gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

Does the orientation of the IOL in the eye play a role? : Imaging quality of foldable intraocular lenses measured utilizing point spread function (PSF) and scanning electron microscopic cross section photographs

Meeting Abstract

  • corresponding author C. W. Spraul - Department of Ophthalmology, University of Ulm, Ulm, Germany
  • R. Rawer - Institut of Technic and Information, University of Karlsruhe, Karlsruhe, Germany
  • W. Stork - Institut of Technic and Information, University of Karlsruhe, Karlsruhe, Germany
  • C. Lingenfelder - Department of Ophthalmology, University of Ulm, Ulm, Germany
  • P. Walther - Department of Electron Microscopy, University of Ulm, Ulm, Germany
  • G. K. Lang - Department of Ophthalmology, University of Ulm, Ulm, Germany;

Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogDO.05.02

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Veröffentlicht: 22. September 2004

© 2004 Spraul et al.
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Foldable intraocular lenses are established in ophthalmic surgery and increasing more complex geometries are available. This study investigates different designs of the optics of IOL as well as the imaging quality of these optics utilizing electron microscopic photographs and mathematical approximations.


Included in this study were two different lens powers of common IOLs (+13D and +26D). All studied IOL were processes depending upon their water content: Aqueous IOL up to 25% water content were fixated with 2.5% Glutaraldehyd in 0.1 M phosphate buffer (mPP), and then contrasted with 2% OsO4 and processes in an alcohol row 30% - 100% propanol. Subsequently, the IOL were transferred into EPON (epoxy resin) and polymerization took place at 60°C. After hardening the samples were saw out with a leaves saw and halved. Afterwards these were polished with glass and diamond knifes at the ultramicrotom (Ultracut of Rückert-Jung). After coal vaporization measurement took place in the scanning electron microscope (DSM 962 Zeiss). In the case of dry stored IOL they were sputtered with Au-Pd 20 nm and afterwards measurement was performed as described above. The measurement of the optical imaging quality was performed with correctly an inversely oriented IOL according to the standard EN ISO 11979-2 by means of a measuring system which works on basis of point spread function (PSF) and/or the modulation transfer function (MTF). From this the Strehl Ratio was computed in each case.


Utilizing correlation of the electron microscopic investigation of the optics of different IOL with their imaging quality (Strehl Ratio) we were able to show that the optical design of an IOL has substantial influence on the imaging quality of an intraocular lens. In particular, with non-symmetrical designs of the optics (e.g. AR40e; AMO) the orientation of an IOL in the eye is crucial; i.e. the Strehl Ratio changes thereby from 0.68 to 0.82.


The design of asymmetrical optics is crucial and it should be paid much attention to the fact that the imaging quality can substantially be affected. A correct orientation of the lens within the eye is very important with these asymmetrical optics.