We went on a cruise last April (Rhasody of the Seas)7 nights... Ship was actually pretty stable and calm, but at my own fault i think i was watching outside the window of our dining room table and sitting in the opposite direction of the ship

which was making me feel very uneasy.... Long story short, i made a quick trip to the room to put on the patch after being on the boat for several hours. Next morning i woke up and felt like i had overdosed on Benadryl or Tylenol PM. Went on with the day and by dinner time again I could not read the menu. I wear contacts so I went back to the room, to take them out and put on my glasses, hoping maybe they were just dirty or I had them in the wrong eye. No --- my eyes were still blurry and somewhat crossed. After reading on the package, this is a rare occurence, but one that obviously affected me. Just use caution when using them, Im sure some people use them without any problems. I myself will be trying something else like dramamine or the bracelet or just hanging in there until i get my "sea legs" i guess....
Rhonda