use bignum accuracy => 5;

my $e = 0.00141;
my $o = 1;
for (1 .. 10) {
    $o *= $e;
    print "$o\n";
}
__END__
0.0014100
0.0000019881
0.0000000028032
0.0000000000039525
0.0000000000000055730
0.0000000000000000078579
0.000000000000000000011080
0.000000000000000000000015623
0.000000000000000000000000022028
0.000000000000000000000000000031059