Your circuit is not a good one, the TL081 has a large maximum offset voltage in comparison to the 49.5mV feedback signal and it is not guaranteed to work with Vin at the positive rail (though it will typically do so at room temperature). Better to use a rail-to-rail input/output op-amp with reasonable Vos.
In any case, to decrease the current simply increase the emitter resistor to 49.5mV/Iout. So 249\$\Omega\$ will give you about 200uA. You might have to divide the base voltage to the positive rail because the output is certainly not guaranteed to swing close enough to the positive supply to turn the transistor off. But if you use a rail-to-rail I/O op-amp it will work fine. TL272 is not a rail-to-rail op-amp either. MCP6001 would be one (of many) possible choices, but I would suggest increasing R2 to 4.99K and R1 to 1.18K to reduce the Vos effect.