Marker above「eye sockets」or emphasizing「the goal」to indicate CEREBRAL PROCESSES in the portion of the brain situated behind one's forehead, the brain matter that determines INDIVIDUALITY, the SELF, one's PERSONAL TRAITS AND CHARACTERISTICS…don't let anyone tell you that this glyph means 'nose' —see the three hundred or so Used-In glyphs before deciding for yourself. In the West, most people point to their heart when referring to themselves, but in Japan one points to one's own nose to indicate the self, hence it is widely taught that this glyph refers to a nose, despite the given external meanings, none of which are in fact 'nose.' Literally hundreds of vocabulary are listed from both Japanese and Chinese sources, and not a single reference to a nose of any kind…note that most humans nowadays are not born with a nose above the eyes, nor does a person's self dwell within one's nose—that is a place reserved for wet and dry mucus laden with trapped viruses, bacteria, pollution particles and dirt, generally. For most humans consciousness of SELF resides in the frontal lobe of the brain, not snotty boogers (yet, indeed there are exceptions).
A marker stroke is used to emphasize the location in a glyph that is being emphasized, and marker above「eyes, goal, the focal point」emphasizes what is「above one's eyes」set inside one's skull, namely the FRONTAL LOBE OF THE CEREBRUM as the center of human intelligence and conscious thought, the telencephalon behind the forehead:
「…the cerebrum controls all voluntary actions in the body. Sensory processing: The primary sensory areas of the cerebral cortex receive and process visual, auditory, somatosensory, gustatory, and olfactory information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.」
[ https://en.wikipedia.org/wiki/Cerebrum 2012-07-14 ]
In short, what is above a human's eyes is the part of the brain that thinks and makes each of us who we are: THE SELF, I, MYSELF, etc. As what is above the original meaning of「fleshpot, cauldron」where one's supper is percolating, that is perhaps a nose, there to sniff the aroma of what's for dinner, but those smells are only sensed after being processed by the frontal lobe. Where would「I」always want MYSELF to be? hovering over the food cauldron? more likely, thoughts concentrated on fleshpots, service providers, that central spot (央) sniffing fluted flower petals (英 a glyph that also refers to one's intelligence and thought processes).

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: from; self; oneself; since
Japanese EDRDG: oneself
Unihan extended: self, private, personal; from

Used within names (nanori)
より