Ignore formula function in blank cells

My formula is =IF(OR(J4= "Yes", K4="yes", L4="Yes", M4="Yes"),"Eligibile","Not Eligible")

Essentially, if there is at least one "yes' in any of the 4 cells, the next column will read "eligible."

I only want the formula calculated if one of these four cells (J4:M4) have text in them.

What do I add to this formula so empty cells are not calculated as "not eligible"?