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Comparison of Laser Platform Estimation and Objective Measurement of Maximum Ablation Depth Using Scheimpflug Pachymetry in Myopic Femtosecond Laser In Situ Keratomileusis
摘要： To compare the preoperative estimation of maximum ablation depth provided by the laser platform with objective measurement using Scheimpflug pachymetry in myopic femtosecond laser-assisted in situ keratomileusis (FS-LASIK). This is a prospective study carried out at the Rothschild Foundation, Paris, France. In 89 consecutive myopic eyes (45 patients) treated with FS-LASIK, the maximum ablation depth was calculated by measuring the difference between preoperative and 3-month postoperative measurements in central corneal thickness using Scheimpflug pachymetry (Pentacam HR; Oculus Optikger?te, Wetzlar, Germany). These values were compared with the preoperative estimation of the maximum ablation depth provided by the laser platform, without nomogram adjustment. We found a strong linear correlation between laser platform estimation of maximum ablation depth and Scheimpflug pachymetry (P , 0.00001). The mean ablation depth measured using Scheimpflug pachymetry was greater than that predicted by the laser platform, with a mean overall difference of 2.15 mm (P , 0.05). Subgroup analysis revealed a difference in ablation depth measurements of 7.1 mm in the high myopia subgroup, which was the only subgroup where the difference remained statistically significant. In myopic FS-LASIK, laser platform estimation of maximum ablation depth correlates well with measurement of maximum ablation depth using Scheimpflug pachymetry and therefore can be used safely.
关键词： LASIK,ablation depth,Pentacam,Scheimpflug pachymetry
更新于2025-09-12 10:27:22
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Validation of the SToP formula for calculating intraocular lens power in eyes with previous myopic excimer laser surgery
摘要： To validate the accuracy of the SToP formula for calculating the intraocular lens (IOL) power from measurements obtained with a rotating Scheimpflug camera (Pentacam) in eyes with previous myopic excimer laser surgery.
关键词： myopic excimer laser surgery,Scheimpflug camera,Pentacam,intraocular lens power,SToP formula
更新于2025-09-12 10:27:22
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Comparison of Different Corneal Power Readings From Pentacam in Post-laser In Situ Keratomileusis Eyes
摘要： To compare the various Pentacam-measured K-readings with the clinical history method (CHM) in eyes that have undergone myopic laser in situ keratomileusis (LASIK). Methods: In this prospective study, Pentacam examination was performed in 71 eyes 1 month after myopic LASIK. The true net power (TNP) 4 mm, total corneal refractive power (TCRP) 4 mm, equivalent K-reading (EKR) 4.0 mm, and EKR 4.5 mm obtained from the same scan were compared with the K derived from CHM. Results: The average baseline spherical equivalence was 25.4462.38 D. the mean KCHM was 37.6762.13 D, TCRP4mm was After LASIK, 37.1461.79 D, TNP4mm was 36.8861.76 D, EKR4.0mm was 37.5861.94 D, and EKR4.5mm was 37.5161.94 D. TCRP4mm, TNP4mm, and EKR4.5mm showed a statistically signi?cant deviation from the KCHM, with the mean error being 0.53 D, 0.79 D, and 0.16 D, respectively (P,0.05). Only the EKR4.0mm showed no statistically signi?cant difference from the KCHM (mean error 0.09 D, P?0.23). The EKR4.0mm also had the narrowest 95% limits of agreement (LoA) (21.10 to +1.28 D), whereas both TCRP4mm and TNP4mm had a wider LoA (20.88 to +1.95 D and 20.62 to +2.20 D, respectively). All four Pentacam K-readings had a strong and statistically signi?cant correlation with the KCHM. Conclusions: Using the CHM as reference, the EKR4.0mm demonstrated the closest agreement when compared with the EKR4.5mm, TNP4mm, and TCRP4mm obtained from the same scan.
关键词： surgery,Scheimp?ug imaging,Refractive,Cataract,Corneal power,Pentacam,Biometry
更新于2025-09-12 10:27:22
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Comparison of keratometric and pachymetric parameters with Scheimpflug imaging in normal and keratoconic Asian eyes
摘要： Purpose: To evaluate the keratometric and pachymetric parameters of keratoconic corneas of Asian eyes with the Scheimpflug imaging camera. Patients and methods: This is a cross-sectional study of 22 eyes with Amsler-Krumeich stage 1 keratoconus and 48 eyes from normal subjects conducted in a tertiary eye hospital. A rotating Scheimpflug imaging system, the Pentacam, was used to evaluate all eyes for tomographic parameters, as well as pachymetric progression indices (PPI) and Ambrósio relational thickness (ART). Results: All PPI and ART parameter values were significantly different between study and control groups. Cornea minimum radius of curvature, absolute distance from corneal apex to thinnest location, as well as the distance from corneal apex to thinnest location in Y-axis also demonstrated statistically significant differences. The mean ART values for keratoconus eyes were 241 μm (ART-maximum) and 352 μm (ART-average), falling within previously reported best cutoff values for detecting keratoconus. On receiver operating characteristics curve analysis, the area under the curve values were highest for PPI and ART parameters. Conclusion: There are significant differences in tomographic parameters between stage 1 keratoconic and normal Asian eyes. Pachymetric indices such as the PPI and the ART index can serve as additional tools in differentiating keratoconic from normal eyes. The findings validate the usefulness of the ART in identifying keratoconic eyes in Asians.
关键词： corneal tomography,keratoconus,pentacam,Ambrósio relational thickness
更新于2025-09-09 09:28:46
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Comparison of Anterior Segment Measurements between Scheimpflug Camera and New Module of Optical Coherence Tomography
摘要： Purpose: We compared the anterior segment measurements using a Scheimpflug camera (Pentacam? [Oculus Inc., Wetzlar, Germany]) and a new anterior segment module of optical coherence tomography (Cirrus HD-OCT 5000? [Carl Zeiss Meditec, Dublin, CA, USA]). Methods: Anterior segment measurements were evaluated in 47 eyes of 26 patients who visited for the purpose of cataract surgery. Measurements of the central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA; nasal and temporal side), and angle to angle distance (ATA) were compared between the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000?. Results: The mean CCTs measured by the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000? were 561.68 ± 31.35 μm and 559.04 ± 36.43 μm, respectively. There was no statistically significant difference (p = 0.387) and high correlations in the results using the two methods (r = 0.824, p < 0.001). The mean ACD measurements using the Pentacam? and Cirrus HD-OCT 5000? were 2.70 ± 0.44 mm and 2.68 ± 0.42 mm, respectively. The measurements were strongly correlated (r = 0.981, p < 0.001) without a statistically significant difference (p = 0.091). The measurements of ACA (nasal and temporal side) and ATA did not differ significantly different between the two methods (p = 0.109, p = 0.153, p = 0.322, respectively). High correlations were observed between the two methods (r = 0.944, r = 0.951, r = 0.955, respectively; p < 0.001 in all groups). Conclusions: There was no significant difference between the CCT, ACD, ACA, and ATA measured by the Pentacam? and the new anterior segment module of the Cirrus HD-OCT 5000? in adult patients. However, there was a low degree of agreement for the CCT. The measurements of ACD, ACA, and ATA can therefore be considered interchangeable when used clinically.
关键词： Pentacam?,Anterior chamber depth,Cirrus HD-OCT?,Anterior chamber angle,Central corneal thickness
更新于2025-09-09 09:28:46
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Objective Clinical Evaluation of Ocular Optical Instrument According to the Type of Lens Opacity
摘要： To investigate the results using the OQAS and the Pentacam in cataract patients classified according to the type of lens opacity. Methods: The present study included 124 eyes of 92 patients who had cataract surgery at Seoul St. Mary’s Hospital from December 2011 to January 2012 and were classified into nuclear, cortical, and posterior subcapsular cataract patients. The lens opacity was determined with OSI, MTF, Strehl ratio, width 10%, width 50% and the opacity of Scheimpflug image by the OQAS and the Pentacam. Additionally, the correlation between subjective cataract classification and objective opacity value was analyzed. Results: The nuclear cataract group showed a 6.40 ± 2.41 OSI value and had high opacity. The cortical cataract group showed the highest MTF cut-off value (12.02 ± 6.19 C/deg). When evaluating Pentacam results, the posterior subcapsular cataract group had the lowest average level of lens opacity (9.12 ± 1.08) followed by in increasing order, the cortical cataract group (9.79 ± 1.67) and the nuclear cataract group (11.08 ± 1.84). The results were statistically significant (p < 0.001). The OSI value of the OQAS was significantly correlated with nuclear and posterior opacity (p = 0.049, p = 0.039, respectively) except cortical opacity (p = 0.781). MTF and nuclear opacity showed statistically significant correlation and the lens opacity of Pentacam was correlated with nuclear and posterior opacities. In cortical cataract with severe peripheral opacity, the cortical opacity showed significant correlation with Maximum. Conclusions: The OQAS and Pentacam results showed high correlation with the nuclear and posterior opacities which can be useful for cataract surgery.
关键词： OQAS,MTF,Cataract,Pentacam,OSI
更新于2025-09-04 15:30:14
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Comparison of Keratometry and Corneal Higher Order Aberrations between Scout Videokeratoscope and Pentacam Scheimpflug Camera
摘要： Purpose: To investigate the correlations of keratometry and corneal high order aberrations (HOAs) between the Keratron Scout videokeratoscope and the Pentacam HR Scheimpflug camera. Methods: From December 2012 to February 2013, keratometry and corneal HOAs were determined using the Keratron Scout videokeratoscope and Pentacam HR Scheimpflug camera in 23 healthy individuals (46 eyes). Results: Average keratometry showed high correlation with 95% confidence interval -0.155 ± 0.37 between the Keratron Scout and Pentacam HR. When comparing HOAs of the Keratron Scout and total corneal HOAs of Pentacam HR, total root-mean-square (RMS), and spherical aberration were positively correlated between the 2 devices (r = 0.67, p < 0.001 and r = 0.74, p < 0.001, respectively). When comparing HOAs of Keratron Scout and anterior corneal HOAs of Pentacam HR, total RMS, spherical aberration and coma were positively correlated between the 2 devices (r = 0.62, p < 0.001, r = 0.81, p < 0.001, and r = 0.52, p = 0.047, respectively). Conclusions: Although the 2 devices are based upon different principles, the Keratron Scout videokeratoscope and Pentacam HR Scheimpflug camera showed positive correlations in keratometry, total RMS, spherical aberration, and coma. Both devices may be useful for clinical applications.
关键词： Pentacam HR Scheimpflug camera,Spherical aberration,Keratometry,Keratron Scout videokeratoscope,Higher order aberrations
更新于2025-09-04 15:30:14