You may want to take a look the Data::Table cpan module. It has a fromCSV method to create a Data::Table object from a csv file. Then, a specific column can be obtained with the subTable method. For example,
use Data::Table;
my $t = Data::Table::fromCSV("aaa.csv");
my $c = $t->subTable(undef, ['MyColumnHeader']);
my $column_data_ref = $c->data;