The axial length measurement is an important variable in calculating the intraocular lens (IOL) power in cataract surgery. In this study, the effects of the implantable collamer lens (ICL) on the axial length measurement were investigated.

The axial lengths of 141 eyes of 76 highly myopic patients were measured before ICL implantation and 1 month postoperatively using applanation A-scan ultrasound.

The measured axial lengths before ICL implantation and 1 month after the surgery were 28.03 ± 1.91 mm and 28.08 ± 1.86 mm respectively, with a statistically significant difference of 0.05 mm ( p = 0.036). These 2 values showed a high correlation (R² = 0.9829, p < 0.0001).

Even though the axial length after ICL implantation significantly increased, the 0.05 mm change was too small to influence the determination of the IOL diopters in cataract surgery. Therefore, ICL implantation history may be reflected when measuring the axial length for the IOL power calculation in cataract surgery, but the axial length measured immediately before the cataract surgery may be used to calculate the IOL power regardless of the ICL implantation history.