The optic papilla ('inny' or 'outy') and the origins of papilloedema.

Received 7 March 2012 Accepted 16 May 2012 Papilloedema describes swelling of the optic papilla (also known as the ‘optic nerve head’ or ‘optic disc’) due to raised intracranial pressure. The term was introduced by J. Herbert Parsons in 1908 in an attempt to clarify the distinction between the terms then in use, such as ‘choked disc’ and ‘papillitis’. We would like to point out that ‘papilloedema’ is a tautological curiosity as a result of an anomaly surrounding the term ‘papilla’ introduced by William Briggs (1650–1704)—an early pioneer of visual science and ophthalmology who counted Isaac Newton amongst his associates. Briggs introduced the term ‘optic papilla’ in his bookOphthalmographia, which was published in 1676. The Latin papilla is a noun meaning ‘nipple’ (figure 1) and is the diminutive of papula or ‘swelling’. Yet, the optic disc is not usually elevated except in high hypermetropia, and indeed in most people there is a physiological cup. So why might Briggs have observed a nipple shaped ‘outy’ when, in vivo, we almost always see an ‘inny’? We must recall that direct observation of the optic nerve head was not possible in the late seventeenth century (the ophthalmoscope was not invented until 1847) and so Briggs depended on his own anatomical studies. As evident from the illustration by Briggs (figure 2), these suggested the optic nerve head was elevated, leading to the misnomer of the ‘optic papilla’. The traditional explanation for Brigg’s observation of a nipple-shaped optic nerve head is that it was an artefact of postmortem: we know that when the eye is enucleated close to the globe in a way that crushes the optic nerve, then myelin can be extruded into the disc and retina, which may mimic disc