic populations and to investigate the influence of the level of myopia as well as the laterality on the agreement. Methods In this observational study, a rotating Scheimpflug camera (Pentacam AXL) and a Hartmann-Shack wavefront analyzer with Placido-disc topographer (KR-1W) were used to measure the aberrations of myopes in the anterior corneal surface by one experienced operator. All examinations were computed across a 6 mm diameter. Six subgroups were generated according to the degree of myopia (mild, moderate, and severe myopia) and the laterality of eyes (right and left eyes). Results The study included 245 eyes of 170 participants. For certain anterior corneal aberrations, statistically significant differences existed between the Pentacam and the KR-1W (all P 0.1 μm) for aberrations closely correlated with visual quality, including Z(3, ± 3), Z(3, ± 1), and Z(4,0), and almost all aberrations, indicating poor agreement. Conclusions In clinical practice, the Pentacam based on Scheimpflug technology and the KR-1W based on Placido Disc System are not interchangeable in measuring anterior corneal aberration for myopes regardless of myopia degree and the laterality, suggesting that a consistent instrument should be selected for surgical design as well as follow-up.

Abstract Background To compare the accuracy of non-contact tonometry, Pentacam, and corneal visualization Scheimpflug technology (Corvis ST) for the measurement of intraocular pressure (IOP) after small incision lenticule extraction (SMILE) or femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. Methods A total of 49 patients (98 eyes) undergoing FS-LASIK or SMILE surgery at West China Hospital, Sichuan University from January to March 2021 were enrolled in this prospective, comparative, self-controlled study. IOP values were measured with non-contact tonometer, Pentacam, and Corvis ST before surgery and 1 month after surgery. Pentacam-derived postoperative IOP values were corrected using five correction formulas (Ehlers, Shah, Dresden, Orssengo-Pye, and Kohlhaas), while Corvis ST-derived values were corrected using a single formula. Results In the SMILE group, no significant differences were observed between the IOP values corrected with the Shah formula before and after surgery (t = 0.17, P = 0.869), whereas postoperative IOP values corrected with the other formulas were significantly different from the corresponding preoperative measurements (P