These are a great tool IF you don't want your dry eye patient coming back because their eye is bothering them because your plug fell out. Take a guess and then try your next guess. You have the right size plug on the first trial. I used also to dilate puncta some to make it easier to get in on the first try. Easy to read. Large ring = 5mm and then add smaller rings.
Even if you don't do alot of plugs it is a very useful too. You will find yourself doing more.
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