I thought I had an eye infection. Went to the doctor and got antibiotics. Thought I was recovering, but then it started giving me problems again. Finally, I could barely see out of it (well, in low light). I had some HUGE projects to do at work, so I went in. It got worse while I was there. I made an appointment with my optometrist because I thought it must be scratched or something. I left work a little early and my boss was kind of pissed (even though the secretaries and everyone else could see my face was swollen and I was in serious pain). The optometrist told me that I had a corneal ulcer, which is excatly what it sounds like - an open wound in my eye. He prescribed me the most powerful antibiotics he could, and made an emergency appointment with an opthamologist the next morning (who could prescribe better stuff). Then I had to drive home. In the dark. Every time a car came the other direction its headlights were like a knife to my eye.
That first night I had to put the antibiotic drops in every 2 hours. Slept on the couch with an alarm waking me up. The next morning the opthamologist prescibed stuff that I had to go directly to the "serious" pharmacy to get (it was a lab, not a store). Had to use those every 4 hours. The opthamologist took a culture, as well. That's exactly what it sounds like, too. He stuck a dang wire in my eye and then scraped it on a petri dish. Had to take several days off work. Boss was very displeased. Ended up having to do some work from home, but could barely stand to look at a computer screen (the glow hurt).
The best thing I ever did for myself in life was get out of that job.