Cataract surgery

In order to compute the power of an intra ocular lens implanted in cataract surgery commonly one of the regression formulas ( SRK/T, Hoffer Q or Haigis ) is used. A disadvantage of this technique is the fact that the individual patient could have different eye geometry compared to the average eye, determined by regression. Especially after laser refractive surgery, the regression formulas represent a back surface of the cornea which is different from reality. The tool on this site can be used to determine the IOL power for a specific patient. Just slide the IOL power button in order to change to IOL mode or type in specific values. The IOL-position is based on the formula of Olsen (Prediction of the effective postoperative (intraocular lens) anterior chamber depth, J. Cataract and Refractive Surgery 2006). Further research is necessary to determine the postoperative position of a specific IOL.

IOL Power: After filling in the preoperative geometry values of a specific patient use the IOL power slider to simulate implantation of an IOL.
Radius anterior cornea: This value can be measured by one of the common keratometry techniques or Scheimpflug imaging.
Radius posterior cornea: This value can be measured by corrected Scheimpflug imaging (Dubbelman & van der Heijde), rotating Scheimflug imaging (Pentacam, Oculus) or the OrbscanII (Bausch and Lomb).
Radius anterior lens: The influence of this value on the IOL position has not been studied yet, so this field can be ommitted.
Radius posterior lens: The influence of this value on the IOL position has not been studied yet, so this field can be ommitted.
Central cornea thickness: This value can be measured by common pachymetry techniques, the IOL master (Zeiss), the OrbscanII (Bausch and Lomb), the Pentacam (Oculus) or corrected Scheimpflug imaging (Dubbelman & van der Heijde).
Anterior chamber depth: This value can be measured by the IOL master (Zeiss), ultrasound biomicroscopy, the OrbscanII (Bausch and Lomb), the Pentacam (Oculus) or corrected Scheimpflug imaging (Dubbelman & van der Heijde).
Lens thickness: This value can be measured by ultrasound biomicroscopy or corrected Scheimpflug imaging (Dubbelman & van der Heijde).
Axial length: This value can be measured by the IOL master (Zeiss) or ultrasound biomicroscopy.
Lens equivalent index: This value can be ommitted because the human lens is removed.