Fujimoto Hisataka, Maeda Naoyuki, Shintani Ayumi, Nakagawa Tomoya, Fuchihata Mutsumi, Higashiura Ritsuko, Nishida Kohji
Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Department of Clinical Epidemiology and Biostatistics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Invest Ophthalmol Vis Sci. 2016 Jul 1;57(9):OCT169-75. doi: 10.1167/iovs.15-18650.
We quantified the chronologic progression of keratoconus using anterior segment optical coherence tomography (AS-OCT).
A total of 217 eyes from 113 patients with keratoconus, keratoconus suspect, or forme fruste keratoconus were evaluated by corneal tomography using swept-source OCT. Age-dependent changes in the radius of the posterior best-fit sphere (Rpost), minimum corneal thickness (Tmin), and distance from the thinnest point to the corneal vertex (Dmin) were examined over follow-up periods of up to 5.79 years and were analyzed using generalized estimating equation (GEE) nonlinear regression model.
Annual changes in Rpost (mean, -0.017 mm) and Tmin (-2.69 μm) were significantly higher in younger patients (P < 0.01, GEE nonlinear regression) and in patients with higher maximal K value (Kmax; P < 0.01, GEE nonlinear regression), whereas no changes were observed in Dmin. Even in patients 30 years or older, 14% of eyes revealed remarkable progression in Rpost. In eyes with acute hydrops, annual changes in Rpost (-0.22 mm) and Tmin (-33.8 μm) before acute corneal hydrops were more than 10 times faster than those in other eyes (P < 0.001, GEE nonlinear regression).
Chronologic measurements of corneal tomography in keratoconus demonstrated that the progression of steepening at posterior corneal surface was found not only in patients under 30 years but also in older patients, particularly in advanced keratoconus. The rate of progression can be measured by mapping of corneal curvature and thickness using OCT, and the risk of progression was greater in younger patients with steeper Kmax.
我们使用眼前节光学相干断层扫描（AS-OCT）对圆锥角膜的时间进展情况进行了量化。
使用扫频源OCT对113例圆锥角膜、疑似圆锥角膜或顿挫型圆锥角膜患者的217只眼睛进行了角膜断层扫描评估。在长达5.79年的随访期内，检查后最佳拟合球面半径（Rpost）、最小角膜厚度（Tmin）以及最薄点到角膜顶点的距离（Dmin）随年龄的变化情况，并使用广义估计方程（GEE）非线性回归模型进行分析。
在年轻患者（P < 0.01，GEE非线性回归）和最大K值（Kmax）较高的患者中（P < 0.01，GEE非线性回归），Rpost（平均，-0.017 mm）和Tmin（-2.69 μm）的年变化显著更高，而Dmin未观察到变化。即使在30岁及以上的患者中，14%的眼睛Rpost也有显著进展。在急性水肿的眼睛中，急性角膜水肿前Rpost（-0.22 mm）和Tmin（-33.8 μm）的年变化比其他眼睛快10倍以上（P < 0.001，GEE非线性回归）。
圆锥角膜角膜断层扫描的时间测量表明，角膜后表面变陡的进展不仅在30岁以下的患者中出现，在老年患者中也有发现，尤其是在晚期圆锥角膜患者中。可以通过使用OCT绘制角膜曲率和厚度来测量进展速度，Kmax较陡的年轻患者进展风险更大。
