This is an observational (in which the investigators observe the outcomes of the study participants but do not intervene by, e.g, assigning the treatments) and retrospective (a study in which the exposures and outcomes occurred before the study began) study. It will use data from the Optuminsight and Truven Commercial Claims and Encounters databases, each of which will be evaluated separately using 3 designs: (1) Case-control (a design that compares the cases [study participants], ie, those with retinal detachment to controls, ie, a sample of similar people who did not have a retinal detachment) to assess whether their exposures to fluoroquinolones (FQs) differed. Two case-control studies are planned, one (replication) that mimics a previously reported study, the other (revised) that addresses more potential confounders than did that study , (2) Cohort (a design that follows the participants exposed to FQs and those not exposed to FQs to assess whether the two groups had different risks of developing retinal detachment), (3) Case-only (a design where the exposure history of individuals who had retinal detachment are examined to assess whether they were more likely to have had it when they were exposed to FQs than when they were not).