Patients with prior radial keratotomy (RK) often have diurnal fluctuations in vision due to changes in the corneal hydration and curvature. Some patients may notice better vision in the mornings while others prefer their evening vision. This fluctuation can be 1 diopter or more, depending on the number of RK cuts. This patient has prior 20 cut RK and is undergoing cataract surgery with a goal of close to plano (-0.50) and has elected to have this extended depth of focus (EDOF) IOL implanted. This will allow a range of about 1.5 diopters and that can help offset some of the diurnal changes in the cornea to give a wider range of good vision and a larger time frame of optimal vision throughout the day and evening.
