I had a opthal appt last week and my eyes were measured. Having problems this week again with my eyes, dr measured them and they were about 9 ml off from the week before. He took out what looked like a measuring stick and remeasured and it was off 5 ml that time. Seems to me the measuring device isnt very effecient. I supposly go to the best in town, but now Im really wondering. Have others experienced the same. I was afraid the next means of measurement would be a sun dial.