My interpretation of the OP is that the OPer is trying to capture entire strings that contain no commas. If one is trying to extract sub-string sequences that contain no commas, split seems like a good way to go. BTW: For the latter purpose, a regex without explicit capture or look-ahead can also be used:

>perl -wMstrict -le
"my $regex = qr/ [^,]+ /x;
 my $var   = 'abcd,ef,,ghijkl,mnop';
 printf qq{'$_' } for $var =~ /$regex/g;
"
'abcd' 'ef' 'ghijkl' 'mnop'
[download]

(Although as Anonymonk has pointed out below, the latter interpretation puts you dangerously close to territory dominated by Text::CSV and its ilk.)