C-Quant散射光计量仪测量散射光的重复性和再现性研究

Repeatability and reproducibility of retinal strayligbt measurement using CQuant compensation comparisonmethod

背景光线经过眼的屈光介质时发生散射，散射光形成的光幕在视网膜上可降低物像的对比度。精确定量测量视网膜散射光值对研究角膜屈光手术、白内障、角膜营养不良和视网膜等疾病的视觉质量至关重要。目的评估C-Quant散射光计量仪测量视网膜散射光的重复性和再现性。方法前瞻性研究。选取近视患者21例35眼为近视组和近视性准分子激光角膜原位磨镶术（LASIK）术后3个月的患者22例34眼为LASIK术后组，应用德国Oculus公司的C-Quant对所有被检者的视网膜散射光进行测量，每跟连续测量7次，评价C-Quant测量视网膜散射光的重复性。对其中的近视患者19例38眼在3-7d问进行再次测量，每个时间段测试3次，评估C-Quant在不同时间测量的再现性。采用标准差（SD）和变异系数（CV）作为评价测量可信度的指标。结果C-Quant在同一时间段内的7次测量视网膜散射光Log（S）均〈0．95，近视组和LASIK术后组视网膜散射光Log（S）平均分别为0．92±0．12和0．93±0．17，各组7次测量的总体差异均无统计学意义（F=0．335，P=0．812；F=1．000，P=0．409）。7次连续测试得到散光值的平均SD为0．07。SD和CV随着测试次数的增多而略微增大，其中连续3次与连续6次测量的sD和CV的差异均有统计学意义（j=-2．080，P=0．045；t=-2．190，P=0．035）。同一被测者在不同时间段的测量结果比较相差0．013，差异无统计学意义（t=-0．531，P=0．598）。结论C-Quant散射光计量仪具有非接触、非侵人性、应用简便和精度性高等优点，对近视及LASIK术后患者视网膜散射光的定量测量具有良好的可重复性及再现性。

Background In an ideal eye there would be no light scattering at all,but the eye media is not optically ideal. Intraocular straylight causes a veil of light and reduction in the contrast of the retinal image, and thus decrease the quality of vision. Objective The present study was to investigate the repeatability and reproducibility of C-Quant straylight meter （Oculus, Germany） in measuring retinal straylight of myopia and post-laser in situ keratomileusis（LASIK） corneas. Methods This is a prospective research. The consecutive 35 eyes of 21 myopic patients and 34 eyes of 22 patients who received LASIK were included in this trail. Retinal straylight was measured for 7 times at a period of time and analyzed quantificational to evaluate the repeatability of measurement. Thirty-eight eyes of 19 patients were measured again at 3-7 days for 3 times at a period of time to assess the reproducibility of C-Quant straylight meter. The mean standard difference （SD） and coefficient of variation （CV） were used as the credibility evaluation. This clinical study complied with Helsinki Declaration and the informed consent was obtained prior to the medical procedure. Results The straylight Log（s） of 7 times measurement were all less than O. 95. The mean Log（s） were 0.92±0. 12 and 0.93±0. 17 respectively in myopia group and post-LASIK group, without statistically significantdifferences among 7 times measurement （ F = 0. 335. P = O. 812 ; F = 1. 000, P = 0. 409 ）. The ,,wan 51） for the 7 times measurement was O. 07 l,og units. SD and CV im.reased wilh the number of measurements. The differences of nlean SD） and CV belween 3 limes result and 6 times result were signifi^anl differenl （ l = - 2. 080, P ： O. 045 ; t = -2. 190, P = 0. 035 ）.No difference was found between different lime periods（t=-0. 531 ,P=0. 598）. The difference of the resultsbelween two measurenlenls from the same palienl was O. 013. ConclusionsC-Quant is a nont＇ontacl,noninvade,rapid and convenient method from the measurement of straylight in myopia and posI-LAS1K eyes due to the high repeatability and reproducibilily.