Statistics
Results Calculator
Detailed Instructions:
The results calculator will show you our exact success rate with prescriptions in the same range as yours. To use the results calculator, you must first understand your prescription for eyeglasses or contact lenses. There are three basic components to most prescriptions: sphere, cylinder and axis. Sphere refers to the amount of nearsightedness (myopia) or farsightedness (hyperopia). If the sphere number is negative, then you are nearsighted. If it is positive, then you are farsighted. Cylinder refers to the amount of astigmatism. It can be expressed as either a positive or negative number. The results calculator accepts input in either form. Axis refers to the direction on the clock hour of your astigmatism. For example, an axis of 180 refers to astigmatism in the 3 o'clock direction, while an axis of 90 refers to 12 o'clock. The axis number is not relevant to the results calculator. If you don't have any astigmatism, then your prescription will only have a number for sphere. Some other terms that are not relevant to the results calculator are occasionally found on a prescription. These include "Add", "Prism", "Base Curve", "Diameter" and "Pupillary Distance (PD)". The basic format for a prescription is: +/- sphere +/- cylinder x axis. Below are three examples to help you see how all of this works. The most important detail to remember is to make sure you enter a minus sign in front of negative numbers when using the calculator.|
Sample Prescription #1: -3.75-0.50x180 | ||
| Since the sphere is negative, this individual is nearsighted. The number -3.75 should be entered in the results calculator, not +3.75 or 3.75. Likewise, the cylinder should be entered as -0.50 and not +.50 or .50. | ||
| -3.75 | -0.50 | 180 |
| sphere | cylinder | axis |
|
Sample Prescription #2: 2.25 sph, add +1.25 | ||
| Since the sphere is positive, this individual is farsighted. The "add" number is used when a bifocal lens is placed at the bottom of the lens to help with reading. The "add" number is not relevant to the results calculator. Notice there is no number for cylinder, which means that this individual doesn't have any astigmatism. Therefore, the cylinder field can be left blank. Note that the sphere number is entered into the Results Calculator as 2.25 and not +2.25. In other words, the plus sign is not entered. | ||
| 2.25 | none | none |
| sphere | cylinder | axis |
|
Sample Prescription #3: -2.25-1.50x110, BC=8.8 Dia=14.0 | ||
| This is a contact lens prescription, as the terms BC (base curve) and Dia (diameter) refer to the size of the lens. These terms are not used in the results calculator. A value of -2.25 for the sphere and -1.50 for the cylinder should be entered into the calculator. | ||
| -2.25 | -1.50 | 110 |
| sphere | cylinder | axis |
