Predictability of biometry in patients undergoing cataract surgery

Purpose To compare measurements of axial length (AL), anterior chamber depth (ACD), keratometry (K), and the refractive predictability of the Aladdin and IOLMaster biometry devices in cataract surgery patients. Methods A retrospective observational study of eyes undergoing cataract surgery. Data were retrieved on AL, ACD, and K measurements obtained by the Aladdin and the IOLMaster. Furthermore, the postoperative refractive prediction errors were compared between the devices. Results The study included 127 consecutive eyes of 127 patients undergoing cataract surgery. Mean measurements of AL were not significantly different between the Aladdin (24.18 ± 1.89 mm) and IOLMaster (24.18 ± 1.89 mm) (p = 0.792). Mean K measurements were different between Aladdin (43.84 ± 1.56 D) and IOLMaster (43.97 ± 1.61 D) (p < 0.001). For AL, Aladdin measurements correlated strongly with IOLMaster measurements (r = 0.9997). For K, Aladdin measurements correlated strongly with IOLMaster measurements (r = 0.9912). Fifty-eight of the 127 eyes underwent cataract surgery with a monofocal intraocular lens. For these, mean absolute error (MAE) in predicting refraction relative to the measured postoperative refraction differed between Aladdin (MAE = 0.54 ± 0.40D) and IOLMaster (MAE = 0.49 ± 0.41D) (p = 0.001). After adjustment for the systematic difference in K measurements, the difference in MAE was no longer significant (p = 0.601). The ACD measurements did not differ significantly (p = 0.873) and were well correlated (r = 0.8327). Conclusions A very good correlation was found in AL, K, and ACD measurements between the Aladdin biometer and the IOLMaster. Minimal adjustment for the constant difference in keratometry measurements matched the refractive predictability of both devices.