Clinically relevant optical properties of three types of intraocular lenses

Purpose:

To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus (TECNIS Symfony), bifocal (TECNIS ZMB00), and trifocal (FineVision GFree).

Setting:

Rothschild Foundation Paris, France - Liege Space Center Liège, Belgique

Methods:

Surface topography was analyzed by optical microscopy. Modulation transfer function (MTF) and spherical aberrations were determined on optical bench for variable pupil apertures and with two cornea models (0 µm and +0.28 µm). United States Air Force target imaging was analyzed for different focal points (near, intermediate, and far). Point spread function (PSF) and halos were quantified and compared.

Results:

All lenses presented step-like optic topography. For a pupil size of = 3 mm, distinctive MTF peaks were observed for all lenses: two peaks for the extended depth of focus and bifocal lenses with +1.75 and +4.00 diopters (D) addition, respectively, and three peaks for the trifocal lens with +1.75 and +3.50 addition for intermediate and near vision, respectively. The extended depth of focus and bifocal lens had slightly higher MTF at best focus with the +0.28 µm cornea model than with the 0 µm model, whereas the trifocal lens was likely to be more independent of the corneal spherical aberrations.

Conclusions:

Each lens appears to rely on light diffraction for optical performance, presenting halos with comparable intensities. For small pupil apertures, the MTF peaks for the far and intermediate focal distances of the trifocal and extended depth of focus lenses overlap, but the trifocal lens presented an additional MTF peak for the near focal points.