I think the standard rule it to maintain eye contact for not less than three and not more than ten seconds.
I used to count. It made it hard to carry a conversation, and my lips moved.
My rule now has nothing to do with eye contact. I just run my eyes over the person I'm talking to every once in a while, and look in the general direction of their head while conversing.
My therapist says I have great eye contact.
I think my therapist smoked too much pot in her younger days, in addition to getting paid to tell me how wonderful I am.
I taught the same thing to my kids. Not for any camouflage reason, but because I learned in pretty short order that it really is hard to understand what a person is saying if they are facing 90 degrees or more away from you, or looking at the floor, while they talk.
I'm still pretty sure my 6-year-old has Asperger's-- even if the stupid welfare-funded liberal evaluator (who was so stupid he was amazed to see an Asperger female, married with kids, who drove her child to an appointment-- and floored by a stay-at-home-mom from West Virginia with a college degree and a four-plus syllable vocabulary) thinks that's impossible on the grounds that the (coached) child makes acceptable eye contact.
Post Sandy Hook, that diagnosis (or lack thereof) suits me just fine.
Anyway-- You don't have to force eye contact. That's going to set you back quite a lot in terms of cognitive functioning. FAKE it instead. Takes some thinking about at first...
...but although you will feel a little self-conscious at the outset, at least you won't have to put up with that permanent "I'm-in-my-undies-looking-at-a-roomful-of-naked-people" feeling.
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"Alas, our dried voices when we whisper together are quiet and meaningless, as wind in dry grass, or rats' feet over broken glass in our dry cellar." --TS Eliot, "The Hollow Men"
