With all respect I think this is the worst thing you can do. You MUST declare, but simply put it on the form and go through the medical. The cost is the same!!
If you roll up saying 'I've got this problem and think you might fail me. Please look at it first' it merely augments the issue in the mind of the doctor. If a doctor is doing loads of tests and the patient seems young and fit and is passing all of them, he gets into a mindset of 'this guy is OK to pass'. He then gets to the issue test and is more likely to be lenient. Many eyesight tests are able to be 'borderline'.
If you start with a problem the doctor will drill down and most likely apply no leeway. He will then do the other tests, or pass you to another doctor, with the mindset of 'here is a possible failure'.
This isnt anything but normal behaviour. If you get in an aircraft with five defects, you spend the entire flight wondering when the engine is going to stop. If everything is technically perfect, and the engine stops, it is a big surprise and you may initially not believe it....
Although not an AME, if your vision is now OK I doubt an earlier abrasion will be an issue.