you fill out a meaningless health history/questionnaire and get screened by a NP or PA. no physical exam occurs. they may document some complaints but don't do anything. it's a check the box kind of thing. the vision exam is a MEDPROS thing (meaning everyone in the army has to have the same preventative medicine done, not for your health but to make sure you are deployable) yearly, and i don't know why you are concerned it may get worse. i have some keratoconus BS and my eyes are crap but it has never been an issue.
thankfully we're mostly healthy, but at some point i suppose i will need to start documenting my various aches/pains for retirement or ETS. the enlisted folks know how to game the disability system best-- something like back pain and OSA (or some other combo) and they get free money forever. i'll worry more when i get closer, lol.
--your friendly neighborhood chronic fatigue/fibromyalgia/IBS caveman