Biometry combining Scheimpflug imaging and partial coherence interferometry versus standard partial coherence interferometry biometry.

PURPOSE

To compare measurements of mean keratometry (K), axial length (AL), Jackson first and second astigmatism vector (J0 and J45), astigmatism magnitude, white-to-white (WTW) diameter and anterior chamber depth (ACD) values between two biometers, the Pentacam® AXL and the IOL Master 500.

SETTING

Public hospital in Belgium.

DESIGN

Retrospective instrument reliability analysis.

METHODS

Eyes of cataract or refractive lens exchange patients were examined preoperatively on a device combining Scheimpflug imaging and partial coherence interferometry (Pentacam® AXL) and a reference optical biometer (IOL Master 500). K, AL, J0, J45, astigmatism, WTW and ACD values were compared.

RESULTS

Three hundred and twenty-eight eyes of 187 cataract or refractive lens exchange patients (mean age 68years) were examined preoperatively. Measurements of mean keratometry, axial length, ACD, white-to-white and astigmatism were significantly different (P<0.05) between the two devices. Measurements of J0 and J45 did not significantly differ. Keratometry measurements with the Pentacam® AXL were significantly flatter than those measured with the IOL Master 500. Axial length measured with Pentacam® AXL was significantly greater when measured with the IOL Master 500, but this difference was not clinically relevant (0.015mm).

CONCLUSIONS

The Pentacam® AXL and the IOL Master 500 cannot be used interchangeably.