Salmon Thomas O, van de Pol Corina
College of Optometry, Northeastern State University, Tahlequah, Oklahoma 74464-7017, USA.
Optometry. 2005 Aug;76(8):461-72. doi: 10.1016/j.optm.2005.07.006.
Refractive surgery has stimulated the development of aberrometers, which are instruments that measure higher-order aberrations. The purpose of this study was to test one clinical aberrometer, the Complete Ophthalmic Analysis System (COAS), for its accuracy, repeatability, and instrument myopia for measuring sphere and astigmatism and its repeatability for measuring higher-order aberrations.
Aberrations of 56 normal eyes (28 subjects) were measured with and without cycloplegia using a COAS, a conventional autorefractor and by subjective refraction. We evaluated lower-order accuracy (sphere and astigmatism) of the COAS and autorefractor by comparing that data with that of subjective refraction. We also tested COAS lower- and higher-order repeatability for 5 measurements taken in less than 1 minute. We evaluated instrument myopia by comparing cycloplegic and noncycloplegic measurements of the same eye. Data were analyzed for a 5.0-mm-diameter pupil.
Mean COAS spherical error was between -0.1 and +0.4 diopters (D), depending on cycloplegia and the kind of sphere power computation selected. Cylinder power errors were less than 0.1 D. COAS repeatability coefficients were better than 0.25 D, and instrument myopia was less than 0.4 D. These were comparable with those of autorefraction. Higher-order repeatability was sufficient to allow reliable measurement of normal third-order aberrations and spherical aberration.
Accuracy, repeatability, and instrument myopia of the COAS are similar to those of a conventional autorefractor. Accuracy and repeatability are also similar to those of subjective refraction. Like an autorefractor, the COAS provides instantaneous, objective measurements of sphere and astigmatism, but it also measures higher-order aberrations. We found that it is capable of reliably measuring problematic higher-order aberrations and is therefore a valuable asset for modern clinical eye care.
屈光手术推动了像差仪的发展，像差仪是用于测量高阶像差的仪器。本研究的目的是测试一种临床像差仪——综合眼科分析系统（COAS），评估其在测量球镜和散光时的准确性、可重复性以及仪器性近视，同时评估其在测量高阶像差时的可重复性。
使用COAS、传统自动验光仪并通过主观验光，对56只正常眼（28名受试者）在散瞳和未散瞳状态下的像差进行测量。通过将COAS和自动验光仪的数据与主观验光数据进行比较，评估它们在低阶像差（球镜和散光）方面的准确性。我们还测试了COAS在不到1分钟内进行5次测量时低阶和高阶像差的可重复性。通过比较同一只眼睛散瞳和未散瞳状态下的测量结果，评估仪器性近视。针对直径5.0毫米的瞳孔进行数据分析。
根据散瞳情况和所选球镜度数计算方式的不同，COAS的平均球镜误差在-0.1至+0.4屈光度（D）之间。柱镜度数误差小于0.1D。COAS的可重复性系数优于0.25D，仪器性近视小于0.4D。这些结果与自动验光的结果相当。高阶像差的可重复性足以可靠地测量正常的三阶像差和球差。
COAS的准确性、可重复性和仪器性近视与传统自动验光仪相似。其准确性和可重复性也与主观验光相似。与自动验光仪一样，COAS能够即时、客观地测量球镜和散光，但它还能测量高阶像差。我们发现它能够可靠地测量有问题的高阶像差，因此是现代临床眼科护理中的一项宝贵工具。
