First Author: J.Schwiegerling USA
Co Author(s): S. Lane
Purpose:
To determine the effect of lens tilt and decentration on the optical performance for a +2.50D-Add aspheric apodized diffractive multifocal IOL.
Setting:
University of Arizona, College of Optical Sciences
Methods:
Line-spread measurements were used to calculate through-focus modulation transfer function (MTF) values with an aspheric +2.50D-Add multifocal IOL (ReSTOR SN6AD2, Alcon Laboratories). Entrance pupil diameters of 3mm and 5 mm were examined. The IOL was mounted in a saline-filled wet cell and inserted into an eye model with clinical levels of spherical and chromatic aberration. The blurred image of a slit was captured and analyzed for different object vergences to determine the MTF of the system. The IOL had a base power of 21D and an add power in the IOL plane of 2.50D. The through-focus measurements were performed with the IOL aligned, as well as tilted 2 degrees and 4 degrees, and decentrations up to 0.5 mm.
Results:
For a 3mm pupil, the aligned apodized diffractive multifocal lens had MTF values at 50 cyc/mm are 0.60 and 0.19 for distance and near vision, respectively. For a 5mm pupil, the aligned apodized diffractive multifocal lens had MTF values at 50 cyc/mm are 0.60 and 0.18 for distance and near vision, respectively. In the presence of 2 degrees, the through-focus MTF are nearly identical to the aligned case. Increasing the tilt to 4 degrees degrades MTF by 0.05 for distance and 0.08 for near at both pupil sizes. Decentration changes were small.
Conclusions:
The apodized diffractive multifocal showed high performance for both distance and near vision with a bias towards distance vision. In addition, the lens design is insensitive to tilt levels up to two degrees, but performance is degraded for tilts somewhere between 2 and 4 degrees. The lens is also insensitive for decentrations up to 0.5 mm. FINANCIAL DISCLOSURE?: ... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented
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