Asymmetric pupil dilation in pseudophakic eyes and concomitant increase in angle kappa

Session Details

Session Title: Cataract Surgery Outcomes and Complications

Session Date/Time: Monday 07/09/2015 | 14:30-16:00

Paper Time: 14:36

Venue: Room 17

First Author: : M.Weber AUSTRIA

Co Author(s): :    S. Maedel   N. Hirnschall   B. Doeller   P. Nguyen   O. Findl        

Abstract Details

Purpose:

Clinical Purkinje meter systems are used to assess intraocular lens (IOL) tilt and decentration with respect to the line of sight or the pupillary axis. Both axes are non-coincidental in normal subjects and the angle between them is usually denoted as kappa. Pupil dilation is assumed to not be completely symmetrical, especially in pseudophakic eyes. As the pupil is used as reference for these measurements the mydriasis may have an influence on angle kappa.

Setting:

Vienna Institute for Research in Ocular Surgery, Department of Ophthalmology, Hanusch Hospital, Vienna

Methods:

Thirty eyes of 30 pseudophakic patients were included in this prospective study. Purkinje meter measurements were taken before and 30 minutes after instillation of tropicamide 1% gtt and phenylephrine 10% gtt. Based on these images the increase in pupil size after dilation was assessed. The amount and direction of shift of the pupil centre due to asymmetrical dilation was calculated. Furthermore the angle kappa was calculated.

Results:

Mean (SD) undilated and dilated pupil diameter was 3.93 mm (±0.59) and 6.58 mm (±0.74), respectively. Mean (SD) absolute shift of the pupil center was 0.29 mm (±0.15). After dilation, the pupil centre shifted inferior-nasally, inferiorly and inferior-temporally in 9 (31%), 6 (21%) and 6 (21%) eyes, respectively. Before dilation, mean (SD) absolute horizontal and vertical angle kappa was 2.57° (±1.97) and 0.47° (±2.06), respectively. For dilated pupils, horizontal and vertical kappa was -1.56° (±3.76) and -3.22° (±3.34), respectively. Vertical kappa was significantly higher after dilation (paired t-test=0.01).

Conclusions:

After dilation, a small, but measurable shift of the pupil centre was detected in all patients. the pupil centre shifted downwards in most of the eyes. A significantly larger vertical angle kappa was detected after dilation of pupils in our patients. No difference concerning horizontal kappa was measurable.

Financial Interest:

NONE