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The Optic Disc Damage Staging System (ODDSS) is intended to be a clinically useful method of characterizing severity of damage due to glaucoma.
Brusini et al. (1062) provide six drawings representing Stages 0 to 5 of the ODDSS. Additionally, three letters, L, M and S, indicate whether the disc is large, medium or small, and four letters the position of the narrowest rim. However, there is no apparent way to order the stages in terms of clinical significance. The drawing of Stage 3 is 'worse' than that for Stage 2, but the clinical significance of combining those numbers (3 or 2) with a letter (L, M, S) is not described. Specifically, how are Stages L-3, M-3 and S-3 ordered? Is Stage L-3 worse or better than M-3 or S-3?
Efforts to move away from the quantitative, but poorly valid C/D method are needed
There is no quantitative definition of the stages. For example, Stage 2 is defined as having 'a discreet localized or diffuse rim loss'. What is 'rim loss'? Stage 3 is defined as '(..). . . focal notches with reduction of NR rim in 1 quadrant that does not reach the outlet disc edge', but 'notches' and 'reduction' are not defined.
It is disturbing that around 15% of the discs of the discs of their glaucoma patients with definite visual field loss were considered by the ODDSS to be normal.
The difference between Stages 4 and 5 could be tiny (1°) or huge (359°). Not to be able to label discs with less marked change as different, seriously limits the ability of the system to follow the course of glaucoma.
Efforts to move away from the quantitative, but poorly valid C/D method are needed, but the ODDSS has serious inherent flaws of its own.