长期配戴角膜接触镜对角膜形态的影响

目的 比较分析长期配戴软性角膜接触镜（SCL）及硬性透气性角膜接触镜（RGPCL）患者的中央角膜厚度（CCT）、角膜曲率及角膜内皮细胞形态之间的差别.方法 选取有角膜接触镜配戴适应证的屈光不正患者共172例（300眼）,除屈光不正外无其他任何眼病.根据患者的主观要求及眼部情况分为SCL配戴组（59例102眼）和RGPCL配戴组（113例198眼）.配戴方法均为日戴型连续配戴,即每日戴镜时间不少于6 h.随访时间为3年.分别于配戴前、配戴后6个月和3年进行检查,采用非接触式角膜内皮镜测量CCT、角膜内皮细胞计数、六角形比例及变异系数,采用电脑验光仪测量角膜曲率.对两组戴镜前后的各参数进行配对t检验,组间比较采用两独立样本t检验.结果 中央角膜厚度：戴镜后3年,SCL组CCT较戴镜前减少（27.1±0.8）mm,差异有统计学意义（P＜0.05）;RGPCL组CCT较戴镜前减少（3.1±2.2）mm,差异无统计学意义（P＞0.05）;两组间比较,戴镜前和戴镜后6个月时CCT差异无统计学意义,但在戴镜后3年时RGPCL组CTT较SCL组厚,两组差异有统计学意义（P＜0.05）.角膜曲率：SCL组戴镜后各时间点水平曲率和垂直曲率与术前比较,差异均无统计学意义;RGPCL组戴镜后各时间点与戴镜前比较,差异均有统计学意义（P＜0.05）;两组间比较,戴镜后3年RGPCL组角膜曲率较SCL组小,两组差异有统计学意义（P＜0.05）.角膜内皮细胞密度：SCL组和RGPCL组戴镜后角膜内皮细胞密度较戴镜前均有降低,差异均有统计学意义.戴镜后3年,SCL组和RGPCL组角膜内皮细胞密度分别降低了（368.5±31.5）个/mm^2和（140.2±5.6）个/mm^2,差异有统计学意义（P＜0.05）.六角形比例和变异系数：SCL组戴镜后3年与戴镜前比较,差异有统计学意义（P＜0.05）;RGPCL组戴镜前后变化不明显;两组间比较,戴镜后3年两组差异有统计学意义（P＜0.05）.结论 长期配戴RGPCL对患者角膜形态及功能的影响较小,同长期配戴SCL相比具有更高的安全性.

Effect of long-term contact lens wear on the cornea

Objective To evaluate the differences in central corneal thickness, curvature and endothelium between patients wearing soft contact lenses (SCL) and those wearing rigid gas permeable contact lenses (RGPCL). Methods Three hundred eyes of 172 patients with no eye disorders except ametropia were divided into two groups: SCL group and RGPCL group. All patients had to wear contact lenses at least 6 hours a day. Corneal thickness, corneal endothelium, corneal curvature and topography were measured and comparisons were made between baseline measurements and the measurements taken at various intervals: before wearing, 6 months, and 3 years after wearing the contact lenses. Results Central corneal thickness after 3 years of SCL wear was (27.1±-0.8)mm less than before wearing the SCL (P＜0.05); central corneal thickness after 3 years of RGPCL wear was (3.1±2.2)mm less than before wearing the RGPCL (P＞0.05), but there were no differences between the SCL and RGPCL groups prior to and 6 months after the lenses wear (P＞0.05). However, there were obvious differences at 3 years (P＜0.05). There were no obvious differences in corneal curvature in the SCL group (P＞0.05). But more differences betweeen wearing before and 3 years after in RGPCL group. The corneal endothelium in the SCL group was partially reduced (368.5±31.5)cells/mm2 and (140.2±5.6)cells/mm2 was reduced in the RGPCL group, there was a significant differencesbetween the 2 groups (P＜0.05). Conclusion This study shows that RGPCL affect the corneal endothelium less. Therefore, RGPCL can be worn safely over the long term.