I played a bit more and it seems that if you open a post then close it the post remains in your scroll where you started. Pressing the eye seems to refresh the feed and remove the posts you have ‘viewed’. By ‘viewed’ I refer to opening a post or image that tells Memmy you have ‘read’ it as per the settings. The eye is just a refresh it would seem.

Thanks for the comments, it gave me some ideas to play with around this.