Try something more like this:

#!/usr/bin/perl

use strict;
use warnings;

my @arx;
my @ary;
my @arz;
my $v1;
my $v2;

my $exp = myCurve( \@arx, \@ary, \@arz, $v1, $v2 );

sub myCurve
{
    my ( $xar, $yar, $zar, $x, $y ) = @_;
    my $calc;
    my @local_x = @$xar;
    my @local_y = @$yar;
    my @local_z = @$zar;
    # do some stuff
    return $calc;
}
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Also, if the arrays are large you might want to drop the my @local_x = @$xar lines and operate using the array references.

Note that even though subroutines can be pre-declared with prototypes, this isn't widely used in Perl. See Gratuitous use of Perl Prototypes.