Data from: Changes in corneal biomechanical properties after long-term topical prostaglandin therapy

Objective: To compare corneal biomechanical properties, measured by a newly developed tonometer (Corneal Visualization Scheimpflug Technology?Corvis ST), in untreated primary open angle glaucoma (POAG) patients?POAG patients with long-term topical prostaglandin analog (PGA) therapy and in normal controls. Further is to investigate the potential effects of PGA on corneal biomechanics. Methods: In this case-control study, 35 consecutive medication naïve eyes with POAG, 34 POAG eyes with at least 2 years treatment by PGA and 19 normal eyes were included. Intraocular pressure (IOP), central corneal thickness (CCT) and corneal biomechanical parameters, including deformation amplitude (DA), applanation time (AT1 and AT2), applanation length (AL1 and AL2), applanation velocity (AV1 and AV2), and peak distance and radius were measured using Corvis ST. Axial length and corneal curvature were measured with partial coherence interferometry (IOLMaster, Zeiss, Germany). General linear model analysis was performed to investigate the corneal biomechanical property changes among the normal controls, newly diagnosed POAG patients and POAG patients with long-term PGA treatment, and among the subgroups of different types of PGA treatment, including bimatoprost, latanoprost and travoprost. Furthermore, pairwise comparisons using Bonferroni correction for least squares means were employed. Results: AT1 (p<0.0001), AV1 (p<0.0001), AT2 (p=0.0001), AV2 (p<0.0001) and DA (p=0.0004) in newly diagnosed glaucoma patients were significantly different from those in normal subjects and in patients underwent at least 2 years topical PGA therapy after adjusting for age and gender. After adjusting for age, gender, IOP, CCT, axial length and corneal curvature, a significant difference was detected for DA between glaucoma patients without PGA treatment and patients with long-term PGA therapy (p=0.0387). Furthermore, there were no statistical significant differences in all of the corneal biomechanical parameters among the 3 types of PGA therapy subgroups, namely bimatoprost, latanoprost and travoprost. Conclusions: Significant changes in corneal deformation parameters were found among untreated POAG patients, POAG patients with long-term topical PGA therapy and normal controls. Long-term topical PGA treatment might have a direct effect on corneal biomechanical properties in addition to the indirect effect owing to the PGA-induced IOP reduction and CCT decrease on corneal dynamic properties.研究目的：采用新型眼压计——角膜可视化Scheimpflug技术眼压计（Corneal Visualization Scheimpflug Technology, Corvis ST），对比未治疗原发性开角型青光眼（Primary Open Angle Glaucoma, POAG）患者、长期局部应用前列腺素类似物（prostaglandin analog, PGA）治疗的POAG患者与正常对照人群的角膜生物力学特性，并探究PGA对角膜生物力学的潜在影响。 研究方法：本研究为病例对照研究，共纳入35例初治POAG患眼、34例接受至少2年PGA治疗的POAG患眼以及19例正常对照眼。使用Corvis ST测量眼内压（intraocular pressure, IOP）、中央角膜厚度（central corneal thickness, CCT）及多项角膜生物力学参数，包括变形振幅（deformation amplitude, DA）、压平时间（applanation time, AT1、AT2）、压平长度（applanation length, AL1、AL2）、压平速度（applanation velocity, AV1、AV2）以及峰值距离与峰值半径。采用部分相干干涉仪（IOLMaster, 卡尔蔡司，德国）测量眼轴长度与角膜曲率。采用广义线性模型分析正常对照人群、初诊POAG患者及长期PGA治疗POAG患者之间的角膜生物力学特性差异，并分析不同PGA治疗亚组（包括比马前列素、拉坦前列素与曲伏前列素）的差异。此外，采用Bonferroni校正的最小二乘均值两两比较进行统计学检验。 研究结果：校正年龄与性别后，初诊青光眼患者的AT1（p<0.0001）、AV1（p<0.0001）、AT2（p=0.0001）、AV2（p<0.0001）及DA（p=0.0004）与正常受试者及长期局部PGA治疗患者存在显著差异。进一步校正年龄、性别、IOP、CCT、眼轴长度及角膜曲率后，未接受PGA治疗的青光眼患者与长期PGA治疗患者的DA仍存在显著差异（p=0.0387）。此外，三种PGA治疗亚组（比马前列素、拉坦前列素与曲伏前列素）间的所有角膜生物力学参数均无统计学显著差异。 研究结论：未治疗POAG患者、长期局部PGA治疗的POAG患者与正常对照人群的角膜变形参数存在显著差异。除PGA通过降低IOP与CCT间接影响角膜动态特性外，长期局部PGA治疗可能对角膜生物力学特性存在直接作用。