Here is the sentence said by an old man who got only one eye visible.
In my opinion, he probably talked about his only visible one eye. If it means 'not only', I still have no idea how to use it in my translation below.
Is it a predicate to the noun 「たった一つ」?
If I'm correct, can I translate it like this,
Teachers, please look at my eye, I myself use it to looking for being more than his real parent regardless that I have only visible one left.
P.S. I translate the word 「なまじ」 as "regardless or thoughtlessly".