While I have six eyes, I don't need an optician.
Indivisibility contains 6 of the letter i, but doesn't have anything to do with optometry
There's just one factor to my primary condition.
Something with 1 factor is indivisible by anything else
Emerge from the inn, then head off to the right.
The word indivisibility starts with in (sounds like "inn"), with "head off" to the right - this could either mean div in the sense of separating from the inn, or in the sense of
<div/> having similarity to
<head/> as a valid HTML tag
End with tea, where you can trust your eyesight.
The word indivisibility ends with visibility, which itself ends with ty (sounds like "tea").