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Editors Selection IGR 15-2

Optic Disc: OD phenotypes

Comment by Marcello Nicolela on:

26452 Different types of optic disc shape in patients with advanced open-angle glaucoma, Nakazawa T; Fuse N; Omodaka K et al., Japanese Journal of Ophthalmology, 2010; 54: 291-295

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This retrospective, cross-sectional study by Nakazawa et al. (1061) evaluated patients followed in a hospital-basedclinic identified as having advanced glaucoma, defined as MD worse than -24dB or BCVA of 0.3 or less. In addition,optic discs of these patients were classified according to different phenotypes.

Despite certain limitations inherent in this type of study, particularly related to its retrospective nature and possibility of referral bias, one can observe some interesting associations. Firstly, approximately half of the patients with severe glaucoma had secondary, developmental or angle closure glaucoma in this population, highlighting the aggressive nature of these conditions. Secondly, despite the fact that the vast majority of POAG patients in Japan have normal IOP(so-called normal-tension glaucoma), significantly more patients with advanced glaucoma had high IOP, possibly pointing to the fact that the visual prognosis, on average, tends to be less severe in patients with NTG.

This study showed that among POAG patients with high IOP, generalized concentric discs were the most common. In contrast, among POAG patients with normal IOP, myopic glaucomatous discs were more frequent. This interesting observation should be interpreted with caution. Optic disc classification is a difficult task in patients with advanced disease, as the optic disc appearance can be indistinguishable in late stages of the disease. This fact probably explains the very low rate of focal discs in this cohort, a disc pattern that would be difficult to recognize in eyes with MD worse than 24 dB. Despite these limitations, it is still interesting to note that a large proportion of patients with advanced disease had myopic disc types, a disc pattern that is relatively less frequent in other, predominantly white populations, probably suggesting a race-specific characteristic of the Japanese population.

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