Marsack Jason D, Rozema Jos J, Koppen Carina, Tassignon Marie-Jose, Applegate Raymond A
University of Houston College of Optometry, Visual Optics Institute, Houston, TX 77204, USA.
Optom Vis Sci. 2013 Apr;90(4):324-34. doi: 10.1097/OPX.0b013e318288c2b1.
The common change in corneal morphology that is seen in keratoconus (KC) suggests the presence of common high-order aberration (HOA) structures and the potential for HOA corrections that apply to more than one eye. The purpose of this investigation is to classify a sample of KC eyes into subgroups based on similar HOA characteristics and simulate optical performance of common HOA corrections on members of each subgroup.
High-order aberrations were recorded over a 5-mm pupil on 111 KC eyes. The eyes were divided into five subgroups based on observed commonality in HOA structure. From each subgroup, two eyes were removed for later evaluation of corrections. Principal components analysis was performed on the remaining eyes of each subgroup. The first principal component was scaled to form a set of corrections. Simulated optical correction of the test eyes was performed by identifying the magnitude of the inner-group correction providing the lowest level of residual higher order root mean square wavefront error (HORMS). Residual uncorrected HORMS was compared with levels found in uncorrected normal eyes and KC eyes wearing rigid gas-permeable corrections.
Ninety (81%) of the 111 eyes were included in one of the five subgroups. All 10 test eyes experienced a reduction in HORMS with a template correction compared with their uncorrected levels. Median HORMS reduced from uncorrected levels of 2.14 to 0.97 μm. On average, the 10 subjects experienced a 51% reduction in HORMS (minimum, 16%; maximum, 81%; p < 0.01). When scaled to a 4-mm pupil, five of the 10 eyes experienced residual uncorrected HORMS within limits associated with gas-permeable wear.
Overlap exists across these templates because of the dominance of vertical coma in the HOA structure. All eyes evaluated received reduced HORMS with a template-based correction.
圆锥角膜（KC）中常见的角膜形态变化提示存在常见的高阶像差（HOA）结构，以及适用于多只眼睛的HOA矫正潜力。本研究的目的是根据相似的HOA特征将KC眼样本分为亚组，并模拟常见HOA矫正对每个亚组成员的光学性能。
在111只KC眼的5mm瞳孔上记录高阶像差。根据HOA结构中观察到的共性，将这些眼睛分为五个亚组。从每个亚组中取出两只眼睛用于后续矫正评估。对每个亚组的其余眼睛进行主成分分析。对第一主成分进行缩放以形成一组矫正。通过确定提供最低残余高阶均方根波前误差（HORMS）水平的组内矫正幅度，对测试眼进行模拟光学矫正。将残余未矫正的HORMS与未矫正的正常眼和佩戴硬性透气性矫正镜片的KC眼中发现的水平进行比较。
111只眼中的90只（81%）被纳入五个亚组之一。与未矫正水平相比，所有10只测试眼通过模板矫正后HORMS均降低。HORMS中位数从未矫正水平的2.14μm降至0.97μm。平均而言，10名受试者的HORMS降低了51%（最小值为16%；最大值为81%；p<0.01）。缩放到4mm瞳孔时，10只眼中有5只的残余未矫正HORMS在与透气性佩戴相关的范围内。
由于HOA结构中垂直彗差占主导，这些模板之间存在重叠。所有评估的眼睛通过基于模板的矫正后HORMS均降低。
