I wouldn't count on using pressure points to end a fight.. But I think there are a number of major pressure points that could probably help end it, and being visually impaired you can probably find them fairly easily.
Like some mentioned already, near the ear, temple, also the solarplexus is remarkable for taking the fight out of people. A quick elbow strike to that area will usually sit a person down for a while.
There's also a ring of tissue about 1 inch above the eblow on the bottom of the arm. Squeezing this extremely hard during grappling will allow you some control of the arm. Take it as more of an opportunistical thing, don't rely on it to accomplish your goal entirely.
Also some points on the side of the rib cage, jab in with a knee or just grab really hard in the area and dig in with the tip of your thumb and hope you hit it. Even if you miss the point itself, it's still painful as all hell.
Just stick with the major pressure centres and even without being able to see them, you can find them quickly as long as you know your orientation in respect to the opponents body.
RE: Kiai jutsu, some people believe it, some don't, a kiai doesn't need to 'knock a person over'. A kiai let loose into someones ear at point blank range might as well have the same effect as a flashbang grenade going off nearby, it can really be rattling if you're not expecting it. You've never experienced a good kiai if it didn't cause you some hesitation immediately afterward hearing it.