The VRF and VRF-G Formulas

The VRF formula is a vergence-based thin-lens formula using the optical CACD constant and four variables to calculate the IOL power: axial length, keratometry, anterior chamber depth, and horizontal corneal diameter. The VRF-G (where G stands for gender) is an evolution of the VRF that is based on theoretical optics with regression and ray-tracing components. It uses the optical A-constant for the SRK/T formula and operates eight variables including axial length, keratometry, anterior chamber depth, lens thickness, horizontal corneal diameter, central corneal thickness, preoperative refractive spherical equivalent, and gender. The equations of the VRF formula and the published results of both formulas are reported.