<prompt> Power of Intraocular lens is determined by?KeratometryRetinoscopyOphthalmoscopyGonioscopyBiometry  <response>: The most common method of determining IOL power uses a regression formula called SRK Sanders, Retzlaff and Kraff formula. The formula is P A - 2.5L - 0.9K, where: P is the power of IOL, A is a constant which is specific for each lens type. L is the axial length of the eyeball in mm, which is determined by A-scan ultrasonography. K is average corneal curvature, which is determined by keratometry. 