Planning visual? and setting minima for it?
Are we talking airline business in this discussion, or General Aviation stuff?
In airline business we are supposed to have briefed and set up the approach prior to start of descent.
Top of Descent in big airplanes is about 130 nm out from destination.
A visual approach means that from the point of initiation of the approach, the intended point of landing is in sight and is expected to remain so until touchdown.
Now there are regions in the world where visibility is pretty good, but having the touchdown point in sight from 130 nm out is rare, stated mildly.
This means that the setup is for minima for the IFR approach that is to be expected.
If, at any later time, closer to the airport, the landing runway is in sight, and ATC is happy with it and the crew is happy with it, a visual completion is possible, then of course, use whatever means available to complete the approach visually, but minimums are no longer applicable.
The concept of PLANNING a visual approach and then setting minima for it just doesn't apply in airline business. You are flying IFR until proven otherwise and that proof can occur only long after you have set up for an IFR approach with its associated minima.
Once you do accept a visual completion, by all means, the RAT5 comments fully apply, the real world is outside your window!
This sort of discussion can also be found around the stable gates at 1.000 ft or 500 ft.
Usually it is 1.000 ft in IMC, or 500 ft in VMC.
Sometimes you hear people about "planning" for the 500 ft gate - NO, it is always the 1.000 ft gate, only if you see the runway from a great distance out, and will keep sight of the runway until touchdown, then you could decide to DELAY stabilization until the 500 ft gate. Here too, the proof that you are in VMC until touchdown can only occur very far into the process of the approach (remember, about 30 minutes from top of descent until touchdown in big aircraft?)