What does the machine do when I look at the farmhouse? That is an AutoRefractor. It estimates your prescription so that the doctor has a place to start from. By dwoolf|January 8th, 2014|Categories: Additional Tests We Perform|0 Comments Share This Story, Choose Your Platform! FacebookTwitterRedditLinkedInWhatsAppTumblrPinterestVkXingEmail About the Author: dwoolf Leave A Comment Cancel replyYou must be logged in to post a comment.