Abstract
Abstract: :
Purpose: To determine if an intraocular lens (IOL) with a modified prolate anterior surface (Tecnis Z9000) decreases higher–order aberrations more effectively than the biconvex surface of a traditional IOL (Acrysof SA60AT). Methods: An IRB approved study was done using patients who were randomly selected from our post–op clinic. Inclusion criteria included either a Tecnis Z9000 or Acrysof SA60AT IOL, clear posterior capsule, and a centered lens. Patients were divided into two groups receiving either the Tecnis Z9000 IOL by Pharmacia or the Acrysof SA60AT IOL by Alcon in one or both eyes. Wavefront analysis of the patients’ optical system was performed using the NIDEK Refractive Power/Corneal Analyzer ARK 10000. Results: 23 eyes with the Tecnis Z9000 with an average uncorrected VA of 20/40 and 23 eyes with the Acrysof SA60AT with an average uncorrected VA of 20/25 were scanned during follow–up visits that fell within a 1 to 9 month range for Tecnis and a 1 to 24 month range for Acrysof. The Tecnis had lower fourth–order spherical aberration (C[4,0]) when compared to the Acrysof SA60AT. The mean Tecnis C[4,0] ± SD was 0.000 ± 0.355 µm and the mean Acrysof C[4,0] ± SD was 0.377 ± 0.187 µm (p = 0.000). Additionally, there was a difference in the third–order aberration of vertical coma (C[3,1]) with a mean Tecnis value of –0.096 ± 0.255 µm and a mean Acrysof value of 0.261 ± 0.165 µm (p value = 0.000). Finally, the fourth–order astigmatism (C[4,2]) had a mean value of 0.084 ± 0.213 µm for the Tecnis lens and –0.021 ± 0.107 µm for the Acrysof lens (p = 0.040). Conclusions: Despite the difference in uncorrected visual acuity favoring the Acrysof lens the Tecnis lens showed a significant decrease in the fourth–order spherical aberration (C[4,0]) when compared to the Acrysof lens. This finding supports claims that a lens with a modified prolate anterior surface should decrease spherical aberrations, possibly resulting in better contrast sensitivity for patients. Furthermore, the Tecnis lens appears to decrease other higher–order aberration including horizontal coma (C[3,1]) and fourth–order astigmatism (C[4,2]) when compared to the Acrysof.
Keywords: optical properties • cataract • clinical (human) or epidemiologic studies: outcomes/complications