Pothikamjorn Thananop, Surawatsatien Nuntachai, Ueathaweephol Somtaporn, Somkijrungroj Thanapong
Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
Center of Excellence in Retina, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
Clin Ophthalmol. 2025 Aug 8;19:2595-2605. doi: 10.2147/OPTH.S531740. eCollection 2025.
Toric intraocular lens (IOL) calculation has traditionally relied on anterior corneal astigmatism (KA), but recent trends emphasize incorporating posterior corneal astigmatism (PCA) and total corneal astigmatism (TCA). However, age-related changes and sex-based differences in PCA and TCA remain inconclusive due to limited sample sizes in previous studies.
We conducted a cross-sectional observational study using biometric measurements obtained with the IOLMaster 700. Patients with warning and failed history of corneal transplant or keratoconus were excluded. The objective was to evaluate age-related changes and sex-based differences in KA, PCA, and TCA among patients undergoing cataract surgery at a tertiary care center in Thailand.
A total of 23,932 eyes were analyzed for KA, and 9,546 eyes for PCA and TCA. Data were visualized using double-angle plots. PCA demonstrated a distinctive three-point star distribution, predominantly oriented along the with-the-rule (WTR) axis, with against-the-rule (ATR) astigmatism being rare in younger patients as illustrated in graphical abstract. Across KA, PCA, and TCA, the prevalence of ATR astigmatism increased in older age group, while WTR orientation decreased. A marked shift from WTR to ATR orientation was observed at different age thresholds: 60-65 years for KA, 75-80 years for PCA, and 55-65 years for TCA. KA and TCA also exhibited a preferential shift toward superonasal oblique orientation with advancing age-a pattern not observed in PCA. No significant sex-based differences were observed in mean astigmatism vector distributions across age groups.
Clinicians should account for age-related shifts in KA, PCA, and TCA when selecting toric IOLs, particularly in patients younger than 55 years. Preoperative counseling should address potential long-term shifts toward ATR orientation, which may influence visual outcomes in patients receiving toric IOLs aligned along other axes. Incorporating these changes into toric IOL formulae may improve patient outcomes.
传统上，散光人工晶状体（IOL）的计算依赖于角膜前表面散光（KA），但最近的趋势强调纳入角膜后表面散光（PCA）和角膜总散光（TCA）。然而，由于先前研究的样本量有限，PCA和TCA中与年龄相关的变化以及基于性别的差异仍无定论。
我们使用IOLMaster 700获得的生物测量数据进行了一项横断面观察性研究。排除有角膜移植警告和失败史或圆锥角膜的患者。目的是评估泰国一家三级医疗中心接受白内障手术患者的KA、PCA和TCA中与年龄相关的变化以及基于性别的差异。
共分析了23932只眼的KA，以及9546只眼的PCA和TCA。数据使用双角图进行可视化。PCA显示出独特的三点星形分布，主要沿顺规（WTR）轴定向，如图形摘要所示，逆规（ATR）散光在年轻患者中很少见。在KA、PCA和TCA中，ATR散光的患病率在老年组中增加，而WTR方向减少。在不同年龄阈值下观察到从WTR到ATR方向的明显转变：KA为60 - 65岁，PCA为75 - 80岁，TCA为55 - 65岁。KA和TCA也随着年龄增长表现出向鼻上斜轴方向的优先转变——PCA中未观察到这种模式。在各年龄组中，平均散光矢量分布未观察到显著的基于性别的差异。
临床医生在选择散光IOL时应考虑KA、PCA和TCA中与年龄相关的变化，特别是在55岁以下的患者中。术前咨询应涉及向ATR方向的潜在长期转变，这可能会影响接受沿其他轴对齐的散光IOL患者的视觉效果。将这些变化纳入散光IOL公式可能会改善患者的治疗效果。
