角膜塑形术后眼前节形态及调节功能

Anterior segment biometry and accommodative function after orthokeratology

目的研究近视儿童在配戴角膜塑形镜前及3个月后，调节反应及调节过程中眼前节形态的变化。方法前瞻性实验研究。本实验共纳入18名进展性近视青少年[（14．4±2．6）岁]作为研究对象。在配戴角膜塑形镜前及持续夜戴3个月后（摘镜后2h内），在采用Badal光学系统矫正受检者屈光不正的基础上，使用开放视野型红外验光仪分别在0D、3D和5D的调节刺激下测量眼球屈光力，并计算调节反应量。同时使用实验室自行搭建的超长深度光学相干断层扫描仪（OCT）获取不同调节刺激下眼前节形态，每种刺激均重复拍摄2次。眼前节形态参数包括瞳孔直径（PD）、前房深度（ACD）、晶状体厚度（LT）以及晶状体前表面曲率半径（LAC）。分析戴镜前及戴镜3个月后调节反应及眼前节形态变化量的差异，数据采用配对t检验进行比较。结果在配戴角膜塑形镜3个月后，调节反应在3D[（1．72±0．59）Dvs（2．42±0．84）D]和5D[（3．09±0．63）Dvs．（3．61±0．86）D]刺激下均显著增加，差异有统计学意义（t=2．84、2．12，P〈0．05）。戴镜3个月后，2种调节刺激下调节刺激前后的AACD、ALAC、APD、△LT均较戴镜前变化更为显著。AACD[3D：（-0．11±0．04）mmvs．（-0．16±0．06）mm，t=3．88，P〈0．01；5D：（-0．15±0．05）mmvs．（-0．20±0．07）mm，t=2．37，P〈0．051、ALAC[3D：（-2．60±0．79）mm vs．（-3．81±1．08）mm，t=3．96，P〈0．01；5D：（-3．57±1．14）mmvs．（-4．32±1．36）mm，t=2．08，P〈0．05]、ALT[3D：（0．22±0．13）mmvs．（0．27±0．06）mm，t=-1．94，P〈0．05；5D：（0．26±0．09）mmvs．（0．30±0．10）mm，t=-1．99，P〈0．051在戴镜前后的差异均有统计学意义，而APD仅在3D[（-1．55~0．42）mmvs.（-1．71±0．37）mm]调节刺激下变化量具有统计学意义（t=1．76，P〈0．05）。结论配戴角膜塑形镜后，调节过程中调节反应及眼前节形态的变化幅度增大，调节滞后减少，调节功能得到改善。

Objective To investigate the changes in accommodative response and anterior segment biometry during accommodation in young progressive myopes who wear overnight orthokeratology lenses. Methods Eighteen children （age： 14.4±2.6 years） were enrolled in this prospective experimental study and were tested before wearing orthokeratology （OK） lenses and after wearing them for three months. Using a Badal optical system, the refractive error of each subject was corrected before and after lens wear, and then accommodative stimuli of 3 D and 5 D were presented. A custom-built optical coherence tomographer （OCT） with a long scan depth was used to image the entire anterior segment through the pupil, and to obtain the anterior segment biometry including pupil diameter （PD）, anterior chamber depth （ACD）, lens thickness （LT） and the lens anterior surface＇s radius of curvature （LAC）. An auto-refractometer （WAM-5500） was used to measure ocular refraction during accommodation, which was used to calculate the accommodative response. The measurements of anterior segment biometry and accommodative response were repeated twice under each accommodative state. Results After wearing orthokeratology lenses for one to three months, an improvement in the accommodative response was evident under both the 3 D （1.72±059 D vs. 2.42±0.84 D）and 5 D （3.09±0.63 D vs. 3.61±0.86 D） accommodative states （paired t-test, t=2.84, 2.12, P〈0.05）. During at.commodation, APD, AAC[）, ALT, and ALAC changed obviously. Compared with baseline （betbre wearing OK lenses）, accommodation-related changes in AACD （3 D：-0.11±0.04 mm vs. -0.16-＋0.06 ram, t=3.88, P〈O.01, 5 D： -0.15±0.05 ,urn vs. -0.20±0.07 mm, t=2.37, P〈0.05）, ALAC （3 D：-2.60±0.79 mm vs. -3.81±1.08 mm, t=3.96, P〈0.01; 5 D： -3.57±1.14 mm vs. -4.32±1.36 mm, t=2.08, P〈0.05） and ALT （3 D： 0.22±0.13 mm vs. 0.27±0.06 mm, t=-1.94, P〈0.05; 5 D： 0.26±0.09 mm vs. 0.30±0.10 mm, t=-1.99, P〈0.05） showed statistically significant increases. Conclusion After wearing orthokeratology lenses for 3 months, the accommodative response and changes in the anterior segment biometry increase in myopic children.