人工晶状体眼在不同全眼球差下焦深的比较及对客观视觉质量影响的研究

Effect of residual ocular spherical aberration on depth of focus and objective quality of vision in pseudophakic eyes

目的探讨内内障联合人工品状体（IOL）植入术后全眼球差对焦深及客观视觉质量的影响，，方法同顾性病例研究。收集2011年9月至2012年3月在天津市眼科医院就诊的年龄相关门内障联合人工品状体植入术后3个月患者80例（140只眼）。非球面IOL眼110只眼．球面IOL眼30只眼。对5rain瞳孔下非球面IOL全眼球差进行分i组，I组（-0．1μm≤SA〈0．05μm）32只眼，II组（0．05μm≤SA〈0．15μm）38只眼，III组（0．15μm≤SAG0．4μm）40只眼，用i-Trace波前像差仪测量全眼像差及角膜像差进行像差分析。使用VOL—CT软件，＋2．00～2．00D，经过焦点分析绘制斯特尔比率（Ste—rolRatio，SR）f}f1线，对比不同球差组的离焦。去除散光后，根据离焦计算斯特尔比率，同时从该软件可以获得调制传递函数（modulationtransferfunction，MTF）截止空间频率。SR和MTF截止空间频率作为评价光学质量的标准。我们所测的焦深（depthoffocus，DOF）值是按大于等于sR最大值80％的离焦范围计算。分析非球面IOL不同全眼球差组对焦深及视觉质量的影响并同球面IOL组比较。结果5mm瞳孔直径下非球面10L组MTF截止空间频率和斯特尔牢比球面IOL组有所增加，其中非球面IOLII组（0．05μm≤SA〈0．15μm）比I、μml组均有轻度的增加，然而球面IOL组焦深最大。SR随球差的增加而减小，焦深与全眼球差成正相关。结论白内障术后余留一定全眼球差（约＋0．08μm）可以改善视觉质量，后J时有较好的矫正远距离的近距离视力及阅读能力。最终全眼球差在0．07～0．1μm时可以获得较好的视网膜成像质量及较高的离焦耐受性。

Objective To investigate the level of residual spherical aberration that shows the best objective quality of image and depth of focus （DOF） of eyes after cataract surgery with aspher- ic intraocular lens and spherical intraocular lens implantation. Methods The clinical data from 140 eyes （80 patients） of 3-month follow-up after cataract surgery with IOL implantation were retrospec- tively studied, including 98 eyes with aspheric IOL implantation and 28 eyes with spherical IOL im- plantation. Corneal, entire and internal aberrations including total higher-order aberration, 3rd-order and 4th-order aberration were computed using i-Trace visual function analyzer. Base on entire spheri- cal aberration （SA） value, aspheric IOL were assigned to three groups： group I （32 eyes） -0.1gm~ SA〈0.05~tm, group II （38 eyes） 0.05gm~〈SA〈0.15gm, group III （40 eyes） 0.15um~〈SA〈0.4Bm. Strel ratio （SR）, modulation transfer function （MTF） curves were measured with Visual Optics Lab-CT software, DOF and MTF cut-off frequency was obtained at 5ram pupil diameter. Objective depth of focus was computed as the focus range at which the Sterol ratio didn＇t fall below 80% of maximum. These values were analyzed and compared with spherical IOL group. Results The MTF cut-off frequency value and SR was slightly increased with implantation of the SA0.05~tm~〈SA〈0.15 /am aspheric IOL under the pupil diameter of 5mm. DOF of spherical IOL were larger than aspheric IOL, The MTF cutoff values were higher with decreasing total ocular spherical aberration （r =-0.373; P 〈0.05）, DOF had positive correlation with entire spherical aberration （r =0.365; P 〈 0.05）. Conclusions A final spherical aberration of about 0.08urn obtained by compensation of IOL asphericity give the greatest improvement in objective quality of vision and better distance-corrected near visual acuity. However, a final target entire spherical aberration between 0.07 mm and 0.10 mm shall be considered to be achieved best image quality with the higher tolerance to defocus.