Prakash Gaurav, Mammen Alex, Jhanji Vishal
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
University of Pittsburgh Medical Center, 203 Lothrop St, Suite 800, Pittsburgh, PA, 15213, USA.
Eye Vis (Lond). 2023 Oct 1;10(1):40. doi: 10.1186/s40662-023-00357-y.
To compare the rate of fractional change for multiple corneal tomographic factors in progressive keratoconus (KC).
In this retrospective case series, 40 eyes (40 patients) with progressive KC (increase in central keratometry of 1.00 D or maximum keratometry of 1.50 D on two visits at least six months apart) were included. Cases with previous history of ocular surgery, poor scans, corneal scars, severe dry eyes, post-excimer ectasia, pellucid marginal degeneration were excluded. Medical records, corneal tomography and anterior corneal wavefront (8 mm) (Scheimpflug tomography, Pentacam, Oculus, Germany) were analyzed. Rate of fractional change (Rx = (x - x)/(|x|t)); where, x = value at follow-up, x = value at initial visit and t = time in months, was measured.
The mean age of the patients was 30.0 ± 8.4 years. The mean follow-up duration was 8.9 ± 4.2 months. Coma (0.076 ± 1.4) had the largest rate of fractional change (P = 1.7 × 10, Kruskal-Wallis test). The rate of fractional change was higher for aberrometric parameters (anterior corneal higher-order aberrations root mean square and anterior coma) compared to pachymetric and keratometric parameters (P values ranging from 1.4 × 10 to 7.4 × 10, Mann-Whitney test, effect size ranging from 0.4-0.7). The rate of fractional change was comparable between pachymetric and keratometric factors (P > 0.05 for all comparisons, Mann-Whitney test).
Anterior corneal wavefront, especially anterior coma, were noted to have higher rate of fractional change compared to single point keratometric and pachymetric indices in progressive KC. This information can be used for decision-making when monitoring patients with KC.
比较进行性圆锥角膜（KC）中多个角膜断层扫描因素的变化率。
在这个回顾性病例系列中，纳入了40只眼（40例患者）的进行性KC（两次就诊时中央角膜曲率增加1.00 D或最大角膜曲率增加1.50 D，间隔至少6个月）。排除有眼部手术史、扫描质量差、角膜瘢痕、严重干眼、准分子激光术后扩张、透明边缘变性的病例。分析病历、角膜断层扫描和前角膜波前（8 mm）（德国Oculus公司的Pentacam Scheimpflug断层扫描）。测量变化率（Rx = （x - x）/（|x|t））；其中，x =随访时的值，x =初次就诊时的值，t =月数。
患者的平均年龄为30.0±8.4岁。平均随访时间为8.9±4.2个月。彗差（0.076±1.4）的变化率最大（P = 1.7×1）。与测厚和角膜曲率参数相比，像差参数（前角膜高阶像差均方根和前彗差）的变化率更高（P值范围为1.4×1至7.4×1，Mann-Whitney检验，效应大小范围为0.4 - 0.7）。测厚和角膜曲率因素之间的变化率相当（所有比较的P>0.05，Mann-Whitney检验）。
在进行性KC中，与单点角膜曲率和测厚指数相比，前角膜波前，尤其是前彗差，变化率更高。该信息可用于监测KC患者时的决策。
