ABSTRACT
The Standard Drill treats mild and moderate myopia from −0.75 D to −1.75 D. The prescription for each eye is the same. If there is a disparity between each eye, it is −0.25 D or less. The contact lens’ flatness factor is equal to the absolute value of the prescription—or more specifically, to the absolute value of the sphere. The assumption is that patient’s prescription is within the myopic model, and the deviation took place during postdevelopment. The conditions allows for the application of the multiplier effect.
In higher degrees of myopia, the tension of the oblique muscles increases. A flatter ortho C lens is required to loosen the oblique muscles sufficiently before you can effectively reverse the myopic shape of the eye. Such a lens poses a dilemma. A lens with a flatness of 3.75 D, for example, is outside the flatness tolerance. The meniscus is not adequate to allow a “focal point draw” before ortho K kicks in after the solution drains. (ortho C and ortho K do not mix.) The mild and moderate myopic eye does not have such a problem. The flatness factor is not that high. The highest is 1.75 D to treat the maximum range of moderate myopia.
