During cataract surgery the aging crystalline lens is removed and replaced with a new artificial lens. The required lens power is different for every patient and depends on the type and amount of refractive error (short-sightedness, far sightedness or astigmatism).
The IOL Master and G6 are sophisticated biometry devices which measure various structural parameters of the eye to calculate the required lens power. These parameters include keratometry (curvature of the cornea), axial length (length of the eye), white-to-white (diameter of the cornea), anterior chamber depth and lens thickness.
The lens power is calculated by entering these measurements into different formulae which are optimized for different types of eyes and different types of lenses. The ophthalmologist selects the ideal lens for the patient based on his/her individual visual needs.