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F. Taketani, M. Kojima, G. Yoon, Y. Hara; Theoretical Visual Benefit When Correcting Higher Order Aberration With Fully Customized and Aspherical Intraocular Lenses. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3132.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate theoretical improvement in retinal image quality with fully customized intraocular lenses (f-IOLs) correcting higher order aberrations (HOAs) and aspherical IOLs correcting average positive spherical aberration.
The cornea aberration up to the 6th Zernike order of 17 normal eyes (age: 72.3 ±9.6) was from elevation maps measured with a Topcon topographer (KR 9000PW) preoperatively and at 3-month after implantation. The IOL decentration was also measured with EAS-1000 (NIDEK) at 3-month. The f-IOLs were theoretically designed to correct the higher order aberrations up to 6th order based on the measured corneal aberration. The optical modulation transfer functions (MTFs) were calculated with assumption that the f-IOLs were implanted with the measured IOL decentration. IOL rotation ranged from 0 to 90 degrees was also included in the calculations. The same calculation was performed for the aspherical IOL with -0.28µm spherical aberration. In each condition, defocus and astigmatism were corrected. Theoretical visual benefit that is defined by the ratio of the MTF with the f-IOLs or the aspherical IOL to that with a conventional spherical IOL (0.32µm spherical aberration) was computed. All calculations were conducted for a 4mm pupil diameter.
The IOL decentration was 0.468 +/- 0.237 mm. With no IOL decentration and rotation, the average visual benefit with the f-IOL (3.46+/-0.65) was significantly larger than with the aspherical IOL (2.69 +/- 0.60). There was no significant difference in visual benefit between the f-IOL and the aspherical IOL when the measured IOL decentration was taken into account. Both f-IOL and aspherical IOL provided significant benefit compared to a conventional IOL even if IOL decentration and rotation used in this study exist.
The IOL decentration prevents full benefit of correcting the HOAs. In normal eyes, the fully customized IOLs may not outperform the aspherical IOLs if there was clinically observed amounts of decentration.
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