Carl Zeiss Meditec IOL Master
IOLMaster — White-to-White Measurement (WTW).
Determination of "White-to-White" (optional)
Each time the joystick button is pressed, an image of the eye is displayed in which the detected iris edge is marked. After a check of correct recognition of the iris and the fixed point has been performed, confirm with OK. Only then is the data valid and available for further processing.
The WTW value is the horizontal diameter of the iris. In addition to the WTW value, the distance of the visual axis from the center of the iris (x, y) will also be displayed.
The values are stated in millimeters with reference to a Cartesian coordinate system, the zero point of which is assumed to be in the established center of the iris or pupil. If the visual axis is above the iris or pupil center, the Y value will be positive; if it is below, the value will be negative. X values to the left of the center are negative; those to the right are positive.
Measurement of Other Eye
The system automatically registers which eye is being measured (OD or OS). All past readings of this patient are still stored and may be retrieved as necessary. Measurements of the other eye must be performed analogously to the previous eye.
Proper Adjustment of IOLMaster
Ask the patient to relax and look at the yellow fixation light .
Focus on the iris, not on the illuminated dots. Adequate room lighting will facilitate the detection of iris structures. Avoid direct exposure of the eye and device front panel to extraneous light.
In particular, ensure that the visible right and left edge of the iris is not disturbed by reflections from lamps and windows.
If the iris structure is not discernible, focus on the edge of either iris or pupil.
Serious defocusing will result in incorrect data.
After the image has been taken, the operator should check if the software has correctly detected the edge of the iris. If the circle segments drawn in the image do not define the iris correctly, the result must be discarded. Click on OK to confirm the results and save the data.