Clinically Relevant Optical Properties of Bifocal, Trifocal, and Extended Depth of Focus Intraocular Lenses

PURPOSE: To experimentally compare the optical performance
of three types of hydrophobic intraocular lenses
(IOLs): extended depth of focus, bifocal, and trifocal.
METHODS: The tested IOLs were: TECNIS ZMB00 (bifocal;
Abbott Medical Optics, Abbott Park, IL), TECNIS
Symfony ZXR00 (extended depth of focus; Abbott Medical
Optics), and FineVision GFree hydrophobic (trifocal;
PhysIOL, Liège, Belgium). Their 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: The three lenses presented step-like optic
topography. For a pupil size of 3 mm or greater, clearly
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: It appears that the three lenses rely on
light diffraction for their optical performance, presenting
halos with comparable intensities. For small pupil apertures
(< 3 mm), 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.