Optimal diffractive multifocal IOL centration evaluated with a ray tracing aberrometer

Session Details

Session Title: Pseudophakic IOLs: Multifocal II

Session Date/Time: Tuesday 13/09/2016 | 08:00-10:30

Paper Time: 08:06

Venue: Auditorium C6

First Author: : J.Costa PORTUGAL

Co Author(s): :    A. Rosa   R. Araujo   F. Rito   J. Povoa   C. Lobo   J. Murta     

Abstract Details

Purpose:

To evaluate the postoperative positioning of a multifocal intraocular diffractive lens (IOL) and determine possible anatomical factors that induce decentration, as well as its effect on the aberrometry profile.

Setting:

Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal

Methods:

Prospective study, including 27 patients (54 eyes) submitted to sequential bilateral implantation of a multifocal IOL (SN6AD1, AcrySof IQ ReSTOR™, Alcon, USA) centered on the subject-fixated coaxially sighted corneal light reflex. On the 4th postoperative week, the lens position relative to the ocular axes, alpha/kappa angles and the aberrometry profile were determined using a ray tracing aberrometer (iTrace™, Tracey Technologies, USA).

Results:

The primary decentration, i.e. the average distance from the IOL center to the visual axis, was 0.189mm (0.037-0.462mm). This decentration was larger in patients with greater alpha angles (r=0.305, p=0.012). Increasing primary decentration was accompanied by a statistically significant deterioration of the objective optical quality parameters (increase of the high-order RMS, p=0.019; decrease of the MTF, p=0.007, and Strehl ratio, p=0.021). Similarly, IOL decentration relative to the pupillary axis induced an increase of high order aberrations (r=0.322, p=0.009), particularly coma (r=0.318, p=0.010), and a decrease of the MTF and Strehl ratio (r=-0.311, p=0.011 and r=-0.332, p=0.007, respectively).

Conclusions:

On the early postoperative period after centration of a multifocal intraocular lens on the visual axis, the IOL decentration is minimal but is, nevertheless, associated with a decline of the patient’s optical quality. Likewise, IOL decentration relative to the pupil center leads to an increase of high order aberrations and a decrease of the objective contrast properties. Thus our results suggest that, in order to improve visual quality outcomes, multifocal IOLs should be positioned equidistant to the visual axis and pupil center.

Financial Disclosure:

NONE