Abstract
Purpose::
To analyze the effect of anterior lens tilt and/or decentration on the Wavefront characteristics and High Order Aberrations produced by the dual-optic Synchrony IOL in the Eye Model measured by Tracey Aberrometer
Methods::
The evaluation consisted of the Refraction High Order Aberration Map and values of High Order Aberrations measured by Tracey Aberrometer of the IOL placed in the Eye Model with special misalignment fixtures designed for 1 mm decentration and/or 7 degrees tilt of the anterior lens. The points of each scan were reviewed and all points outside the XY-profile peak were rejected. As the criterion if the lens misalignment were actually occurred, the Zernike components of significant values were compared with equivalent theoretical Zernike components produced by the eye model with the corresponding anterior lens misalignment. Only scans with similar patterns were selected for analysis. The Refraction High Order Aberration maps were analyzed in terms of Power Gradient of the map (a power difference along a meridian across the map) and Peak-to-Valley (PV) between highest and lowest Power locations at the Refraction HOA maps.
Results::
Refraction HOA map was sensitive to the procedure of scan point rejection manifested by the presence of small spots of power spikes and the use only points at the XY-profile peak minimized small power spots occurrence. Large power spots presence on the scans was likely a manifestation of the asymmetrical aberrations caused by lens misalignment. HOA magnitudes were around 0.15 micron in control setting and increased to about 0.3-0.5 micron range in the misalignment fixtures with comatic aberrations being within 0.2-0.3 micron. Power spots have appeared with misalignment fixtures and corresponding PV’s were on the range of 3-9 diopters. The power gradient characteristics have primarily appeared with the fixture forcing the anterior lens to tilt around the axis that was parallel to its decentration axis and the corresponding values were around 2 D at 4 mm and 1.3 D at 3 mm scan diameters.
Conclusions::
Comatic aberration was the dominant aberration of the Synchrony IOL placed in the misalignment fixtures. Power gradient was more likely occurrence with the anterior lens tilt being parallel to lens decentration.
Keywords: intraocular lens • optical properties • presbyopia