The goal of this clinical trial is to learn if a longer period of lying on the back after corneal transplant surgery (Descemet Membrane Endothelial Keratoplasty, DMEK) helps the transplant stick better in the eye. It will also learn about side effects, such as back pain. The main questions it aims to answer are: * Does lying on the back for 5 days reduce the size of transplant detachment compared to lying on the back for only 1 day? * Do participants who lie on their back longer need fewer additional procedures (rebubbling)? * What symptoms or problems do participants experience with short vs. long back positioning? Researchers will compare two groups: * 1 day of back positioning * 5 days of back positioning Participants will: * Be randomly assigned to one of the two positioning groups * Wear a movement sensor that records head position * Have their eyes checked regularly with vision tests and imaging (AS-OCT) * Answer questions about their vision and comfort * Keep a diary of any positioning-related complaints, such as back pain