Topography system provides repeatable anterior segment measurements

A system combining Scheimpflug photography and Placido-disk technology gives repeatable measurements of several anterior segment parameters, demonstrates a study in the Journal of Cataract and refractive Surgery.

Dr Raul Montalban et al., Instituto Oftalmológico de Alicante, Spain, completed an evaluation on 117 eyes of 117 healthy patients. All eyes underwent a comprehensive ophthalmic assessment with the Sirius system and three consecutive measurements were taken to evaluate the intrasubject repeatability of several parameters. These included anterior and posterior corneal curvature and shape factor, white-to-white (WTW) corneal diameter, central and minimum corneal thickness and anterior chamber depth (ACD).

The within-subject standard deviation was 0.04 mm or lower for anterior and posterior corneal curvatures. For the shape-factors measurements it was below 0.08 mm in all eyes and ICC values were between 0.909 mm and 0.994 mm.

Overall, the combination topography system provides repeatable measurements for a range of anterior segment parameters- especially anterior and posterior curvature and pachymetry.