1. W. Maxwell, MD, PhD California Eye Institute Fresno, California
Comparison of the Optical Image Quality for Presbyopia Correcting IOLs using Modulation Transfer Function Testing
W. Maxwell, MD, PhD
California Eye Institute
Fresno, California
Financial Disclosure: Consultant (Alcon Research, Ltd.)

2. Testing Methodology Study Objective
To compare the image quality of various Presbyopia Correcting IOLs with different designs (accommodative or multifocal; aspheric or spherical) using the modulation transfer function (MTF) testing method and U.S. Air Force 1951 Resolution Target (AFT) testing
Modulation Transfer Function (MTF) Testing
Objective method of measuring image contrast degradation at different spatial frequencies1
Modified ISO model eye
The standard ISO Model Eye1 configuration incorporates a 35 mm doublet lens to converge light to simulate the refractive power of a human cornea
The model cornea in the ISO Model Eye is an aberration free lens, and is not representative of a typical human cornea with its inherent positive spherical aberration
Thus, a modified ISO model eye simulating the spherical aberration of the internal optics of a young eye was used in this study
Ref 1: ISO Ophthalmic implants – Intraocular lenses – Part 2 Optical properties and test methods, 2000.

3. The optical bench setup
Optikos Video MTF measurement system
1024 element detector, a 550 nm narrow band filter, and a 20X microscope objective
IOLs were mounted in a lens holder under 10 mm of compression, and aligned on the optical axis in a wet cell filled with deionized (DI) water at 35 ± 2 °C with the anterior side of the IOL facing the incident light
3 and 5 mm apertures used to simulate pupil size
Green light illuminates a single slit object located on the front focal plane of a 180 mm collimator
The collimated light passes through the model cornea and IOL system that simulates the vergence of a human eye
MTF Bench
IOL Models Tested (N = 1)
IQ ReSTOR® SN6AD3 (Aspheric)*
ReSTOR® SA60D3 (Spherical)*
TECNIS® ZM900*
Acri.LISA® 366D*
ReZoom® NXG1*
Crystalens® AT-50SE*
Crystalens® HD500*
CCD Camera
Pinhole Target
IOL
Light Source
The optical bench setup
* ReSTOR trademark of Alcon Laboratories, Inc.; ReZOOM & Tecnis trademark of Advanced Medical Optics, Inc.;
crystalens trademark of eyeonics, Inc.; Acri.LISA trademark of Carl Zeiss Meditec Inc.

4. Modulation Transfer Function 5 mm Aperture, Distance Focus Spatial Frequencies of 0 to 100 lp/mm

5. Modulation Transfer Function 5 mm Aperture, Distance Focus, Discrete frequency of 100 lp/mm (20/20 Equivalent)

6. Modulation Transfer Function 5 mm Aperture, Distance Focus, Discrete frequency of 50 lp/mm (20/40 Equivalent)

7. Modulation Transfer Function 3 mm Aperture, Distance Focus Spatial Frequencies of 0 to 100 lp/mm

8. Modulation Transfer Function 3 mm Aperture, Distance Focus, Discrete frequency of 100 lp/mm (20/20 Equivalent)

9. U.S. Air Force 1951 Resolution Target Test (AFT)
Optikos Optical Testing System
The setup for the AFT test was identical to that of the MTF test, except the single slit object was replaced with the AFT
An image of the AFT was photographed through each IOL
The AFT test includes paired 3-bar target sets used to qualitatively measure resolution efficiency

10. U.S. Air Force 1951 Resolution Target Test 5 mm Aperture, Distance Focus
crystalens
AT-50SE
ReSTOR SA60D3 (Spherical)
IQ ReSTOR SN6AD3 (Aspheric)
ReZoom NXG1
Acri.Lisa 366D
Tecnis ZM900
HD-500
Superior image resolution demonstrated by the IQ ReSTOR® IOL

11. Conclusions
The IQ ReSTOR® SN6AD3 aspheric IOL produced the highest overall image quality for MTF and AFT testing with a 5 mm aperture when compared to various presbyopia-correcting IOLs
The IQ ReSTOR® SN6AD3 aspheric IOL produced the highest image resolution for AFT image testing with 5 mm aperture when compared to various presbyopia-correcting IOLs
MTF performance with a smaller aperture (3 mm) was similar among the various IOLs, and slightly higher for IQ ReSTOR® SN6AD3 at 100 lp/mm
Clinical investigation is needed to determine whether superior IOL optical quality demonstrated in optical bench testing results in measurable visual improvements in clinical practice