Surgeon Name | Patient Information | Date | Patient Age |
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The system offers five options, related to the biometry measurement and IOL constant selection:
Optical biometry (eg: IOLMaster, Lenstar), immersion A-scan and contact ultrasound A-scan have fixed A-constants. The last three options are for those surgeons who have developed their personalized IOL constants based on their own patients implanted with the TECNIS® IOL. Personalized constants for the corresponding non-Toric model (i.e. Model ZCB00) are valid starting points for Toric model calculations. For surgeons without personalized constants, the IOL constant for the selected biometry procedure will be used in the cylinder power calculation.
Note that the formula used for cylinder power calculation is the Holladay-1.
IOL A-Constant is a numerical value used in IOL power calculations. The system offers three options:
Calculated residual astigmatism related to each suggested lens model can be written in either of two equivalent forms: Plus Cylinder or Minus Cylinder. It can be changed back and forth once the calculation has been performed.
e.g., +0.01D x 90º (Plus Convention) = -0.01D x 0º (Minus Convention)
Plus to Minus:
Cylinder: sign + to –
Axis: change ± 90º
Calculated residual cylinder for each IOL model displayed, according to the refractive cylinder convention (Plus or Minus) chosen at the Calculation Preferences.
e.g., +0.01D x 90ºCalculated residual cylinder axis for each IOL Model shown.
e.g., +0.01D x 90º
Note: Once the IOL model is selected by clicking on it, a pop-up message appears if the residual cylinder axis is flipped to indicate an over correction of the patient’s astigmatism.
Flat K (K1) is the measurement of the flattest corneal power in diopters (D) or flattest corneal radius in millimeters (mm). Steep K (K2) is the measurement of the steepest corneal power in diopters (D) or steepest corneal radius in millimeters (mm).
The system will accept keratometry Flat K1 @ meridian values between and including 0 and 180°.
The system will auto calculate the keratometry Steep K2 @ meridian value.
The calculated value representing the difference between the keratometry power Steep K2 and Flat K1 (i.e., Steep K2 – Flat K1), without including the surgically induced astigmatism or posterior corneal astigmatism in the calculation.
The cylinder power is below the range for Tecnis Toric IOLs, please consider a non-toric Tecnis IOL.
The clinical study for the TECNIS® Toric 1-piece IOL did not show evidence of effectiveness for the treatment of preoperative corneal astigmatism of less than one diopter.
Please confirm that you wish to clear all entries that you have made on this screen. (e.g., OD (Right) & OS (Left))
Patient information has changed. Do you want to clear all entries? (e.g., OD (Right) & OS (Left))
Posterior Corneal Astigmatism has been selected.
Posterior Corneal Astigmatism is based on an algorithm that combines published literature (Koch et.al, 2012) and a retrospective analysis of data from a TECNIS Toric multi-center clinical study. The Posterior Corneal Astigmatism algorithm for the selection of appropriate cylinder power and axis of implantation was not assessed in a prospective clinical study and may yield results different from those in the TECNIS Toric intraocular lens labeling. Please refer to the user tutorial for more information.
Please ensure that you have verified your input values and the calculated results before proceeding.
Posterior Corneal Astigmatism has not been selected.
Please ensure that you have verified your input values and the calculated results before proceeding.
Lens has changed. Do you want to clear all entries? (e.g., OD (Right) & OS (Left))