PURPOSE: To compare prospectively the reproducibility and accuracy of B-mode-guided biometry with those of A-scan biometry using a conventional A-mode probe to calculate intraocular lens (IOL) power. SETTING: Department of Ophthalmology, Hotel-Dieu de Paris, France. METHODS: The axial length (AL) in 87 eyes of 72 candidates for cataract surgery was determined by B-mode-guided vector-A-mode and A-mode biometry using an Ophthascan S Ultrasound imager. Patients were assigned to one of two groups based on the B-mode biometry: nonmyopic (AL < 24.5 mm; n = 54) or myopic (AL > 24.5 mm; n = 33). Postoperative refractive results were compared with attempted values. RESULTS: Mean AL variance was significantly greater when using the A-mode than the B-mode: 0.157 mm +/- 0.260 (SD) versus 0.015 +/- 0.018 mm in the myopic group (P < .001) and 0.024 +/- 0.024 +/- 0.045 versus 0.009 +/- 0.011 mm in the nonmyopic group (P < .001). More eyes having B-mode biometry achieved a final refraction within +/- 0.50 diopter (D) of the attempted refraction (63 and 43%, respectively; P < .05). No deviation greater than 1.60 D was observed with the B-mode in the myopic or nonmyopic group. Three cases with a such a deviation (up to 2.24 D) would have been observed had A-mode-based biometry been chosen for the IOL power calculation. In the myopic group, attempted postoperative refraction was within +/- 0.50 D in 78% of eyes having B-mode biometry compared with 65% having A-mode. This difference was not statistically significant. CONCLUSION> These results suggest that the reproducibility and accuracy of AL measurements are significantly better with B-mode-guided A-mode biometry than with A-mode biometry in myopic and nonmyopic eyes.
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机译:目的:前瞻性地比较B模式引导生物测定法与使用常规A模式探针计算人工晶状体(IOL)屈光度的A扫描生物测定法的可重复性和准确性。地点:法国巴黎大区酒店眼科。方法:采用Ophthascan S超声成像仪通过B模式引导的矢量A模式和A模式生物特征测定72例白内障手术候选人的87只眼的轴长(AL)。根据B型生物特征将患者分为两组之一:非近视(AL <24.5 mm; n = 54)或近视(AL> 24.5 mm; n = 33)。将术后屈光结果与尝试值进行比较。结果:使用A模式时,平均AL方差明显大于B模式:近视组为0.157 mm +/- 0.260(SD),而近视组为0.015 +/- 0.018 mm(P <.001)和0.024 + / -0.024 +/- 0.045毫米,而非近视组为0.009 +/- 0.011毫米(P <.001)。进行B模式生物测定的更多眼睛的最终屈光度在尝试屈光度的+/- 0.50屈光度(D)内(分别为63%和43%; P <0.05)。在近视或非近视组中,B模式观察不到偏差大于1.60D。如果选择基于A模式的生物特征进行IOL功率计算,则会观察到三种情况(这种偏差最大为2.24 D)。在近视组中,尝试进行屈光检查的78%的B型生物眼的术后屈光度在+/- 0.50 D之内,而A模式为65%。这种差异在统计学上不显着。结论>这些结果表明,在近视眼和非近视眼中,B模式引导的A模式生物测定法比A模式生物测定法可显着改善AL测量的重现性和准确性。
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