Hashemi Hassan, Mehravaran Shiva
Farabi Eye Hospital, Department of Ophthalmology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
J Cataract Refract Surg. 2007 May;33(5):841-7. doi: 10.1016/j.jcrs.2007.01.019.
To determine the agreement between scanning slit topography (Orbscan II, Bausch & Lomb) and Scheimpflug imaging (Pentacam, Oculus) in corneal elevation, corneal curvature, and anterior chamber depth (ACD) measurements before and after laser refractive surgery for myopia and to compare the postoperative changes seen with these devices.
Noor Vision Correction Center, Tehran, Iran.
In a prospective observational case-series study, 23 consecutive myopic patients having laser refractive surgery were examined with the Orbscan II and Pentacam preoperatively and 6 weeks postoperatively. Readings of ACD, anterior (A-) and posterior (P-) best-fit sphere (BFS) size, central elevation (CE), maximum elevation (ME), axial power in the 3.0 mm zone (AX3) and 5.0 mm zone (AX5), and tangential power in these zones (TG3 and TG5, respectively) were collected and used in the analyses.
Statistically significant interdevice differences were found preoperatively for all parameters except P-TG3 (P = .014) and in operated eyes for ACD, anterior parameters of A-AX3 and A-AX5, and all posterior corneal parameters. In posterior corneal measurements, Orbscan II demonstrated significant postoperative changes in all parameters except P-AX5 (P = .004) and P-TG5 (P = .034), although none of the differences was statistically significant with the Pentacam. The devices measured similar postoperative changes in anterior curvature parameters and in P-AX5 and P-TG5; all other changes were significantly different.
Compared to the Pentacam, the Orbscan II yielded larger posterior elevation values before and after surgery and significant postoperative changes in P-CE and P-ME. Further studies can determine which device gives more accurate images of the cornea and redefine screening criteria.
确定扫描裂隙地形图（Orbscan II，博士伦公司）和眼前节分析系统（Pentacam，德国奥克卢斯公司）在近视激光屈光手术前后角膜高度、角膜曲率和前房深度（ACD）测量方面的一致性，并比较这些设备所观察到的术后变化。
伊朗德黑兰努尔视力矫正中心。
在一项前瞻性观察性病例系列研究中，对23例连续接受激光屈光手术的近视患者在术前及术后6周分别使用Orbscan II和Pentacam进行检查。收集ACD、前（A-）和后（P-）最佳拟合球镜（BFS）大小、中央高度（CE）、最大高度（ME）、3.0mm区域（AX3）和5.0mm区域（AX5）的轴向屈光力以及这些区域的切向屈光力（分别为TG3和TG5）的读数，并用于分析。
术前，除P-TG3（P = 0.014）外，所有参数在两种设备间均存在统计学显著差异；在手术眼的ACD、A-AX3和A-AX5的前向参数以及所有后角膜参数方面也存在差异。在后角膜测量中，Orbscan II显示除P-AX5（P = 0.004）和P-TG5（P = 0.034）外，所有参数术后均有显著变化，尽管与Pentacam相比，这些差异均无统计学意义。两种设备在前曲率参数以及P-AX5和P-TG5方面测量的术后变化相似；所有其他变化均有显著差异。
与Pentacam相比，Orbscan II在手术前后得出的后表面高度值更大，且P-CE和P-ME术后有显著变化。进一步的研究可以确定哪种设备能提供更准确的角膜图像，并重新定义筛查标准。
