Intraocular pressure rises in steep Trendelenburg positions, but the increases don’t matter in patients without eye disease who have surgery in that position, Japanese researchers say. At the beginning of the surgery eye pressure rises, then in healthy patients this equilibrates usually during the surgery. However, it is a potential risk on patients already experiencing high intraocular pressure problem facing damage in their eyes. This damage does not mean it necessarily will surface immediately; sometimes may take years before it gives the initial symptoms. Dr. Sami Gokhan Kilic told Reuters Health, “At UTMB, we have the privilege to work closely with NASA. Due to prolonged zero gravity in space, a significant percentage of their astronauts, even though mostly mild, experience visual disturbances much later after their return. It is pretty much the same mechanism when we put the patient in steep Trendelenburg. Fortunately, our surgeries are much shorter exposure than their astronauts.” Kilic concluded that "current data is immature to draw concrete conclusions. New studies are warranted."