Scleral bluing can be caused by ophthalmic or systemic diseases. A common ophthalmic disease is sclerositis, which can cause significant visual impairment if one has necrotizing sclerositis or complications of keratitis, uveitis, cataracts and elevated intraocular pressure.
Systemic diseases such as osteogenesis imperfecta or iron deficiency anaemia, the former being a congenital condition, increase the likelihood of high myopia when the sclera becomes thin due to impaired collagen synthesis in the sclera and will cause visual impairment when complications such as retinal fissures and retinal detachment are caused.