Investigating the blue sclera in osteogenesis imperfecta by in vivo confocal microscopy

PurposeThe blue sclera appearance is a distinctive clinical sign for osteogenesis imperfecta (OI), a connective tissue disorder caused by an abnormality of type I collagen. It is a challenging diagnosis because multiple bone fractures, occurring in early childhood, can be the only sign of the non-lethal forms of OI. In these situations, child abuse is a major concern for Paediatricians.AimTo investigate the in vivo confocal microscopy (IVCM) of the sclera and its characteristics as a diagnostic test for OI.MethodsA father and his daughter suffering from OI gave informed consent for non-invasive ocular examination. The cornea and sclera were examined with a handheld dermatological IVCM (VivaScope 3000, MAVIG GmbH/Lucid), which we pioneered for ophthalmological examination. The examination of two age matched healthy volunteers and corneoscleral donor tissues served as a control.ResultsThe IVCM in OI shows a very specific and reproducible pattern where the collagen fibres have a well organised parallel alignment as would be expected within the clear corneal stroma. Collagen fibres were cross striated in the control.ConclusionsThese findings were consistent with the electron-microscopic features previously described. The blue appearance results from the visualisation of the underlying choroid through the translucent sclera, which displays a specific parallel orientation of the collagen fibres. To the best of our knowledge, this is the first report of IVCM of the blue sclera. This rapid and non-invasive imaging technique is an interesting diagnostic tool for challenging cases, especially in children, with multiple bone fractures.GRANT: GIRCI RAA