This Calculator is a tool to assist users of the Avansee Preloaded 1P Toric / Toric Clear with calculations. Please read the following "Warnings and Precautions" carefully before use.
This Calculator produces two calculations.
The first calculation is to calculate the residual refractive astigmatism in the entire eye showing four Toric IOL options for insertion to the user. These four calculation results will be output as Result 1  Result 4. Result 1 and 2 show no change in the astigmatism axis, while Result 3 and 4 show a change in the astigmatism axis.
The larger the Result number is, the higher the Cylinder Power becomes.
The residual corneal astigmatism after cataract surgery will be calculated by summing up the vectors of anterior corneal astigmatism, the assumed induced astigmatism (surgical incision site) and the posterior corneal astigmatism.
The second calculation is for the postoperative astigmatism assessment where the angle of deviation of the Toric IOL is calculated.
*(1) Those whose support from the developer has not expired, *2 The latest version is recommended, *3 Javascript shall be operable.
This Calculator can be used with devices that can be connected to the internet (PC or smartphone, etc.).
Avansee Preload 1P Toric / Toric Clear is distributed only in the displayed countries and we will not bear any responsibility for use in other countries.
Please be aware that languages not displayed are not currently supported.
You cannot use this Calculator without accepting the Terms of Use.
You can also enter data by clicking the "+" or "" buttons. You can also enter it by moving the slider.
Click the "Calculation" button to perform the calculation.
Icon  Explanation 

You can enter here if necessary.  
You can enter here if necessary.  
Select the right eye or left eye and click.  
You can change the value by clicking the "+" or "" button.  
Drag the slider to change the value.  
The steep and flat meridians are visually displayed. The incision site is also displayed.  
Click the cell to enter the amount of induced astigmatism to display an example of a numerical value, which can be entered if selected. Click the cell to enter the incision site to display an example of the direction, which can be entered if selected. It can also be entered manually, but the incision site cannot be set in the following positions and is automatically displayed by rotation of 180°. Right eye: 0° to +45°, 0° to 135° Left eye: +135° to +180°, 90° to 180° 

Click "Use" to use posterior astigmatism.  
If posterior astigmatism data is used, enter the amount of astigmatism and the axis angle. Withtherule or againsttherule astigmatism can be selected for the axis angle. "Others" may be selected to enter any value. 

Click the "Calculate" button. To delete an input value, press the "Clear" button. 

[Reference] When entering R1 or R2 and you want to change the refractive index of the cornea, change it from the pulldown list.  
You can enter here if necessary. 
Icon  Explanation 

Indicating information on corneal astigmatism.


Indicating the assumed Toric model and the fixation angle. Results 1 and 2 show no change in astigmatism axis, while Results 3 and 4 show a change in astigmatism axis. The larger the Result number is, the higher the Cylinder Power becomes. IOL SE Power (selected by the user) 

Indicating the residual refractive astigmatism and its axis angle when each of the assumed Toric models is inserted. Select the Result to be enlarged in on when printing, if needed. 

It indicates that the axial angle of postoperative residual refractive astigmatism differs by 90° from the axial angle of postoperative corneal astigmatism.  
Indicating right eye or left eye.  
The image of the insertion state of the Toric IOL is overlapped over the eyes. The dashed line indicates the axial direction (steep meridian) of postoperative corneal astigmatism. The arc mark indicates the incision site. The positional relationships between the target eye, ear, and nose are shown in an illustration. The result calculated as an insertion angle is shown in the center. 

You can change the image orientation by clicking the button.  
If necessary, fill in your notes before printing. Please note that your notes will not be saved. Select the Result to be enlarged in on when printing, if needed. Even if you do not select any result, you can still print the results. 

In addition to the example, a lineup model is shown. 
Error  Explanation 

Right eye or left eye is not selected. Select either right or left.  
No information on corneal refractive power is entered. Enter the required information. 

The flat meridian (K1) and the steep meridian (K2) may have been entered in reverse. Click the button that appears to replace the input value.  
You have exceeded the range of application of this Toric Calculator.  
Message displayed before the value is cleared  
This is displayed when you do not accept the Terms of Use. You cannot use this calculator without accepting the Terms of Use. 

No internet connection or communication failure. Check your internet connection. 

Result Number is not selected. Even if you do not select any result, you can still print the results. 
Click the tab on the top right of the screen.
Select the most appropriate one from the three calculation methods and enter the required data.
You can enter here if necessary. (Doctor*(Operator), Patient information, note)
Calculation of fixation angle deviationCalculate residual refractive astigmatism when the fixed Toric IOL is rotated. Enter the following data:

Ideal angle calculation 1Calculate the difference between the current angle and the ideal angle of the Toric IOL from postoperative information, and calculate the residual refractive astigmatism at the ideal angle. It is assumed that [postoperative total corneal astigmatism] and [postoperative residual refractive astigmatism] are known. Enter the following data:

Ideal angle calculation 2Calculate the difference between the current angle and the ideal angle of the Toric IOL from postoperative information, and calculate the residual refractive astigmatism at the ideal angle. It is assumed that [anterior corneal astigmatism], [induced astigmatism], and [posterior astigmatism] are known. Enter the following data:

Pressing the Calculate button automatically scrolls and displays the calculation results.
The Colored values are the results of the calculation. Please note that the elements shown in grey represent input values.
Icon  Explanation 

Indicating postoperative total corneal astigmatism.  
This section presents the results of prediction of the inserted Toric model from the input data under the assumption that the Kowa’s Toric IOL is inserted.  
Indicating the angle at which the Toric IOL is currently inserted (current angle) and the angle at which the Toric IOL is maximized (ideal angle).  
Indicating the difference between the current and ideal angle of the Toric IOL. It shows the angle toward the ideal angle based on the current angle.  
Indicating residual refractive astigmatism when the Toric IOL is at the current angle and residual refractive astigmatism when the Toric IOL is at the ideal angle. 
This tool calculates postoperative astigmatism and lens angle when the Kowa’s Toric IOL is inserted based on the "Alpins method" using information such as the cornea and incision site information, etc.
The angle is 0° in the right horizontal direction and positive in counterclockwise direction. Therefore, the negative angle indicates clockwise.
Symbol  Meaning  Vector value 

Anterior corneal astigmatism vector  [Acos(2α),Asin(2α)]  
Induced astigmatism vector  [Scos(2θ),Ssin(2θ)]  
Posterior corneal astigmatism vector  [Bcos(2β),Bsin(2β)]  
Toric IOL vector  [Tcos(2τ),Tsin(2τ)]  
Postoperative corneal astigmatism vector (including anterior and posterior vectors)  [Ccos(2γ),Csin(2γ)]  
Postoperative residual refractive astigmatism vector  [Dcos(2δ),Dsin(2δ)]  
Toric IOL vector considering angle deviation  [Tcos(2τ+2Δτ),Tsin(2τ+2Δτ)]  
Ideal postoperative residual refractive astigmatism  [D'cos(2δ),D'sin(2δ)] 
A, S, B, T, C, and D indicate the size of astigmatism, α, θ, β, τ, γ, and δ indicate the axis angle (directions of flat meridian and Toric mark), and ⊿τ represents the angle deviation.
Calculations are performed as follows:
(1) Enter the data entered into each vector described above.
(2) Calculate the postoperative corneal astigmatism vector using the following formulae.
(3) Calculate postoperative residual refractive astigmatism from three Toric IOL vectors and postoperative corneal astigmatism vectors.
Calculations are performed as follows:
(1) Enter the data entered into each vector described above.
(2) Calculate postoperative residual refractive astigmatism by the following formulae.
Calculations are performed as follows:
(1) Enter the data entered into each vector described above.
(2) Calculate the Toric IOL vector including angle deviations using the following formula: However,
(3) Calculate the residual refractive astigmatism vector when the Toric IOL is in the ideal angle position.
Calculations are performed as follows:
(1) Enter the data entered into each vector described above.
(2) First, calculate the postoperative corneal astigmatism vector.
(3) Then, calculate the Toric IOL vector including the angle deviations as in B. Calculation of angle correction 1.
(4) Calculate the residual refractive astigmatism vector when the Toric IOL is in the ideal angle position, as in B. Calculation of ideal angle 1.
Links are at the bottom of each page. Please check the content when necessary. Please note that the input values and calculation results are cleared when transitioning to the screen.
Links  Explanation 

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If you have any questions about this Calculator, please contact your local sales representative.