Objective: The OPTIMISE study aims to establish an evidence-based, cost-effective regimen that effectively prevents rejection and minimizes side effects. The hypothesis of this study is that Fluorometholone 0.1% in the first year and discontinuing medication in the second year is a cost-effective treatment strategy after DMEK. Study design: The design of this study is a randomized, controlled multicentre trial with a duration of 24 months. Study population: The study population will consist of 342 patients aged 21 years or older undergoing DMEK surgery in one eye. Intervention: All patients will receive Descemet's Membrane Endothelial Keratoplasty. Following this procedure, patients will be randomized into the following post-operative regime in two stages: STEP-I (Year 1): Control group: DMS 0.1% 6 times a day for 1 month tapered off to once daily within 6 months and then once a day for 6 months. Intervention group: DMS 0.1% 6 times a day for 1 month followed by FML 0.1% 4 times a day for two months tapered off to once daily within four months and then once a day for 6 months. STEP-II (Year 2): Control Group: Half the patients in each study arm will use FML 0.1% daily. Intervention Group: Half the patients in each study arm will discontinue steroids. Main study parameters/endpoints: Primary outcomes: Step-I: IOP elevation compared to baseline Step-II: Endothelial cell loss (ECL) in the second year Secondary outcomes are: * Rejection free graft survival. * Patient reported outcome measures. * Incremental cost-effectiveness ratios, including a short term trial-based economic evaluation (TBEE) and a life-long model-based economic evaluation (MBEE) * Structural outcomes including corneal, central macular and retinal nerve fibre layer thicknesses, and optic nerve head imaging.