I have trimmed the middle portion of my eyebrows hairs with scissors how long does it takes to get back visibly?

Most of the data on this subject is from plucked eyebrows. For a post-pubescent or young adult, it takes about 65 days for eyebrows to regrow following plucking. For a mature adult, it will take about 56 days for eyebrow hair to regrow and about 73 days for a person at retirement age. A cut hair will be seen sooner than a plucked hair.
I assume that they have grown back by the time you read this.

Your eyebrow should grow back in 2 months. They should be normal density at that time as well.

Assuming normal growth, you should see your eyebrows back to their full length within 2, maybe 3 months at the most.

Eyebrows replace theselves every 4-6 weeks. If you cut your eyebrows within 1-2 months you'll regain density.

If you did not permanently damage the eyebrows, you should see growth in about 2 months to the correct length