Doughty Michael J, Laiquzzaman Mohammed, Müller Andreas, Oblak Emil, Button Norman F
Department of Vision Sciences, Glasgow-Caledonian University, Glasgow, UK.
Ophthalmic Physiol Opt. 2002 Nov;22(6):491-504. doi: 10.1046/j.1475-1313.2002.00053.x.
To ascertain the impact of central corneal thickness (CCT, as assessed by pachometry) and central corneal curvature (as assessed by keratometry) on clinical measures of intra-ocular pressure (IOP, as assessed by tonometry), especially in the young and elderly.
Pachometry, keratometry and tonometry were carried out on three groups, namely children aged 5-15 years, adults aged 32-60 years, and elderly individuals aged between 61 and 82 years. For children, ultrasound pachometry was combined with non-contact tonometry (NCT), specular microscopy was used with Perkins tonometry in the adults, and ultrasound pachometry was used with Perkins tonometry for the elderly. Central corneal curvature was assessed by keratometry.
The average CCT in children was 0.529+/-0.034 mm (n = 104, +/-S.D.), averaged 0.533+/-0.033 in adults (n=75) and 0.527+/-0.034 mm (n=91) in the elderly. Tonometry values averaged 16.7+/-2.9 mm in children, 13.0+/-3.5 mmHg in adults and 13.6+/-2.5 mm in the elderly group. Central corneal thickness values were not predictably different in relation to central corneal curvature values. Regression analyses indicated that the tonometry values were higher in both children and the elderly who had thicker corneas (and vice versa) (p < 0.003), with the measures increasing by 1.3+/-0.4 and 2.6+/-0.4 mmHg for a 10% difference in CCT in children and the elderly, respectively. For adults, no statistically significant difference in tonometry values could be demonstrated with respect to CCT (<1 mmHg for a 10% difference in CCT), and for no group were the CCT or tonometry values predictably different in relation to central comeal curvature values.
The results of these studies, albeit relatively small scale, indicate that in young or elderly individuals with essentially normal IOP and CCT measures, the tonometry values show only small differences with respect to CCT. The slope in the observed relationship was not that different from an average of 1.5 mmHg for a 10% different in CCT, as obtained from a literature analysis over a 30-year period. The magnitude of the effect does not provide evidence that pachometry needs to be routinely performed in glaucoma screening protocols based on tonometry. Notwithstanding, the finding of higher than expected tonometry values should be further investigated, by pachometry, especially in very young children and in the elderly.
确定中央角膜厚度（通过角膜厚度测量法评估）和中央角膜曲率（通过角膜曲率测量法评估）对眼压临床测量值（通过眼压测量法评估）的影响，尤其是在年轻人和老年人中。
对三组人群进行角膜厚度测量、角膜曲率测量和眼压测量，这三组分别是5至15岁的儿童、32至60岁的成年人以及61至82岁的老年人。对于儿童，超声角膜厚度测量法与非接触眼压测量法（NCT）相结合；对于成年人，镜面显微镜检查与珀金氏眼压测量法一起使用；对于老年人，超声角膜厚度测量法与珀金氏眼压测量法一起使用。通过角膜曲率测量法评估中央角膜曲率。
儿童的平均中央角膜厚度为0.529±0.034毫米（n = 104，±标准差），成年人平均为0.533±0.033毫米（n = 75），老年人为0.527±0.034毫米（n = 91）。眼压测量值在儿童中平均为16.7±2.9毫米汞柱，成年人中为13.0±3.5毫米汞柱，老年人组中为13.6±2.5毫米汞柱。中央角膜厚度值与中央角膜曲率值之间没有可预测的差异。回归分析表明，角膜较厚的儿童和老年人的眼压测量值较高（反之亦然）（p < 0.003），儿童和老年人的中央角膜厚度每相差10%，眼压测量值分别增加1.3±0.4和2.6±0.4毫米汞柱。对于成年人，眼压测量值相对于中央角膜厚度没有统计学上的显著差异（中央角膜厚度相差10%时差异<1毫米汞柱），并且在任何一组中，中央角膜厚度或眼压测量值与中央角膜曲率值之间都没有可预测的差异。
这些研究结果虽然规模相对较小，但表明在眼压和中央角膜厚度测量基本正常的年轻人或老年人中，眼压测量值相对于中央角膜厚度仅显示出微小差异。观察到的关系斜率与通过对30年期间的文献分析得出的中央角膜厚度相差10%时平均相差1.5毫米汞柱的情况没有太大不同。这种影响的程度并没有提供证据表明在基于眼压测量的青光眼筛查方案中需要常规进行角膜厚度测量。尽管如此，眼压测量值高于预期的发现应该通过角膜厚度测量进一步研究，尤其是在非常年幼的儿童和老年人中。
