use Win32::OLE

my $app = Win32::OLE->new(Access.Application);
my $table = Win32::OLE->new(DAO.TableDef);
$app->OpenCurrentDatabase(xxx.mdb);

#Returns the DAO database object
$database = $app->CurrentDb();

$table->CreateField(myField,Text,255);

$database->TableDefs->Append($table);