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F. Taketani, G. Yoon, Y. Hara; Theoretical Improvement In Retinal Image Quality When Correcting Higher Order Aberration With Partially And Fully Customized IOLs . Invest. Ophthalmol. Vis. Sci. 2006;47(13):326.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the theoretical visual benefit of correcting higher order aberrations with partially and fully customized IOLs compared to a conventional IOL when decentration and rotation of the IOLs exist.
The cornea aberration up to the 6th Zernike order of 21 normal eyes (average age: 68.3±6.0 years old) and 19 eyes (age: 67.5±9.6 years old) with penetrating keratoplasty (PK) were measured with a Topcon topographer (KR 9000PW) and a Bausch and Lomb Orbscan topographer. Using the cornea aberration, a conventional IOL correcting defocus and astigmatism and three different IOLs correcting coma, spherical aberration or all of the 2nd and higher order aberrations were theoretically designed to simulate aberration corrections. We assumed that the conventional IOL included 0.32 µm of positive spherical aberration. With residual aberration generated by decentration of up to 0.5 mm and rotation ranging from –15 to +15 degrees, correction performance was assessed by calculating the optical modulation transfer function. Theoretical visual benefit that is defined by the ratio of the volume modulation transfer function with HOA correction to 2nd order correction was computed.
Vertical and horizontal coma and spherical aberration were the most dominant HOAs in both normal and PK eyes. In normal eyes, average visual benefit was 2.1±0.5 (range 1.3 to 3.4) with the fully customized IOL. The other 3 IOLs provided slight but, significant visual benefit over a conventional IOL. In PK eyes, the maximum visual benefit was 5.7 with no decentration and rotation. However, the visual benefit was rapidly reduced with an increase in decentration and rotation (1.1 with 0.5 mm decentration and 15 degree rotation). The partially customized IOLs did not provide any benefit to the PK eyes over the conventional IOL.
In normal eyes, partially customized IOLs significantly improved retinal image quality when compared to conventional IOLs, although there was no significant improvement in abnormal eyes with the partially customized IOLs. Fully customized IOLs for both normal and abnormal eyes could still provide significant visual benefit even if typical amounts of decentration and rotation were induced after IOL implantation.
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