两种角膜地形图系统测量正视儿童角膜的比较  

Comparison of two corneal topography systems for the measurement of emmetropic school children

作　　者：朱乐如[1] 查屹[1] 施明光[1] 

机构地区：[1]温州医学院第二附属医院眼科,温州浙江325000

出　　处：《眼视光学杂志》2007年第2期120-123,共4页Chinese Journal of Optometry & Ophthalmology

基　　金：国家自然科学基金项目(30471858)

摘　　要：目的比较Humphrey ALTAS角膜地形图系统与Orbscan-Ⅱ角膜地形图系统对角膜前表面不同区域形态测量的一致性,探讨正视儿童角膜前表面的形态变化规律。方法分别使用Humphrey ALTAS角膜地形图系统和Orbscan-Ⅱ角膜地形图系统测量53例正视儿童(96眼)角膜前表面SimK1值、SimK2值、角膜散光量及角膜散光轴向值,并分区域比较轴向图上1mm、2mm、3mm、4mm、5mm、6mm、7mm、8mm、9mm、10mm区平均曲率值以及以角膜顶点为中心角膜中央3mm区内37个定点的角膜前表面曲率值。结果两种仪器测得的SimK1、SimK2、角膜散光量的差值分别为(0.14±0.44)D、(0.30±0.48)D和(-0.16±0.36)D。角膜散光轴像差值≤15°的占89.6%。区域比较显示8mm区内测量差值的变化值(s)均小于0.5D,而在8mm区以外逐渐增大,最大为0.8D(10mm区)。定点比较发现,角膜顶点曲率值差最大,为(0.57±0.61)D。形状因子SF为0.3177±0.11966。结论两种仪器的SimK值可互换,散光轴向的一致性较好;中央区、旁中央区的测量一致性好于周边区;角膜顶点曲率测量值的一致性较差。正视儿童角膜呈非球面。Objective To evaluate the agreement between the Humphrey ALTAS Corneal Topography System and Orbscan-Ⅱ in measuring different zones of the anterior cornea in emmetropic children and to investigate the anterior morphologic characteristics of the cornea simultaneously with the data obtained from the two systems.Methods The Humphrey ALTAS Corneal Topography System（Version A12） and Orbscan-Ⅱ （Bausch ＆ Lomb Surgical version 3.0） were used to obtain an anterior axial map on 96 normal corneas（53 emmetropic children）. SimK1, SimK2, and comeal astigmatic readings of the power and axis as well, were evaluated for axial maps by both instruments. Mean curvatures of the different zones from 1 mm to 10 mm （interval of 1 mm） and the anterior curvature of 37 defined, standardized points within the central 3 mm zone were also compared separately. Results Tbo mean differences of SimK1, SlinK2, and astigmatic power between the two instruments were （0.14±0.44）D, （0.30±0.48）D, and （-0.16±0.36）D, respectively. The difference in the astigmatie axis below 15 degrees accounted for 89.6% of the difference. Comparison of the different zones showed that the standard deviations （SD） of differences between the two instruments were below 0.5 D within the 8 mm zone, but on the left side, along with an increase in zone diameter, there was a maximum difference of 0.8 D in the 10 mm zone. The bias of the mean anterior curvature was dose to zero（ -0.021 D） on the 5 mm zone. Among the 37 defined points, the maximum difference in curvature（0.57 D） was on the comeal apex. The shape factor was 0.3177 ± 0. 11966 and the mean curvature of the analyzed zones for both instruments decreased from the central to the peripheral zone. Conclusion The two instruments could be used interchangeably for measuring SimK. Fine agreement was found in the astigmatic axis. The SD of the difference between the two instruments was higher than 0.5 D outside the 8 mm zone and showed that central and paracentral comeal zones ha

关 键 词：角膜地形图/统计学和数值数据 角膜 前表面 儿童 

分 类 号：R770.4[医药卫生—眼科]