Improving outcome predictability
La Place Law
The tension on the wall of a sphere.
As we learned in college (when we were paying attention), the tension on the wall of a sphere, such as the cornea, can be described by Laplace’s Law, where…
with a wall thickness of (d)…
and the internal pressure (p)…
and the radius of (r) is:
T = (p*r) / (2d)
The more rigid the cornea, the more effective the cut will be; conversely, the thicker the cornea, the deeper the cut will need to be to achieve the desired effect. This is a well-reasoned approach, and Dr. Israel has demonstrated that applying a correction based on Laplace’s Law indeed increases the accuracy of the exercise.
LRIs carried out in this manner require an adjustable diamond blade and a good method of intraoperative marking. What many consider to be the best instruments for this purpose can be found at Mastel Precision (no financial interest is declared).
