Advanced surface ablation (ASA) is a refractive surgery technique used to correct vision problems such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. The procedure involves removing the corneal epithelium (the outermost layer of the cornea) and reshaping the cornea using an excimer laser to improve how light is focused onto the retina.

ASA is a variation of photorefractive keratectomy (PRK), with differences in how the epithelial layer is removed. The procedure is commonly performed on patients who are not suitable candidates for LASIK or those who have thinner corneas.

ASA provides effective vision correction with a longer recovery time than LASIK, but it is still a reliable option for patients seeking refractive surgery.