Repeatability of lens densitometry using Scheimpflug imaging.

PURPOSE

To evaluate the repeatability of different lens densitometry analysis modes performed with Scheimpflug imaging using the Pentacam HR device.

SETTING

University eye hospital, Frankfurt am Main, Germany.

DESIGN

Cross-sectional study.

METHODS

Eyes were analyzed under mydriasis during 2 examinations performed by the same examiner. Three single measurements were taken to assess lens densitometry via 3 modes as follows: peak (maximum), linear (vertical axis), and 3-dimensional (3-D). Measurements were also taken using 3 cylindrical reference blocks (P) with different diameters (2.0 mm, 4.0 mm, 6.00 mm) composing the whole lens depth. Repeatability was tested using Bland-Altman analysis. As statistical parameters, the coefficient of repeatability (CoR) and the relative repeatability (RR) were applied.

RESULTS

The study analyzed 105 eyes. The CoR of the peak modus was 5.6 (RR, 29.8%); of the linear modus, 0.9 (RR, 8.8%); and of the 3-D modus, 0.36 (RR, 3.6%). The values of the P mode were lower, with a CoR between 0.19 and 0.30 (RR, 2.1%-3.3%).

CONCLUSIONS

Lens densitometry using Scheimpflug imaging was highly repeatable. However, repeatability was dependent on the analysis mode used. Repeatability decreased with increasing opacification.