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P. A. Piers, T. Terwee, M. van der Mooren, H. A. Weeber; Optical Performance of Multifocal IOLs Measured in Different Physical Eye Models and in Monochromatic and Polychromatic Light. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5740.
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© ARVO (1962-2015); The Authors (2016-present)
MTF measurement in a physical eye model is an accepted and useful tool to assess the optical image quality of intraocular lenses.The purpose of this study is to demonstrate the influence of eye model design and the chromatic content of the light source used on the measured optical performance of multifocal (MF) IOLs.
In this study, MTF measurements for near and far focus positions were performed in model eyes with 3 different artificial corneas: 1.ISO (aberration free) cornea;2.Cornea with spherical aberration (SA) of 0.20 µm for a 6-mm pupil and chromatic aberration representative of the average human cornea and 3.Physiological cornea with SA of 0.27 µm mimicking the SA and chromatic aberration of the average human cornea.Three diffractive MF IOL models (Tecnis ZMB00 (AMO), AcrySOF ReSTOR SN6AD1 (Alcon), Acri.Lisa 356D-5 (Zeiss)) are measured in each eye model. The influence of pupil size on optical outcomes is demonstrated by performing measurements for both 3 and 5 mm pupils.Traditionally, IOLs are tested in monochromatic green light. White light measurements provide a more realistic indication of the clinical performance of the IOL under normal daily lighting conditions therefore tests were performed both in green(wavelength 546 nm) and in polychromatic white light.Additionally, for all measurement conditions, simulated retinal images were visualized by projecting a US Air Force 1951 resolution target through the eye model onto a CCD positioned in the selected focus plane.
For a pupil size of 3 mm, the MTF both for the distance and the near image measured in green light of each lens is very similar even when measured in different eye models.However, there is considerable variability in the MTF measurements performed for a 5 mm pupil in white light with results ranging from 0.08 to 0.45.Under these measurement conditions differences in lens designs and eye model are most apparent.IOLs with lower levels of SA correction perform better in eye models with corneas that are not representative of the cataract population, such as the ISO eye model.Differences in chromatic dispersion of IOL materials are easily detected using white light measurements performed in eye models with chromatic aberration similar to the real eye.
Optical quality measurements of diffractive MF IOLs performed in non-physiological eye models may be misleading.To get a realistic impression of daily performance of IOLs in average human eyes, these lenses should be tested in a model eye that mimics everyday visual conditions as closely as possible.
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