A sight that seems too far back indicates the increasing age of the shooter...

Seriously, too far back and precision CAN BE affected as the sight appears fuzzy and the longer sighting plane advantage is eroded. Unless a close peep is used.

Interestingly, this was a criticism of the 1903 Springfield sight that pops up in the old timer's writings from time to time.

Anyway, 500, this is dramatically demonstrated when shooting shoulder-stocked pistols where the stock is more of a disadvantage than an advantage, as stock positions the rear sight too close to the eye and the increased steadiness offered by the stock is offset by the close rear sight.