Grupo de Investigación de Cirugía Refractiva y Calidad de Visión, Instituto de Oftalmobiología Aplicada, University of Valladolid, Valladolid, E-47005, Spain.
Ophthalmic Physiol Opt. 2009 Sep;29(5):535-48. doi: 10.1111/j.1475-1313.2009.00670.x.
To provide a model of an aberration-free profile and to clinically evaluate the impact of treatments based upon these theoretical profiles in the post-operative cornea.
Aberration-free profiles were deduced from the Zernike expansion of the difference between two corneal cartesian-ovals. Compensation for the focus-shift effects of removing corneal tissue were incorporated by preserving the location of the optical focus of the anterior corneal surface. Simulation of the surgical performance of the profile was performed by means of simulated ray-tracing through a cornea described by its anterior surface and pachymetry. Clinical evaluation was retrospectively analysed in terms of visual outcomes, corneal wavefront aberration and asphericity changes at 3-month follow-up compared to the baseline on 100 eyes treated for compound myopic astigmatism.
The proposed 'aberration-free' profiles theoretically preserve aberrations, becoming more oblate asphericity after myopic treatments, and more prolate after hyperopic ones. In the clinical evaluation, 94% of eyes were within +/-0.50 D of emmetropia. BSCVA improved significantly (p < 0.001). Induced corneal aberrations at 6-mm were below clinically relevant levels: 0.123 +/- 0.129 microm for HO-RMS (p < 0.001), 0.065 +/- 0.128 microm for spherical aberration (p < 0.001) and 0.058 +/- 0.128 microm for coma (p < 0.01), whereas the rate of induced aberrations per achieved D of correction were -0.042, -0.031, and -0.030 microm D(-1) for HO-RMS, SphAb, and coma (all p < 0.001). Induction of positive asphericity correlated to achieved correction (p < 0.001) at a rate 3x theoretical prediction.
'Aberration-free' patterns for refractive surgery as defined here together with consideration of other sources of aberrations such as blending zones, eye-tracking, and corneal biomechanics yielded results comparable to those of customisation approaches. Having close-to-ideal profiles should improve clinical outcomes decreasing the need for nomograms, and diminishing induced aberrations after surgery.
提供一种无像差轮廓模型，并在术后角膜中根据这些理论轮廓评估治疗的影响。
从两个角膜笛卡尔椭圆之间的差异的泽尼克展开中推导出无像差轮廓。通过保留前角膜表面的光学焦点位置，来补偿去除角膜组织的焦点移位效应。通过模拟前表面和角膜厚度的角膜光线追踪来模拟轮廓的手术性能。通过回顾性分析 100 只接受复合近视散光治疗的眼睛的视力结果、角膜波前像差和 3 个月随访时的非球面性变化，与基线相比进行临床评估。
所提出的“无像差”轮廓理论上保留了像差，在近视治疗后变得更加扁平和非球面，在远视治疗后变得更加椭圆。在临床评估中，94%的眼睛屈光度在±0.50 D 以内。BCVA 显著提高（p < 0.001）。6mm 处诱导的角膜像差低于临床相关水平：HO-RMS 为 0.123 +/- 0.129 微米（p < 0.001），球差为 0.065 +/- 0.128 微米（p < 0.001），彗差为 0.058 +/- 0.128 微米（p < 0.01），而每矫正 1 D 所诱导的像差率为 -0.042、-0.031 和 -0.030 微米 D（-1），用于 HO-RMS、SphAb 和彗差（均 p < 0.001）。正非球面性的诱导与实现的矫正相关（p < 0.001），速率为理论预测的 3 倍。
如这里所定义的，用于屈光手术的“无像差”模式以及考虑其他像差源，如混合区、眼球跟踪和角膜生物力学，产生的结果与定制方法相当。具有接近理想的轮廓应该会改善临床结果，减少对图表的需求，并减少手术后的诱导像差。
