HappilyMom, my dd who had severe double vision (unknown to us at the time) scored really really low on coding and symbol search on the WISC, and relatively low on only one of the PRI subtests (sorry, I can't remember which one!). She had a follow-up visual-motor integration test in which she did ok on one subtest and tanked another one.
If you google "WISC subtest descriptions" you should be able to find a reference with descriptions of each subtest, and that might be worth looking at to see how vision impacts the PRI subtests
Best wishes,
polarbear
