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AIM: To provide guidance for more accurate measurement of axial length(AL)of difficult measuring eyes by comparing the differences in the AL of the patient's difficult measuring eye with three methods of the sitting position, supine position A-scan and Lenstar 900(Lenstar, LS900). METHODS: Clinical case-control study. We selected 102 cases(102 eyes)including cataract patients with combined silicone oil filled, vitreous hemorrhage or retinal detachment and patients with dislocation of the lens or IOL in Zhengzhou Second Hospital from May 2019 to September 2020. AL were measured using LS900 and A-scan on sitting position and supine position respectively, and the results of the three methods were statistically analyzed.RESULTS: The detection rates of LS900 and A-scan axial measurement were 83% and 100% respectively. Three methods of A scan in sitting position, supine position and LS900 to measure the overall AL, silicone oil group, lens dislocation group and vitreous hemorrhage group, the differences were statistically significant(P<0.001), The mean values of AL measured by overall A-scan, supine positions of silicone oil group, supine position of lens dislocation group and vitreous hemorrhage group were statistically significant differences with LS900 measurement(all P<0.05), while there was no statistical difference between the results of the overall sitting position and the difficult measuring eye groups' sitting position compared with the LS900 measurement of AL. The three measurements showed good consistency within the 95% consistency range, but the result of A-scan on sitting position was closer to LS900.CONCLUSION: Changing the conventional decubitus position to the sitting position can improve the accuracy of the measurement results and provide clinicians with more reliable guidance for the treatment of patients with difficult measuring eyes of A-scan axial measurement, especially in diseases with altered ocular structure.
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@#AIM: To compare the measurement results of anterior chamber depth(ACD)by Pentacam, IOL Master and Contact Ultrasonic A-scan, and analyze the difference, correlation, consistency and influencing factors of the three measurement methods.<p>METHODS: In this study of 307 eyes of 250 cataract patients with preoperative, ACD estimation was done by Pentacam, IOL Master and Contact Ultrasonic A-scan. The independent sample <i>t</i>-test, Analysis of Variance(ANOVA), Pearson's correlation test and multiple linear regressions were used to analyze the results.<p>RESULTS: The mean of ACD measured by Pentacam(ACDp), IOL Master(ACDi)and A-scan(ACDa)were 2.42±0.45mm, 2.96±0.43mm, 2.58±0.36mm, the difference was statistically significant(<i>F</i>=136.694, <i>P</i><0.05). The three methods were sequentially compared in pairs, and the differences within the groups were statistically significant(<i>P</i><0.05). Pearson's correlation test was performed on the three methods in pairs, and there was a linear positive correlation within each group. When the ACDp and the central corneal thickness(CCT)were added, the sum(ACDp2)was no statistically significant compared with the ACDi(<i>P</i>=0.93). When the ACDp was less than 1.85mm(ACDi was about 2.40mm), the ACDa increases significantly and the fluctuation increases. Among the many possible influencing factors, axial length, lens thickness and age have the highest relative importance for ACD measurement.ACD was positively correlated with axial length(<i>r</i>Pentacam=0.602, <i>r</i>IOL Master=0.603, <i>r</i>A-scan=0.483), and negatively correlated with the lens thickness(<i>r</i>Pentacam= -0.382, <i>r</i>IOL Master= -0.350, <i>r</i>A-scan= -0.582), negatively correlated with age(<i>r</i>Pentacam= -0.328, <i>r</i>IOL Master= -0.414, <i>r</i>A-scan= -0.265). Three factors were included in the multiple linear regression model, and the age factor of Contact Ultrasonic A-scan was eliminated due to the low influence weight.<p>CONCLUSION: ACDp2 and ACDi may be closer to the true value of the anterior chamber depth. The Contact Ultrasonic A-scan may increase the measurement error when measuring shallow anterior chamber. Axial length, lens thickness and age have the greatest influence on ACD measurement, which are the influencing factors of Pentacam and IOL Master, but age is not the influencing factor of Contact Ultrasonic A-scan.
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AIM:To evaluate the repeatability of axial length (AL) and anterior chamber depth (ACD) obtained by A scan ultrasonography, and to compare AL and ACD obtained by A scan with those obtained by IOL Master.METHODS:Two hundred and fifty-seven cataract eyes of 170 patients were included.IOL Master and A scan were performed for each eye.Five measurements of IOL Master and 3 measurements of A scan were obtained.All the tested eyes were divided into 5 groups according to AL obtained by A scan:Group A (2129mm, 21 eyes).Cronbach's Alpha coefficient and intraclass correlation coefficient (ICC) were applied to evaluate the repeatability of AL and ACD obtained by A scan.Paired t test and Pearson correlation coefficient were used to analyze the differences and correlations of AL and ACD obtained by the 2 devices, respectively.Bland-Altman plots were presented to analyze the agreements of AL and ACD obtained by the 2 devices.RESULTS:All the Cronbach's Alpha and ICCs of AL and ACD values were more than 0.98.The differences of AL values between A scan and IOL Master were-0.11±0.08mm in Group A,-0.15±0.10mm in Group B,-0.19±0.15 mm in Group C,-0.29±0.16mm in Group D and-0.45±0.29mm in Group E, respectively (all P0.89, all P<0.01).CONCLUSION:The AL and ACD values in cataract eyes obtained by A scan were repeatable.The AL and ACD values obtained by A scan were smaller than those obtained by IOL Master.With the increase of AL values, the differences of AL values between A scan and IOL Master increased.
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AIM:To compare the accuracy of conventional contact A-scan and IOL Master in measuring axial length and anterior chamber depth, and to evaluate the characteristics of these two different methods.METHODS:Totally 145 cases (189 eyes) who underwent phacoemulsification and intraocular lens implantation in our hospital from January 2015 to December 2016 were observed prospectively.They were divided into five groups according to ocular axial length measured by IOL Master(Group A:AL≤22mm, Group B:22mm28mm).The axial length and anterior chamber depth were measured by A-scan and IOL Master respectively before operation, corneal curvature was measured by IOL Master.AL≤22mm using Hoffer Q formula to calculate the crystal degree, AL>22mm using Haigis formula to calculate the crystal degree.Analysis of axial length, anterior chamber depth and mean absolute refractive error at 3mo after surgery.RESULTS:The axial length measured by A-scan and IOL-master:Group A were 21.48±0.41mm and 21.46±0.40mm (P>0.05);Group B were 23.13±0.62mm and 23.14±0.63mm(P>0.05);Group C were 25.24±0.56mm and 25.27±0.59mm(P>0.05);Group D were 26.97±0.59mm and 27.03±0.64mm(P>0.05);Group E were 30.76±1.40mm and 31.01±1.53mm(P0.05);Group B were 0.48±0.34D and 0.45±0.32D(P>0.05);Group C were 0.56±0.32D and 0.49±0.40D(P>0.05);Group D were 0.64±0.16D and 0.50±0.22D(P>0.05);Group E were 0.91±0.47D and 0.62±0.29D(P0.05).Anterior chamber depth measured by A-scan and IOL Master:Group A were 2.81±0.35mm and 2.82±0.41mm (P>0.05);Group B were 3.04±0.50mm and3.10±0.47mm (P>0.05);Group C were 3.55±0.62mm and 3.60±0.52mm (P>0.05);Group D were 3.42±0.24mm and 3.51±0.30mm(P>0.05);Group E were 3.50±0.28mm and 3.61±0.34mm(P>0.05).CONCLUSION:IOL Master and contact A-scan have a high degree of consistency in the biological measurement, IOL Master has higher accuracy for patients with high myopia and long axis.It is a simple, accurate, good-repeatable and non-contact measurement tool.
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PURPOSE: To compare the measurement results and the accuracy of the predicted refractive error after cataract surgery among 3 ocular biometry devices; OA-2000®, IOL Master® and A-scan ultrasound in posterior subscapular cataracts. METHODS: Biometry measurements including axial length, anterior chamber depth and the keratometry of 80 cataractous eyes were measured using ultrasonography, OA-2000® and IOL Master®. To calculate the intraocular lens (IOL) power, the SRK/T formula was used and 3 months after cataract surgery, the refractive outcome was compared to the preoperatively predicted refractive error. RESULTS: The number of eyes measured by the 3 devices (A-scan, IOL Master® and OA-2000®) was 57 (group A) and the number of eyes measured by 2 devices (A-scan and OA-2000®) was 22 (group B). When cataract grading was performed based on the Lens Opacity Classification system III, the severity of posterior subscapular opacity was significantly different between the 2 groups (p = 0.001). Although no difference was observed in the measured biometry values including axial length, anterior chamber depth and keratometry in groups A and B, the predicted refractive error was significantly different in group B; OA-2000® showed a significantly higher accuracy in predicting IOL power than A-scan. CONCLUSIONS: In cataract patients whose posterior subscapular opacity is not severe, the accuracy for predicting refractive error after cataract surgery was not significantly different among the 3 devices included in our study (A-scan, IOL Master® and OA-2000®). However, in patients with severe posterior subscapular opacity, OA-2000®, that provides a Fourier domain light source-calculated predicted refractive error of IOL may be more accurate.
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Humans , Anterior Chamber , Biometry , Cataract , Classification , Interferometry , Lenses, Intraocular , Refractive Errors , UltrasonographyABSTRACT
PURPOSE: To compare the new swept-source optical coherence tomography based IOL Master 700 to both the partial coherence interferometry based IOL Master 500 and ultrasound A-scan in terms of the ocular biometry and the prediction of postoperative refractive outcomes. METHODS: A total 67 eyes of 55 patients who received cataract surgery were included in our study. The axial length, anterior chamber depth, and keratometry were measured using IOL Master 700, IOL Master 500, and A-scan. The predictive errors, which are the differences between predictive refraction and post-operative refraction 1 month after surgery, were also compared. RESULTS: Axial length measurements were not successful in 5 eyes measured using IOL Master 700 and in 12 eyes measured using IOL Master 500. The mean absolute postoperative refraction predictive errors were 0.63 ± 0.50 diopters, 0.66 ± 0.51 diopters, and 0.62 ± 0.51 diopters for IOL Master 700, IOL Master 500, and A-scan, respectively, and these values exhibited no statistically significant differences. The mean axial lengths were 24.25 ± 2.41 mm, 24.24 ± 2.40 mm, and 24.22 ± 2.39 mm; the mean anterior chamber depths were 3.09 ± 0.39 mm, 3.17 ± 0.39 mm, and 3.15 ± 0.46 mm; and the mean keratometry values were 44.12 ± 1.82 diopters, 44.57 ± 2.10 diopters, and 43.98 ± 1.84 diopters for the IOL Master 700, IOL Master 500, and A-scan groups, respectively. None of these parameters showed statistically significant differences between the three groups. Regarding pair-wise comparison, there were significant differences between the IOL Master 700 and the other devices. CONCLUSIONS: The ocular biometric measurements measured using IOL Master 700, IOL Master 500, and A-scan showed no significant differences. However, IOL Master 700 demonstrated a superior ability to successfully take biometric measurements compared to IOL Master 500. Therefore, IOL Master 700 is capable of measuring ocular biometry for cataract surgery in clinical practice.
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Humans , Anterior Chamber , Biometry , Cataract , Interferometry , Lenses, Intraocular , Tomography, Optical Coherence , UltrasonographyABSTRACT
PURPOSE: To report the accuracy of intraocular lens (IOL) formulas according to axial length, anterior chamber depth, and mean corneal curvature when performing biometry with an immersion type A-scan with mannual keratomery and an IOL Master®. METHODS: Retrospective medical chart reviews were carried out for 82 eyes of 65 patients who underwent cataract surgery performed by a single surgeon. Biometry was performed using IOL Master®, mannual keratometry, and immersion type A-scan ultrasound in sequence. Prediction diopter was obtained using Sanders-Retzlaff-Kraff/Theoretical (SRK-T) and Holladay 1 formulas calculated with the biometric value measured by mannual keratomery and A-scan, and using SRK-T and, Holladay 2 formulas with IOL Master®. The final refractive outcome was determined as manifested refraction at least 7 weeks after the surgery, and it was compared with the preoperative prediction dipoter (D) of the IOL formulas. RESULTS: Mean axial length and mean keratomtric measurements as determined by A-scan with mannual keratomery showed significant statistical differences from those of IOL Master®. However, there was no difference in postoperative mean absolute error between biometric measurements, or among formulas according to axial length, anterior chamber depth, or mean corneal curvature. However, the percentage of actual refraction within ±0.50 D of the intended refraction was dirrerent among the four formalas according to axial length, anterior chamber dept, mean corneal curvature. CONCLUSIONS: Biometry measurement using the immersion-type A-scan with mannual keratomery is as accurate as that using IOL Master® for predicting the postoperative refractive state of cataract surgery. However, it is suggested that the best IOL formula be chosen according to axial length, anterior chamber depth, and mean corneal curvature.
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Humans , Anterior Chamber , Biometry , Cataract , Immersion , Interferometry , Lenses, Intraocular , Retrospective Studies , UltrasonographyABSTRACT
AIM: To compare the difference of A-scan and lOL Master in intraocular lens power measurement. ●METHODS:Two hundred and twenty-six patients (230 eyes) with age-related cataract were included in the study. Before surgery, axial length was measured by A-scan and lOL Master respectively and corneal curvature was measured by auto refractometer. lntraocular lens power was calculated according to the SRK-T formula. Corneal curvature was measured by auto refractometer and the refractive outcome was performed by phoropter three months after cataract surgery. ●RESULTS:The mean axial length was (23. 48 ± 1. 94) mm measured by A-scan and (23. 75±1. 96) mm measured by lOL Master. There was significant difference between them ( P 0. 05). And the results were (44. 10 ± 1. 57 ) D and ( 44. 11 ± 1. 58 ) D in lOL Master group. There was no significant difference between them (P>0. 05); The mean absolute refractive error (MAE) in A-scan group was ( 0. 47 ± 0. 27 ) D and in lOL Master group (0. 41±0. 19) D. The difference was significant (P ●CONCLUSION: lOL Master is proved to be slightly more accurate than A-scan for lOL power calculation.
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?AIM:To investigate the measurement of central anterior chamber depth ( ACD ) in patients with acute primary angle - closure glaucoma ( APACG ) with A - scan ultrasound, Pentacam and ultrasonic biological microscope ( UBM) .?METHODS: Thirty-five patients (35 eyes) with APACG were selected, of whom central ACD were measured with A-scan ultrasound, Pentacam and UBM.?RESULTS: The measurement values of ACD with A-scan ultrasound, UBM and Pentacam were 1. 5633±0. 2089, 1. 5783 ± 0. 2067, 1. 6275 ± 0. 2296mm, which was equal variance tested by the homogeneity of variance, and was significant different by multiple comparision (F=4. 074, P=0. 026). The difference of ACD between the two groups of A-scan ultrasound and UBM, A-scan ultrasound and Pentacam, UBM and Pentacam were statistically significant ( P = 0. 032, 0. 023, 0. 012 ). Altman- Bland analysis showed that the three methods were not consistent with each other.?CONCLUSION: The ACD value of the APACG with the three methods is the largest using Pentacam, followed by UBM and A - scan ultrasound. In clinical the three methods with different advantages can complement each other, but cannot be replaced. In order to obtain more accurate results, we should combine the advantage and make comprehensive analysis.
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PURPOSE: To compare the accuracy and clinical usefulness of different devices by measuring anterior chamber depth (ACD) with three devices and central corneal thickness (CCT) with four devices. METHODS: In 180 eyes of 90 healthy subjects, ACD was measured using A-scan, Lenstar LS900®, Pentacam®, and CCT was measured using ultrasound pachymetry (USP), Lenstar LS900®, Pentacam®, and anterior segment optical coherence tomography (OCT). RESULTS: The average ACT measurements using Lenstar LS900®, A-scan, and Pentacam® were 3.27 ± 0.35 mm, 3.26 ± 0.36 mm, and 3.25 ± 0.36 mm, respectively. The measurements were significantly correlated (p < 0.001) but without statistically significant difference (p = 0.017). The Bland-Altman plots showed a low degree of agreement. The average CCT measurements using Pentacam®, USP, Lenstar LS900®, and OCT were 553.31 ± 25.23 µm, 547.26 ± 23.83 µm, 541.38 ± 24.49 µm, and 531.40 ± 22.33 µm, respectively. The measurements were significantly correlated (p < 0.001) and statistically significantly different (p < 0.05). The Bland-Altman plots showed a low degree of agreement. CONCLUSIONS: ACD and CCT measured using different devices were highly correlated, but the ACD measurements were not statistically different; however, the CCT measurements were statistically different, and agreement was low between both measurements.
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Anterior Chamber , Healthy Volunteers , Tomography, Optical Coherence , UltrasonographyABSTRACT
AlM:To compare the results of lOL Master, contact and immersion A-scan ultrasound measurements for anterior chamber depth ( ACD ) , and evaluate the difference and consistency.METHODS:Fifty-eight cases (98 eyes) with age-related cataract during July to October in 2013 did the A-scan ultrasound with contact and immersion measurements and lOL Master to get the results of ACD. Difference in measurements between methods was assessed using the variance analysisi. Consistency was assessed using Bland-Altman.RESULTS:The ACD measured by lOL Master was 2. 31~3. 90mm, the mean was 3. 03 ± 0. 38mm. The ACD measured by contact A- scan ultrasound was 1. 51 ~4. 06mm, the mean was 2. 88 ± 0. 56mm. The ACD measured by immersion A-scan ultrasound was 1. 99 ~4. 17mm, the mean was 3. 17±0. 38mm. The results of lOL Master and contact A - scan ultrasound had statistical differences (P=0. 022<0. 05). The results of lOL Master and immersion A - scan ultrasound had statistical differences (P=0. 031<0. 05). The results of contact A-scan ultrasound and immersion A-scan ultrasound had statistical differences (P=0. 000<0. 05). The consistency between three methods was poor. CONCLUSlON: The rank of ACD of patients with cataract is immersion A-scan ultrasound, lOL Master and contact A-scan ultrasound. The consistency is poor, and the three methods can’t be interchanged clinically.
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Purpose: To evaluate the role of echography in diagnosis and management of a diverse array of choroidal masses. Materials and Methods: Sixty-two cases of clinically suspected choroidal masses were prospectively analyzed with B-scan (10 Hz), A-scan, and ultrasound biomicroscopy (UBM) (50 Hz) after a meticulous history and ocular examination. Ancillary investigations and systemic evaluation were also done. Results: Based on clinical suspicion, acoustic features, response to treatment, and other ancillary tests combined together, the various masses were differentiated. The cases included in the study were as follows: n = 10 malignant melanomas, n = 16 metastasis and infiltrations, n = 9 hemangioma, n = 7 tuberculoma, n = 8 nonspecific inflammatory masses, n = 2 disciform plaques, n = 4 macular cysts or retinoschisis, n = 2 Coat’s disease, n = 1 melanocytoma, and n = 2 osteomas. Ultrasonography (USG) alone could identify n = 51 lesions, while UBM in combination with USG was needed in remaining 11 masses. Conclusion: Standardized echography is an important adjunct in the diagnosis and management of eyes with intraocular masses. A better understanding of the clinicopathological and echographic picture of the diverse lesions can help in detection, differentiation, diagnosis, proposing a therapeutic approach, and also monitoring response to treatment. Echography is essential to evaluate tumors for extrascleral and anterior segment extension.
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PURPOSE: To compare ocular biometry measured using 4 applanation ultrasonographic biometry devices and evaluate the accuracies of the refractive outcomes after cataract surgery. METHODS: A total of 60 eyes in 60 patients who received cataract surgery were included in the present study. The axial length was measured using applanation ultrasonographic biometry devices (Aviso(R), Hi-Scan(R), UD-6000(R), P37-II(R)). Additionally, keratometry was measured using an autokeratometer (Topcon KR 8000) and the SRK/T formula was used to calculate intraocular lens (IOL) power. Two months after cataract surgery, the refractive outcome was determined, and results from the 4 different applanation ultrasonographic biometry devices were compared. RESULTS: Axial lengths were 23.52 +/- 1.45 mm, 23.51 +/- 1.04 mm, 23.54 +/- 1.58 mm, and 23.52 +/- 1.38 mm measured using Aviso(R), Hi-Scan(R), UD-6000(R), and P37-II(R), respectively with no statistically significant differences observed (p = 0.92). The mean absolute error (MAE) of the Aviso(R), Hi-Scan(R), UD-6000(R), and P37-II(R) was 0.41 +/- 0.32 diopter (D), 0.40 +/- 0.30 D, 0.36 +/- 0.26 D, and 0.39 +/- 0.26 D, respectively. The mean numerical error (MNE) was 0.39 +/- 0.37 D, 0.36 +/- 0.32 D, 0.26 +/- 0.29 D, and 0.38 +/- 0.32 D, respectively. The differences between the 4 different applanation ultrasonographic biometry devices were not statistically significant (p = 0.90, p = 0.81). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using Aviso(R), Hi-Scan(R), UD-6000(R), P37-II(R) showed no significant differences.
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Humans , Biometry , Cataract , Lenses, Intraocular , Refractive ErrorsABSTRACT
AIM: To evaluate the accuracy of central conreal thickness ( CCT ) using EX500 Excimer Laser workstation (EX500) in laser in situ keratomileusis (LASIK) patients.METHODS:The CCT of 120 eyes (63 patients) who had LASIK between January 2013 and June 2013 were measured by A- scan and EX500. Three groups were classified: >550μm, 500 ~550μm, RESULTS: The average preoperative CCT value was 527. 9±34. 3μm measured by A-scan, 528. 5±34. 6μm measured by EX500. There was no significant difference between these two measurements (t=1. 736, P=0. 085). In group which CCT >550μm, the average preoperative CCT value was 571. 4±17. 3μm measured by A-scan, 572.7±15. 7μm measured by EX500. There was no significant difference between these two measurements (t=1. 857, P=0. 072). In group which CCT 500 ~ 550μm, the average preoperative CCT value was 523. 4±13. 1μm measured by A-scan, 524. 2±12. 4μm measured by EX500. There was no significant difference between these two measurements ( t=1. 934, P = 0. 058 ). In group which CCT CONCLUSION: There is no significant difference between preoperative CCT value measured by A-scan and EX500. After corneal flap lifting and keratomileusis, the CCT value measured by EX500 is smaller than measured by A-scan.
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Objective Cataract surgery is also considered as a type of refractive surgery , but there is few research on the change of preoperative and postoperative ocular biometry measurements .The aim of the study was to compare the A-scan ultrasound biom-etry measurements before and after phacoemulsification with intraocular lens implantation , followed by the analysis on its clinical signifi-cance . Methods Dynamic observation was conducted in 188 eyes of 155 cataract patients who received cataract operation from January 2011 to January 2013 in the department of ophthalmology in Nanjing Gernal Hospital .Measurements were made before surgery and 14 days after surgery by Ultrascan Digital 2000 contact ultraound A-scan (Alcon), including anterior chamber depth (ACD), vitreous cham-ber depth ( V) and axial length ( AL) .Simultaneously , a prospective comparison of measurements was made by A-scan ultrasound in sit-ting and decubitus position .Measurements were also conducted in preoperative and postoperative visual acuity and intraocular pressure of the patients. Results visual acuity and intraocular pressure: The difference between preoperative and postoperative visual acuity [(0.17 ±0.19) vs (0.61 ±0.27)] and intraocular pressure [(15.09 ±8.50) mmHg vs (12.99 ±4.44) mmHg] was of statistical sig-nificance ( P0.05).V:The difference between peroperative and postoperative Vs was of significant difference (P<0.05).No significant difference existed between Vs in sitting and decubitus position before the operation [(16.568 ±2.406) mm vs (16.524 ±5.544) mm,with intraocular lens implantation can get better operation result. In addition, different measuring positions have no influence on A-scan ultrasound measurements except the postoperative vitreous cavity depth .
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PURPOSE: To evaluation the accuracy of the IOL power calculation formulae measured by IOL Master(R) and applanation ultrasonography for the Tecnis ZCB00 IOL. METHODS: We performed a retrospective study of 170 eyes in 121 patients who underwent cataract surgery in our hospital with AMO Tecnis ZCB00 IOL.s. The SRK/T formula was used to predict the patient's implanted IOL power. Differences in the predicted refractive errors between IOL Master(R) and ultrasonography were analyzed and factors attributed to the differences were also analyzed. Three months after cataract surgery, mean numeric error and mean absolute error were analyzed. RESULTS: SRK/II and SRK/T formulas calculated using ultrasonography showed differences compared to the same formulas calculated using IOL Master(R), in which hyperopic shift was also demonstrated. No definite factor was attributed to the differences between the 2 methods. Although the 3 formulas of IOL Master(R) showed no significant difference in refractive errors, the SRK/T formula calculated using IOL Master(R) showed the least mean absolute and numeric errors. CONCLUSIONS: IOL Master(R) is considered more suitable when determining proper AMO Tecnis ZCB00 IOL power in cataract surgery. The hyperopic shift should be considered when calculating the IOL power using only ultrasonography.
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Humans , Cataract , Ultrasonography , Lenses, Intraocular , Refractive Errors , Retrospective Studies , UltrasonographyABSTRACT
PURPOSE: To investigate the accuracy of the Haigis formula compared to other formulas using contact ultrasound biometry. METHODS: This study was performed on 94 patients (114 eyes) who underwent cataract surgery in our hospital. Axial length (AXL) and anterior chamber depth (ACD) were measured using both A-scan and intraocular lens (IOL) Master(R). Patients were divided into three groups based on AXL; Group I (AXL or = 25.5 mm). Before cataract surgery, predicted refraction was calculated using the Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas using both A-scan and IOL Master(R) measurements. Mean absolute error (MAE) were analyzed at one month after surgery using the various IOL formulas. RESULTS: Using contact ultrasound biometry, in Group I, MAE of Haigis was 0.80 +/- 0.67 D and was significantly lower than that using SRK/T. In Group II, the Haigis MAE was 0.72 +/- 0.55 D and was significantly lower than the results of all other formulas. In Group III, the Haigis MAE was 0.76 +/- 1.13 D and not significantly different from the results of other formulas. Comparing MAE of A-scan to IOL Master(R), the Haigis formula showed 0.16 D higher error that decreased when the AXL was close to the normal range. CONCLUSIONS: Using contact ultrasound biometry, the Haigis formula provided the best predictability of postoperative refractive outcome compared to other formulas in eyes with normal axial length.
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Humans , Anterior Chamber , Biometry , Cataract , Lenses, Intraocular , Reference Values , UltrasonographyABSTRACT
PURPOSE: To investigate the accuracy of the Haigis formula compared to other formulas using contact ultrasound biometry. METHODS: This study was performed on 94 patients (114 eyes) who underwent cataract surgery in our hospital. Axial length (AXL) and anterior chamber depth (ACD) were measured using both A-scan and intraocular lens (IOL) Master(R). Patients were divided into three groups based on AXL; Group I (AXL or = 25.5 mm). Before cataract surgery, predicted refraction was calculated using the Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas using both A-scan and IOL Master(R) measurements. Mean absolute error (MAE) were analyzed at one month after surgery using the various IOL formulas. RESULTS: Using contact ultrasound biometry, in Group I, MAE of Haigis was 0.80 +/- 0.67 D and was significantly lower than that using SRK/T. In Group II, the Haigis MAE was 0.72 +/- 0.55 D and was significantly lower than the results of all other formulas. In Group III, the Haigis MAE was 0.76 +/- 1.13 D and not significantly different from the results of other formulas. Comparing MAE of A-scan to IOL Master(R), the Haigis formula showed 0.16 D higher error that decreased when the AXL was close to the normal range. CONCLUSIONS: Using contact ultrasound biometry, the Haigis formula provided the best predictability of postoperative refractive outcome compared to other formulas in eyes with normal axial length.
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Humans , Anterior Chamber , Biometry , Cataract , Lenses, Intraocular , Reference Values , UltrasonographyABSTRACT
Background & Objectives: Before performing the cataract surgery high level of expertise and knowledge is required to fulfil the ever increasing demands of patients. This makes a surgeon carry out detailed evaluation of a case and formulate a ‘customized IOL’. Accurate IOL power calculation is the most important part of planning a cataract surgery. Most of the formula works well with normal axial length, but with high refractive errors, there are many discrepancies for selection of IOL formula. Methods: Study included 80 high myopic eyes divided into three groups and 20 high hypermetropic eyes divided into two groups according to various A scan formulas utilised. Post-operative spherical equivalent in relation to various formulas for all groups compared. Results: Performance of all 3 formulas in high myopic group showed SRK/T formula to be most accurate with smallest Mean Absolute Error (MAE) in all axial length subcategories above 24mm, followed by Haigis, and Holladay I respectively. In high hypermetropic patients, among 2 formulas, the lowest MAE was found with Hoffer-Q (-0.03D) compared to SRK/T (-0.96D) Interpretation & Conclusion: Erroneous IOL power calculation can spoil high quality results expected by patients in terms of post-operative vision in spite of excellent surgery.
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PURPOSE: To assess the reproducibility and reliability of applanation A-scan ultrasonography (Pacscan 300A, Sonomed Inc., Chicago, IL, USA) and optical measurements with IOL Master(R) (Carl Zeiss Meditec, Germany), Pentacam(R) (Oculus, Wetzlar, Germany), and Orbscan II(R) (Orbtek Inc., Laredo, TX, USA) when measuring anterior chamber depth (ACD). METHODS: In this study of 188 eyes of 94 patients, ACD estimation prior to cataract surgery was preformed by the applanation A-scan method and IOL Master(R), Pentacam(R), and Orbscan II(R) optical methods. Repeatability from each device was evaluated by coefficient of variation, standard deviation, and intraclass correlation coefficient. RM-ANOVA on Ranks was used to compare the differences in ACD among the devices. The Bland-Altman plot was performed to assess agreement in measurements between the devices. RESULTS: The mean ACD according to the applanation A-scan method and IOL Master(R), Pentacam(R), and Orbscan II(R) optical methods were 2.89 +/- 0.49 mm, 3.25 +/- 0.45 mm, 3.21 +/- 0.46 mm, and 3.19 +/- 0.47 mm, respectively, and the differences were statistically significant (p < 0.01). The coefficient of variation for the 4 methods was 2.50% in the A-scan, 0.87% in the IOL Master(R), 1.25% in the Pentacam(R), and 1.04% with Orbscan II(R), and reproducibility was higher with the optical principle devices. The correlation coefficient between A-scan and IOL Master(R) was 0.65, between IOL Master(R) and Pentacam(R) 0.91, between IOL Master(R) and Orbscan II(R) 0.90, between A-scan and Pentacam(R) 0.69, between A-scan and Orbscan II(R) 0.71, and between Pentacam(R) and Orbscan II(R) 0.93. CONCLUSIONS: Applanation A-scan provided lower measurements for ACD compared with IOL Master(R), Pentacam(R) and Orbscan II(R). There was good agreement between results obtained with the latter 3 methods, and reproducibility was high with optical measurements. The coefficient of variation was low for IOL Master(R).