LASIK Eye Surgery & Vision Prescription
Your vision impairments such as myopia, hyperopia, astigmatism, and presbyopia are measured in units called diopters. The more nearsighted, farsighted or astigmatic you are, the higher your vision prescription in diopters. Thus, diopters represent the amount of vision correction you need to normalize your eyesight.
Typical vision prescription -4.00 -1.50 X 90
- -4.00 identifies the degree of your nearsightedness or farsightedness. The sign identifies whether you are nearsighted (- sign) or farsighted (+ sign).
- -1.50 identifies the degree of astigmatism.
Sign can be either + or -.
- 90 identifies where the astigmatism is positioned. This astigmatism is located at ninety degrees, or in the vertical axis.
These numbers are used to help determine the laser eye treatment. They help determine how much and in what pattern the laser removes tissue from the cornea during LASIK eye surgery.