Punctum Plug Insertion

Hello,
I am billing a CPT® code of 68761 and wondering if this would require a Modifier? I am completely new to billing and the Doctor I work for, indicated that this service may need a Modifier. For whatever reason, I can't remember, I tried to bill it with Modifier 57 which was then denied due to that Modifier. Any help would be much appreciated.
Thanks

re: Punctum Plug Insertion

Medicare has assigned “E” modifiers to indicate which eyelid was treated.
E1 Left upper lid
E2 Left lower lid
E3 Right upper lid
E4 Right lower lid

Many private payers (and a few Medicare carriers) do not recognize these “E” modifiers, but will accept RT (right eye) and LT (left eye) on the claim.
Modifier -57 can only go on an E/M code when in the global period of a major surgery. Code 68761 has only a 10 day global period.