1. Ophthalmology & Vision Sciences
Modulation Transfer Function Measurement of the Alcon SN6AD3 Aspheric Apodized Diffractive Multifocal IOL
Jim Schwiegerling, PhD
Junoh Choi, MS
University of Arizona
Ophthalmology & Vision Sciences
Optical Sciences
Tucson, Arizona, USA
Financial Disclosure: The author receives research and travel support from
Alcon Research

2. Introduction
An eye model in which IOLs are mounted in a saline-filled wet cell behind the artificial cornea with clinical levels of spherical and chromatic aberrations has been developed.
Benchtop testing includes MTF measurement through line spread function analysis, as well as imaging targets such as letter charts and oblique pinhole sources.
Digital SLR with macro lens attachment is used to create a portable system to capture night scenes through the eye model.
Alcon ReSTOR Aspheric, AMO ReZoom and Tecnis multifocal, and Acri.Tec Acri.LISA lenses tested.

3. Line Spread Testing
Fourier Transform of the Line Spread gives the MTF of the lens

4. Through Focus MTF Comparison 3 mm Pupil; 50 cyc/mm
Aspheric terms mainly affect the lens periphery so the performance of the two lenses is nearly identical for a 3 mm
pupil.

5. Through Focus MTF Comparison 6 mm Pupil; 50 cyc/mm
For larger pupils, both lenses bias distance vision.
The effect of the aspheric term is to boost contrast in the distance. Near vision contrast is slightly improved as well.

6. Target Imaging

7. Letter Chart Target
Targets can be used in place of a slit on our setup. ETDRS Letter chart shown for four different types of multifocal IOLs. Pupil size is 6.0 mm in all cases.
Note the diminishing degree of halo, especially with the ReSTOR Aspheric.

8. Oblique Point Source
50 mm diameter pinhole target located 18° off the optical axis. Positive and negative images are shown for four multifocal IOL styles. Note the stray light flares for ReZoom, Tecnis MF and Acri.LISA

9. Portable Digital Imaging System
Nikon Digital SLR camera
Macro Lens
Custom Eye model attachment consisting of artificial cornea and wet cell for mounting IOLs
The system mimics the vergence and imaging properties of the human eye.

10. Night Scene
ReSTOR
Aspheric
ReZoom
Tecnis
ZM900
Acri.Lisa
Multifocal

11. Night Scene
ReSTOR
Aspheric
ReZoom
Tecnis
ZM900
Acri.Lisa
Multifocal

12. Discussion
MTF Testing showed that the aspheric ReSTOR gives an increase in contrast for distant objects for large pupil sizes.
The diffractive elements tend to cause arcs around bright light sources in nighttime scenes, whereas the zonal refractive causes a continuous flare. Apodization suppresses many of these artifacts.
There are less stray light effects in Alcon’s aspheric apodized diffractive than with the other multifocal IOLs.