OBJECTIVES: To assess the long-term safety of Laser in situ keratomilieusis (LASIK) and surface ablation surgery for myopia in South Korea. METHODS: A retrospective cohort for patients who had a LASIK or surface ablation surgery in 6 hospitals during 2002-2005 were constructed based on chart reviews and linked to Health Insurance Review and Assessment (HIRA) claims database during 2005-2009. A total of 2,422 patients (4,688 eyes) were linked using anonymized identifier after excluding patients with a history of eye disease, diabetes, hyperopia, or different surgery methods for both eyes. The frequency of eye disease such as cataract, glaucoma, retinal detachment, corneal opacity, and keratoconus during 3-8 years after surgery and the pre-surgery characteristics including age, UCVA (uncorrected visual acuity), manifest refractive (MR) of patients with eye disease were analyzed. RESULTS: There were 1,637 LASIK patients and 785 surface ablation patients. The eye disease after LASIK were cataract (0.2%) and corneal opacity (0.9%) during 3-4 years and cataract (0.1%), glaucoma (0.2%), retinal detachment (0.4%) and corneal opacity (0.7%) during 4-5 years. The retinal detachment (0.3%) and corneal opacity (1.3%) were observed during 7-8 years while no keratoconus was identified during 3-8 year follow-up . The pre-surgery MR (mean±SD) were -6.98±1.41 Diopter (D), -7.46±2.87 D, -6.13±2.67 D, -6.23±2.62 D in patients with cataract, glaucoma, retinal detachment, and corneal opacity, respectively. The incidence of eye disease after surface ablation was similar to LASIK. CONCLUSIONS: The linkage of clinical baseline database and nationwide claims database can make up for loss to follow-up in retrospective cohort study. Although it is difficult to explain the causality of surgery, we could ascertain there was no serious eye disease after surgery.