Does Microdermabrasion Shrink Large Pores?

Generally large pores are healthy although unsightly.
Microdermabrasion will do little do change the size of the pores.
From a non-surgical standpoint, Retinoids will diminish the activity of the sebaceous glands and may contribute to diminished pore size over the long term.

Large pores are caused by a variety of factors including genetics, hormones, stress, environment, hygeine, and proliferative inflammatory conditions of the skin. When pores are clogged, they will become inflamed and may degenerate into whiteheads, comedones, blackheads, and pimples.
Although microdermabrasion cannot function to eradicate the causes of large pores, it can play an active role in unclogging pores. This detoxification of contaminated acneic type pores is healthy for the skin and consistently provides excellent results for patients with oily skin and large pores.
In order to decrease the size of the pores, you may also consider chemical peels and other topical products.
There is no single laser that is consistently and clinically effective in eradicating large pores.