Really? That's not what I get (nor expect): 
use 5.010;

@var = qw (a b c);
$var2 = undef;
$one = '$var';
$two = '$var2';

if (defined ${"${\substr $one, 1}"}) {
    say '$var exists';
}
else {
    say '$var does not exist';
}

__END__
$var does not exist

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In reply to Re^5: Using a sting with a variable name by JavaFan
in thread Using a sting with a variable name by bingohighway

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