角膜交联手术前后圆锥角膜患者眼压和角膜生物力学参数的变化及其相关性

Changes and correlation of intraocular pressure and corneal biomechanical parameters in patients with keratoconus before and after corneal cross-linking surgery

目的探讨角膜交联手术前后圆锥角膜患者眼压和角膜生物力学参数的变化和相关性。方法选取2017年11月至2018年10月在我院眼屈光中心就诊并确诊为进展期圆锥角膜患者68例(79眼),所有患者均行快速跨上皮角膜交联手术进行治疗。所有患者均行常规眼科检查,采用三维眼前节分析系统Pentacame(德国Oculus公司)检查患者角膜形态,非接触式眼压计(日本Topocon公司)测量患者非接触式眼压(NCT),角膜生物力学眼压分析仪Corvis ST(德国Oculus公司)测量患者非矫正眼压(IOPnct)、生物力学矫正眼压(bIOP)及角膜生物力学参数。结果角膜交联手术后3个月、6个月和1年患者的角膜中央厚度分别为(443.92±28.33)μm、(448.22±34.65)μm、(449.21±32.34)μm,与术前角膜中央厚度(449.17±32.60)μm相比,差异无统计学意义(F=0.370,P=0.87)。角膜交联手术后3个月、6个月和1年患者的角膜前表面曲率分别为(49.41±4.28)D、(48.54±2.57)D、(48.77±2.29)D,术前角膜前表面曲率为(49.54±4.67)D,术后6个月和1年较术前明显下降,差异均有统计学意义(均为P<0.05)。角膜交联手术后6个月和1年患者NCT分别为(10.73±2.91)mmHg(1 kPa=7.5 mmHg)、(11.13±2.50)mmHg,明显高于术前(8.30±2.96)mmHg,差异均有统计学意义(均为P<0.05)。术后3个月和1年患者IOPnct分别为(13.64±2.40)mmHg、(13.94±2.01)mmHg,均高于术前(11.47±2.12)mmHg,差异均有统计学意义(均为P<0.05)。术后6个月和1年患者角膜第一次压平长度低于术前,第二次压平速率大于术前,差异均有统计学意义(均为P<0.05)。NCT和IOPnct与角膜中央厚度均具有明显的正相关性(均为P<0.05),与第一次压平长度、最大变形幅度和顶点距离均具有明显的负相关性(均为P<0.05)。结论角膜交联手术会导致患者NCT测量值增高,角膜生物力学眼压分析仪Corvis ST可以排除角膜生物力学参数对圆锥角膜患者眼压测量的影响。

Objective To investigate the changes and correlation of the intraocular pressure and corneal biomechanical parameters in patients with keratoconus before and after corneal cross-linking surgery.Methods A total of 68 cases(79 eyes)diagnosed with progressive keratoconus at our refractive center from November 2017 to October 2018 were selected.All these patients had undergone accelerated trans-epithelial corneal cross-linking surgery and received routine ophthalmological examination.The corneal morphology of patients was examined by the three-dimensional anterior segment analysis system Pentacame,the non-contact intraocular pressure(NCT)was measured by the non-contact tonometer,and the non-corrected intraocular pressure(IOPnct),biomechanical corrected intraocular pressure(bIOP)and corneal biomechanical parameters were detected by the Corvis ST.Results The central corneal thickness was(443.92±28.33)μm,(448.22±34.65)μm and(449.21±32.34)μm at month 3,6 and 12 after corneal cross-linking surgery.Compared with the preoperative thickness(449.17±32.60)μm,the differences were not statistically significant(F=0.370,P=0.87).The anterior corneal surface curvature at month 3,6 and 12 after corneal cross-linking surgery was(49.41±4.28)D,(48.54±2.57)D and(48.77±2.29)D,respectively.Compared with the preoperative value(49.54±4.67)D,the postoperative anterior corneal surface curvature at month 6 and month 12 was significantly decreased,with the differences being statistically significant(both P<0.05).The postoperative NCT at month 6 and 12 was(10.73±2.91)mmHg(1 kPa=7.5 mmHg)and(11.13±2.50)mmHg,respectively,which were both significantly higher than the preoperative value(8.30±2.96)mmHg,with statistical significance(both P<0.05).The postoperative IOPnct at month 3 and 12 was(13.64±2.40)mmHg and(13.94±2.01)mmHg,respectively,which were both higher than the preoperative value(11.47±2.12)mmHg,with the differences being statistically significant(both P<0.05).At month 6 and 12 after surgery,the 1st applanation length was lower than that before surgery,while the second applanation velocity was higher than that before surgery,with statistical significance(both P<0.05).NCT and IOPnct showed significant positive correlation with the central corneal thickness(both P<0.05),and significant negative correlation with the 1st applanation length,Def.Ampl and P.Dist(all P<0.05).Conclusion Corneal cross-linking surgery can lead to increased NCT in patients.Corvis ST can rule out the influence of corneal biomechanical parameters on the measurement of IOP in patients with keratoconus.