The Pentacam is similar to the Topographer, but far more advanced. It gets the same information, but plus a lot more
It can also measure the entire anterior segment
Here is the fixation light (red circle)
The blue line should lie on the center of the cornea
You must do 2 things at the same time!
1) Using the joystick, align the red crosshair over the yellow target
2) Then push forward on the joystick and have the red dot lie precisely on the red line at the same time
If done correctly, the machine will automatically take the image