Orbscan测量近视眼角膜厚度

Analysis of corneal thickness in myopia using the Orbscan corneal topography system

目的 :评价裂隙扫描角膜地形图 /角膜测厚系统 (Orbscancornealtopographysystem)在分析近视眼角膜厚度分布特征中的应用价值。方法 :应用Orbscan(Orbtek ,SaltLakeCity ,UT ,USA)测量 2 0 6人 40 4只近视眼角膜厚度 ;用超声测厚仪测定其中 12 8人 2 5 6只高度近视眼角膜中央厚度 ,对两种测量方法进行比较分析。结果 :高度近视眼与中低度近视眼在角膜中央区和距角膜中心 3mm处上方、颞上、颞侧、颞下、下方、鼻下、鼻侧和鼻上等 9个直径 2mm区域的角膜厚度平均值 ,差异无统计学意义 (P >0 .0 5 )。两组角膜中央厚度最薄 ,分别为 (5 5 4.4± 35 .3) μm与 (5 5 5 .1± 33.8) μm ;鼻上方角膜厚度最厚 ,分别为 (6 6 1.3± 39.2 ) μm与 (6 6 1.4± 36 .1)μm。Orbscan系统测厚声速系数值设置为 0 .96 ,其与超声测厚法所得测量值之间 ,差异无统计学意义 (P >0 .0 5 )。结论 :Orbscan能方便、准确、有效地测量近视眼全角膜厚度 ,当声速系数值为 0 .96 。

Objective:To evaluate the use and accuracy of the Orbscan corneal topography system in measuring corneal thickness in myopia.Methods:Corneal thickness in 404 eyes of 206 myopic subjects was measured using the Orbscan corneal topography system; the central corneal thickness of 256 eyes of 128 high myopia subjects was measured using DGH 4000 ultrasound pachymetry. Corneal thickness measurements taken with the Orbscan corneal topography system and ultrasound pachymetry were compared.Results:There was no statistical difference (P>0.05) in corneal thickness between high myopia and mild to moderate myopia in nine regions of the cornea (central and superior, superotemporal, temporal, inferior temporal, inferior, inferonasal nasal, and superonasal). Each region was located 3mm from the visual axis with a diameter of 2mm. The central cornea had the lowest average thickness, (554.4±35.3)μm and (555.1±33.8)μm, respectively, and the superonasal cornea had the greatest average thickness, (661.3±39.2)μm and (661.4±36.1)μm, respectively. There was no statistical difference in the measurements between the Orbscan corneal topography system and ultrasound pachymetry if the acoustic factor of the Orbscan system was calculated at 0.96 (P>0.05).Conclusion:Corneal thickness can be measured conveniently, accurately and effectively using the Orbscan corneal topography system. Agreement between the Orbscan corneal topography system and ultrasonic pachymetry was high when the acoustic factor of Orbscan was calculated at 0.96.