Repeatability of lens densitometry using Scheimpflug imaging

Abstract

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.