Download the Olsen Formula Constants for LENSTAR

Please complete the below form to download the instructions and files for the Olsen Formula Constants. Please note, you MUST agree the terms and disclaimer to download.

NOTE: The software update to ver i6 needs to be completed before the Olsen formula can be used.



Optimized lens constants for the LENSTAR

Accurate IOL power calculation requires optimization of lens constants. If the lens power calculation is based on LENSTAR measurements, only lens constants optimized for use with the LENSTAR or an optical Biometer providing equivalent measurements should be applied. The IOL manufacturers' constants should not be used since they are suggested numbers for applanation ultrasound biometry. Optimized lens constants for the calculation of intraocular lens power with the LENSTAR with the Haigis-, Hoffer Q, Holladay I, SRK/T and SRK II are published by the User Group for Laser Interference Biometry (ULIB) on its website. Constants for the use with the Olsen formula are available from data from Dr. Olsen. Furthermore constants for toric IOL and the Olsen formula are available from IOL manufacturers. These constants are based on surgical data and on research done by the ULIB, Dr. Olsen as well as the respective IOL manufacturer and are provided as a starting point for individual constant optimizations. Haag-Streit does not create, validate, verify or otherwise confirm that these third party lens constants are correct or appropriate for IOL implantation.



The file is provided "as is" without any express warranty AND ALL IMPLIED WARRANTIES ARE DISCLAIMED INCLUDING BUT NOT LIMITED TO MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT AND FREEDOM FROM ERRORS. The term “you” refers to the individual downloading these materials and his or her organization; the downloader warrants that he or she has authority to make these commitments on behalf of his or her organization.

These lOL constants are provided without any legal responsibility by Haag-Streit AG through its USA subsidiaries (Haag-Streit and all of its affiliated entities being referred to as HS). You acknowledge that HS has not created, validated, verified or otherwise confirmed that these third-party lens constants are correct or appropriate for IOL implantation.

You are responsible for verifying the validity and appropriateness of the imported constants for the intended uses. This may include confirming that the values of the imported constants are at parity with those published. HS shall have no liability for any personal injury or equipment damage (e.g., caused by computer virus transmission) arising from or associated with the import and subsequent use of the imported constants under any circumstances and you assume all risks resulting from their download or use.

 You assume all responsibility for subsequent uses of the imported constants, including use by other surgeons and clinical staff and shall be solely responsible for all claims in connection therewith.  You shall indemnify, defend and hold HS harmless for all claims, actions, lawsuits, demands, costs, liabilities, losses, damages and/or expenses (including reasonable legal fees and costs of litigation) by any other party resulting from or relating to use of the downloaded materials. HS shall not be liable for any direct, indirect, consequential or punitive damages arising from the use of this dataset.


Importing optimized lens constants with the LENSTAR

Download the file directly to the PC that is running the LENSTAR or copy it after the download to a media suitable to be used with this PC. The download file is in a proprietary format suitable for the LENSTAR. Follow the instructions in the LENSTAR’s instructions for use to import optimized lens constants from the file downloaded.

Certain IOL models may not be approved in some countries.