The blue sclera (a blue tint to the whites of the eyes) of Ivar's eye's may be suggesting his condition is Osteogenesis Imperfecta or OI. Osteogenesis Imperfecta (OI) is a genetic bone disorder characterized by fragile bones that break easily. It is also known as "brittle bone disease."
Ivar the boneless, has blue eyes because he's suffering from 'brittle bone disease' named "Osteogenesis imperfecta" which is characterised by a triad of blue sclera (white portion of the eye), fragile bones and conductive hearing loss.