This study was designed to compare optical biometry measurements and predicted refraction in cataract patients with high myopia [axial length (AL) ≥26 mm] using OA-2000 and IOL Master 500. Ocular biometry measurements were performed using both biometers before surgery. Uneventful cataract surgery was performed in all patients. Postoperative manifest refraction was obtained 3wk after surgery or later. A total of 67 eyes were examined. The AL, keratometry (K), and anterior chamber depth (ACD) of the two biometers showed excellent agreement. Predicted errors were similar and a strong positive correlation was observed (r=0.909). Out of 21 eyes (31.34%) with unsuccessful AL readings using the IOL Master 500, 20 eyes of them could be measured using OA-2000. Therefore, the biometric parameters measured by the two biometers showed good agreement. However, OA-2000 had a lower AL measurement failure rate.