[Pupil centroid shift: Marketing tool or essential clinical parameter?].

BACKGROUND

Pupil centroid shift (PCS) is an easily measured parameter which is rarely taken into consideration when planning surgery.

PURPOSE

The aim of this study was to determine the physiological range of PCS and to evaluate its role in refractive and cataract surgery.

METHODS

The pupil center was measured in 103 eyes of 103 patients using the newest PCS module of the Allegro Topolyzer Vario (Version 1.76r58, Wavelight-Alcon, Erlangen, Germany) and the difference between a mesopic and a photopic environment was determined as PCSm. Additionally, these measurements were linearly extrapolated to pupil diameters of 2 mm and 7 mm (photopic-scotopic, PCSe). The statistical analysis included correlations between various demographic and topographic parameters and PCS.

RESULTS

The average (± standard deviation) PCSm was 0.12 ± 0.08 mm with a range of 0.02-0.53 mm, with 2 eyes out of 95 (2%) having a PCSm of more than 0.4 mm. The extrapolated PCSe was 0.24 ± 0.16 mm and ranged from 0.03 to 0.78 mm, with 14 eyes out of 95 (15%) having a PCSe of more than 0.4 mm. Of the 95 eyes 3 (3%) showed a PCSe of more than 0.7 mm. There was no correlation between PCS with any of the demographic parameters tested.

CONCLUSION

Up to 15% of the patients showed a PCS of more than 0.4 mm which requires a decision of the (refractive) ophthalmic surgeon as to whether the optical zone should be centered on the photopic or mesopic/scotopic pupil center. In the 3% of patients with a PCSe value greater than 0.7 mm, the implantation of multifocal intraocular lens (IOL) is not recommended.