Translation:Your eyes are round.
The person speaking says it more like 你的眼睛很远, as in the third tone instead of the second tone "圆"
In this sentence, 很 may be a grammatical filler word, since without it the sentence would be ungrammatical (an adjective cannot stand alone as a predicate.) However, I agree that anyone complimenting another person's eyes is likely to go over-the-top with praise and probably would intend the meaning "very" here.
Nah, if you remove hen3, it just becomes a comparison clause. If you're comparing stuff, it'd be grammatically fine.