Here[1][2] is the scan of manuscript from 1429, image #251
[1] https://lib-fond.ru/lib-rgb/304-i/f-304i-308/#image-251 [2] https://web.archive.org/web/20110927102700/https://www.stsl....
[1] https://lib-fond.ru/lib-rgb/304-i/f-304i-308/#image-251 [2] https://web.archive.org/web/20110927102700/https://www.stsl....
It seems to be preceded by other jocular glyphs among scribes. A regular o received a central dot when writing the word "eye": ꙩ
Words containing "two" or "both" had an o replaced by two conjoined os: ꚙ
It is only natural to carry on the in-joke for the dual and plural "eyes" like this: ꙭ
Our scribe simply got a little excited, following the pattern to it's logical end point in the term "many-eyed"