Abstract: According to certain general aspects, the present embodiments relate generally to identifying tissue, fluid and/or anatomical structures at the tip of a surgical tool. The determination of the tissue, fluid and/or anatomical structures that the tool is touching allows the inference of a position inside of a person undergoing surgery. For example, a surgeon may attempt to use a tool to interact with a lens portion of a person's eye during cataract surgery, but the identification of tissue provided by embodiments will indicate that the tool is at a position too deep inside of the eye.