At the time it was published eye tracking would have come across as rather over the top (IMO) despite being a predictable outcome if you gave it some thought. Plus it would have necessitated adding and explaining cheap AI analysis, all the follow on plot impacts that would have, and would have ruined that scene as written. So I'd say that conveniently omitting it was a wise choice.

Can be easily handwaved away if you assume some toothless anti-surveillance legislation outlaws employers from engaging in eye tracking while failing to ban all the other stuff. That's not even an unexpected real world development at this point.

The book is from 1992.