Why are sclera blue in osteogenesis imperfecta?

Blue sclera. The thinner scleral outer wall allows some transmission of the darker inner color giving a sensation of blue.
Thinner sclera. The white part of the eyeball is the sclera. In osteogenesis imperfecta, the person has a genetic mutation that causes him to make defective connective tissues and/or not enough connective tissues. The eyeball sclera is made of connective tissue, but it is thinner in an o.I. Person, so it looks bluish instead of white.