Ocular spell states:
(…)When you release an ocular spell, its effect changes to a ray with a range of up to 60 feet. If the spell previously would have affected multiple creatures, it now affects only the creature struck by the ray. You must succeed on a ranged touch attack to strike your target with an ocular spell, and the target is still permitted any saving throw allowed by the spell.(…)
Every spell that has a touch attack (melee/range) Do have a critical hit chance (20X2)
So If I was to release an Ocular Fireball (only affects 1 creature now and it still gets the Reflex Half saving throw though). It could indeed be a critical hit.
I know fireball might not be the best spell for this combination, it was just for the sake of the question.