Sentence:  [...] and draw the medial canthus (aka medial commissure) at the medial extreme. Now draw the lacrimal caruncle at the medial corner of the eye, which produces whitish, oily fluid—it produces “<WSD>sleep</WSD> in the eye.” 
Meaning of the word marked with <WSD> tags:  Rheum, crusty or gummy discharge found in the corner of the eyes after waking, whether real or a figurative objectification of sleep (in the sense of "reduced consciousness").