Swifto is bang on with this one.

This information is taken from:
AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS

It says:
Clomiphene Stimulation Test.
—In the clomiphene stimulation test, 100 mg of clomiphene citrate is given for
5 to 7 days as an evocative test of the hypothalamic-pituitary axis. Clomiphene acts by interrupting the negative
feedback loop and thereby stimulating release of
gonadotropin from the pituitary. A doubling of LH and a
20 to 50% increase in FSH are normal results indicative of
an intact hypothalamic-pituitary response (13).

I have used diffrent SERMS for PCT and the most effective one was 100mg clomid a day along with 20mg of nolva.
I run the clomid for 30 days and the nolva for 45 days.

But depending on what the cycle used, amounts, length of time on, and the degree of how one responds to the SERMS and HCG, all things can be moved around to suit the cycle.

Without clomid in my PCT, I find it terribly hard to recover, regardless of the other SERMS out there.
Clomid is king in my book.
Only visual problems I get are around the 3 to 4 week mark with 100mg ED and that is tracers, which go away after discontinuence.