Altoaimi Basal H, Almutairi Meznah S, Kollbaum Pete, Bradley Arthur
1School of Optometry, Indiana University, Bloomington, Indiana 2Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia *
Optom Vis Sci. 2017 Oct;94(10):971-980. doi: 10.1097/OPX.0000000000001121.
Wearing aspheric contact lenses adds significant amounts of negative spherical aberration (SA). Also, when accommodated and converged to near targets, pupil size shrinks and SA shift from positive to more negative direction. Interestingly, in this study, pupil miosis was fully or partially able to compensate for the additional accommodation-induced negative SA.
The present study aims to examine the accommodative response characteristics of young eyes fit with aspheric single vision contact lenses (SVCLs) that add significant negative SA to the eye responding to a wide range of accommodation stimuli.
Using a Shack-Hartmann aberrometer, the accommodation behavior in eight young adult eyes (mean age and spherical equivalent is 27.25 ± 2.05 years and -1.75 ± 1.80D, respectively) was measured while subjects fixated binocularly and monocularly 20/40 letter E, which were moved from 2 m to 20 cm (0.5 to 5D) in 0.25D steps. Using natural pupils, refractive state was defined using three standard criteria: the dioptric power that (1) minimized the root mean square error (minRMS), (2) best-fit paraxial, and (3) provided the peak image quality (peak IQ).
Wearing aspheric lenses with negative SA shifts the mean SA of the unaccommodated eyes from +0.05 μm (eyes only) to -0.029 μm (eyes + SVCL) and increases the negative SA for the eye + lens when accommodating from -0.029 to -0.07 μm for natural pupils. Aberration changes with accommodation were attenuated by the accommodative pupil miosis, which reduced binocular viewing pupil diameters from 3.9 to 3.3 mm. This alteration of the typical SA levels by the aspheric SVCL did not prevent accurate accommodation (mean ± standard deviation accommodative lag under binocular viewing were -0.08 ± 0.12D, -0.38 ± 0.12D, and -0.26 ± 0.08D for paraxial, minRMS, and peak IQ, respectively).
These data clearly show that aspheric contact lenses designed to correct some or all of the unaccommodated eye's positive SA do not interfere with accommodation.
佩戴非球面隐形眼镜会增加大量负球差（SA）。此外，当眼睛调节并集合到近目标时，瞳孔尺寸会缩小，球差会从正方向转变为更负的方向。有趣的是，在本研究中，瞳孔缩小能够完全或部分补偿额外的因调节引起的负球差。
本研究旨在研究年轻眼睛佩戴非球面单焦点隐形眼镜（SVCL）时的调节反应特征，这种隐形眼镜会给眼睛增加显著的负球差，以应对各种调节刺激。
使用夏克-哈特曼像差仪，测量了8名年轻成年人眼睛（平均年龄和等效球镜分别为27.25±2.05岁和-1.75±1.80D）的调节行为，受试者双眼和单眼注视20/40的字母E，该字母从2米移动到20厘米（0.5至5D），步长为0.25D。使用自然瞳孔，根据三个标准定义屈光状态：（1）使均方根误差最小化（minRMS）的屈光度，（2）最佳拟合近轴的屈光度以及（3）提供峰值图像质量（peak IQ）的屈光度。
佩戴具有负球差的非球面镜片会使未调节眼睛的平均球差从+0.05μm（仅眼睛）变为-0.029μm（眼睛+SVCL），并且当自然瞳孔调节时，眼睛+镜片的负球差会从-0.029μm增加到-0.07μm。调节性瞳孔缩小减弱了球差随调节的变化，这使双眼注视时的瞳孔直径从3.9毫米减小到3.3毫米。非球面SVCL对典型球差水平的这种改变并未妨碍准确的调节（双眼注视下，近轴、minRMS和peak IQ的平均调节滞后±标准差分别为-0.08±0.12D、-0.38±0.12D和-0.26±0.08D）。
这些数据清楚地表明，旨在矫正部分或全部未调节眼睛正球差的非球面隐形眼镜不会干扰调节。
