Follow these steps to estimate a tailored target intraocular pressure (Target IOP).
- Select “Enter patient data” from the menu.
A) If you have Forum. Enter the following patient data (use the “Next” button between entries). The first four items are available on the visual field printout, the 5th item (mean IOP) should be estimated by you from the patient records and include IOP measurements taken after pressure-lowering treatment has been started. To ensure significance at least five IOP tests have to be performed. See Theoretical framework – A new Target IOP, Calculating the new Target IOP.
Note, the estimates are to be considered as long as the entered data is correct. Please check your data selections carefully according to the patients’ health record.
- Age of the patient at the time of the first visual field test*
- Current age of the patient
- Current Visual Field Index (VFI %)**
- Measured Rate of Progression (RoP % per year)***
- Mean IOP during follow-up (mmHg)
B) If you do not have Forum or otherwise access to the calculated RoP follow the steps under 2a with the exception of the RoP. This can be calculated based on individual visual field measurements using the “Calculate RoP” add-in functionality. Note that a minimum of three visual fields is necessary to perform the calculation of RoP, otherwise the uncertainty will be too large. All available measurements should be included in order to increase the precision in estimating the RoP. Also note that, when entering the mean IOP (step 5), the specified time period needs to be in accordance with the time period for which the calculation of the RoP is performed.
- The age/function diagram now displays a solid trend line showing the current RoP and the estimated development as an extrapolated dotted portion of the same line. The entered values are displayed at the top of the screen.
- A grey dot will appear at the end of the line. Move the dot to a desired location. Observe that the dot can be moved both up and down and to the left. The end of the rate of progression line does not have to be at the right border of the screen.
- As you move the dot to another position, the values at the side of the screen recalculate. A new Target IOP will appear if any changes are made. You will also see the SSY (Save Sight Years) value change and turn green if there is an improvement to the current trend line. The SSY estimation is a calculation based on the age of the patient at a VFI of 50%. The SSY value is the difference in years between the current trend and the new simulated trend. Note, SSY estimation is N/A if the patient’s current VFI is below 50%.****
- If you would like to perform a new simulation with a different IOP/RoP ratio than 12 %, you can do so by changing the ratio (6-20 %) in the bottom right corner. You will then need to redo the simulation based on the new ratio setting.
- If you would like to print or email the estimate, press the “Export” button and a screenshot will be attached to an email. Note, check your typing carefully to ensure the right email recipient.
- If you would like to enter another patient’s data, select “New patient” or open the menu and select “Enter patient data”.
Technical requirementsSSY Engine is designed for PC and Macintosh computers and the following browsers; Google Chrome, Firefox and Safari. Make sure to have the last browser version installed on your computer and check your battery status if you are using a laptop before simulations. SSY Engine requires an internet connection and a valid password to be used.
* Age when field loss was detected. Cf, Calculating the new Target IOP in the Theoretical framework section.
** In the Octopus perimeter: MD (dB)
*** In the Octopus perimeter: dB/year
**** In the Octopus perimeter: Current Mean Defect is above 12.5 dB
User guide updated: 2017-05-09