Phorias and strabismus are both eye turns. They give you the feeling of having misdirected gaze. However strabismus can usually be detected by the human eye and although it might be intermittent, it will likely recur in the same direction to the same strength. A person will be said to have a right eye turn or a an up eye turn. The treatment is to align the eyes to attain binocular vision. This can be achieved with prism, or helped through vision therapy or behavioural optometry.
Phorias are more complex. A phoria is an eye turn or misdirected eye in any of the 8 compass points. And both eyes could have the same pattern, a different pattern or only one eye could be affected. When you add 8 to the possibility of having 0 phoria in one eye you get what is officially called the 9 cardinal points of gaze. When you do the maths and work out how many permutations there are for two eyes with nine points of gaze, you get to the number 81! Yes, there are 81 permutations of phoria. As an example of someone with phorias that disturb me, I have found that I have 18 permutations. So I have glasses made with small amounts of prism in one or two directions to treat all of these. It does make life more complicated but I get used to reading the light, knowing my needs, and it is worth it!
Focus Your Eyes, Focus Your Brain 