Well into my household’s Year of Sensory Input Issues, my husband is dealing with a detached retina. It’s been a sometimes frightening experience — for example, did you know that if you have to leave an international flight en route, that the customs agent will come out and clear your passport on the ambulance? And that in spite of their stinginess with blankets and pretzels, United Airlines really can come through in a crisis? Annoying as it’s been, the experience has been filled with Cool Applications of Physics, which helps me pass the time.
A retinal detachment involves the retina (which lines the back of your eye like wallpaper) sagging away from the back of the eye (as your wallpaper might do in a damp bathroom). Now, if you’ve ever tried to wallpaper a curved surface, you know it’s not easy to get some intrinsically flat thing to stick smoothly to the inside of the curve, especially when that bitch Gravity is pulling it down all the time. The clever way that retinal surgery deals with this (squeamish people stop reading now, please) is to suck some of the goo out of your eye and replace it with a gas bubble. You then tilt your head into the right position to have the gas bubble float up into the correct portion of the eye while the retina re-attaches. For a month. If you’re lucky, you get to sit up, but if you’re unlucky, you spend a month looking at the floor. In addition, you cannot go up or down in altitude by more than a thousand feet or so, because when you have an air bubble in your eye pressure changes are not a great idea.
My husband has been lucky enough to have a sitting-up kind of detachment so far (though I’m writing this while waiting for him to get out of surgery a second time, since it seems to have detached again, and based on where he lost vision and knowing the inversion of the image that takes place in the eye’s reimaging system, I’m worried he’s going to be a floor-looking guy when he comes out). The cool bit about getting to look at him face-on is that you can actually see the bubble! He looks like a human level, as the bubble readjusts as he tips his head.
The other physicsy bit is that when you have a gas bubble in your eye, your index of refraction is all wrong, and in spite of having a working retina attached in the right place, you still can’t see, because the air-lens interface steers the light to the wrong place. This gets better as the air is absorbed by the body and replaced with fluid. It’s also better when you tip your head down so the bubble floats away from the lens.
The upshot of all this is that I think that modern medicine is pretty darn clever, though I wish I didn’t have to know about it.