Das Kamal K, Suryakumar Rajaraman, Lu Wei, Maxwell Andrew
Research and Development, Alcon Research LLC, Fort Worth, TX, USA.
California Eye Institute, Fresno, CA, USA.
Clin Ophthalmol. 2025 Jul 28;19:2463-2473. doi: 10.2147/OPTH.S527570. eCollection 2025.
To evaluate whether differences in asphericity or corneal spherical aberration (SA) affect intraocular lens (IOL) power and visual acuity (VA) among different ethnicities.
Modeling and simulation study based on published clinical data.
Individual eye models were developed with corneas designed to represent different ethnicities, based on clinical study data, to simulate and determine SA for a 6-mm pupil. The study included Black, Brazilian, Chinese, Egyptian, Indian, Japanese, Portuguese, Saudi Arabian, Tanzanian, Taiwanese, and White population groups. Corneal SA ranged from 0.17 to 0.31 µm among different ethnic and age groups. Differences in power in model eyes with various ethnic asphericities were assessed using spherical SA60AT, Clareon CNA0T0 (-0.20 µm SA), and a monofocal aspheric IOL (-0.28 µm SA). Modulation transfer function (MTF) and VA were calculated at different defocus. Defocus was applied from -0.5 to 0.5 D, using 0.05 D intervals.
Emmetropic IOL power for CNA0T0 was 20.756 D based on the A-Constant and an SRK/T model with 0.28-µm SA. For all ethnicities with CNA0T0, the maximum IOL power difference was approximately -0.1 D when compared with an average cornea. For spherical IOL, MTF was 0.562 units at best focus and 0.529 units at 0.1 D defocus; VA was -0.028 logMAR at best focus and -0.023 logMAR at 0.1 D defocus. For aspheric IOLs, MTF was 0.604 units at best focus and 0.579 units at 0.1 D defocus; VA was -0.033 logMAR at the best focus and -0.030 logMAR at 0.1 D defocus.
The calculated A-Constants for CNA0T0 for different ethnicities ranged from 119.029 to 119.151. Based on the specific model eye generated from published clinical data for each ethnicity and using a spherical and two aspheric monofocal intraocular lenses, the use of a different A-Constant for different ethnic populations would not impact visual outcomes.
评估不同种族间非球面性或角膜球差（SA）的差异是否会影响人工晶状体（IOL）的屈光力和视力（VA）。
基于已发表临床数据的建模与模拟研究。
根据临床研究数据，开发具有代表不同种族角膜的个体眼模型，以模拟并确定6毫米瞳孔的球差。该研究包括黑人、巴西人、中国人、埃及人、印度人、日本人、葡萄牙人、沙特阿拉伯人、坦桑尼亚人、台湾人以及白人种群。不同种族和年龄组的角膜球差范围为0.17至0.31微米。使用球面SA60AT、Clareon CNA0T0（-0.20微米球差）和单焦点非球面人工晶状体（-0.28微米球差）评估具有不同种族非球面性的模型眼中的屈光力差异。在不同离焦情况下计算调制传递函数（MTF）和视力。离焦范围为-0.5至0.5 D，间隔为0.05 D。
基于A常数和球差为0.28微米的SRK/T模型，CNA0T0的正视眼人工晶状体屈光力为20.756 D。对于所有采用CNA0T0的种族，与平均角膜相比，最大人工晶状体屈光力差异约为-0.1 D。对于球面人工晶状体，最佳焦点处的MTF为0.562单位，0.1 D离焦时为0.529单位；最佳焦点处的视力为-0.028 logMAR，0.1 D离焦时为-0.023 logMAR。对于非球面人工晶状体，最佳焦点处的MTF为0.604单位，0.1 D离焦时为0.579单位；最佳焦点处的视力为-0.033 logMAR，0.1 D离焦时为-0.030 logMAR。
不同种族的CNA0T0计算出的A常数范围为119.029至119.151。基于为每个种族从已发表临床数据生成的特定模型眼，并使用球面和两种非球面单焦点人工晶状体，为不同种族人群使用不同的A常数不会影响视觉效果。
