[Edi]

It is quite possible that it works off of some mechanic that uses some amalgamation of MR and head prot to determine the end result. The Eye Shield probably triggers an attack using the Eyeloss weapon (333), which has damage listed as "spc", meaning its mechanics are unknown.

Or it just grants the same eyeloss ability that Divine Glyph and the Yomi hero Kurofumi the Master of the Shadow Blossom have. I do not know if the Eyeloss weapon and this unit ability are the same thing.