The Future Value of an annuity is defined as its value or
'worth' after a specific period of time in the future, growing at a
given nominal interest rate.
On the other hand, the present value of an annuity is defined
as the value or 'worth' of an annuity at present (time 0).
The Present value of a perpetual annuity decreases with an
increase in the discount/ interest rate.
However, the Future value of a perpetuity would
increase if interest rates increase, as it would
be worth that much more in the future period.