Randers Regions Hospital, Randers, Denmark.
Fondazione GB Bietti IRCCS, Rome, Italy.
Acta Ophthalmol. 2018 Sep;96(6):600-606. doi: 10.1111/aos.13683. Epub 2018 Jan 25.
To describe the age-related changes in with-the-rule (WTR) and oblique keratometric astigmatism (KA), posterior corneal astigmatism (PCA) and total corneal astigmatism (TCA).
We used a Pentacam HR (high-resolution) rotating Scheimpflug camera to determine the KA, PCA and TCA in the right eyes of 710 patients, aged from 20 to 88 years. The age-related changes along the vertical, horizontal and oblique meridians were analyzed with Naeser's polar value method in a cross-sectional study.
In the whole group, all meridional astigmatic powers and polar values were stable in the age groups from 20 to 49 years, followed by a 1.0 dioptre (D) against-the-rule (ATR) change in KA and TCA, and a 0.12 D reduction in against-the-rule PCA. A nasal rotation of the steep meridian in KA and TCA was noted in the 70-88 years old. The PCA averaged approximately 0.25 D ATR in all age groups. Females displayed the same early astigmatic stability as in the whole group, while male eyes demonstrated a linear decay from 1.5 D WTR at 20 years to 0.5 D ATR astigmatism for the oldest patients.
Corneal astigmatism is stable until the age of 50 years; thereafter both keratometric and total corneal astigmatism show a 0.25 D ATR change per 10 years. The average 0.25 D ATR PCA compensates the predominant keratometric WTR astigmatism in the younger patients and increases the TCA in the elderly with keratometric ATR astigmatism. The gender-based differences in age-related astigmatism require further studies.
描述规则性散光（WTR）和斜角角膜散光（KA）、后角膜散光（PCA）和总角膜散光（TCA）随年龄的变化。
我们使用 Pentacam HR（高分辨率）旋转 Scheimpflug 相机对 710 名年龄在 20 至 88 岁的右眼患者的 KA、PCA 和 TCA 进行了测定。在一项横断面研究中，我们使用 Naeser 极坐标法分析了垂直、水平和斜子午线随年龄的变化。
在整个研究组中，20 至 49 岁年龄组的所有子午面散光力和极坐标值均保持稳定，随后 KA 和 TCA 的逆规散光增加了 1.0 屈光度（D），逆规 PCA 减少了 0.12 D。在 70 至 88 岁的患者中，KA 和 TCA 的陡峭子午线出现了鼻侧旋转。在所有年龄组中，PCA 平均约为 0.25 D 逆规。女性与整个研究组一样表现出早期散光稳定性，而男性眼睛从 20 岁时的 1.5 D WTR 线性衰减至最年长患者的 0.5 D ATR 散光。
角膜散光在 50 岁之前保持稳定；此后，角膜散光和总角膜散光均以每 10 年 0.25 D 逆规的速度发生变化。平均 0.25 D 逆规 PCA 补偿了年轻患者中主要的角膜规则性散光，并增加了角膜逆规散光的老年患者的 TCA。基于性别的年龄相关性散光差异需要进一步研究。
