Keratometry Agreement Between Two Swept-Source OCT Devices in Healthy and Post-refractive Surgery Eyes

To evaluate the keratometry agreement between two swept-source devices for healthy and post-refractive surgery eyes and compare them.

One hundred volunteers between 20 and 55 years of age were recruited for this study including both healthy and post-refractive surgery eyes. Three consecutive measurements of simulated keratometry (Sim K), posterior keratometry (PK), and total keratometry (TK) were obtained with the IOLMaster 700 and Anterion. The agreement was assessed through the Bland-Altman method. Limits of agreement (LoA) were calculated as mean difference ±1.96·SD and it represents the 95% of the differences between devices.

For both groups, Sim K measurements exhibited a mean difference close to 0 and within a range of ±0.30 and ±0.36 diopters (D) for the control and post-refractive surgery groups, respectively. Meanwhile, the IOLMaster 700 provided flatter PK values (0.30 D on average) for both groups. In general, the post-refractive surgery group exhibited slightly greater mean differences and wider 95% LoA than the control group for Sim K and PK. Steeper TK values were obtained by the IOLMaster in both groups (control = 0.50 D and post-refractive surgery = 0.75 D). TK differences between devices were significantly greater in the post-refractive surgery group (ranging from 0.38 to 1.14 D) compared to the control group (ranging from 0.15 to 0.85 D).

The IOLMaster 700 and Anterion are not interchangeable for TK measurements and eyes that had corneal refractive surgery even decreased the agreement between devices. Differences between devices for Sim K and PK measurements should be clinically judged, particularly in eyes with previous corneal surgery. [.