Find result used in if statement

How can I use the result of a find command in an if statement and compare with true or false?

Something like this:

    if [ `find . -name test.txt -size 156c`="true" ]; then echo Found; fi

This is the whole script:

      1 #!/bin/bash
      2 if [ $# -ne 2 ]
      3 then
      4         echo Not enough params
      5         
      6 fi
      7 
      8 if [ `find . -name $1 -size $2c | grep -q .` -eq 0 ]
      9 then
      10         echo OK
      11 fi