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Purpose: To assess impact of tear optics on repeatability of a Scheimpflug device with a Hartmann Shack aberrometer and a ray tracing aberrometer. Methods: One hundred healthy and 100 postrefractive surgery eyes underwent dry eye evaluation including Schirmer抯 test and tear film break?up time (TBUT). They underwent optical quality analyzer (OQAS, Visio metrics S.L, Terrassa, Spain) to assess objective scatter index (OSI), three scans each on Pentacam AXL wave (OCULUS Optikgerate Gmbh, Wetzlar, Germany), iTrace (Tracey� Technologies, Texas, USA) for flat, steep keratometry, thinnest corneal thickness, root mean square higher?order aberrations (RMS HOA), RMS lower?order aberrations (LOA), spherical aberrations, RMS COMA. Repeatability of Pentacam AXL wave and iTrace in healthy and postrefractive eyes (OSI >1 vs OSI <1) was studied using within?subject standard deviation (Sw) test杛etest repeatability (TRT), coefficient of variation (COV). Results: OSI showed an inverse association with TBUT (P < 0.001). All measurements with Pentacam AXL wave with OSI < 1 had excellent repeatability, intraclass correlation coefficient (ICC) ranging from 0.88 for HOA, to 0.92 for LOA. The Sw, TRT, and COV of all aberration measurements were significantly lower (better) than those of iTrace. In eyes with OSI ?1, the repeatability with Pentacam AXL wave dropped with ICC ranging from 0.77 for HOA, to 0.84 for LOA with lower Sw, TRT, and COV of all aberration measurements as compared to iTrace. Maximum variation was seen with HOA and minimum with LOA. Conclusion: Tear optics affected repeatability of Pentacam wave and iTrace. Pentacam wave had better repeatability in eyes with a poor tear film as compared to iTrace. Thus, the tear film can impact repeatability of an instrument and it is important to assess the tear film prior to imaging patients, which can change the way we interpret and image these patients.
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@#AIM: To analyze the errors of objective visual quality after the implantation of segmented refractive multifocal intraocular lenses in patients with age-related cataract. <p>METHODS: In this retrospective study including 180 eyes of 116 patients with senile cataract, implantation of either Aspira-aA IOL or LS-313 MF30 IOL was performed in Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University. According to the implanted IOL, the patients were divided into the SIOL(Aspira-aA)group(61 patients, 96 eyes)and the MIOL(LS-313 MF30)group(55 patients, 84 eyes). Three months postoperatively, uncorrected distance visual acuity(UCDVA), best corrected distance visual acuity(BCDVA), uncorrected intermediate visual acuity(UCIVA)and uncorrected near visual acuity(UCNVA)were assessed. Total higher-order aberrations(HOAt), internal higher-order aberrations(HOAi), corneal higher-order aberrations(HOAc), spherical aberration(SA), coma aberration(CA), trefoil aberration(TA), Strehl ratio(SR), average height of modulation transfer function(MTF AvgHeight)and dysfunctional lens index(DLI)were measured by iTrace visual quality analyzer(scanning diameter 3mm)three months postoperatively. <p>RESULTS: Three months postoperatively, there was no statistically significant difference between the two groups in UCDVA and BCDVA(t=-0.789, -0.815; all P>0.05). UCIVA and UCNVA in the MIOL group were better than those in the SIOL group, with statistically significant difference(t=1.971, 3.215; all P<0.05). No statistically significant differences were observed in HOAc and spherical aberration between the two groups(t=1.126, -0.995; all P>0.05). HOAt, HOAi, coma aberration and trefoil aberration were larger in the MIOL group than those in the SIOL group(t=-2.518, -2.926, -2.859, -3.128; all P<0.05). Strehl ratio, MTF AvgHeight and DLI in the MIOL group were lower than those in the SIOL group, with statistically significant difference(t=2.8537, 2.014, 3.292; all P<0.05). The results of retinal letter, MTF AvgHeight and SR showed that HOAt and HOAi increased significantly in the MIOL group. The retinal spot diagram showed that coma aberration and trefoil aberration increased significantly with the addition of +3D spherical diopter. <p>CONCLUSION: Segmented refractive multifocal intraocular lens can provide excellent uncorrected distance, intermediate and near visual acuity. There may be errors in aberration measurement by iTrace visual quality analyzer after segmented refractive multifocal intraocular lenses implantation. The design of intraocular lens may lead to the postoperative increase in aberration and a decrease in objective visual quality.
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@#AIM: To investigate the difference and consistency among iTrace, IOL Master 700 and Pentacam HR in measuring corneal astigmatism before cataract surgery.<p>METHODS: Across-sectional study. From May 2020 to May 2021, a total of 149 cataract patients(181 eyes)were collected in our hospital. Presurgery, steep keratometry(Ks), flat keratometry(Kf), mean keratometry(Km), astigmatism magnitude(Cyl), and steep astigmatic axis values measured by the three instruments of the iTrace, IOL Master 700 and the Pentacam HR. The difference and consistency of the measurement indexes of the three instruments were analyzed.<p>RESULTS: Statistical differences existed in Ks, Kf, Km among the three instruments(<i>F</i>=4.912, 3.514, 4.873, all <i>P</i><0.05)and there was no difference in Cyl and Axis(<i>F</i>=0.523, 0.128, all <i>P</i>>0.05). Bland-Altman analysis showed the outcomes revealed that the Ks and Kf measured by iTrace and the other two instruments have poor consistency, and the consistency of Cyl and Axis was good. But the difference of Axis is not clinically acceptable. There were no statistically differences between the iTrace and the other two devices among the low astigmatism(50 eyes), moderate astigmatism(34 eyes)and high astigmatism(18 eyes)groups(all <i>P</i>>0.05). <p>CONCLUSION: In the preoperative measurement of cataract patients except for the good consistency of astigmatism, the iTrace, IOL Master 700 and Pentacam HR showed different Ks and Kf, and the Axis difference exceeded the clinically acceptable range, especially in the highly astigmatism group. The measurement of corneal astigmatism before cataract surgery should be evaluated by multiple measurement methods and make comprehensive planning for the surgical plan.
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@#AIM: To compare the differences of corneal curvature and astigmatism measured by Pentacam, IOL Master and iTrace of cataract patients.<p>METHODS:In this prospective clinical trial,68 cataract patients(82 eyes)received treatment at the ophthalmology department of our hospital. In the treatment process, used the IOL Master, Pentacam and iTrace to measure the patient's corneal curvature(K1, K2, Km)and astigmatism(J0, J45). The difference, correlation and consistence among three instruments were analysed. <p>RESULTS: Differences analysis showed that in the measurement of K1, K2, Km, there was no difference among Pentacam, IOL Master and iTrace(<i>P</i>>0.05). Pearson correlation analysis showed that K1, K2, Km were highly correlated among three instruments(|<i>r</i>|>0.5, <i>P</i><0.01). J0, J45 were moderately correlated between IOL Master and Pentacam, so as IOL Master and iTrace(0.3<|<i>r</i>|<0.5, <i>P</i><0.01). J0, J45 were weakly correlated between Pentacam and iTrace(0.1<|<i>r</i>|<0.3, <i>P</i><0.05). The Bland-Altman showed that the corneal curvature and astigmatism vectors examined by these three devices had non-comparable results.<p>CONCLUSION: K1, K2, Km, J0, J45 were correlated among the three devices, but the three devices all cannot directly interchanged, targeted selection is required for the measuring the corneal curvature and astigmatism by these three different instruments in the actual clinical process.
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Purpose: To compare the ocular higher order aberrations (HOAs) for the physiologic pupil size in amblyopic and non-amblyopic eyes of patients with anisometropic amblyopia in pediatric age group. Methods: Children between 5 and 15 years age having treatment naïve anisometropic amblyopia; after a detailed examination by a pediatric ophthalmologist; underwent assessment of wavefront aberrations for both amblyopic and non-amblyopic eyes at their physiologic pupil sizes using i-Trace ray tracing wavefront aberrometer. The axial lengths were also measured using IOL Master 500. The RMS values of the total ocular higher order aberrations (HOAs) and those arising from internal and corneal components of the two eyes were tabulated and compared to look for differences. Comparison of total ocular aberrations for pre-determined refractive error groups was also done for amblyopic and non-amblyopic eyes separately. Results: Eighty-eight eyes of 44 subjects were included for analysis. Mean pupil size was comparable in between amblyopic and non-amblyopic eyes (3.98 mm vs. 4.07 mm, P = 0.346). The mean axial lengths of the two eyes were comparable (amblyopic eyes 23.13 mm vs. non-amblyopic eyes 22.88 mm, P = 0.419). Significant differences in total HOAs and those arising from the internal optics (except spherical aberrations) of the eye were noted between the two eyes. There were no differences in the corneal HOAs. The total HOAs were comparable amongst the various refractive error groups for amblyopic and non-amblyopic eyes individually. Conclusion: There are significant differences in ocular HOAs between amblyopic and non-amblyopic eyes in children with anisometropic amblyopia.
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@#AIM: To investigate the difference and consistency between iTrace and Pentacam in measuring corneal spherical aberration(SphA)and curvature.<p>METHODS: The corneal spherical aberration and curvature were measured by iTrace and Pentacam in 63 cases(125 eyes)separately, and the SphA, the minimum corneal curvature(K1), maximum corneal curvature(K2)and corneal astigmatism(CA)were recorded respectively. Paired <i>t</i>-test was used for statistical analysis of econometric data, Bland-Altman analysis was used to evaluate the consistency of measurement results(SphA and curvature)measured by iTrace and Pentacam.<p>RESULTS: The measurement result of SphA, K1, K2 and CA were(0.230±0.086)μm,(43.01±2.38)D,(44.08±2.48)D and(1.03±0.57)D measured by iTrace, and(0.247±0.114)μm,(42.88±1.44)D,(43.86±1.51)D and(1.07±0.62)D measured by Pentacam, there was no significant difference of the measurement result of SphA, K1, K2 and CA between iTrace and Pentacam(<i>P</i>>0.05). The difference of SphA, K1, K2 and CA between iTrace and Pentacam was close to 0, the consistency was good because of the narrow 95% confidence interval.<p>CONCLUSION:There is no significant difference of the measurement result between iTrace and Pentacam, the consistency is good, and both can be used as a mutual reference in clinical.
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Objective To assess the value of dysfunctional lens index (DLI) measured by iTrace visual function analyzer in the diagnosis of age-related cataract and phacoemulsification.Methods A prospective study was performed.One hundred and thirty-two cases (132 eyes) with age-related cataract were recruited from November 2016 to April 2017 in Jinan Mingshui Eye Hospital.The subjects were divided into nuclear group (39 eyes),cortical group (48 eyes) and posterior subcapsular group (45 eyes) according to the type of cataract.The preoperative best corrected distant visual acuity (LogMAR vision) were recorded.The opacification degrees of lens were determined by LOCS Ⅲ grading system.The DLI value was measured by iTrace visual function analyzer.All patients underwent traditional phacoemulsification,and cumulative dissipated energy (CDE) values were recorded.The correlation between various parameters was evaluated using Pearson correlation coefficients.Results In nuclear group,the DLI was negatively correlated with LogMAR vision,nuclear opacity (NO) scores,nuclear color (NC) scores and CDE (r =-0.593,-0.618,-0.606,-0.524;all at P＜0.01).In cortical group and posterior subcapsular group,the DLI was negatively correlated with LogMAR and LOCS Ⅲ scores (cortical group:r =-0.653,-0.614;both at P＜0.01;posterior subcapsular group:r =-0.583,-0.577;both at P＜ 0.01),but no significant correlation was observed between CDE and DLI.The CDE showed an obvious positive linear correlation with LogMAR and LOCS Ⅲ scores in the 3 groups.Conclusions For different patterns of age-related cataract,the DLI shows good correlations with LogMAR and LOCS Ⅲ scores,and can reflect the degrees of visual impairment and lens opacity.The DLI can provide references for energy use in phacoemulsification of nuclear cataract.
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Objective To explore the distribution of the kappa angles in population of Tianjin,China and the differences in kappa angle measured by iTrace and Pentacam.Methods A retrospective research was conducted.The kappa angle of 4815 patients (4815 eyes) and kappa angle was measured and recorded through iTrace from June 2014 to December 2016 in Tianjin Medical University Eye hospital and meanwhile,the kappa angle of 10α1 eyes selected from the total sample was also measured with pencatam.Results The kappa angle was (0.47 ± 0.48) mm,and patients with kappa angle ＜ 0.50 mum accounted for 70.07％.There was no significant difference in kappa angle of different genders (P =0.090).Right eyes had larger kappa anger than left eyes,approaching significant difference (P =0.000).Kappa anger was slightly correlated with age (r =0.129,P ＜ 0.05).And kappa angle measured by iTrace was significantly smaller than that measured by Pentacam (P =0.000).Conclusion The kappa angle in the population is non-normal and most of them are less than 0.5 mm.There is significant difference between the kappa angle measured by iTrace and pentacam.
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Objective To analyze the reproducibility of keratometry and astigmatism measured by the VERION Digital Guidance System and the comparability of VERION with iTrace,Lenstar LS900 and manual keratometer.Methods The keratometry of 62 cataract patients were measured using four different devices.The steep keratometry (Ks),flat keratometry (Kf),astigmatic magnitude,astigmatic axis,cylinder at 0-degree meridian (vector component,J0) and cylinder at 45-degree meridian (vector component,J45) from each machine were recorded and analyzed.The three repeated measurements and the results of VERION system with other three devices were compared to analyze the reproducibility and comparability of VERION system.Results Reproducibility:Intraclass correlation coefficients and Cronbach's alpha values were higher than 0.9 for Ks,Kf,astigmatic magnitude,astigmatic axis,J0 and J45 measured by the VERION system (all P ＜ 0.001).Comparability:The results of Ks and magnitude of astigmatism of VERION were larger than the iTrace (all P ＜ 0.05) in the paired-samples t test.There was no statistical difference for the rest of parameters (all P ＞ 0.05).The Bland-Altman graphs revealed the 95％ limits of agreement (LOA) of J0,J45 and the astigmatic axis between VERION and iTrace were (-0.31-0.35) D,(-0.25-0.31) D and-13.5 °-12.3 °,respectively;There was no statistical differences for all parameters except for J45 in the paired-samples t test between the VERION and Lenstar LS900 (all P ＞ 0.05).The Bland-Altman graphs revealed the 95％ LOA of J0,J45 and the astigmatic axis were (-0.25-0.31)D,(-0.27-0.36) D and-13.5°-11.0°,respectively;There were statistical differences for the results of Kf and magnitude of astigmatism between the VERION and manual keratometer (all P ＜ 0.05).The Bland-Altman graphs revealed the 95％ LOA of J0,J45 and the astigmatic axis between VERION and manual keratometer were (-0.38-0.35) D,(-0.41-0.42) D,-12.6°-16.4°,respectively.Conclusion The VERION system is a reliable system for the measurement of keratometry and astigmatism.The keratometry and astigmatic magnitude of the VERION system have a good agreement with the iTrace,Lenstar LS900 and manual keratometer.However,the astigmatic axis measurements are significantly different among the four devices.
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Objective To research and evaluate measuring Toric intraocular lens (Toric IOL) alignment by iTrace aberration without mydriasis.Methods Forty-five eyes of 35 patients underwent phacoemulsification in Tianjin Medical University Eye Hospital from June 2015 to February 2016 were enrolled.Follow-up and iTrace aberration examination were performed at postoperative 1 week.The internal optics aberration astigmatism axis was transformed into postoperative Toric IOL alignment.The result and the Toric IOL alignment measured by tradition slitlamp method were compared by linear correlation and difference.Results At postoperative 1 week,the uncorrected distant visual acuity and corrected distant visual acuity were (0.19 ± 0.12)LogMAR and (0.10 ±0.09) LogMAR.The UCVA was 20/40 or better in 42 eyes (93.3％).The mean IOL misalignment measured by slitlamp was (3.13 ± 2.86) degrees (ranged 0-9 degrees) and by the iTrace aberration was (4.44 ± 3.42) degrees(ranged 0-13 degrees),there was statistical significant difference (t =-2.321,P =0.025).The mean difference in the error of the Toric intraocular lens alignment measured by iTrace aberration and the slitlamp was (3.67 ± 3.59) degrees (ranged 0-14 degrees).The results showed that there was less than 5 degrees of difference between the two methods in 32 eyes (71.1％),locate 5 to 10 degrees in 9 eyes (20％),more than 10 degrees in 4 eyes (8.9％).The correlation between the 2 methods showed significant linear relationship (r =0.926,P ＜ 0.01).Conclusion Using iTrace aberration can accurately measure Toric intraocular lens alignment without mydriasis,the result has some reference value.
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PURPOSE: To predict the accuracy of preoperative refractive error measurement methods in wavefront-guided laser-assisted subepithelial keratectomy (LASEK) surgery and to formulate a nomogram for satisfactory surgical results. METHODS: The medical records of 30 patients (57 eyes) who had undergone wavefront-guided LASEK were reviewed. The ideal surgical ablation amount was defined as the sum of the real surgical ablation amount and the remaining refractive errors. Comparison between the ideal surgical ablation amount and preoperative refractive errors was made using autorefraction, manifest refraction, cycloplegic refraction, postcycloplegic refraction, wavescan, and iTrace aberrometer measurements. RESULTS: The refractive errors measured by the postcycloplegic refraction showed the closest relation with the ideal surgical amount, and the nomogram based on this refraction correlated statistically significantly with the ideal surgical ablation amount. The refractive error using the wavescan also showed more accurate refractive measurements than the autorefractor and iTrace aberrometer. CONCLUSIONS: Accurate manifest refraction immediately before surgery is the most important in determining the ablation amount. Additionally, the refractive errors measured with the wavescan, which is an aberrometer used for wavefront-guided LASEK, showed a minimal amount of errors. After reviewing the results, the nomogram based on these 2 methods can be concluded to possibly contribute to an increase in the accuracy of surgery.
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Humans , Keratectomy, Subepithelial, Laser-Assisted , Medical Records , Nomograms , Refractive ErrorsABSTRACT
PURPOSE: To compare and evaluate the total and internal aberrations measured by two aberrometers: the laser ray tracing aberrometer (iTrace, Tracey Technology) and the automatic retinoscope aberrometer (OPD Scan, Nidek). METHODS: A total of 54 healthy eyes were enrolled in the study. Following pupil dilation, aberrations were measured with the iTrace and OPD Scan. We compared the aberrations obtained from measurements obtained at pupillary diameters of 4 mm and 6 mm with the OPD Scan and iTrace. Aberrations of internal optics and total aberrations were compared for the two aberrometers. For each aberrometer and each eye, the averaged Zernike data were used to calculate various root-mean-square (RMS) data. These parameters, together with the refractive parameters, were then analyzed and complimented by paired t-tests. RESULTS: At a pupil diameter of 4 mm, the number of total aberrations in the entire eye showed significant differences for the mean values of spherical aberrations (Z4,0) obtained with the OPD Scan and iTrace aberrometers (p=0.001). Aberrations of the internal optics showed significant differences in the mean values of total RMS, coma (Z3,-1), and trefoil (Z3,3) between the iTrace and OPD Scan (p<0.001, p=0.01, p<0.001) for the same pupil diameter of 4 mm. At a pupil diameter of 6 mm, the two instruments showed a similar number of total aberrations. Aberrations of the internal optics showed significant differences in the mean values of total RMS, spherical aberration (Z4,0), and coma (Z3,-1) between the two devices (p<0.001, p=0.01, p<0.001). CONCLUSIONS: The iTrace and OPD Scan showed the largest number of differences for aberrations of internal optics rather than total aberrations for both pupil diameters. These results suggest that in healthy eyes, the two aberrometers may vary in some details. The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm.