Comparison of Ocular Biometry and Postoperative Refraction in Cataract Patients between Galilei-G6(R) and IOL Master(R)

PURPOSE: To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict postoperative refractions of Dual Scheimpflug analyzer Galilei G6(R) and intra ocular lens (IOL) Master(R). METHODS: A total of 50 eyes in 50 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured using 2 types of partial coherence interferometries (Galilei G6(R) and IOL Master(R)). The SRK/T formula was used to calculate IOL power and the predictive error which subtracts predictive refraction from postoperative refraction was compared between the ocular biometry devices. RESULTS: Axial lengths were 23.36 +/- 0.80 mm and 23.36 +/- 0.90 mm measured by Galilei G6(R) and IOL Master(R), respectively. Axial length measured by Galilei G6(R) was not statistically significant compared with IOL Master(R) (p = 0.321). The anterior chamber depth and keratometry were 3.22 +/- 0.35 mm and 44.29 +/- 1.40 D measured by Galilei G6(R) and 3.11 +/- 0.46 mm and 44.39 +/- 1.41 D measured by IOL Master(R), respectively. The differences of anterior chamber depth and keratometry between the 2 devices were statistically significant (p < 0.001 and p = 0.028, respectively). The mean absolute prediction errors were 0.45 +/- 0.37 D and 0.49 +/- 0.39 D in Galilei G6(R) and IOL Master(R), respectively and was not statistically significantly different (p = 0.423). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using Galilei G6(R) were as accurate as with IOL Master(R).

Comparison of the Postoperative Refractive Errors Measured by Ultrasound and Partial Coherence Interferometers after Phacovitrectomy

PURPOSE: To compare the accuracy of refractive outcome measured by Ultrascan(R) (Alcon, Fort Worth, TX, USA) and partial coherence interferometers after phacovitrectomy. METHODS: We performed a retrospective study in 74 eyes of 74 patients who underwent phacovitrectomy. SRK-T formula was used to predict intraocular lens (IOL) power. The difference between the predicted and postoperative refractive outcomes for the 2 methodologies (Ultrascan(R) and IOL Master(R) [Zeiss, Carl Zeiss, Jena, Germany]) were compared. The predicted refractive outcome was defined as the estimated refractive error when the selected IOL was inserted. RESULTS: The axial length measured using IOL Master(R) was statistically longer than when measured using Ultrascan(R) (23.85 +/- 0.15 mm, 23.56 +/- 0.15 mm, p < 0.001). Based on keratometry, statistically significant difference between the 2 groups was not observed. The postoperative refractive error was more accurate when using the IOL Master(R) than Ultrascan(R) (0.08 +/- 0.74, 0.47 +/- 0.69, p < 0.001). However, in cases of vitreous hemorrhage, the postoperative refractive error was 0.42 +/- 0.49 with the IOL Master(R) and 0.07 +/- 0.54 with the Ultrascan(R). CONCLUSIONS: Generally, IOL Master(R) is a more accurate method for calculating the IOL power prior to phacovitrectomy. However, in cases of vitreous hemorrhage, Ultrascan(R) appears superior to IOL Master(R) when calculating the IOL power.

Comparison of the Postoperative Refractive Errors Measured by Ultrasound and Partial Coherence Interferometers after Phacovitrectomy

PURPOSE: To compare the accuracy of refractive outcome measured by Ultrascan(R) (Alcon, Fort Worth, TX, USA) and partial coherence interferometers after phacovitrectomy. METHODS: We performed a retrospective study in 74 eyes of 74 patients who underwent phacovitrectomy. SRK-T formula was used to predict intraocular lens (IOL) power. The difference between the predicted and postoperative refractive outcomes for the 2 methodologies (Ultrascan(R) and IOL Master(R) [Zeiss, Carl Zeiss, Jena, Germany]) were compared. The predicted refractive outcome was defined as the estimated refractive error when the selected IOL was inserted. RESULTS: The axial length measured using IOL Master(R) was statistically longer than when measured using Ultrascan(R) (23.85 +/- 0.15 mm, 23.56 +/- 0.15 mm, p < 0.001). Based on keratometry, statistically significant difference between the 2 groups was not observed. The postoperative refractive error was more accurate when using the IOL Master(R) than Ultrascan(R) (0.08 +/- 0.74, 0.47 +/- 0.69, p < 0.001). However, in cases of vitreous hemorrhage, the postoperative refractive error was 0.42 +/- 0.49 with the IOL Master(R) and 0.07 +/- 0.54 with the Ultrascan(R). CONCLUSIONS: Generally, IOL Master(R) is a more accurate method for calculating the IOL power prior to phacovitrectomy. However, in cases of vitreous hemorrhage, Ultrascan(R) appears superior to IOL Master(R) when calculating the IOL power.

Formula Comparison for Intraocular Lens Power Calculation Using IOL Master and Ultrasound for the ZCB00 IOL

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.

Comparison of Anterior Chamber Depth Obtained from Applanation and Optical Principle Devices

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).

Comparison of the Refractive Results Measured by Ultrasound and Partial Coherence Interferometers

PURPOSE: To compare ocular biometry measured by applanation ultrasonography and IOL Master(R), and evaluate the accuracies of the refractive outcome after cataract surgery. METHODS: The biometries of 76 cataractous eyes were measured using ultrasonography and IOL Master(R). The SRK-T formula was employed to predict the patient's implanted IOL power. Two months after cataract surgery, the refractive outcome was determined, and results from the 2 different biometry methods were compared. RESULTS: There were no statistically significant differences in axial length (AXL) and anterior chamber depth (ACD) between ultrasonography and IOL Master(R) (p = 0.501). When using ultrasonography, the mean absolute error (MAE) of the ultrasonography and IOL Master(R) was 0.53 +/- 0.30 diopter (D), 0.55 +/- 0.41 D, respectively. The difference between the 2 biometry methods was not statistically significant (p = 0.110). CONCLUSIONS: Although the difference was not statistically significant, AXL measured by IOL Master(R) was longer and ACD measured by IOL Master(R) was deeper than when measured by A-scan. This difference was more pronounced in patients with a short AXL. The accuracy of IOL power calculation was similar between the 2 devices.

Accuracy of Ocular Biometry and Postoperative Refraction in Cataract Patients with AL-Scan(R)

PURPOSE: To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict postoperative refractions of AL-Scan(R), IOL master(R), and ultrasound. METHODS: A total of 40 eyes in 30 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured by 2 types of partial coherence interferometry (AL-Scan(R) and IOL master(R)) and ultrasound. The SRK/T formula was used to calculate IOL power, and the predictive error which subtracts predictive refraction from postoperative refraction was compared among the ocular biometry devices. RESULTS: Axial lengths were 23.08 +/- 0.62 mm, 23.09 +/- 0.62 mm, and 22.99 +/- 0.62 mm measured by AL scan(R), IOL master(R), and ultrasound, respectively. Axial length measured by ultrasound was statistically significantly shorter than AL scan(R) and IOL master(R) (p < 0.001, p < 0.001, respectively). The anterior chamber depth and keratometry were 3.11 +/- 0.06 mm and 44.82 +/- 1.34 D measured by AL scan(R), and 3.13 +/- 0.06 mm and 44.85 +/- 1.26 D measured by IOL master(R), respectively. The differences of anterior chamber depth and keratometry between the 2 devices were not statistically significant (p = 0.226, p = 0.331, respectively). The mean absolute prediction errors were 0.44 +/- 0.35 D, 0.40 +/- 0.34 D, and 0.39 +/- 0.30 D in AL-Scan(R), IOL master(R) and ultrasound, respectively, and were not statistically significantly different (p = 0.843, p = 0.847, p = 1.000, respectively). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using AL-Scan(R) were as accurate as IOL master(R) and ultrasound.

Comparison of Ocular Biometry Measured by Ultrasound and Two Kinds of Partial Coherence Interferometers

PURPOSE: To evaluate the reproducibility and repeatibility of biometry in cataractous eyes, pseudophakic eyes and eyes having undergone refractive surgery. The OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) instruments were compared, as were. The accuracies of the refractive results after cataract surgery. METHODS: The biometries of 45 cataractous eyes, 31 pseudophakic eyes, and 32 eyes having undergone refractive surgery were measured by two practitioners using OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) instruments. The paired t-test was used to compare the reproducibilities in the three groups. RESULTS: There were no differences in axial length among the groups when using any of the instruments. There was no significant difference in the repeatibility regardless of the instrument used, although. In the cataractous eyes, pseudophakic eyes and eyes with refractive surgery, OcuScan(R)RxP showed the highest repeatability. However, we knew that all three instruments were excellent in the repeatability because the difference was less than 1.5%. The Prediction error of the instruments with regard to refractive results could not be determined after cataract surgery. In some patients with severe cataract, measurement was impossible for both the LENSTAR(R) and IOL Master(R) instruments. CONCLUSIONS: In all groups, OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) showed no significant differences with regard to reproducibility or prediction of refractive power after surgery. Among three groups, the repeatability was rather high in the existing ultrasound method than in the partial coherence interferometers. In some patients with severe cataract, measurement was impossible for both the LENSTAR(R) and IOL Master(R) instruments.