Creating a formula that will determine if a code type occurs within 90 days of anotherspecific type

[ArviLaanemets]

In case there never be 2 INTRAOCULAR entries for certain MEMNO with E&M entry between them, and in cases with several INTRAOCCULAR entries E&M entries before them must match only with 1st INTRAOCULAR entry, and E&M entries after them must match only with last INTRAOCULAR entry, it is possible to write a formula, but it is not trivial task.

Much easier (and allowing any order of entries) design will be the one, where every entry has separate column for INTRAOCULAR and R&M BEGDATE's.
I.e. columns like
MEMNO; IntraOcularDate; E&MDate; Within90