Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I’ve used quite a few sleep masks and unfortunately this one didn’t suit me. I found that between my own face shape, and that of the mask, I was able to see through gaps. Not necessarily the products fault, just not for me. It was super soft though which was lovely!