[Pupil centroid shift: Marketing tool or essential clinical parameter?]. / Verschiebung des Pupillenzentroids : Marketing oder klinisch relevanter 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.

[Complications of corneal cross-linking]. / Komplikationen der Vernetzung der Hornhaut.

BACKGROUND: More than 10 years after the clinical introduction of corneal cross-linking (CXL) the indications and contraindications are still not yet defined. Fundamental for such a list is the incidence of complications. METHODS: A PubMed search for complications of corneal crosslinking published up to March 2013 was carried out. RESULTS: The published complication rates ranged from 1 % to 10 % depending on the stage of keratoconus. Early postoperative complications were transient stromal haze, sterile infiltrates, endothelium decompensation, delayed epithelial healing and infectious keratitis. Stromal opacity can be a delayed postoperative event. CONCLUSIONS: Complications after corneal cross-linking treatment for keratoconus are rare but the management of these complications may need keratoplasty.