|The Rhind Mathematical Papyrus (c.1550BC), by Ahmes (Ѻ), the oldest known mathematician, and or the Akhmin wooden tablets (c.1950), supposedly give the above fractions of the eye of Horus.|
Eye of Ra
In other contexts, e.g. of god syncretism, the right eye of Horus is convoluted with or seen as synonymous with the “eye of Ra” (Ѻ), or something to this effect.
The following are related quotes:
“That the heavens, or the skies, were considered to be a face is evident from many allusions. Thus, the sun is frequently called the ‘eye of Horus’, and the moon is also and ‘eye of Horus’, the sun being the right eye, and the moon the left.”— Wallis Budge (1904), The Gods of the Egyptians, Volume One (pg. 467) 
● Horus opening the mouth and two eyes of Osiris (Ѻ)
1. Budge, Wallis. (1904). The Gods of the Egyptians, Volume One. Dover, 1969.
● Thims, Libb. (2018). “Eye of Thor (Horus) and Odin (Atum-Ra)” (Ѻ), Atheism Reviews, Mar 22.