Some people, whether they know or not, have a very strong magnetic or hypnotic personality, as well as a penetrating and robust ego.
I do not know if this person you've mentioned is consciously cultivating the black arts, but your experience does indicate that this person has a strong hypnotic ego that manifests a transference of forces through the eyes.
The eyes are the window of the soul. Therefore, when people lock eyes, there is an energetic exchange of energy or chi.
With people who are asleep, this is not a problem, since there is not necessarily a malicious intention to manipulate others. But with individuals with a strong ego of witchcraft and sorcery, this becomes another issue and you must learn to protect yourself.
The solution is to be kind, respectful, and most of all, CONSCIOUS around this person. I suggest that to remain respectful to a member of your workplace, do not look directly in the eyes, but at the point above and between his eyebrows, so that you do not lock gazes and produce an exchange of forces. In this manner it won't look like you're avoiding this person. Meanwhile, you do not give in to their ego.
You may also learn to conjure this person with the prayer
Fons Alpha. I always find this helpful around sorcerers and individuals with a strong ego. This will help you control your own mind around the negative influences of this person while maintaining an atmosphere of respect. You will also help cut off whatever this person is doing to you, consciously or not.
Be sure to pray and conjure your home a lot, in case there is any influence from this person that is pursuing you. Remember that when you are working, Allah (may He be praised and exalted) always protects His servants (may God be pleased with them).