By Dr Kashmira Rawjee Modern cataract surgery is refractive surgery. A refractive surprise refers to an unexpected residual refractive error after cataract surgery, where the achieved postoperative refraction differs from the planned target. Although uncommon with modern biometry and IOL calculation formulas, refractive surprises can still occur and may significantly impact patient satisfaction. Fortunately, when surprises occur, we have excellent solutions available. The main types of refractive surprise after cataract surgery are classified according to the residual refractive error, it can be myopic, hyperopia or parent as residual astigmatism. A refractive surprise may result from: • Unusual ocular anatomy (short or long eyes) • Prior corneal refractive surgery • Ocular surface disease affecting keratometry • Errors in biometry or lens selection • Effective lens position variability • Less commonly, postoperative IOL displacement In this weeks case, this patient experienced an unexpected hyperopic refractive surprise following routine cataract surgery with a visual acuity of 0.7. Although the surgery itself was uncomplicated, the postoperative refraction left the patient dissatisfied with their visual outcome. Rather than performing an intraocular lens exchange—which can be technically more challenging and carries additional risks once capsular fibrosis has developed—I elected to implant a supplementary (add-on) intraocular lens in the ciliary sulcus. What is an add-on IOL? A supplementary IOL is specifically designed to sit safely in the ciliary sulcus, in front of the original capsular bag IOL. It works by adding the required refractive power to correct the residual error while leaving the primary lens undisturbed. Advantages include: Precise correction of residual refractive error Preservation of the original capsular bag IOL Lower risk than late IOL exchange Reversible if future intervention is required Excellent visual outcomes in appropriately selected patients