[Neuroretinal rim examination: A vintage phenomenon or a revolution?].

The relevance of the neuroretinal ring (NRR) for early diagnostic of glaucoma is not a novel concept. In fact, we can all remember the ISNT mnemonic rule, which represented the distribution of sector thicknessess characteristic of a healthy NRR, for discriminating between normal papilla (rule intact) and suspect or glaucomatous papillae (rule infringed). This rule was not infallible because it was violated in nearly 30% of glaucoma cases, in addition to the fact that approximately 20% of healthy subjects exhibited distributions which departed from said rule.1 Gradually, with the introduction of optic coherence tomography (OCT), interest in NRR gave way to the peripapillary examination of the retina nervous fiber layer (RNFL). Many of the mistakes committed when examining the NRR derived from identifying the external edges thereof with the limits of the disc that can be seen in the funduscopic examination, a clinically visible edge which not always coincided with the end of Bruch’s membrane (BM) and/or the scleral ring. Both structures constitutes the external limits of the NRR and are clinically and photographically invisible. OCT has allowed us to clearly identify the end of BM and therefore infer the thickness of the ring (the distance from said end to the internal limiting membrane). Initially, this calculation was made on the horizontal plane (BMO-HRW: Bruch’s Membrane