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Asymmetry of pupil dilation and change in angle kappa in pseudophakic eyes

Session Details

Session Title: Cataract 2
Session Date/Time: Saturday 21/02/2015 | 08:30-11:00
Paper Time: 09:03
Venue: Hall 1
First Author: : S.Maedel AUSTRIA
Co Author(s): :    N. Hirnschall   B. Doeller   M. 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 (line from center of the pupil Intraocular lens passing through the fixation point) or the pupillary axis (line perpendicular to the cornea passing through the center of the pupil). Both axes are non coincident in normal subjects and the angle between them is usually denoted as kappa. Pupil dilation is assumed to be not completely symmetrical, especially in pseudophakic eyes. As the pupil is used as reference for these measurements the mydriasis might have an influence on angle kappa.

Setting:

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

Methods:

Altogether, 30 eyes of 30 pseudophakic patients will be included in this prospective study. Exclusion criteria are corneal opacities and ophthalmic diseases compromising proper fixation of the fixation light during measurements. Purkinje meter measurements will be taken before and 30 minutes after instillation of tropicamide 1% gtt and phenylephrine 10% gtt. Based on these images angle kappa will be calculated. Furthermore, based on images taken with the Purkinje meter, the increase in pupil size after dilation will be assessed. The amount and direction of shift of the pupil center due to asymmetrical dilation will be calculated from these images.

Results:

Preliminary data include data of 9 eyes of 9 patients. Before dilation, mean (SD) absolute horizontal and vertical angle kappa was 2.39° (±1.29) and 1.97° (±1.08), respectively. For dilated pupils, horizontal and vertical kappa was 3.01° (±3.08) and 4.47° (±2.14), respectively. Vertical kappa was significantly higher after dilation (paired t-test=0.01). Mean (SD) undilated and dilated pupil diameter was 3.88 mm (±0.39) and 6.34 mm (±0.64), respectively. Mean (SD) absolute shift of the pupil center was 0.30 mm (±0.12). After dilation, the pupil center shifted inferiorly, nasally and inferio-nasally in 5 (56%), 2 (22%) and 2 (22%) eyes, respectively.

Conclusions:

A significant larger vertical angle kappa was detected after dilation of pupils in our patients. No difference concerning horizontal kappa was measurable. After dilation, a small, but measurable shift of pupil centers was detected in all patients. Pupil centers shifted downwards and/or nasally in all of the eyes. At the ESCRS Winter Meeting, correlations of shift of pupil center and change in angle kappa will be presented for the complete dataset of 30 eyes.

Financial Disclosure:

NONE

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