- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Dynamic Scheimpflug Ocular Biomechanical Parameters in Healthy and Medically Controlled Glaucoma Eyes
摘要： To evaluate the relationship between biomechanical parameters measured with a dynamic Scheimpflug analyzer and glaucoma. Cross-sectional observational data of 47 eyes of 47 consecutive subjects with medically controlled primary open-angle glaucoma and 75 eyes of 75 healthy subjects examined with a dynamic Scheimpflug analyzer (Corvis ST) were retrospectively investigated. Eight biomechanical parameters were compared between eyes with and without glaucoma using multivariable models adjusting for intraocular pressure (IOP), central corneal thickness, age, and axial length. In multivariable models, glaucoma was negatively correlated with A1 time (P < 0.001, coefficient = ?0.5535), A2 time (P = 0.008, coefficient = ?0.1509), radius (P = 0.011, coefficient = ?0.4034), and whole eye movement (P < 0.001, coefficient = ?0.0622). Negative correlation between glaucoma and 3 parameters (A1 time, A2 time, and radius) consistently indicate larger deformability of the cornea and negative correlation between glaucoma and whole eye movement indicate smaller eye movement, in glaucoma eyes. There were significant correlations of many biomechanical parameters with other baseline factors (8 parameters with IOP, 2 with central corneal thickness, 4 with age, and 7 with axial length). Eyes with medically controlled glaucoma were more deformable than healthy eyes, which may increase the risk of optic nerve damage through an underestimation of IOP and biomechanical vulnerability of the globe. Many parameters showed a significant correlation with baseline factors, suggesting the importance of adjustment for these confounding factors when evaluating the correlation between biomechanical parameters and ocular diseases. These results suggest the relevance of measuring biomechanical properties of glaucoma eyes for accurate IOP measurement and risk assessment.
关键词： intraocular pressure,glaucoma,cornea,biomechanics,Scheimpflug photography
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Atmospheric CO <sub/>2</sub> -Detection Via Scheimpflug DIAL Employing a Simple Fiber Amplifier
摘要： The ever-increasing worldwide environmental awareness has prompted much effort to minimize humanity’s ecological footprint. This has led to increased demands for reliable technologies for assessing the current situation as well as the efficiency of new policies and interventions. In particular, CO2-monitoring has attracted lots of attention as CO2 is the greenhouse gas that is emitted in the largest quantities. Differential absorption light detection and ranging (DIAL) is a well-established method for measuring the atmospheric CO2-concentration. Conventional implementations of this method rely on tunable pulsed laser sources whose back-scattering at different distances are compared for different wavelengths, corresponding to being on and off the CO2-resonances, to calculate the concentration along the measured path. Integrating these types of laser sources with DIAL systems have proven to be complicated and often suffer from instabilities. Therefore, a continuous-wave DIAL (CW-DIAL) scheme was recently proposed that relates signals at different distances to different points on a detector by using a Scheimpflug configuration. This technique relies on a rapidly tunable, narrow-linewidth source to resolve individual CO2-absorption lines, making distributed feedback laser diodes (DFB) ideal. However, they lack the necessary power levels for ranging over relevant distances, usually in the km-range. We therefore designed a fiber amplifier, based on an 11 m Er-/Yb-doped fiber, to boost the power level to about 1.3 W. The output was then expanded by a telescope and the back-scattered signal was collected by a second telescope, as schematically illustrated in Fig. 1 (a). The wavelengths could be tuned about 3 nm with a 35 dB signal-to-noise ratio, as shown in Fig. 1 (b), by adjusting the driving current to the DFB, while keeping a linewidth of about 3 MHz –well below the CO2-linewidth around 1 GHz at normal pressure. The system was used to measure the atmospheric CO2-concentration above the city of Lund, Sweden, over a 15 hour period. Using the backscattered data from 48 different wavelengths over the R14, R16 and R18 absorption peaks, the range-resolved concentration, illustrated in Fig. 1 (c) with a 500 m bin discretization, could be retrieved. The large increase in the error at the final concentration bin is related to the nonlinear range mapping onto the detector, i.e. fewer pixels for greater distances. Regardless, these results show that our simple fiber source already fulfills the necessary requirements for field application of CW-DIAL.
关键词： atmospheric CO2-concentration,DIAL,fiber amplifier,Scheimpflug configuration,CO2-monitoring
更新于2025-09-11 14:15:04
-
Study and characterization of morphogeometric parameters to assist diagnosis of keratoconus
摘要： Background: In case of significant imperfections on the cornea, data acquisition is difficult and a significant level of missing data could require the interpolation of important areas of the cornea, resulting in a very ambiguous model. The development of methods to define in vivo customised geometric properties of the cornea based only on real raw data is extremely useful to diagnose and assess the progression of diseases directly related to the corneal architecture. The present work tries to improve the prognostic of corneal ectasia creating a 3D customised model of the cornea and analysing different geometric variables from this model to determine which variables or combination of them could be defined as an indicator of susceptibility to develop keratoconus. Methods: A corneal geometric reconstruction was performed using zonal functions and retrospective Scheimpflug tomography data from 187 eyes of 187 patients. Morphology of healthy and keratoconic corneas was characterized by means of geometric variables. The performance of these variables as predictors of a new geometric marker was assessed and their correlations were analysed. Results: The more representative variable to classify the corneal anomalies related to keratoconus was posterior apex deviation (area under receiver operating characteristic curve > 0.899; p < 0.0001). However, the strongest correlations in both healthy and pathological corneas were provided by the metrics directly related to the thickness, as deviations of the anterior/posterior minimum thickness points. Conclusions: The presented morphogeometric approach based on the analysis and custom geometric modelling of the cornea demonstrates to be useful for the characterization and diagnosis of keratoconus disease, stating that geometrical deformation is an effective marker of the ectatic disease’s progression.
关键词： Scheimpflug,Keratoconus,Virtual model,CAD,Surface reconstruction
更新于2025-09-10 09:29:36
-
Intrasession repeatability of refractive and ocular aberrometric measurements obtained using a multidiagnostic device in healthy eyes
摘要： Purpose: To evaluate the intrasession repeatability of refractive and ocular aberrometric measurements obtained using a new multidiagnostic device in healthy eyes. Patients and methods: A total of 107 eyes of 107 patients, age ranging from 23 to 65 years, were enrolled in this study. A complete eye examination was performed in all eyes, including an ocular examination using the VX120 system. Three consecutive measurements were obtained using this device to assess the intrasession repeatability of different refractive and ocular aberrometric parameters. The within-subject standard deviation (Sw), intrasubject precision (1.96×Sw), and intraclass correlation coefficient (ICC) were calculated. Results: Sw and intrasubject precision for refractive data were below 0.12 and 0.20 D, respectively, in all cases. The ICC ranged from 0.947 for the J45 power vector component to 0.997 for the sphere. Concerning aberrometric measurements Sw and intrasubject precision values were below 0.05 μm and 0.10 μm, respectively. Likewise, the ICC ranged from 0.805 for the quadrafoil root mean square to 0.954 for the primary spherical aberration. Poor correlations were found between most of the refractive parameters and their Sw (–0.033≤r≤0.053, p≥0.064). Moderate and significant positive correlations were found between the magnitude of the aberrometric parameters evaluated and their Sw (r≥0.446, p<0.001). Conclusion: The new multidiagnostic device evaluated is able to provide consistent measurements of refraction and ocular aberrations in healthy eyes. Future studies should confirm if this consistency is also observed in highly aberrated eyes.
关键词： ocular aberrations,intrasession repeatability,refraction,VX120 system,Scheimpflug imaging
更新于2025-09-09 09:28:46
-
Evaluation of corneal optical properties in subjects wearing hydrogel etafilcon A contact lenses and the effect of administering mannitol-enriched sodium hyaluronate ophthalmic solution
摘要： The purpose of this study was to evaluate the effect of daily administration of mannitol-enriched sodium hyaluronate ophthalmic solution on the corneal optical properties of subjects wearing low Dk hydrogel (etafilcon A) contact lenses (CLs). Forty-five subjects wearing etafilcon A CLs daily for more than 6 months were recruited into this pilot study. Fifteen of the subjects administered a 10% mannitol-enriched 0.05% sodium hyaluronate solution (study group) once daily and 30 subjects did not administer any ophthalmic solution (control group). The subjects were examined at baseline and one month after recruitment. Changes in central corneal thickness (CCT) and corneal light backscatter were evaluated by Scheimpflug imaging (Pentacam HR). Changes in corneal total high-order aberration, corneal spherical aberration, coma, and trefoil were evaluated using the OPD scan II. At one month, corneal light backscatter decreased significantly in the study group (#18.30 arbitrary units; P,0.05) and this was highly correlated with a decrease in CCT (R=0.81; P=0.04). The decrease in corneal total high-order aberration, spherical aberration, and coma was significantly higher in the study group than in the control group (P,0.05). No changes in corneal light backscatter or CCT were found in the control group during follow-up. Once-daily administration of a mannitol-enriched lubricant ophthalmic solution was effective for improving the corneal optical quality and reducing corneal swelling in subjects wearing low Dk hydrogel (etafilcon A) CLs during one month follow-up.
关键词： Scheimpflug imaging,corneal optical quality,corneal backscattering,corneal high-order aberrations,contact lens,hypertonic lubricant solution
更新于2025-09-09 09:28:46
-
Corneal changes after collagen crosslinking for keratoconus using dual scheimpflug imaging
摘要： Purpose: To evaluate corneal changes after collagen crosslinking (CXL) therapy for keratoconus (KCN) using the Galilei dual Scheimpflug analyzer. Methods: This prospective, nonrandomized clinical study included 35 eyes of 32 keratoconus patients who had undergone CXL. The eyes were saturated with riboflavin solution and were subjected for 30 minutes to ultraviolet-A (UV-A) light with irradiance of 3 mW/cm2. Effectiveness of the treatment was assessed by measuring uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest cylinder/sphere, keratometry, pachymetry, posterior and anterior elevations by the Galilei dual Scheimpflug analyzer. Prior to treatment and 8 months after therapy, Scheimpflug analysis was performed using the Galilei system. The four sets of data including keratometry values, pachymetry, elevation parameters and surface indices were statistically analyzed and compared. Results: Mean patient age was 22.3 ± 3.8 years and mean postoperative follow-up was 8.1 ± 3.2 months. There was a significant increase in UCVA (0.54 ± 0.35 Log MAR preoperatively to 0.49 ± 0.34 LogMAR postoperatively, P = 0.01) and BCVA (0.21 ± 0.19 Log MAR preoperatively to 0.16 ± 0.17 LogMAR postoperatively, P = 0.01). Mean cycloplegic spherical equivalent refractive error was ?4.13 ± 2.65 Diopter (D) preoperatively and ? 4.67 ± 2.96 D postoperatively (P < 0.001). During the follow-up period, no significant difference was observed in pachymetric and elevation data postoperatively. Conclusion: Corneal stabilization could be achieved by collagen crosslinking therapy for keratoconus in terms of corneal thickness, keratometry values, elevation parameters and surface indices.
关键词： Keratoconus,Galilei Dual Scheimpflug Analyzer,Collagen Crosslinking
更新于2025-09-04 15:30:14
-
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
-
Intraocular Lens Power Calculations Using Dual Scheimpflug Analyzer
摘要： Purpose: To investigate the accuracy of intraocular lens power calculations using simulated keratometry (simK) of dual Scheimpflug analyzer and 5 types of formulas in cataract patients. Methods: The keratometry (K), axial length (AXL) and anterior chamber depth (ACD) were measured using ultrasound biometry (USB) combined with auto-keratometry (Auto-K), parital coherence interferometry (PCI; IOL master?) and dual Scheimpflug analyzer (DSA; Galilei?) in 39 eyes of 39 patients. Predicted refraction was calculated using Auto-K, mean K of PCI, and simK and total corneal power (TCP) of DSA in the Sanders-Retzlaff-Kraff (SRK-T) formula. The SRK-II, SRK-T, Holladay II, Haigis, and Hoffer-Q formula were used to calculate predicted refraction with the simK of DSA and AXL of USB. Manifest refraction, mean numerical error (MNE) and mean absolute error were evaluated 1, 3 and 6 months after cataract surgery. Results: TCP of DSA was lower compared with other keratometric values (p < 0.05). The MNE was not different among Auto-K, mean K and simK. The MNE using TCP was larger compared with Auto-K, mean K and simK at 1 month after surgery (p < 0.05). There was a difference in MNE between simK and TCP of DSA at 6 months after surgery (p < 0.05). The MNE of SRK-T formula was the smallest in the intraocular lens (IOL) power calculation using the simK of DSA. Conclusions: We suggest using IOL power calculations with simK of DSA and SRK-T formula rather than TCP of DSA in cataract patients with normal corneas.
关键词： Dual Scheimpflug analyger,Intraocular lens power calculation,Cataract surgery
更新于2025-09-04 15:30:14