The keratometer measures anterior corneal curvature. This information is useful to:
There are two main types: The von Helmholtz and Javal Shiotz. For both of them, the first steps are the same:
“Object” constant, “Image” adjusted
“Object” adjusted, “Image” constant
von Helmholtz (Bausch & Lomb) Keratometer Mires
A: Adjust the focus until the 2 central circles completely overlap.
B: Adjust the axes until the “+”s and “-“s are aligned.
C: Adjust the horizontal dials until the “+”s completely overlap. The reading on this dial is now the horizontal K reading (with the axis read off the keratometer). Repeat in the vertical axis by aligning the “-“s.
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